Biomedical subjects

C Zhao

Publications and source records attributed to C Zhao.

At least 109 records · Page 6Linked to original sources

PubMed2000

Secretory lipophilins: a tale of two species.

Secretory lipophilins are "lipid-loving" proteins that are major constituents of several mammalian secretions, including the prostatic fluid of rats and the tears of humans and rabbits. These proteins form covalent heterodimers that are stabilized by three intramolecular cystine disulfide bonds. The heterodimers, some of which are glycosylated, may undergo additional non-covalent assembly to form tetramers. The peptide components found in secretory lipophilins are from two subfamilies: lipophilins A/B and lipophilin C. The C subfamily members described in this report are three rabbit and one human lipophilin, plus human mammaglobin and the C3 subunit of rat prostatein. Human A/B and C lipophilins are expressed by many tissues and are especially prominent in endocrine-responsive organs. The gene for human lipophilin B resides at chromosome 10q22-23. This region harbors the PTEN/MMAC1 gene and is believed to contain additional tumor suppressor genes. Although the functions of secretory lipophilins are imperfectly understood, their abundance in glandular secretions and in hormone-responsive tissues suggests that they deserve considerably more attention than they have received to date.

Animals↗

PubMed2000

Comparison of mechanical properties of various suture repair techniques in a partially lacerated tendon.

The technique of surgical repair for zone two flexor tendon injuries has been debated extensively throughout the years, yet adhesion formation, suture rupture, and suture locking on the pulley edge remain possible consequences of a poor repair. The partially lacerated tendon is especially challenging to treat since there can be justification for not intervening surgically. In a partial laceration canine model we measured failure load and suture gap formation for tendons repaired with the Lee, modified four-strand Savage, Kessler, modified Kessler, and Augmented Becker core suture techniques and with a simple running peripheral suture. The modified Kessler (106.3 N, SD 18.8 N) and modified Savage (108.2 N, SD 19.9 N) repair techniques had a significantly higher failure load than the Lee (85.0 N, SD 20.6 N) suture method (P < 0.05), while there were no differences among the other techniques. There were no significant differences in resistance to gap formation among the repair techniques, with the mean values ranging from 38.9 N/mm (SD 15.7 N/mm) using the simple running suture to 53.2 N/mm (SD 25.8 N/mm) with the Kessler repair. The mean load to produce a 1.5 mm repair site gap ranged from 71.1 N (SD 21.5 N) in the Lee repair to 91.3 N (SD 22.2 N) in the Augmented Becker repair although there were no significant differences among repair methods. All repair methods were much weaker than tendons left unrepaired (184.7 N, SD 41.3 N).

Animals↗

PubMed2000

Reprogrammable recognition codes in bicoid homeodomain-DNA interaction.

We describe experiments to determine how the homeodomain of the Drosophila morphogenetic protein Bicoid recognizes different types of DNA sequences found in natural enhancers. Our chemical footprint analyses reveal that the Bicoid homeodomain makes both shared and distinct contacts with a consensus site A1 (TAATCC) and a nonconsensus site X1 (TAAGCT). In particular, the guanine of X1 at position 4 (TAAGCT) is protected by Bicoid homeodomain. We provide further evidence suggesting that the unique arginine at position 54 (Arg 54) of the Bicoid homeodomain enables the protein to recognize X1 by specifically interacting with this position 4 guanine. We also describe experiments to analyze the contribution of artificially introduced Arg 54 to DNA recognition by other Bicoid-related homeodomains, including that from the human disease protein Pitx2. Our experiments demonstrate that the role of Arg 54 varies depending on the exact homeodomain framework and DNA sequences. Together, our results suggest that Bicoid and its related homeodomains utilize distinct recognition codes to interact with different DNA sequences, underscoring the need to study DNA recognition by Bicoid-class homeodomains in an individualized manner.

Amino Acid Sequence↗

PubMed2000

Target selectivity of bicoid is dependent on nonconsensus site recognition and protein-protein interaction.

