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Biomedical subjects

M Z Liu

Publications and source records attributed to M Z Liu.

At least 19 recordsLinked to original sources
PubMed2001

Essential role for NHERF in cAMP-mediated inhibition of the Na+-HCO3- co-transporter in BSC-1 cells.

Prior studies have indicated a requirement for the PDZ domain-containing protein, Na(+)/H(+) Exchanger Regulatory Factor (NHERF), for protein kinase A (PKA)-mediated inhibition of the renal basolateral Na(+)-HCO(3)(-) co-transporter (NBC). The present studies explore the potential mechanisms by which NHERF transduces cAMP signals to inhibit NBC. In BSC-1 cells, cells that express NBC but lack NHERF, 8-bromo-cAMP (100 microm for 15 min) failed to inhibit transport until wild-type mNHERF-(1-355) was expressed. mNHERF-(116-355) containing PDZ II and C-terminal ezrin-binding sequences or a mutant unphosphorylated form of rabbit NHERF effectively transduced the cAMP signals that inhibited NBC. By contrast, mNHERF-(1-126) encompassing N-terminal PDZ I and mNHERF-(1-325), which lacks ezrin-binding, failed to support cAMP inhibition of NBC activity. NBC and NHERF did not associate with each other in yeast two-hybrid or co-immunoprecipitation assays, and confocal microscopy indicated distinct subcellular localization of the two proteins. NBC was phosphorylated in BSC-1 cells, but its phosphorylation was not increased by cAMP nor was immunoprecipitated NBC phosphorylated by PKA in vitro. Acute exposure of mNHERF-(1-355)-expressing BSC-1 cells to cAMP did not change cell surface expression of NBC. Although these results established an essential role for NHERF in cAMP-mediated inhibition of NBC in BSC-1 cells, they also suggest a novel mechanism for NHERF-mediated signal transduction distinct from that previously characterized from studies of other NHERF targets.

Animals↗
PubMed2001

Comparison of chemical and enzymatic synthesis of 2-acetamido-2-deoxy-D-mannose 6-phosphate: a new approach.

Chemical and enzymatic methods to synthesis of 2-acetamido-2-deoxy-D-mannose-6-phosphate (ManNAc-6-P) have been investigated. A new preparative method has been developed although some established procedures were tried. In this new method, a 6-O-acetyl or 4,6-di-O-acetyl group of the per-O-acetylated 2-acetamido-2-deoxy-D-mannose (ManNAc) were regioselectively removed with an esterase from the yellow yeast, Rhodosporidium toruloides, followed by phosphorylation and O-deacetylation under mild conditions. 1H and 13C NMR data spectra of ManNAc-6-P were recorded.

Acetylation↗
PubMed2001

Chemical synthesis of a P(k)-antigenic globotriose analogue with a functionalized aglycon.

6-Aminohexyl alpha-D-galactopyranosyl-(1-->4)-beta-D-galactopyranosyl-(1-->4)-beta-D-glucopyranoside (2), a globotriose analogue with a functionalized aglycon, was synthesized, using alpha-D-galactopyranosyluronic acid-(1-->4)-D-galactopyranosyluronic acid [di-GalA (3)] as the starting material, which is commercially available or can be readily prepared from pectin.

Carbohydrate Sequence↗
PubMed1999

Perinatal regulation of the ClC-2 chloride channel in lung is mediated by Sp1 and Sp3.

Mechanisms responsible for regulation of pulmonary epithelial chloride-channel expression in the perinatal period are under investigation to better understand normal lung development and airway disease pathogenesis. The ClC-2 epithelial chloride channel is regulated by changes in pH and volume and is most abundant in lung during fetal development. In this study, we identify and sequence the ClC-2 promoter, which is GC rich and lacks a TATA box. By construction of a series of promoter-luciferase constructs, a 67-bp GC box-containing sequence in the promoter is shown to be critical to ClC-2 expression in primary and immortalized fetal lung epithelial cells. Electrophoretic mobility shift assays and antibody supershifts demonstrate that the Sp1 and Sp3 transcription factors are expressed in fetal lung nuclei and interact with the GC box sequences in the promoter. Immunoblotting techniques demonstrate that Sp1 and Sp3 are perinatally downregulated in the lung with the same temporal sequence as ClC-2 downregulation. This work suggests that Sp1 and Sp3 activate ClC-2 gene transcription and that reduction in Sp1 and Sp3 at birth explains perinatal downregulation of ClC-2 in the lung.

