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Biomedical subjects

G Lu

Publications and source records attributed to G Lu.

At least 199 records · Page 11Linked to original sources
PubMed1993

Effect of intra-vas deferens injection of gossypol-polylactic acid on fertility and spermatogenesis in rats.

In order to reduce gossypol's side effects, we applied a controlled drug release system. In this system gossypol is carried on a polymer of polylactic acid which controls drug release and can also be injected into the vas deferens so that the drug can act continuously and directly on spermatogenesis. We used a single dose of gossypol-polylactic acid (0.35 mg/0.1 ml for each vas deferens) which is only 0.2% of the usual antifertility dose. Fertility tests showed that male rats became infertile 4 weeks after intravasal injection of gossypol-polylactic acid. Gross and microscopic findings in the heart, liver, kidneys and lungs revealed no evidence of pathologic change. Treated rats gained body weight as fast as did the controls. The majority of spermatozoa showed breakage of the axial fibers, indicating that gossypol had diffused into the testes. The fertility of the treated rats recovered four to eight months after treatment. Gossypol-polylactic acid injected into the vas deferens exhibited a low degree of toxic side effects and a high antifertility activity, and is therefore an important approach to decreasing the side effects while enhancing the antifertility specificity of gossypol.

Animals↗
PubMed1993

[Changes in circulating lymphocyte triiodothyronine receptors in diabetes mellitus].

Using radioligand binding assay of receptors, we studied the changes of T3 receptors in circulating lymphocytes in 20 normal persons and 43 diabetic patients with or without low T3. The mean value of serum T3 and FT3 was significantly decreased in all diabetic patients compared with that of normal controls. The concentration of serum T3 was negatively correlated with fasting blood glucose level. The serum rT3 was clearly increased in patients with low T3. The serum T4, FT4, FT4 I and TSH were normal in all patients The maximal binding capacity (MBC) of circulating lymphocyte T3 receptors which was negatively correlated with the serum T3 concentrations was obviously elevated in patients with diabetes mellitus. It was still higher in patients with low T3 than in patients with normal T3, whereas the affinity of receptor was not changed. In conclusion, the increment of T3 receptor binding capacity reflects the compensatory mechanisms, which are probably evoked by the T3 deficiency in order to maintain cellular homeostasis.

Adult↗
PubMed1992

Brain proteins in plants: an Arabidopsis homolog to neurotransmitter pathway activators is part of a DNA binding complex.

The G box is a well-characterized cis-acting DNA regulatory element found in the promoters of several seemingly unrelated plant genes, including the alcohol dehydrogenase (Adh) gene of Arabidopsis thaliana. Using a monoclonal antibody screening approach coupled with electrophoretic mobility shift assays, we have isolated a cDNA clone encoding a protein that is part of the in vitro protein/G box complex. The derived amino acid sequence is homologous to a class of proteins in mammalian brains described as protein kinase C inhibitors and as activators of tyrosine and tryptophan hydroxylases, the rate-limiting enzymes in the pathways leading to the catecholamines and serotonin. The fact that a homologous member of this regulatory protein family is found in plants and is associated with binding to transcriptional regulatory elements suggests a much wider role for these proteins.

Amino Acid Sequence↗
PubMed1992

Crystallization and preliminary crystallographic studies of the FAD domain of corn NADH: nitrate reductase.

Crystals of the flavin domain of corn nitrate reductase expressed in Escherichia coli have been obtained at room temperature, using sodium citrate as precipitant. The crystals diffract to at least 2.5 A resolution at a synchrotron radiation source. Precession photographs show that they belong to the rhombohedral space group R3 with unit cell dimensions a = b = 145.4 A, c = 47.5 A, alpha = beta = 90 degrees and gamma = 120 degrees. There is one subunit per asymmetric unit which gives a packing density of 3.2 A3/Da, indicating a high solvent content in these crystals.

Crystallization↗
PubMed1992

Site-specific oligodeoxynucleotide binding to maize Adh1 gene promoter represses Adh1-GUS gene expression in vivo.

There is a 36 bp tract of extreme homopurine/homopyrimidine (PuPy) asymmetry in the maize Adh1 gene promoter (from -44 to -79) that is S1-hypersensitive in plasmids under supercoil tension. Oligodeoxynucleotides corresponding to the PuPy tract were designed to examine the secondary structure of the region and address the possible role of the tract in gene regulation. On the basis of oligodeoxynucleotide band-shift and DNase I footprinting analyses, it was concluded that the homopyrimidine oligodeoxynucleotide can form a triple helix with the duplex PuPy tract in vitro. Transient assays in protoplasts, suspension cells, and seedling roots show that the homopyrimidine oligodeoxynucleotide is also capable of repressing Adh1-GUS gene expression during co-transformation, presumably by the formation of a triple helix with the PuPy tract in vivo. The complementary homopurine oligodeoxynucleotide would not form a triple helix in vitro, nor would it repress Adh1-GUS in vivo. We propose that triple helix formation is a potential regulatory phenomenon in vivo, and that an intraregion triple helix could occur within the Adh1 promoter via the formation of H-DNA.

Alcohol Dehydrogenase↗
PubMed1992

Characterization of rat liver nuclear proteins which recognize the cAMP responsive element.

1. The data herein reveal the existence of cAMP-responsive element (CRE)-binding factors (CRF) in the nuclear extracts from cAMP-treated rat liver. 2. DNAase I and DMS footprinting analysis showed that the CRFs protected the CRE (-77 to -92) in the phosphoenolpyruvate carboxykinase (PEPCK) promoter and the TGACGTCA motif in a consensus oligodeoxynucleotide based on the sequence of the CRE's of 6 cAMP-regulated genes (C32mer). 3. Competition assays indicate that the CRF(s) is a CGTCA-specific, ATF/CREB-like factor(s). 4. Southwestern (SW) blot analysis detected 2 apparent CRFs which have molecular weights of about 30 and 32 kDa, respectively. 5. Based on the comparison of the size and binding specificity of the CRFs with the CREBs reported to date, the CRFs appear to be novel CRE-binding nuclear factors.