We describe experiments to compare the activities of two Drosophila homeodomain proteins, Bicoid (Bcd) and an altered-specificity mutant of Fushi tarazu, Ftz(Q50K). Although the homeodomains of these proteins share a virtually indistinguishable ability to recognize a consensus Bcd site, only Bcd can activate transcription from natural enhancer elements when assayed in both yeast and Drosophila Schneider S2 cells. Our analysis of chimeric proteins suggests that both the homeodomain of Bcd and sequences outside the homeodomain contribute to its ability to recognize natural enhancer elements. We further show that, unlike the Bcd homeodomain, the Ftz(Q50K) homeodomain fails to recognize nonconsensus sites found in natural enhancer elements. The defect of a chimeric protein containing the homeodomain of Ftz(Q50K) in place of that of Bcd can be preferentially restored by converting the nonconsensus sites in natural enhancer elements to consensus sites. Our experiments suggest that the biological specificity of Bcd is determined by combinatorial contributions of two important mechanisms: the nonconsensus site recognition function conferred by the homeodomain and the cooperativity function conferred primarily by sequences outside the homeodomain. A systematic comparison of different assay methods and enhancer elements further suggests a fluid nature of the requirements for these two Bcd functions in target selection.

Animals↗

PubMed2000

Longitudinal study of earthquake-related PTSD in a randomly selected community sample in north China.

OBJECTIVE: This study longitudinally described rates of posttraumatic stress disorder (PTSD) in two groups with different levels of severity of exposure to an earthquake in North China. The effects of diagnostic criteria on the frequency of detected PTSD were also examined. METHOD: Subjects were randomly sampled in two villages at different distances from the earthquake epicenter. A total of 181 and 157 subjects were assessed at 3 months and 9 months after the earthquake, respectively, for PTSD by using both DSM-IV and DSM-III-R criteria. The brief version of the World Health Organization Quality of Life Assessment and three subscales of the SCL-90-R were also administered at both assessment points. RESULTS: The village with a higher level of initial exposure to the earthquake and a higher level of postearthquake support had a lower frequency of PTSD than the village with a lower level of initial exposure and less postearthquake support. The rate of onset of DSM-IV PTSD within 9 months for the two villages was 19.8% and 30.3%, respectively. In both villages, the rate of onset of earthquake-related PTSD within 9 months was 24.2% by using DSM-IV criteria and 41.4% by using DSM-III-R criteria. The introduction in DSM-IV of a criterion requiring clinically significant distress or impairment in functioning for a diagnosis of PTSD was a major contributor to the lower rate of DSM-IV PTSD. CONCLUSIONS: PTSD may be as prevalent and persistent in disaster victims in China as in those elsewhere. Prompt and effective postdisaster intervention could mitigate the impact of initial exposure and reduce the probability of PTSD occurrence. Caution should be used in comparing rates of postdisaster PTSD identified by using different diagnostic criteria.

Adult↗

PubMed2000

Acute overexpression of lactate dehydrogenase-A perturbs beta-cell mitochondrial metabolism and insulin secretion.

Islet beta-cells express low levels of lactate dehydrogenase and have high glycerol phosphate dehydrogenase activity. To determine whether this configuration favors oxidative glucose metabolism via mitochondria in the beta-cell and is important for beta-cell metabolic signal transduction, we have determined the effects on glucose metabolism and insulin secretion of acute overexpression of the skeletal muscle isoform of lactate dehydrogenase (LDH)-A. Monitored in single MIN6 beta-cells, LDH hyperexpression (achieved by intranuclear cDNA microinjection or adenoviral infection) diminished the response to glucose of both phases of increases in mitochondrial NAD(P)H, as well as increases in mitochondrial membrane potential, cytosolic free ATP, and cystolic free Ca2+. These effects were observed at all glucose concentrations, but were most pronounced at submaximal glucose levels. Correspondingly, adenoviral vector-mediated LDH-A overexpression reduced insulin secretion stimulated by 11 mmol/l glucose and the subsequent response to stimulation with 30 mmol/l glucose, but it was without significant effect when the concentration of glucose was raised acutely from 3 to 30 mmol/l. Thus, overexpression of LDH activity interferes with normal glucose metabolism and insulin secretion in the islet beta-cell type, and it may therefore be directly responsible for insulin secretory defects in some forms of type 2 diabetes. The results also reinforce the view that glucose-derived pyruvate metabolism in the mitochondrion is critical for glucose-stimulated insulin secretion in the beta-cell.

Adenosine Triphosphate↗

PubMed2000

[Detection and significance of HPV16, 18 infection, P53 overexpression and telomerase activity in patients with lung cancer].

