Isolation and identification of extracts of Eichhornia crassipes and their allelopathic effects on algae.
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Biodegradation, Environmental↗
Biomedical subjects
T L Li
Publications and source records attributed to T L Li.
Biosynthesis of the vancomycin group of antibiotics: characterisation of a type III polyketide synthase in the pathway to (S)-3,5-dihydroxyphenylglycine.
3,5-dihydroxyphenylacetate, a precursor for the non-proteinogenic amino acid 3,5-dihydroxyphenylglycine occurring in glycopeptide antibiotics, is determined to be catalysed by a type III polyketide synthase using malonyl-CoA as a starter unit.
Actinomycetales↗
Characterisation of a hydroxymandelate oxidase involved in the biosynthesis of two unusual amino acids occurring in the vancomycin group of antibiotics.
ORF22 from the chloroeremomycin gene cluster has been cloned, expressed and characterised as a hydroxymandelate oxidase (HmO) that is involved in the formation of both (S)-4-hydroxyphenylglycine and (S)-3,5-dihydroxyphenylglycine.
Alcohol Oxidoreductases↗
[Comparison of anesthesia in infant undergoing abdominal surgery].
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Anesthesia↗
Pharmacokinetics of lactosaminated recombinant human growth hormone in mice.
AIM: To study the pharmacokinetic characteristics of lactosaminated recombinant human growth hormone (hGH-L) in mice. METHODS: The biodistribution was studied with in vivo radioactive tracer technique. The pharmacokinetics was investigated by radioimmunoassay (RIA) method of hGH-L. The results were compared with that of recombinant human growth hormone (hGH). RESULTS: 125I-hGH-L has remarkable livertaxis. The area under drug concentration-time curve (32686.9 microg . min . L-1) in blood and serum mean residence time (21.4 min) of hGH-L are less than that of hGH (36913.1 microg . min . L-1 and 24.9 min) (P < 0.05). In target organ liver, hGH-L distribution half life (1.8 min) and elimination half life (11.1 min) are shorter than that of hGH (2.1 min and 27.7 min) (P < 0.05). The area under drug concentration-time curve (17621.9 microg . min . L-1) of hGH-L is bigger than that of hGH(12148.2 microg . min . L-1) (P < 0.05) in liver. CONCLUSION: The pharmacokinetic parameters of hGH-L has obvious advantage over that of hGH.
Amino Sugars↗
[Study on the enzyme dependant colon targeting prodrug--dexamethasone succinate dextran and its tablets].
AIM: To develop an orally administered colon targeting drug delivery system dexamethasone succinate dextran (DSD) tablets. METHODS: Dexamethasone succinate dextran was synthesized in an anhydrous environment. Using 4-dimethyl aminopyridine and 1,1'-carbonyldiimidazole as the catalyzer. The chemical structure was identified by UV, IR, NMR and MS. The contents of dexamethasone in various samples were determined by HPLC. RESULTS: Dexamethasone was distributed mainly in plasma and gastric contents after the oral administration of common tablets. In contrast, after oral administration of DSD tablets, the recovery of dexamethasone in plasma and gastric contents decreased significantly, while the percentage of dexamethasone in cecum and colon increased obviously. CONCLUSION: The experimental results showed the good colon targeting property of DSD prodrug compared with free dexamethasone.
Administration, Oral↗
Zinc induces mitochondria apoptogenesis in prostate cells.
