Biomedical subjects

Y Tang

Publications and source records attributed to Y Tang.

At least 163 records · Page 9Linked to original sources

PubMed2000

Economic deprivation and AIDS incidence in Massachusetts.

OBJECTIVES: This study quantified AIDS incidence in Massachusetts in relation to economic deprivation. METHODS: Using 1990 census block-group data, 1990 census population counts, and AIDS surveillance registry data for the years 1988 through 1994, we generated yearly and cumulative AIDS incidence data for the state of Massachusetts stratified by sex and by neighborhood measures of economic position for the total, Black, Hispanic, and White populations. RESULTS: Incidence of AIDS increased with economic deprivation, with the magnitude of these trends varying by both race/ethnicity and sex. The cumulative incidence of AIDS in the total population was nearly 7 times higher among persons in block-groups where 40% or more of the population was below the poverty line (362 per 100,000) than among persons in block-groups where less than 2% of the population was below poverty (53 per 100,000). CONCLUSIONS: Observing patterns of disease burden in relation to neighborhood levels of economic well-being elucidates further the role of poverty as a population-level determinant of disease burden. Public health agencies and researchers can use readily available census data to describe neighborhood-level socioeconomic conditions. Such knowledge expands options for disease prevention and increases the visibility of economic inequality as an underlying cause of AIDS.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Differences in protein kinase C and estrogen receptor alpha, beta expression and signaling correlate with apoptotic sensitivity of MCF-7 breast cancer cell variants.

Widespread use of MCF-7 human breast cancer cells as a model system for breast cancer has lead to variations in these cells between different laboratories. Although several reports have addressed these differences in terms of proliferation and estrogenic response, differences in sensitivity to apoptosis have just begun to be described. Based on the possible differences in apoptotic sensitivity that may arise due to the existence of MCF-7 cell variants, we determined the relative sensitivity of MCF-7 cell variants from three established laboratories (designated M, L and N) to known inducers of apoptosis. Consistent with our previous studies we demonstrate that differences exist among these variants in regards to tumor necrosis factor alpha (TNF)-induced cell death and inhibition of proliferation in a dose-dependent manner. To establish if the difference in apoptotic susceptibility was specific to TNF, the three MCF-7 cell variants were tested for their response to other known inducers of apoptosis: okadaic acid, staurosporine and 4-hydroxy-tamoxifen. Viability and DNA fragmentation analysis revealed a similar pattern of resistance to apoptosis by all agents in the MCF-7 M variant. The MCF-7 L variant was resistant to okadaic acid and 4-hydroxy-tamoxifen but not staurosporine. In contrast, MCF-7 N cells were sensitive to induction of apoptosis by all agents. The role of both protein kinase C (PKC) and estrogen signaling in the regulation of cell survival prompted investigation of these pathways as a mechanism for differential sensitivity of MCF-7 cell variants to apoptosis. While both estrogen receptor alpha (ERalpha) and ERbeta were expressed in MCF-7 M and N cells, the absence of ERbeta in MCF-7 L cells correlated with decreased estrogen responsiveness of the L variant. Variations in estrogenic responsiveness and PKC isoform expression may account for the enhanced susceptibility of both the L and N variants to staurosporine.

Apoptosis↗

PubMed2000

[Yeast (Saccharomyces cerevisiae) secretory expression vector maintained stably in Pro3+ transformants in rich medium].

A yeast (Saccharomyces cerevisiae) secretory expression vector containing PRO3 gene was constructed (pCBy310). beta HCG(Human choriogonadotropin beta subunit)-cDNA was inserted into pCBy310 to form a recombinant plasmid pCBy314. Since yeast proline auxotroph will not survive in rich medium (YPD), YPD could be used as a selection pressure, and pCBy314 could be maintained mitotically stable in transformants of yeast Pro3- auxotroph (MB299-7A) in rich medium. At an improved, yet not optimized cultural condition, the expression of beta HCG in culture medium was 650 micrograms/L. Our results showed not only that YPD could be used as a selection medium, but also that yeast grew better in YPD so as to increase the gene expression product, and that the component of YPD was simple and cheap. Our data suggested that PRO genes might be used widely in constructing vectors to clone and express foreign genes in yeast so that rich medium can be used as a selection pressure for direct selection.

Chorionic Gonadotropin, beta Subunit, Human↗

PubMed2000

[The orthognathic treatment of developmental mandibular asymmetry].

