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Biomedical subjects

Z L Yu

Publications and source records attributed to Z L Yu.

15 recordsLinked to original sources
PubMed2006

Evaluation of acute tacrine treatment on passive-avoidance response, open-field behavior, and toxicity in 17- and 30-day-old mice.

The potential of tacrine in altering cognitive/behavioral function as well as in causing toxicity was evaluated in mice of 17 and 30 days of age. Cognitive and behavioral studies were performed using a step-through passive avoidance task and a habituation open-field test with a 24-h retention interval. Tacrine was subcutaneously injected (1.25-80 micro mol/kg) 30 min prior to the first session of both tests. During the training session in step-through task, tacrine treatment dose-dependently decreased the number of footshocks, with IC(50) values being 7.8 and 23.3 micro mol/kg in 17- and 30-day-old mice, respectively. Treatment with tacrine at a low dose (5 micro mol/kg) significantly prolonged the retention latency in 17-day-old mice only, but it shortened the retention latency at high doses of 20 and 40 micro mol/kg in 17- and 30-day-old, respectively. During the acquisition session in the open-field test, tacrine treatment dose-dependently decreased the locomotor activity in 17- and 30-day-old mice, with IC(50) values being 15.1 and 24.7 micro mol/kg, respectively. High doses of tacrine invariably increased the locomotor activity during the recall session. Tacrine treatment at a dose of 40 micro mol/kg caused a significant increase in serum alanine aminotransferase activity in 17- and 30-day-old mice at 6 h post-dosing, with the extent of stimulation in 30-day-old mice being more prominent. In conclusion, tacrine was more potent in enhancing/disrupting the cognitive function, inhibiting locomotor activity as well as in causing hepatotoxicity in 17-day-old than in 30-day-old mice.

Animals↗
PubMed2005

Enhancement of the Gibberella zeae growth inhibitory lipopeptides from a Bacillus subtilis mutant by ion beam implantation.

Bacillus subtilis JA antagonized the growth of Gibberella zeae. In order to reduce growth of this fungi pathogen to a greater extent, low-energy ion beam implantation was applied in mutant breeding. We studied the effects of different energies and different doses of nitrogen ion implantation. The mutant strain designated as JA026 was obtained showing higher inhibition activity in the screening plate. Its inhibition zone against indicator organism increased by 14.3% compared to the original strain. The electrospray ionization mass spectrometry (ESI/MS) analysis indicated that the antifungal lipopeptides produced by the mutant were identical to those produced by the wild-type strain. The mutant strain exhibited favorable properties including the high yield of antifungal lipopeptides production and faster growth over the parent strain, which suggested that this strain would be a promising biocontrol candidate in agriculture.

Antifungal Agents↗
PubMed2001

[Analysis of the spectrum of damage effects of low energy N+ ions on cytosine aqueous solution].

Low energy N+ ions were produced by gas arc-discharge and the ions were accelerated into cytosine (C) aqueous solution. Changes in UV and infrared spectra of C after this kind of ions' action were investigated. UV spectra showed that absorption at 259 nm gradually decreased and lambda max of C solution moved toward the longer wavelength with the time. Thus, it was deduced that C was damaged and some fragments including -NO2 and -NH2 groups might have been produced. Judging from the IR spectra, the disappearance of the peak of 3,005 cm-1 confirmed the formation of -NO2 groups. All these results revealed that N+ ions caused various damages on C molecules and many new substances were formed. These new substances were not synthesized only by combination of the damage fragments in the solution, but also by "deposition" of N+ from outside.

Cytosine↗
PubMed2000

[Breeding of arachidonic acid producting strain by ion implantation].

With ion implantation, a high-yield arachidonic acid producting strain(Mortierella alpina) I49-N18 was selected, whose biomass was 30.80 g/L. The lipid component of biomass was 25.8%, in which AA content was 45.37%. The results showed that selected high-yield strain was steady on 250 L fermentor, whose AA yield was 4.0 g/L.

Arachidonic Acid↗
PubMed2000

[Establishment of a method for GUS gene transferring into wheat (Triticum astivum L.) embryos by low energy ion beam implantation].