BACKGROUND AND PURPOSE: Prostate secretory epithelial cells have the unique function and capability of accumulating extremely high intracellular levels of zinc. One of the effects of this accumulation is inhibition of cell growth due, in part, to an increase in apoptosis. The present studies were conducted to determine if this zinc-induced apoptosis involves stimulation of mitochondrial apoptogenesis. MATERIALS AND METHODS: The PC-3 a human malignant prostate cell line, which is zinc accumulating, was exposed to medium supplemented with physiologic levels of zinc. RESULTS: By 24 h, zinc treatment resulted in the translocation of cytochrome c from the mitochondria to the cytosol, the activation of caspase-9 and caspase-3, and eventually, the cleavage of nuclear poly(ADP)-ribose polymerase (PARP). Under similar conditions, exposure of freshly prepared rat ventral prostate cells (which are also zinc accumulating) resulted in increased apoptosis following translocation of cyochrome c and activation of caspases-9 and 3. The human prostate PZ-HPV-7 cells, which do not accumulate zinc, did not exhibit any apoptotic effect from zinc treatment. CONCLUSION: The accumulation of high intracellular levels of zinc by prostate cells induces mitochondrial apoptogenesis. This represents a newly identified physiological effect of zinc in the regulation of prostate cell growth.
Animals↗
A nine-year prospective study on the incidence of childhood type 1 diabetes mellitus in China.
To investigate the epidemiological characteristics of childhood type 1 diabetes mellitus in China, newly diagnosed cases of type 1 diabetes with an onset age under 15 years were retrospectively registered by 23 local centers in China following a standardized protocol on the basis of the nationwide registry established by the WHO DiaMond Project China Participating Center, Chinese Academy of Preventive Medicine (CAPM). A population of about 24 million children were covered in the defined areas. A two-sample capture-recapture method was used to estimate case ascertainment. Between 1988 and 1996, 903 diabetic cases were registered in 9 ethnic groups. The overall ascertainment corrected incidence rate (IR) was 0.59 per 100,000 person-year. The IR was 0.52/100,000 (95% CI: 0.50-0.54) for males and 0.66/100,000 (95% CI: 0.64-0.68) for females. The standardized ascertainment corrected IR by the national age-specific population in 1990 was 0.57 per 100,000 person-year. The incidence among various ethnic groups ranged from 0.25/100,000 to 3. 06/100,000. The IRs increased with northern latitude, and the IR of Han population was significantly higher in North China compared with South China (0.67 versus 0.53 per 100,000 respectively, P < 0.01). A correlation model of incidence and calendar time showed that the IR increased significantly between 1988 and 1996 (r = 0.86, P = 0.0027). The relative risk (RR) of type 1 diabetes mellitus for different age-groups estimated by a Poisson regression model showed that taking RR as 1.00 for age-group from 0 to 4 years, the RR for age-group from 5 to 9 year and from 10 to 14 year was 2.30 and 3.60 respectively. The standardized ascertainment corrected IR of childhood type 1 diabetes mellitus in China in much lower than in other countries. The geographic and ethnic variability of the incidence suggests that both genetic and environmental factors play a role in the development of childhood diabetes in China.
Adolescent↗
[Repair of flexor-tendon injury in children's finger using microsurgical technique].
OBJECTIVE: To improve the clinical result of repair on flexor tendon injury, and recover the defected finger function in children as far as possible. METHODS: From January 1990 to October 1997, 12 cases with flexor tendon injury were repaired by microsurgical technique, sutured by modified Kessler method with 3/0 or 5/0 nontraumatic thread and followed by invering suture of the gap edge with 7/0 or 8/0 nontraumatic thread after debridement. Appropriate functional practice was performed postoperatively. RESULTS: All the defected fingers were healed by first intention. Followed up 6 months to 1 year, there was excellent in 7 cases, better in 4 cases, moderate in 1 case and 91.67% in excellent rate according to the TAM standard of International Hand Committee. CONCLUSION: The important measures to improve the clinical result in children's flexor tendon injury are prompt and accurate diagnosis and repair of the injured tendon by microsurgical technique, and effective postoperative functional practice.
Child↗
Na+/Ca2+ exchange current in myocytes isolated from rat hypertrophied heart.