OBJECTIVE: To explore the methods of orthognathic treatment for the developmental mandibular asymmetry to simultaneously achieve satisfactory facial appearance and oral functions and to prevent recurrence of the deformity. METHODS: 37 cases of developmental mandibular asymmetry have been treated in past seven years. The type of the deformity, the management of the cases, and the effects of therapy were summarized in this paper. RESULTS: According to the type of the asymmetric deformity, different means were used. After treatment, all the patients obtained satisfactory facial appearance and oral function. CONCLUSIONS: During the orthognathic treatment, it is important to simultaneously ameliorate facial appearance and achieve good oral function. It should be diagnosed before surgery whether the development of the deformity is steady or not. The correction of skeleton and soft tissues must be performed by stages.

Adolescent↗

PubMed2000

Effect of prenatal tetrandrine therapy on pulmonary vascular structural remodeling in the nitrofen-induced CDH rat model.

OBJECTIVE: To examine the effects of prenatal tetrandrine (Tet) therapy on pulmonary arterial structural remodeling in nitrofen-induced congenital diaphragmatic hernia (CDH). METHODS: CDH was induced in fetal rats by maternal administration of 100 mg nitrofen by gavage on day 9.5 of gestation (term, day 22). Control animals received olive oil (OO). Tet (24 mg/kg per day) or normal saline (NS) was given by gavage every day from 16 to 20 days of gestation, and fetuses were delivered by caesarean section on day 21.5. Lung sections from 3 fetuses in each group were studied. The number of vessels were calculated, the external diameter (ED), medial wall thickness (MT), percent of medial wall thickness, and wall structure were evaluated by image analysis software. RESULTS: In the pre-acinar arteries, CDH-NS pups had a significantly increased %MT compared with the OO-NS group (P < 0.05), while CDH-Tet animals had a reduced %MT compared with the CDH-NS rats (P < 0.05). Similar results were seen in the intra-acinar level. Significant differences were observed between CDH-NS animals and OO-NS controls in the percentage of muscularized intra-acinar blood vessels (P < 0.001). Tet-treated CDH pups had a reduced percentage of muscularized intra-acinar arteries compared with CDH-NS animals. CONCLUSIONS: Medial hypertrophy is present in both the pre-acinar and intra-acinar arteries in the nitrofen-induced CDH rat model. Tet treatment inhibits medial hypertrophy and reduces the percentage of muscularized intra-acinar vessels. Prenatal Tet therapy may be efficacious in reducing the risk of PH in human newborns with CDH.

Alkaloids↗

PubMed2000

Modified sternal elevation for children with pectus excavatum.

OBJECTIVE: To describe our experience in the treatment of pectus excavatum (PE) using a modified sternal elevation procedure. METHODS: From Oct. 1986 to Dec. 1997, 171 patients with PE were admitted to the Department of Pediatric Surgery of the First Hospital of West China University of Medical Sciences. All patients were diagnosed through a history and physical examination. Cardiopulmonary function was assessed by M-mode echocardiography and instrument of pulmonary function in 40 patients before and 4.2 years after surgery which was performed between 1989 and 1994. We performed the following three procedures in the sternal elevation: (1) forming the metal strut in a "arch" shape, (2) suturing the perichondrium into a "pipe" shape, and (3) encouraging patients to do chest expansion exercise after operation. All patients were followed up for 1 to 12 years. RESULTS: The normal contour of the costal cage was enlarged in all but one patient. Exercise tolerance was improved, and cardiac function recovered to the same level as in healthy children, while pulmonary function recovered very slowly after surgery. CONCLUSION: The normal appearance of chest wall can be recovered and normal cardiopulmonary function can be restored by the modified sternal elevation procedure in children with PE.

Adolescent↗

PubMed2000

[High risk factors lead to noscomial pulmonary infections caused by MRSA].

OBJECTIVE: To investigate major risk factors leading to death by noscomial MRSA pulmonary infections. METHOD: The data of hospitalized patients diagnosed as noscomial MRSA pulmonary infections were sorted out and analyzed for recent three years. RESULTS: Case mortality of 64 patients with noscomial MRSA pulmonary infections were 44%. Of these, 18 cases complicated fungi, 11 Klebsiella pneumoniae, 9 Pseudomonas maltophilia and 7 Enterococcus. Case mortality of fungi and Pseudomonas maltophilia were 67% and 61%, respectively. 23 cases had fever, 18 died (case mortality 78%) and 41 had no fever, 10 died (case mortality 24%) (chi 2 = 15.253, P < 0.005). The case mortality with reduction, normal and increase of leukocyte were 80%, 24% and 45%, respectively. The comparison between three groups had obvious significance (chi 2 = 12.554, P < 0.005) and the case mortality of leukocytopenia was higher than that of other two groups (chi 2 = 8.626, P < 0.005). The case mortality of hypoproteinemia was higher than that of the control group (chi 2 = 6.914, P < 0.01). The patients who developed fulminant lesions in liver, kidneys and lungs showed higher mortality rate. CONCLUSIONS: Case mortality of noscomial pneumonia caused by MRSA is very high. In addition to common causes, underling diseases, leukocytopenia, malnutrition and complex infections are also risk factors of MRSA infection.