OBJECTIVE: To investigate if HPV16, 18 infection, P53 expression and telomerase activity have the differences among different ethnic patient groups with lung cancer, and their significance. METHODS: HPV16, 18-DNA, P53 protein overexpression in 110 specimens of lung cancer were detected by PCR and immunohistochemistry, respectively. And telomerase activity in 22 specimens of fresh lung cancer tissues was detected by PCR-TRAP. RESULTS: The positive rate of HPV16, 18-DNA in the lung cancer group was higher than the normal tissues group and inflammatory lesions group (all P < 0.01). The positive rate of P53 protein overexpression was 57% in the lung cancer group, negative in the normal tissues group (P < 0.01). The differences of HPV16, 18 infection and P53 overexpression have no statistic significance among different ethnic groups (all P > 0.05). The telomerase activity was higher in the cancer tissues (86%) compared with the adjacent normal tissues (22%, P < 0.01). CONCLUSIONS: HPV16, 18 infection might have etiologic significance for lung cancer and make p53 gene overexpression to cause carcinogenesis, but each might have its own carcinogenic process. The high telomerase activity could be a marker of biomolecular change in lung cancer. The different ethnic background of HPV16, 18 infection and P53 overexpression of lung cancer need to do further study with a large number of specimens in the future.

Adult↗

PubMed2000

[Evaluation of performance and blood compatibility of polyethersulfone hollow fiber plasma separator].

In this study, we evaluated the performance and blood compatibility of polyethersulfone hollow fiber membrane plasma separator by animal experiment. Hemolysis did not occur under the usual conditions of plasma separation. The sieving coefficients of total protein, albumin and globulin were over 95%, and about 60% of total plasma were extracted from the whole blood. White blood cells, platelets, fibrinogen, and coagulation factors were decreased during the early stage of plasma separation and appeared to be within acceptable ranges for clinical use.

Animals↗

PubMed2000

A randomized controlled clinical trial on etimicin, a new aminoglycoside antibiotic, versus netilmicin in the treatment of bacterial infections.

OBJECTIVE: To compare the efficacy and safety of two aminoglycoside antibiotics, etimicin and netilmicin, in the treatment of bacterial infections. METHODS: A randomized, open label, controlled clinical trial was conducted for the treatment of 65 patients hospitalized with respiratory tract infections, urinary tract infections, and skin and tissue infections. Thirty-four patients received etimicin and thirty-one patients received netilmicin at a dose of 100 mg every 12 hours by intravenous infusion. The duration of treatment was 7-10 days in both groups. RESULTS: 47 patients were enrolled in the etimicin group; 35 patients were assessable for safety and 34 patients were assessable for efficacy, 46 patients were enrolled in the netilmicin group; 32 patients were assessable for safety and 31 patients were assessable for efficacy. The results show that overall efficacy was 85.3% for the etimicin group and 83.9% for the netilmicin group, whereas bacterial clearance rates were 87.5% for the etimicin group and 89.7% for the netilmicin group. The incidence of adverse reactions was 8.6% (3/35) and 9.4% (3/32), respectively. CONCLUSION: Etimicin and netilmicin were effective and safe for the treatment of respiratory tract infection, urinary tract infection, and skin and tissue infections. The results show there was no statistically significant difference between the two groups (P > 0.05).

Adolescent↗

PubMed2000

[The research and development for dental office information system].

OBJECTIVE: To study how to use the technology of information management, data-base and graphics to develop the dental clinic information system. METHODS: Base on the expert's demonstration and investigation, we made up the operative cord of the dental clinic. The PowerBuilder and SQL Anywhere Tools V6.0 was used to develop the information system. RESULTS: There are 7 different sub-functional models in our system, and they are about patients, workers, finance, capital, expandable, technician lab., and maintenance. The system has been used in 8 dental clinics, and about 1,100 cases history were managed. The result showed us that the system has a strong and perfect function for clinical service, and it is easy to be used. CONCLUSION: The system could enhance the user's management level and benefit to patients and clinical service.

Database Management Systems↗

PubMed2000

Right ventricular function of patients with septic shock: clinical significance.

OBJECTIVE: To understand the effect of right ventricular dysfunction on circulatory supportive therapy in patients with septic shock. METHODS: 25 patients with septic shock who were admitted consecutively to the intensive care unit (ICU) of Peking Union Medical College Hospital were observed prospectively. Hemodynamic profile of the left side and right side heart was monitored with right ventricular ejection fraction catheter and transthoracic echocardiography. Intramucosal pH (pHi) and oxygen delivery were also monitored to illustrate any relation with patient outcome. RESULTS: Stroke volume index (SVI) and right ventricular ejection fraction (RVEF) were significantly higher in survivors than in nonsurvivors (P < 0.01 and < 0.05, respectively). The pulmonary vascular resistance index (PVRI) was significantly lower in survivors (P < 0.01). At the onset of shock, the left ventricular end-diastolic volume index (LVEDVI) of both groups was very low, and steadily increased in survivors but not in nonsurvivors. Left ventricular ejection fraction (LVEF) and systemic vascular resistance index (SVRI) decreased during treatment, which were not different in both groups. Right ventricular end-diastolic volume index (RVEDVI) increased in both survivors and nonsurvivors. Oxygen delivery of nonsurvivors was significantly lower than that of survivors. LVEDVI and RVEF were correlated with SVI in both survivors and nonsurvivors. CONCLUSIONS: The impairment of right heart function may be more severe than that of left heart function in the patients with early septic shock. "Right heart priority" must be seriously considered in supportive treatment of patients with septic shock. The present treatment of septic shock has significant limitations, and even aggravates the existing cardiac dysfunction.