Aging↗
PubMed1997

[Studies on chemical constituents of Polygala arillata buch-ham].

Two new compounds were isolated from the roots of Polygala arillata Buch-Ham. On the basis of chemical reactions and spectral (UV, IR, MS, 1HNMR, DIFNOE, 13CNMR) analysis, they were identified as 1,3-dihydroxy-2-methoxyxanthone(I) and 7-hydroxy-1-methoxy-2,3-methylenedioxyxanthone(II). Pharmacological study indicated that I and II have inhibitory effect on aldose reductase activity.

Aldehyde Reductase↗
PubMed1993

[Characterization of a fluorouracil-resistant human gastric carcinoma cell line and its morphological behavior].

A fluorouracil (FU)-resistant human carcinoma cell line (SGC-7901/R) was established in culture by progressively increasing the concentration of FU from 50 ng.ml-1 to 2.5 mg.ml-1. The cell line has been successfully subcultured for more than 150 passages during more than 2 years. Its degree of FU resistance was 139-fold vs that of FU sensitive cell line (SGC-7901/S), and the resistant phenotype was stable when cells were cultured for 23 passages in FU-free medium. The doubling time was 17.3 and 25.6 h for resistant cells and parental cells, respectively. Swiss (nu/nu) nude mice were used for the in vivo experiment, the FU-resistant cell line also exhibited resistance to FU and cross-resistance to mitomycin C. FU inhibited markedly the incorporation of [3H]UR into sensitive cells and only showed a 31.6% inhibition with FU 100 micrograms.ml-1 in resistant cells. For the incorporation of [3H]TdR into DNA, inhibitory rates were seen with different concentrations of FU in resistant cells. By morphologic observation, SGC-7901/R cells showed little secretion but without any tendency to glandular pattern. Their nuclei were allotype with enlarged perinuclear space and a few intranuclear pseudoinclusions. The mitotic phase of cells was found frequently. The phenotype of resistant cell line can be deduced more malignant than that of parental cell line.

Animals↗
PubMed1992

Development of a real-time algorithm for predicting sufentanil plasma levels during cardiopulmonary-bypass surgery using a systems approach.

During cardiopulmonary-bypass (CB) procedures, anesthesiologists have traditionally based the administration of narcotics on general dosage recommendations and past experience. Initial doses are usually based on body weight and supplemental amounts are given in anticipation of, or in response to, the effects of surgical stimuli. There has been considerable recent interest in using the population pharmacokinetics of narcotics to optimize the attainment and maintenance of drug plasma concentrations at analgesic target levels which will blunt the hemodynamic responses to noxious stimuli. Moreover, the undershooting or overshooting of the target can be reduced by application of these principles making drug administration more effective and safer. The present study concerns the development of a model for the computer-guided administration of sufentanil throughout surgical procedures involving CB; there is a paucity of studies which have attempted to model the pharmacokinetics of drugs during CB because of the lack of information on the effects of bypass conditions on the pharmacokinetic parameters. We have attempted to approach the effects of hypothermia on sufentanil clearance by applying a continuous temperature correction to the ultimate elimination rate constant (the terminal eigenvalue). This correction is based primarily on the anticipated effects of temperature on the enzyme-catalyzed reactions which are essential for the elimination of drug from the body. An algorithm for the application of the model is also presented.

Algorithms↗
PubMed1992

[Need for more emphasis on fungal infection in burns].

We have made quantitative bacterial and fungal culture for 148 biopsy specimens from burn patients. Further confirmation was made by frozen section with PAS stain in 82 of the specimens. It was discovered that the fungal infections in these burn patients were characterized by early onset with multiple organisms. It was also found that the incidence of fungal infections was higher in severe burns. Two rare cases of fungal infection were discovered, one of them was infected by Geotrichum SP, and the patient died; the other an infection by Homodendrum SP on the face, and the finally recovered.