Animals↗
PubMed1992

A maize protein associated with the G-box binding complex has homology to brain regulatory proteins.

The G-box element is a moderately conserved component of the promoter of many inducible genes, including the alcohol dehydrogenase genes of Arabidopsis and maize. We used monoclonal antibodies generated against partially purified G-box binding factor (GBF) activity to characterize maize proteins that are part of the DNA binding complex. Antibodies interacted with partially purified maize GBF complexes to produce a slower migrating complex in the gel retardation assay. Immunoprecipitation experiments suggested that the protein recognized by the antibody is not a DNA binding protein in and of itself, but rather is associated with the DNA binding complex. These monoclonal antibodies were used to isolate cDNA clones encoding a protein that we have designated GF14. Maize GF14 contains a region resembling a leucine zipper and acidic carboxy and amino termini, of which the latter can form an amphipathic alpha-helix similar to known transcriptional activators such as VP16 and GAL4. Protein gel blot analysis of cell culture extract showed that a single, major protein of approximately 30 kD is recognized by anti-GF14; the protein is also present predominantly in the kernel and root. The deduced amino acid sequence of maize GF14 is more than 80% identical to Arabidopsis GF14 and Oenothera PHP-O, and is more than 60% identical to a class of mammalian brain proteins described as both protein kinase C inhibitors and activators of tyrosine and tryptophan hydroxylases. GF14 is found in a variety of monocotyledons and dicotyledons, gymnosperms, and yeast. This suggests a deep evolutionary conservation of a potential regulatory protein associated with a core sequence found in the promoter region of many genes.

14-3-3 Proteins↗
PubMed1991

Indomethacin as a postoperative analgesic for total hip arthroplasty.

This prospective, randomized, double-blind trial evaluated the efficacy of rectal indomethacin as an adjunct to morphine for controlling postoperative pain. Fifty healthy patients undergoing elective hip arthroplasty were investigated. Group 1 (n = 25) received placebo suppositories, Group 2(n = 25) received indomethacin suppositories, 100 mg q8hr for five doses, starting at the end of the procedure. Both groups received morphine via a PCA pump, which recorded the amount of morphine delivered each hour. After a standardized general anaesthetic, PCA was begun in the recovery room. Pain was measured with a standard 100 mm VAS at 2, 6, 20, 28, 42 hr after surgery and the morphine consumption recorded. Over the 42-hr study period, patients in Group 2 required less morphine than those in Group 1 (34.8 +/- 21.8 mg vs 89.6 +/- 43.7, P less than 0.01). Pain scores were lower in Group 2 at 20, 28, 42 hr postoperatively. The incidence of side-effects did not differ between groups and no patient had excessive postoperative bleeding. The combination of indomethacin and morphine provided superior pain relief to morphine alone even though the control group had liberal access to morphine. This synergistic effect would make indomethacin a useful adjunct to intramuscular or epidural narcotics.

Administration, Rectal↗
PubMed1991

[The absorption of Fe, Zn, Cu in siwu, sijunzi, and Liuwei dihuang decoction by small intestine in rats].

In this study the absorption of Fe, Zn and Cu in decoctions of siwu decoction, sijunzi decoction and liuwei dihuang decoction by the small intestine in anesthetized rats was observed. The experimental results showed that the absorption of Cu and Fe from siwu decoction was much higher than that from other decoctions which might be related to the hematopoietic function of Cu and Fe rich in the decoction.

Animals↗
PubMed1990

[Contents and solubilties of several elements in siwu decoction and liuwei dihuang decoction].

In this paper the contents and solubilities of copper, zinc, iron, calcium and magnesium in Siwu decoction and Liuwei Dihuang Decoction were studied. The results showed that there was a big difference in the solubilities of the elements among the crude drugs, and the increased solubilities of some elements in the simple recipe and compound prescription were an important factor for the effect of these decoctions. The increased solubilities of some elements might be one of the advantages for the compound prescription.

Copper↗
PubMed1990

In vitro influence of enkephalins on the proliferative response of mouse and rat splenic lymphocytes to phytohemagglutinin.

The opioid peptides leucine enkephalin (LENK) and methionine enkephalin (MENK) were investigated for their effect on the proliferative response of activated BALB/C mouse and Sprague-Dawley rat splenic lymphocytes in vitro. The results showed that LENK and MENK (1 x 10(-3) mg/ml to 1 x 10(-13) mg/ml) significantly suppressed the proliferative response of mouse lymphocytes to phytohemagglutinin (PHA) and enhanced the proliferation of rat lymphocytes at peptide concentrations similar to those effective in mice. It is proposed that endogenous ENKs play a neuroendocrine role between the central nervous system and the immune system.

Animals↗
PubMed1990

[Detection of the anti-cancer biological effect of naphthoquinone pigment-LIII].

Naphthoquinone pigment-LIII, an extract from Arnebia euchroma, could apparently inhibit the proliferation of stomach cancer cell line and esophagus cancer cell line. At the effective concentration of 5 micrograms/ml, the mitotic index and growth curve declined without showing any damage to human normal cells. At 5-10 micrograms/ml, the colony efficiency of cancer cells became significantly low. The anti-cancer effect of Naphthoquinone pigment-LIII might be related to its role of influencing the amount of RNA and ultrastructure of cancer cells which was discussed in this paper.

Antineoplastic Agents, Phytogenic↗