Adult↗

PubMed2000

[Therapeutic effect of interleukin-12 on murine infection with Mycobacterium tuberculosis through modulating Th1 and Th2 cytokine balance].

OBJECTIVE: To study the effect of IL-12 on cytokines of murine infection with Mycobacterium tuberculosis. METHODS: 42 BALB/c mice infected with Mycobacterium tuberculosis were randomized into normal control (PBS) and IL-12 (n = 21) groups, treated with PBS or IL-12 respectively. Blood level of IFN-gamma, IL-4, and IL-10 were detected with ELISA method. The numbers of viable bacteria in organs were counted. Survival rate after treatment was investigated. RESULTS: In IL-12 group, none was dead. The numbers of viable bacteria in lung, liver and spleen were (227 +/- 107) x 10(5) cfu/ml, (4 +/- 3) x 10(5) cfu/ml and (1.5 +/- 0.5) x 10(5) cfu/ml respectively. INF-gamma (1,090 +/- 406) pg/ml. In PBS group, 8 mice were dead. The numbers of viable bacteria in lung, liver and spleen were (659 +/- 405) x 10(5) cfu/ml, (23 +/- 19) x 10(5) cfu/ml and (10.8 +/- 3.5) x 10(5) cfu/ml respectively. IFN-gamma (548 +/- 214) pg/ml. There was significant difference between those two groups. No change of the level of IL-4 in two groups. CONCLUSIONS: IL-12 induced IFN-gamma production, promoted development of Th1 cell responses, modulated Th1 and Th2 cytokine balance, suggesting that IL-12 enhance the host defense against the infection.

Animals↗

PubMed2000

[Management of severe maxillary deficiency through distraction osteogenesis with external distraction device].

OBJECTIVE: To demonstrate a practical method for advancement of the midface using Le Fort I osteotomy and gradual distraction technique. METHODS: With the use of an external adjustable, rigid distraction device, we treated 6 patients with severe maxillary hypoplasia. Ages ranged from 11 to 15 years. They all underwent modified Le Fort I osteotomies assisted by gradual distraction. Four days postoperatively, distraction began at the rate of 1 mm/day for about 2 weeks. 4 weeks with the fixed distraction appliance and 6 weeks with a removable night-time face-mask retention, we then analyzed all those preoperative and postoperative protocols. RESULTS: Predictable results were obtained. Midface advancement ranged from 8 to 13 mm. A satisfactory class I or II molar relationship is achieved. The aesthetic results are excellent. Up to now, no relapses have been observed. CONCLUSIONS: This method of modified Le Fort I midface advancement has been shown to be clinically practical and effective.

Adolescent↗

PubMed2000

[Management of micrognathia deformity associated with obstructive sleep apnea syndrome by distraction osteogenesis].

OBJECTIVE: To review the early results of lengthening of the mandible by distraction osteogenesis for the correction of micrognathia deformity and treatment of the obstructive sleep apnea syndrome (OSAS) simultaneously. METHODS: 5 cases with micrognathia deformity associated with OSAS resulted from unilateral/bilateral temporomandibular joint ankylosis had undergone mandibular distraction osteogenesis. In all of the patients intraoral device was employed. Cephalometric radiographs and polysomnograms were obtained preoperatively and postoperatively. RESULTS: The average distraction distance was 15.28 mm (range 8.5 mm to 24.4 mm). The micrognathia deformity was corrected effectively, at the mean time the incapacious pharyngeal airway was ameliorated. The patients' Apnea Index (AI) had been decreasing, SaO(2) during sleep had got to rise. CONCLUSIONS: Compared with the traditional surgery for the micrognathia associated with OSAS, the technique of mandibular distraction osteogenesis has the advantages of avoiding bone grafting and donor side morbidity, expanding the surrounding soft tissue concurrently, reducing the extent of operation and stability of the treatment effects.

Adolescent↗

PubMed2000

[Pathogenic microbes of biliary infection and their resistance to antibiotics].