Adult↗
PubMed1991

[Detection of Candida albicans infection by indirect immunofluorescence].

It has been a serious problem that candida sepsis is increasing followed thermal injury, which related to the increasing use of antibiotics in part. This paper showed that indirect immunofluorescence assay (IFA) is a more sensitive, efficiency, rapidly and specific method by staining urine sample in early diagnosis or monitoring the candida infection from gut after burn injury. It seems that IFA is more useful to make early diagnosis of candidal infection for the clinical purpose.

Animals↗
PubMed1991

[No promoting effects of sodium tanshinone II-A sulfonate on growth and metastasis of Lewis carcinoma].

From d 3 after transplantation of Lewis pulmonary carcinoma in C57BL mouse leg muscles, the mice were injected ip sodium tanshinone II-A sulfonate (DS-201) 0.2, 0.4, 6.3, 12.5, 25.0, and 50.0 mg.kg-1 qd x 12 d. At the dose of 12.5 mg.kg-1 or below, the mice appeared to be as vivid as those of the control. In the group of 25 mg.kg-1, declining brisk and unkept appearances were seen. At 50 mg.kg-1, the mice were more emaciated and half of them died. On d 2 of cessation of the medication, all remaining mice were dissected. The weights of muscle tumors and the metastatic foci on lungs in the medicated mice showed no significant differences from their controls. These results demonstrate that DS-201 has no promoting effect both on growth of Lewis carcinoma transplanted in C57BL mouse leg muscles and on lung metastasis of the neoplasm.

Animals↗
PubMed1990

[Gene engineering EB virus membrane antigen in detection of MA-IgA antibody--comparison with VCA-IgA and EA-IgA antibodies].

With gene engineering EB virus membrane antigen as the diagnostic antigen, indirect immunofluorescence (IF) assay was used to detect IgA antibody against EB virus membrane antigen (MA-IgA) in sera from 202 nasopharyngeal carcinoma (NPC) patients and 315 controls (normal and patients with other tumors). MA-IgA antibody was positive in 96.8% of the pre-treatment NPC patients with a GMT of 1:36.3. MA-IgA detection by this method was more sensitive than EA-IgA detection by IE. In contrast, patients with tumors other than NPC were negative for MA-IgA antibody. 9.1% of VCA-IgA positive persons were MA-IgA positive with a GMT of less than 1:5. No MA-IgA positive was found in VCA-IgA negatives. The results indicated that this method was relatively specific. In the treatment group, the positive rate and GMT of MA-IgA antibody declined with increase in survival time and the decline was faster than VCA-IgA. When recurrence or distant metastasis developed, similar to VCA-IgA and EA-IgA antibodies, the positive rate and GMT of MA-IgA antibody increased to its pretreatment level. Therefore, MA-IgA detection might be valuable in the early diagnosis and monitor of NPC.

Animals↗
PubMed1989

[Reproductive toxicity of bimolane in mice and rabbits].

Bimolane (AT-1727), 1,2-bis (4-morpholinomethyl-3,5-dioxopiperazinyl)-ethane, is a new antitumor drug, synthesized first in our institute. When the mice were injected ip bimolane 3.7 or 37.2 mg/kg on d 6-15 after mated, 23 or 100% of the embryos were resorbed, while the surviving fetuses remained normal. After ip bimolane 7.4 or 14.9 mg/kg, the weights of living fetuses were all less than that of the control group (P less than 0.01). After ig bimolane 140 mg/kg to the mice on d 6-15 after mated, 43% of the fetuses developed subcutaneous edema, but no other abnormalities were seen. When the rabbits were given ip bimolane 30 mg/kg on d 7-18 after mated, all the embryos were resorbed. On d 10 after mated ip a single dose of bimolane 74.4 mg/kg to the mice caused nanomelia (34%) and subcutaneous hematoma (55%). Therefore, teratogenicity of bimolane was observed in mice.

Animals↗
PubMed1988

Applied anatomy of the anterolateral femoral flap.