Effects of myocardial hypertrophy on the Na+/Ca2+ exchange current in isolated rat cardiac myocytes were investigated, using whole cell patch techniques. Goldblatt 2-kidney, one-clip technique was used to induce cardiomyocyte hypertrophy. The results demonstrated that the Ni(2+)-sensitive Na+/Ca2+ exchange current density was larger in hypertrophied cells than that in normal cells. At a holding potential of mV, the outward current densities were 1.53 +/- 0.31 pA/pF in normal cells and 2.62 +/- 0.53 pA/pF in hypertrophied cells (P < 0.01). At a holding potential of -100 mV, the inward current densities were 0.42 +/- 0.14 pA/pF in normal cells and 1.12 +/- 0.33 pA/pF in hypertrophied cells (P < 0.001). The results suggest that during myocardial hypertrophy the Na+/Ca2+ exchange current is significantly increased.
Animals↗
Effects of processing steps on the contents of minor compounds and oxidation of soybean oil.
The effects of minor compounds on the oxidative stability of soybean oil were studied by measuring the contents of peroxides, headspace oxygen and volatile compounds. The effects of processing on minor component contents were also studied. Fatty acids, mono- and diacylglycerols, thermal or oxidized triacylglycerols, oxidized tocopherols and peroxides acted as prooxidant in soybean oil during storage at 55 degrees C. The phospholipids acted as prooxidant or antioxidant depending on the presence or absence of metals in the oil. The tocopherols acted as prooxidant or antioxidant depending on their concentration in the oil. The chlorophyll acted as a sensitizer to generate singlet oxygen in the photooxidation of soybean oils.
Antioxidants↗
The China Productivity Project: results and conclusions.
Experiments were conducted to determine what factors cause variation in individual work output (economic productivity). Forty-five young male Chinese cycle haulers from Beijing were assessed for physiological work capacity, size and body composition, health, nutritional status, cold resistance, household social environment, and motivation. Experiments were conducted in the laboratory as well as under actual working conditions; ethnographic observations were made in the household and on the job during the Beijing winter of 1992. Overall work motivation correlated to actual monthly distance/load measures of productivity the most strongly (r = 0.518), followed by physiological capacity estimated by heart rate:speed ratio during field experiments (r = -0.473). Alcohol consumption (a negative factor), household health, and carbohydrate intake were all moderate predictors. Maximum oxygen uptake showed lower correlation (r = 0.261), and among anthropometric values only relatively long lower legs were predictive (r = 0.298). Since many of these variable categories were relatively independent of each other, multiple regression analysis showed that together they explained 61.6% of the work output variance. Simultaneous prediction by FASEM (LISREL) is also very strong.
Adaptation, Physiological↗
Si-jun-zi-tang regulate granulocyte macrophage colony-stimulating factor secretion by human peripheral blood mononuclear cells.
Si-Jun-Zi-Tang is one of the widely used Chinese herbal medicines. In this study, human peripheral blood monocytes were treated in vitro with 50% hot ethanol extract of Si-Jun-Zi-Tang and its four major ingredients (Dangshen, Baizhu, Gancao and Fuling). The concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the culture supernatant at 3 hours and 18 hours were measured using an ELISA. Dangshen and Gancao significantly suppressed GM-CSF secretion in a dose-dependent manner. Baizhu showed no statistically significant effect on GM-CSF secretion 18 hours after in vitro drug-treatment. Fuling, by contrast, significantly augmented GM-CSF secretion in a dose-dependent manner after 18 hours of drug treatment. Si-Jun-Zi-Tang showed a suppressive effect on GM-CSF secretion at 3 hours but significantly augmented GM-CSF secretion when the cells were treated with 8 mg/ml of the drug for 18 hours. The data suggested that Si-Jun-Zi-Tang might modulate hematopoiesis and immune response via regulating GM-CSF secretion, and the presence of Fuling in Si-Jun-Zi-Tang could counteract the suppressive effect of Dangshen and Gancao on GM-CSF secretion.
Dose-Response Relationship, Drug↗
[Preparation of hepatic targeting antivirus agent NGA-ACV and its targeting property].
