Biomedical subjects

X Sun

Publications and source records attributed to X Sun.

600 records · Page 34Linked to original sources

PubMedDate not supplied

[Molecular cloning and characterization of a novel WRKY gene from Brassica chinensis].

A new WRKY gene was cloned from Brassica chinensis by rapid amplification of cDNA ends (RACE). The full-length cDNA of BcWRKY was 1175 bp long and contained a 924 bp open reading frame (ORF) encoding a putative W-box-binding protein of 308 amino acids. The predicted BcWRKY protein was found to have a potential bipartite nuclear localization sequence (NLS-BP) in its N-terminal region followed by a WRKY DNA-binding domain. Bioinformatic analysis revealed that BcWRKY resembled other WRKY domain-containing proteins from Arabidopsis (AtWRKY18), tobacco (WIZZ), parsley (PcWRKY4) and wild oat (ABF2). Expression of the BcWRKY gene could be induced by salicylic acid (SA), and influenced by Pseudomonas syringae pv. tomato strain DC3000 infection and wounding treatment. Our study implies that BcWRKY might have similar functions possessed by other WRKY genes such as inducing the expression of some defense-related genes and increasing plant's disease resistance ability.

Amino Acid Sequence↗

PubMedDate not supplied

Pseudo-prolines (psi Pro) for accessing "inaccessible" peptides.

Pseudo-prolines (psi Pro) are introduced as a temporary protection technique for serine, threonine and cysteine side chains in standard Fmoc/tBu solid-phase peptide synthesis (SPPS). The incorporation of these novel building blocks into a growing peptide chain proceeds by means of the coupling of preformed, suitably protected psi Pro dipeptides. For the example of representative model peptides used in protein de novo design, the potential of psi Pro to solubilize otherwise sparingly or completely insoluble peptides is demonstrated. Because of their intrinsic propensity for preventing peptide aggregation and beta-sheet formation, pseudo-prolines offer new possibilities for accessing large peptides by convergent strategies and chemoselective ligation techniques.

Amino Acid Sequence↗

PubMedDate not supplied

The use of analgesics and sedatives in critically ill patients: physicians' orders versus medications administered.

OBJECTIVE: To examine the difference between the prescribed and actually administered dose of analgesic and sedative drugs in critically ill patients. DESIGN: Prospective survey. SETTING: University hospital surgical intensive care unit. SUBJECTS: One hundred fifty consecutive adult patients admitted to a surgical intensive care unit over a 3-month period. METHODS: Data were gathered on a daily basis. The sedation and analgesia given were compared with the daily physician orders. RESULTS: Narcotics and benzodiazepines were most commonly used. On average only 22% to 52% of the mean ordered dose of intravenous and intramuscular morphine was actually administered. Larger doses of morphine were administered to intubated patients than to nonintubated ones. Patients receiving intravenous fentanyl infusions generally were administered more than the ordered dose. The actual and prescribed doses of epidural fentanyl were well matched. Midazolam was the most frequently prescribed benzodiazepine. Like morphine, the amount administered was below the maximum ordered by the physicians. CONCLUSIONS: Physicians tended to write fairly nonspecific orders that were used by the nursing staff as very broad guidelines. A need exists to educate physicians as to what patients actually receive for sedation and analgesia and at the same time improve the dialogue between nurses and physicians as to what patients actually require.

Adolescent↗

PubMedDate not supplied

Anticancer efficacy of methioninase in vivo.

Therapeutics that are selective for cancer would have a high potential for efficacy. We have previously shown that the metabolic defect of enhanced methionine dependence is a broad cancer-selective target. Methionine depletion can completely arrest the growth of methionine-dependent tumor cells in vivo with a reversible pre-mitosis cell-cycle block. Dietary methionine depletion can partially arrest the growth of methionine-dependent rodent tumors in vivo. This report demonstrates that methioninase isolated from Pseudomonas putida can arrest rodent and human tumors in nude mice with no apparent toxic side effects. Methioninase injected i.p. arrested the growth of the Yoshida sarcoma in nude mice and greatly slowed the growth of the H460 human non-small-cell-lung carcinoma in nude mice. The effectiveness of methioninase against H460 was in contrast to 5-fluorouracil and vincristine, which were inactive against this tumor. The activity of the administered methioninase did not cause weight loss for up to 10 days treatment at 40-120 units/day indicating the possibility of low toxicity. In contrast, vincristine was highly toxic despite its ineffectiveness. Methioninase also induced a tumor-specific late cell-cycle block. The tumor-selective late cell-cycle block induced by methioninase should be able to be exploited to enhance the tumor specificity of antimitotic drugs and other agents in future experiments. Thus methioninase is a highly effective antitumor agent with a new tumor-selective mode of action with minimal toxicity, demonstrating potential clinical effectiveness against solid tumors.

Animals↗

PubMedDate not supplied

Polyamides (nylon) composition analysis by capillary zone electrophoresis.

A new and simple method of analysis for polyamide composition is described. Polymer samples were decomposed to their corresponding monomers by hydrobromic acid (HBr) and the decomposed products were analyzed by capillary zone electrophoresis (CZE). Amines from polyamides were derivatized with fluorescamine and detected by UV at 280 nm. Aliphatic acids were detected by direct UV at 205 nm. Sample treatment is much simpler than published methods, and electropherograms show a good separation of decomposed products under the proper conditions.

Electrophoresis, Capillary↗

PubMedDate not supplied

Recombinant methioninase infusion reduces the biochemical endpoint of serum methionine with minimal toxicity in high-stage cancer patients.

The tumor-specific increased minimal requirement for methionine has been shown to be a highly promising therapeutic target. To attack this target we have previously cloned the methioninase gene from Pseudomonas putida and produced recombinant methioninase (rMETase). A pilot Phase I clinical trial has been carried out to determine rMETase toxicity, rMETase pharmacokinetics, and serum MET-depletion in cancer patients. Patients with advanced breast cancer, lung cancer, renal cancer and lymphoma were given a single rMETase treatment at doses ranging from 5,000 to 20,000 units by i.v. infusion over 6-24 hours. No clinical toxicity was observed in any patient after rMETase treatment. rMETase levels reached 0.1 to 0.4 units per ml of serum in the patients which correspond to therapeutic levels in vitro. The lowest serum methionine levels in rMETase-treated patients were 0.1% of the pre-treatment levels corresponding to approximately 0.1 microM, which also correlates to therapeutic levels in vitro. The results of the rMETase pilot Phase I clinical trial therefore indicate that i.v. infusion of rMETase is safe and effectively depletes its biochemical target of serum methionine suggesting potential efficacy in future clinical trials.

Antimetabolites, Antineoplastic↗