OBJECTIVE: To understand the change of the main pathogenic microbes of biliary infection and their resistance rates to 12 antibiotics so as to instruct rational application of antibiotics clinically. METHODS: All isolates were identified by analytic products incorporation (API) bioMerieux. The susceptibility of antibiotics to 470 pathogenic microbes was tested by minimal inhibition concentration (MIC). RESULTS: There were 470 pathogenic microbes with positive biliary culture. The percentage of Escherichia coli, intestinal cocci and Klebsiella pneumoniae was 129 (27.4%), 82 (17.4%) and 76 (16.2%), respectively. In the resistance rates of the gram negative bacilli to 12 antibiotics, the lowest was 4.0% for imipenem followed by. 14.1% Ceftazidime and 16.9% amikacin. In the resistant rates of the gram positive cocci to 12 antibiotics, and had the lowest rate was 6.0% for vancomycin and 16.4% for imipenem. CONCLUSIONS: The main pathogenic microbes of biliary infection were Escherichia coli, intestinal cocci and Klebsiella pneumoniae. Imipenem is the first used for biliary infection in dealing with multiresistant intestinal cocci.

Anti-Bacterial Agents↗

PubMed2000

[Results: of 2000 kidney transplantations].

OBJECTIVE: To analyze the clinical results of renal transplantations. METHODS: From 1973 to 1999, 2000 renal transplantations were performed in 1 739 (1 238 males and 501 females) patients with end-stage renal failure. We analyzed the graft survival rates at 1, 3, 5 years; the main factors contributing to the mortality; the factors affecting the survival rate of re-transplant grafts; features of cancers after renal transplantation; the effect of CsA on liver function after renal transplantation; the treatments of chronic rejection; the effect of HLA typing on renal transplantation. RESULTS: The graft survival rates at 1, 3, 5 years were 87.33%, 80.17% and 67.04% respectively after using CsA since 1985. 282 recipients were over 50 years. The year graft survival rate was 82.27% and the 1-year patient survival rate was 84.75%. Pneumonitis was the dominant factor of death after renal transplantation, the incidence was 4.49%, and the death rate was 34.62%. The incidence of CMV positive after renal transplantation was 40.30%, and the death rate was 8.03%. Patients should wait a longer period (over 6 months) if the first transplant was failed because of acute rejection. The incidence of tumor after transplantation was 1.46%. The most frequent site of the tumors was urological system. The patient's liver function before transplantation and the intraindividual variability of CsA were the major factors on toxicity of the liver. The incidences of acute rejection were 27%, 35.5%, 22.4%, 20.85%, 0%, 0% respectively when the HLA mismatches were 6, 5, 4, 3, 2 and 1. CONCLUSION: Using immunosuppressants reasonably, preventing acute rejection, achieving good HLA typing are the major factors improving long-term graft/patient survival rate.

Adolescent↗

PubMed2000

[CT guided percutaneous fine needle aspiration for early diagnosis of pancreatic infection after acute necrotizing pancreatitis].

OBJECTIVE: To assess CT-guided percutaneous fine needle aspiration (FNA) for early diagnosis of pancreatic infection after acute necrotizing pancreatitis. METHODS: CT-guided percutaneous FNA was employed to diagnose pancreatic infection after acute necrotizing pancreatitis in 14 patients. The aspirates were smeared, cultured and subjected polymerase to chain reaction (PCR) for detecting bacteria. RESULTS: Ten patients were diagnosed as having pancreatic infection and 4 non-pancreatic infection. FNA was totally performed for 15 times: left retroperitoneal route for 12 times, left and right retroperitoneal route for one time, and transperitoneal route for two times. The sensitivity of smear, PCR, culture to diagnose pancreatic infection was 7/10, 9/10, 10/10, respectively. Their specificity was 4/4, and the time for obtaining the results was 30 minutes, 4 hours, 3 days respectively. CONCLUSIONS: Retroperitoneal approach can be used for most patients with acute necrotizing pancreatitis when performing CT guided-percutaneous FNA. PCR of aspirates is a rapid and accurate method to diagnose pancreatic infection.

Adult↗

PubMed2000

[Studies on Legionella-contamination to the air-conditioning cooling towers in big hotels and on its seroprevalence in the related populations in Beijing].

OBJECTIVE: To understand the situation of Legionella-contamination at cooling towers of big hotel and the level of Legionella-infection among related populations in Beijing. METHODS: Thirty-eight cooling towers of hotels were chosen for detection of Legionella. Four hundred and fourteen staff members from the hotels were selected as exposure group, with another 414 from general population as controls, for the detection of Legionella antibodies. RESULTS: Sixteen strains of Legionella pneumophila (Lp) were isolated from 21 of the 38 cooling towers, and the predominant strain was Lp serum group 1 (50%, 8/16). The seroprevalence of Lp antibodies for the exposure group was 9.9% (41/414), comparing to 3.5% (14/414) from the control group. The difference was statistically significant (chi(2) = 14.2, P < 0.01). CONCLUSION: Legionella was discovered in air-conditioning cooling tower of the hotels, which threatened the health to the population exposed to it.