Neoglycoalbumin (NGA), a special ligend of asialoglycoprotein receptor on the hepatocyte, was linked via a butanediacyl bridge to acyclovir to form a conjugate NGA-ACV. By using DTA (Differential thermoanalysis) and HPLC analysis, ACV was shown to be connected with NGA by covalent bonds and stable in blood. The radio-biodistribution of 131I-NGA-ACV with high drug density in vivo was carried out in mice. The maximum absorption of 131I-NGA-ACV in liver was 81.7 +/- 10.4% at 5 min. The radioimage of 131I-NGA-ACV with high or low drug density in rabbit showed no significant difference in liver targeting property. The competitive connection tests indicated that 131I-NGA-ACV was concentrated in liver through receptor mediated mechanism. A tentative test of antihepatitis B of NGA-ACV and ACV in vitro showed that the effective dose of the former was significantly lower than that of the latter.
Acyclovir↗
Work performance of Chinese cycle haulers: controlled field experiments in normal work conditions.
Forty-five male Chinese cycle haulers performed a controlled field experiment under mild winter conditions. The objective was to gain insight into factors that affect work performance. Each man hauled the same 481-kg load around a Beijing street course of 14.18 km. The experiment was a measured sample of the same work they do routinely, on the same roads, using similar human powered hauling cycles (modified only enough to carry observers and instruments). The course was completed at a mean speed of 10.4 kph and mean time of 84.2 min. While there was considerable variation in individual pace and in pace change during work, the haulers performed at relatively high output in reference to their capacities. Mean heart rate was 156.8 +/- 16.1 bpm, 83.9% of maximum. The men had average body build and were average in size for the general Chinese population (X stature = 169.7 cm) although they showed relatively high aerobic capacity (determined in laboratory tests). Performance levels during experiments appear to match habitual work patterns, and self-pacing emerged as a major behavioral finding of this research. Speed, a primary index of job performance, showed significant correlation to heart rate, VO2max, variation in windchill, self-reported health and other variables, with a multiple regression coefficient of 0.811. Similar patterns were seen for heart rate relative to speed, except that physical size, education, and other behavioral variables were also predictors.
Adult↗
[Study of pharmacokinetics of liver targeting antimalarial agent neoglycoalbumin-primaquine conjugate (NGA-PQ) and primaquine phosphate in mouse].
A normal phase high-performance liquid chromatography process was used to separate and detect primaquine in blood and liver after a single intravenous dose of the hepatic targeting agent neoglycoalbumine-primaquine conjugate (NGA-PQ) and primaquine phosphate (PQP) in mice. 6-Methoxy-8-(4-amino-butyrylamino) quinoline synthesized and identified by us was used as an internal standard to be added to biologic samples obtained from mice at different times after given NGA-PQ or PQP. The mixture was extracted with ether after alkalinization in the PQP group. In the NGA-PQ group, the biological samples must be hydrolized by heating under nitrogen and acid condition in a domestic pressure cooker before extraction. The extracts were evaporated to dryness under nitrogen, then dissolved in the mobile phase (chloroform-methanol-amonium hydroxide = 86.8: 12.5: 0.7). The results showed that the hepatic PQ collecting ratio and the retention time of PQ in liver in the NGA-PQ group were higher and longer than those in the PQP group. The results also point out that NGA-PQ has liver targeting property.
Albumins↗
[A comparative study on anti-ulcer action of unprepared and calcined oyster shell].
On experimental gastric ulcer models induced by 0.6mol/L HCl, ethyl alcohol or ligation of the pylorus, the preventive effects of unprepared oyster shell, calcined oyster shell 1(900 degrees C, 1h), calcined oyster shell 2(350 degrees C, 8h) were compared in Wistar rats. Results showed that antagonistic effects of calcined oyster shell 1 to the drug pathogenesis of peptic ulcer and the incidence of peptic ulcer after ligation of the pylorus were markedly greater.
Animals↗
[FeS2 changes in ignited pyritum].
FeS2 changes in Pyritum during igniting process were studied systematically by comparing Pyritum ignited under different conditions in terms of S content, Fe content, yielding ratio of ignited product and appearance features. Calcined Pyritum samples purchased from various parts of China were also compared in regard to their quality.
Hot Temperature↗