Physical parameters influencing transformation of wheat mediated by low energy ion beam, including type of ion, parameters of ion energy, dose and dose rate, were studied. Ar+ was regarded as suitable ions implanted in transformation. 20-25 keV of energy, 4.68 x 10(16) ions/cm2 of dose, 2.6 x 10(15) ions/cm2 of dose rate were chosen as appropriate implantation parameters. The suitable culture conditions for induction and growth of callus and the optimal selection scheme were established, After implantation and selection, resistant calli and hygromycin-resistant plantlets were obtained from three varieties. Molecular analysis data proved that GUS gene had integrated into the wheat genome. The mature embryo transformation efficiency of wherat variety Yangmai 5, Yangmai 158, Wanmai 32 reached 9.5%, 10.8%, 11.2% measured in produced hygromycin-resistant callus and 1.4%, 3.4%, 1.7% measured in regenerated plants, respectively, This experiment provides a basis for further investigation of wheat transformation system. Low energy ion beam mediated transformation can be extended to other plant recalcitrant to Agrobacterium tumefaciens as soon as methodological parameters are optimized.

Gene Transfer Techniques↗
PubMed1997

[Studies on the chemical constituents of Annona muricata].

Annonaceous acetogenin (or polyketide) is a kind of potential antineoplastic agents from Annonaceae plants. Two new acetogenins, Muricatalicin (I) and muricatalin (VI), a mesitoate of a new acetogenin, annonacin-B mesitoate (Vb), and three known acetogenins, annonacin (II), annonacin-A (III) and annonacin-10-one (IV) have been isolated from Annona muricata L. The structures and relative stereochemistry of I, VI and Vb were elucidated on the basis of spectral analysis and examination of their acetates and/or mesitoate.

Annonaceae↗
PubMed1995

Cyclocariosides II and III: two secodammarane triterpenoid saponins from Cyclocarya paliurus.

Two new secodammarane triterpenoid saponins were isolated from the leaves of Cyclocarya paliurus. Based on chemical and spectral analysis they were assigned as (20S)-20-hydroxy-24-O-alpha-L-arabino-pyranosyl-3,4- secodammar-4(28),11,25-trien-3-oic acid, named cyclocarioside II and 25-hydroxy-(20S,24R)-epoxy-12R-O-beta-D- quinovopyranosyl-3,4-secodammar-4(28)-en,3-oic acid, named cyclocarioside III.

Carbohydrate Sequence↗
PubMed1992

Rational use of methotrexate in maintenance therapy of childhood acute lymphoblastic leukemia.

This study was undertaken to research the pharmacokinetics and bioavailability of methotrexate (MTX). Plasma concentrations were measured by fluorescent spectrometry in 20 normal SD rats, and 28 measurements were done in children with acute lymphoblastic leukemia (ALL). Both rats and children were divided into four groups. Either 20 mg/m2 or 40 mg/m2 of MTX was given IV or PO in each group. The plasma MTX concentrations were measured within 8 hours after administration. The concentration versus time curves were fitted by MCPKP program for pharmacokinetics (PK) and the parameters calculated. After PO administration, the peak concentration, duration of therapeutic concentration and bioavailability were much lower than that after IV administration. The differences were more obvious at 40 mg/m2 dosage. The higher the PO dosage, the lower the bioavailability. Absorption of PO MTX in children with ALL varied widely and uniform concentration was not expected even after equal dosage. Drug concentration was not necessarily increased with dosage. It is our conclusion that drug concentrations and PK parameters should be measured in patients receiving PO MTX therapy.

Administration, Oral↗
PubMed1989

[Clinical observation on hypercortisolism treated with amino-glutethimide].

We reported the clinical results in 13 cases of hypercortisolism treated with amino-glutethimide (AG), which was developed by Tiantsin Research Institute of Medical Industry. Of the thirteen cases nine were confirmed by surgery and histology, and the others were diagnosed clinically. Clinical improvements have been achieved in ten of the thirteen cases over a therapeutic course of 8 to 12 wk with a daily dosage of 1.0 to 2.0 g of AG. Plasma and urinary corticosteroids, as well as plasma testosterone levels were significantly decreased after one-month treatment followed, however, by somewhat return and fluctuation. The high levels of blood glucose and serum insulin were declined after therapy consistent with the decrement of corticoids. Serum potassium levels in hypokalemic patients returned to normal after one month of therapy. Radial bone mineral contents in patients with low bone density returned or closed to normal after three-month treatment. The main side effects of AG are anorexia, nausea, drowsy, tierdness, skin rashes, etc, which are mild and transient. Adrenal hypofunction was seen in one case after treatment.

Adolescent↗