Air Conditioning↗

PubMed2000

[Relationship between folate, vitamin B12, total plasma homocysteine and mutation of reductase].

OBJECTIVE: To study relationship between serum and red blood cell (RBC) folate, serum vitamin B(12) (VB(12)), total plasma homocysteine (tHcy), thermolabile genotypes, and activity of methylene-tetrahydrofolate reductase (MTHFR). METHODS: Thirty-four non-pregnant and healthy mothers who gave birth to babies with neural tube defects (NTDs) and 42 mothers to normal babies previously were chosen. Plasma tHcy, RBC and serum folate, serum VB(12), activity of MTHFR and thermolabile genotypes were determined for all of them. RESULTS: There was no significant difference in plasma tHcy, RBC and serun folate between case and control groups. Serum VB(12) was significantly lower in mothers of babies with NTDs than in those with normal ones. Plasma tHcy correlated with RBC folate inversely (P < 0.05). Mean plasma tHcy for thermolabile homozygous mutation of MTHFR was significantly higher than that for either heterozygous mutation or wild homozygous mutation (P < 0.001). There was no significant difference in serum folate between groups with varied MTHFR genotypes. Plasma tHcy was slightly greater in those with lower serum folate than in those with higher one, and correlated inversely with activity of MTHFR. CONCLUSIONS: Increase in plasma tHcy correlates with homozygous mutation of thermolabile MTHFR and decrease in activity of MTHFR. Higher level of folate in the body can interfere the relationship between plasma tHcy and activity of MTHFR.

Adult↗

PubMed2000

[Cephalometrical analysis of effects of premaxillary orthopedic treatment on maxillary growth of Wistar rats with bilateral artificial cleft palate].

OBJECTIVE: To measure the differences between the experimental group and the two controlled groups by using the cephalometric radiography technique to study the effects of premaxillary orthopedic treatments on the growth and development of maxilla. METHODS: To make an animal model with bilateral cleft palate by surgery operation: General anesthesia was carried on by injecting 2.5% pentobarbital (25 mg/kg) into abdominal cavity, then almost the same bone of rats' palate were removed from bilateral palate. An appliance, based on the principle of Latham's appliance was made and designed for premaxillary orthopedic treatment. It was fixed in rats' palate using pins under the condition of general anesthesia. After 20 days of orthopedic treatment, the rats were anesthetized by ether, and cephalometric films were taken under self-designed cephalometer and analysed aided by computer. RESULTS: The distances that represented the maxillary position in the posterior-anterior (PA) direction significantly increased (P < 0.05), while the angles that represented the direction of premaxillary growth significantly decreased (P < 0.05) between the experimental group and the two controlled groups. There were no significant difference between the two controlled groups. CONCLUSION: Premaxilla of rats can be effectively moved backward and rotated downward and backward on the PA direction by appliance. The appliance can move the segment palate forward during the premaxillary backword. The appliance can stimulate maxillary growth.

Animals↗

PubMed2000

[Separation and determination of tyramine by reversed-phase high performance liquid chromatography].

The method for separation and determination of tyramine by reversed-phase high performance liquid chromatography has been established. The effects of mobile phase on mechanism of separation based on the ion interaction are discussed. Using C8 alkyl bonded phase and 40% methanol-water solution containing Trisperchlorate as pH buffer (adjusted pH to 7.9) and ion interaction reagent and applying p-toluene sulfonamide as internal standard substance, the tyramine obtained from decarboxylation of p-tyrosine was determined. The RSD of determination was 0.66%(n = 11). The recoveries of sample were between 99.33% and 100.38%.

Alkylation↗

PubMed2000

[Overproduction and partial characterization of the Ssh7a and Ssh7b proteins from Sulfolobus shibatae].

The Sulfolobus shibatae Ssh7a and Ssh7b proteins have been separately overproduced in Escherichia coli and purified using a simple procedure which includes a heat treatment step. The recombinant and native Ssh7 proteins are similar in the ability to bind both negatively supercoiled and relaxed DNAs. In addition, the recombinant Ssh7a resembles the native Ssh7 protein in constraining negative DNA supercoils. Our data suggest that the two isoforms of Ssh7 interact with DNA in a similar fashion, and the methylation state of Ssh7 interact with DNA in a similar fashion, and the methylation state of Ssh7 does not affect DNA binding and supercoil constraining by the protein.

Archaeal Proteins↗