A study of the source of the blood supply to the anterolateral femoral flap was carried out on 42 lower limbs of adult cadavers (among them 35 cadavers with injection of red latex and 1 with india ink into the arteries and 6 vascular cast specimens), and the surface locations of the vascular pedicle were detected on 50 healthy adults. It was found that the descending branch of the lateral circumflex femoral vessel was an ideal axial vessel. There are constant perforating branches of the myocutaneous artery or cutaneous branches from the intermuscular space to the anterolateral femoral skin. The area extends about 12 x 30 cm. Within the flap, the anterior branch of the anterolateral cutaneous nerve of the high is located. This flap has been widely used for free transplantation in China since 1983 with satisfactory results.

Adult↗
PubMed1987

The study of byssinosis in China: a comprehensive report.

Cross-sectional studies were conducted during 1981-1983 among 861 textile workers in 3 cotton mills and 822 controls in 2 silk factories. Questionnaire and lung function tests were taken and inhalable dust concentrations were measured. Prevalence of byssinosis was 5.6%. Average dust concentrations were highest in carding rooms, 1.47-1.99 mg/m3. The correlations (r) between prevalence of byssinosis and dust concentrations was 0.64 (p less than 0.05). The prevalence of chronic bronchitis was 14.4% in cotton workers and 5.1% in controls (p less than 0.05). Acute FEV1 percent decrement (greater than 5%) was higher among cotton workers (32.1%) compared to controls (14.5%) (p less than 0.001). In one cotton blanket factory, the prevalence of byssinosis and chronic bronchitis was higher among workers in the high-dust work areas. Long-term effect studies included pulmonary function test among 173 cotton workers and 373 controls, retired 1-10 years, using the flow volume curve (FVC); chest X-rays of 140 pairs of cotton workers and controls with working tenures over 20 years; and examination of lobectomy specimens of 8 textile workers matched with 16 controls. In male cotton workers, only smokers had a prominent decrement of lung function indices, except FVC. For non-smoking females, there was no difference between the two groups. Additive effects were seen between smoking and dust exposure. According to the International Labor Organization (ILO) Pneumoconiosis Classification, the prevalence of abnormality (profusion greater than 1/0) was 4.3% and 8.7% in non-smoking controls and cotton workers. The interstitial changes on X-ray due to smoking would be much heavier. Additive effects also existed between smoking and dust exposures. No significant changes attributable to dust exposure were seen on pathological section of lobectomy specimens.

Aged↗
PubMed1987

The health investigation of cotton textile workers in Beijing.

This study reports findings from a survey of byssinosis among 289 cotton workers in certain cotton textile mills in Beijing. Incidence of byssinosis was 4.2% (12 cases). It decreased with a lower concentration of cotton dust and increased with yearly increment of cotton dust exposure. An elevation in body temperature over 37 degrees C was present among 14.2% of the workers on the first working day after rest. Acute lung function decrement was related to high dust concentration in the rooms. The higher the dust concentration in the rooms, the more evident was the chronic lung function decrement. Chronic bronchitis in cotton workers was higher than in controls. Incidence of byssinosis in smoking cotton workers was higher than in nonsmoking cotton workers.

Bacteria↗
PubMed1987

[Heart injuries].

Explore the source record for details and available documents.

Cardiac Tamponade↗
PubMed1986

Radiographic findings in cotton textile workers and the relationship to cigarette smoking.

A group of 140 cotton textile workers from Shanghai, Shandong, Guangxi, and Beijing have had their chest radiographs taken using similar requirements. Most had come from the preparatory departments of cotton mills and had a history of exposure to cotton dust for at least 20 years. As controls, 140 healthy individuals with no dust exposure were matched with respect to sex, age, and smoking history. All the radiographs were read according to the ILO International Pneumoconiosis Classification, and the manifestations belonging to categories 0/0 and 0/1 were grouped as "normal," whereas categories 1/0, 1/1, and 1/2 and above as "abnormal." There was no significant difference in X-ray abnormalities between cotton textile workers and controls (P greater than 0.05). But when the data on the cotton textile workers and controls were combined, an appreciable difference in the incidence of radiographic abnormalities was found between smokers and non-smokers (P less than 0.001). Cotton dust exposure may induce nonspecific interstitial pulmonary changes, but these changes were exaggerated by cigarette smoking. These two factors appeared to have an additive effect on the pulmonary X-ray findings.

Female↗