Adult↗

PubMed2000

[Expression of substance P receptor mRNA in nasal mucosa of rat in allergic rhinitis model].

OBJECTIVE: To study the expression of substance P receptor messenger RNA (SP-R mRNA) in nasal mucosa in allergic rhinitis (AR) rat model. METHODS: Twenty Wistar rats free of disease were randomly divided into two groups. AR model rats were established through repeated intraperitoneal shot of ovalbumin (OV) and consequently confirmed by local challenge with OV. SP-R mRNA in nasal mucosa, obtained from two groups, were used to do reverse transcriptive polymerase chain reaction (RT-PCR) and Southern blot. beta-actin was used as a standard control through out the whole process. RESULTS: The results showed definitely that there were positive expression of SP-R mRNA in normal nasal mucosa. This expressions increased significantly (P < 0.05) during nasal allergy. CONCLUSION: Increased expression SP-R mRNA in nasal mucosa in AR model might play roles in the development of AR.

Animals↗

PubMed2000

[The clinical significance of poststyloid space extension in nasopharyngeal carcinoma].

OBJECTIVE: To explore the clinical significance of poststyloid space extension in nasopharyngeal carcinoma. METHODS: One hundred and ninety-eight patients with newly treated nasopharyngeal carcinoma (stage I-IV a) were analyzed. These patients were divided into two groups depending on whether the poststyloid space was extended or normal. The 5-year survival rate, relapse and distant metastasis after the treatment were estimated using the Kaplan-Meier, Log-Rank methods. RESULTS: The rates of patients with oropharyngeal extension for these two groups were 72.1% and 16.8% respectively (P < 0.001). The rates of the cases with involvement of the 9, 10, 11, 12th cranial nerves were 20.9% and 6.2% respectively (P < 0.01). The rates of metastasis to cervical lymph node were 69.8% and 35.4% respectively (P < 0.01). The 5-year survival rates were 46.76% and 68.88% respectively (P = 0.0027). The local control rates were 63.7%, 78.7% respectively (P = 0.0862). The distant metastasis free survival rates were 71.7% and 84.2% respectively (P = 0.0468). These results showed that the survival rate, the local control rate were reduced and the distant metastasis was increased for patients with poststyloid space extension. CONCLUSIONS: The poststyloid space extension was an important prognostic factor with poorer treatment outcome. It is reasonable to classify such condition as stage T3 of nasopharyngeal carcinoma.

Adult↗

PubMed2000

[Spectroscopic properties of 7-hydroxyquinoline in polymeric matrices].

In this paper, the absorption and fluorescence spectra of 7-Hydroxyquinoline (7HQ) in the copolymer of methyl methacrylate (MMA) and methacrylic acid (MAA) monomers were observed. The influence of different matrices on the species of 7HQ and the excited state proton transfer effect were investigated. The results showed that, as the number of carboxylic group in the matrix was increased, the relative contents of different species of 7HQ should be changed and the excited state proton transfer effect of 7HQ was enhanced.

Adsorption↗

PubMed1999

Network construction of first aid for electrical injury in the east China area of China Power.

Electrical injury is an area of burn medicine that requires specialized treatment. Injury rates have reached 6.56% in 1990, compared to only 1% prior to 1980. In recent years, the morbidity has steadily increased due to the rapid development of the electrical power industry and the popularization of electrical installations. Electrical accidents cause severe damage to muscle and tissue, which makes treatment of these accident patients quite challenging. Therefore, it is very important to promote the widespread use of a first aid network within the electrical power system while strengthening safety measures within the industry to reduce morbidity and mortality among the electrically injured. To date, similar networks have been established in East China, Central China, North China, and Shandong within the six major electrical power industries. We hope to minimize the injury of workers through appropriate supervision, improved safety measures, and improved safeguarding of equipment.

Accidents, Occupational↗

PubMed1999

Partial resistance to infection by R5X4 primary HIV type 1 isolates in an exposed-uninfected individual homozygous for CCR5 32-base pair deletion.

It is known that certain individuals remain persistently seronegative despite repeated exposure to HIV-1. Studies have shown that some exposed uninfected (EU) individuals who are homozygous for a 32-bp deletion in the CCR5 gene are resistant to infection with non-syncytium-inducing (R5) viruses. In the present investigation, we provide evidence that a highly exposed-uninfected individual with the CCR5 32-bp deletion (EUdelta32-1) also has partial resistance to syncytium-inducing (R5X4) HIV-1 viruses, when compared with unexposed-uninfected individuals with (UUdelta32-1 and UUdelta32-2) and without (UU-1 and UU-2) the 32-bp deletion. The partial resistance of EU cells was due neither to altered coreceptor expression, nor to specific mutation or deletion in the coding region of chemokine coreceptors CXCR4 and CCR3. While SDF-1, the ligand for CXCR4, blocked entry of R5X4 viruses to a similar extent in EUdelta32 and UUdelta32, there was a differential production of soluble factors by EUdelta32. Both CD4+ and CD8+ cells from EUdelta32-1 produced soluble factors that efficiently suppressed infection by HIV-1 R5X4 viruses when compared with supernatant from UUdelta32. These data provide evidence that additional soluble factors are involved in resistance to infection with R5X4 viruses.

CD4-Positive T-Lymphocytes↗

PubMed1999

Gab2, a new pleckstrin homology domain-containing adapter protein, acts to uncouple signaling from ERK kinase to Elk-1.

We describe a novel human adapter molecule containing a pleckstrin homolgy (PH) domain at the N terminus that is closely related to human Grb2-associated binder 1, Gab1, and Drosophila daughter of sevenless. We designate this protein as Gab2. Northern blot analysis indicates that Gab2 is widely expressed and has an overlapping but distinctive expression pattern as compared with Gab1, with high levels of Gab2 mRNA detected in the heart, brain, placenta, spleen, ovary, peripheral blood leukocytes, and spinal cord. Upon tyrosine phosphorylation, Gab2 physically interacts with Shp2 tyrosine phosphatase and Grb2 adapter protein. Strikingly, Gab2 has an inhibitory effect on the activation of Elk-1-dependent transcription triggered by a dominant active Ras mutant (RasV12) or under growth factor stimulation, whereas Gab1 acts to potentiate slightly the Elk-1 activity in the same system. In contrast to the reciprocal effects of Gab1 and Gab2 in mediating Elk-1 induction, these two molecules have a similar function in extracellular signal-regulated kinase activation induced by either oncogenic Ras or growth factor stimulation. Taken together, these results argue that Gab1 and Gab2, two closely related PH-containing adapter proteins, might have distinct roles in coupling cytoplasmic-nuclear signal transduction. This is the first evidence that an intracellular molecule with a PH domain operates as a negative effector in signal relay to the regulation of gene expression.

Adaptor Proteins, Signal Transducing↗

PubMed1999

Endogenous and background DNA adducts by methylating and 2-hydroxyethylating agents.

Detection of 7-alkylguanine DNA adducts is useful to assess human exposure to and the resulting DNA damage caused by simple alkylating agents. The background 7-methylguanine (7-MG) and 7-hydroxyethylguanine (7-HEG) adduct levels were determined in human and rat tissues, using thin-layer chromatography (TLC) combined with high pressure liquid chromatography (HPLC). In addition, these two adduct levels were also compared in various tissues between smokers and non-smokers. The results demonstrated that the background level of 7-alkylguanine adducts in WBC and lung tissues of non-smokers was 2.9 and 4.0 adducts/107 nucleotides, respectively. In smokers with lung cancers 7-MG adduct level in lung samples (6.3+/-1.9 adducts/107 nucleotides) and in bronchus samples (6.1+/-1.5 adducts/107 nucleotides) was significantly higher than that in WBC samples (3.3+/-0.9 adducts/107 nucleotides). 7-HEG adduct levels obtained from the same individuals were 0.8+/-0.3 in lung, 1.0+/-0.8 in bronchus and 0.6+/-0.2 adducts/107 nucleotides in WBC, respectively. Animal studies showed that background levels of 7-MG (2.1-2.5 adducts/107 nucleotides) in control rats were approximately 2-4-fold higher than 7-HEG levels (0.6-0.9 adducts/107 nucleotides). After a 3-day exposure to 300 ppm ethene, 7-HEG adducts accumulated to a similar extent in different tissues of rats, with the mean adduct level of 5.6-7.0 in liver, 7.4 in lymphocytes and 5.5 adducts/107 nucleotides in kidney.

Animals↗