Biomedical subjects
Publications and source records attributed to P Guo.
Qualitative and quantitative analyses of the essential oil steamdistilled from the aerial parts of Ligusticum chuanxiong were made by means of GC-MS and GC. Forty-six components which make up 85.82% of the total oil were identified.
Infectious laryngotracheitis virus (ILTV) is the causative agent of a highly contagious upper respiratory tract infection in chickens. At present, ILTV vaccines are not satisfactory because of development of a latent carrier status in vaccinated birds. Development of recombinant virus vaccines has been hampered by the limited information available on the molecular level and organization of this virus. We isolated 3 assembly intermediates, designated A, B, and C from ILTV-infected cells. Analysis of [3H]thymidine-and [35S]methionine-labeled particles, and electron microscopic studies indicated that particle A was the empty capsid, particle B was the procapsid containing scaffolding protein, and particle C was the DNA-filled capsid. The ILTV procapsids could only be found in the nucleus, which indicated that procapsids could not translocate through the nuclear membrane until they packaged the DNA. The DNA-filled capsids migrated through the nuclear membrane and obtained an envelope from the inner membrane of the nucleus. The enveloped particles then migrated through the lumen of the endoplasmic reticulum into vacuoles in the cytoplasm. Infective virions were isolated from within the infected cells, indicating that budding through the cytoplasmic membrane is not a necessary step in ILTV maturation. Abundant arrays composed of tubules about 45 to 50 nm wide were found in the cytoplasm of chicken embryonic liver cells about 30 to 38 hours after infection. Comparison of the assembly intermediates and the DNA packaging pathway of ILTV with that of bacteriophage pi 29 indicates that similarity exists.(ABSTRACT TRUNCATED AT 250 WORDS)
To avoid dumping after Billroth gastrectomy, we designed pylorus and antroseromuscular-flap preserving subtotal gastrectomy (PAFPG). The mean maximal plasma level of VIP (vasoactive intestinal peptide) in PAFPG after oral hypertonic glucose was close to that in the control. Compared with PAFPG group, the plasma VIP concentrations after hypertonic glucose ingestion in BI and BII group were significantly higher, and the concentration of plasma VIP in dumpers was significantly higher than that in non-dumpers after BI or BII gastrectomy. The results suggest that the amount of VIP release is related to the type of reconstruction after gastrectomy.
This paper deals with 2 species of medicinal roots of Aconitum legendrei and A. geniculatum which are used in Sichuan as Caowu. The morphological and histological characteristics of these two roots are described.
An automated dissolution test system was used for the determination of the dissolution rate of famotidine tablets, and a mean cumulative dissolution rate of 97.40 +/- 0.31% in 15 min was obtained. To each of six healthy volunteers, 40 mg of famotidine tablets were administered orally, then an automated HPLC with switching column system was used to analyze famotidine in plasma. Variation of drug concentration vs time were fitted to curves. By comparison of calculated values with observed ones, the results could be described as one-compartment model in human. According to a statistic moment algorithm, the results of calculation showed that T1/2 = 2.92 h and Frel = 118.8%.
An automated clean up and concentration method by column switching is described for the assay of gliquidone, a hypoglycemic agent, in plasma. The system uses Merck Lichroprep RP2 (25-40 microns) as short precolumn packing material for on--line clean up and concentration. A Shimpack CLC--ODS (5 microns) is used as analytical column. Water is used as the pretreatment mobile phase and a mixture of methanol--isopropanol--0.2 mol/L ammonium acetate solution (61:5:34) is used as the analytical mobile phase. The plasma is diluted with a solution of 0.2 mol/L acetic acid and injected directly on the precolumn. The low speed of 0.2 ml/min of pretreatment mobile phase during transfer of plasma sample on the precolumn can get recovery of 80.7%. The detection is at 310 nm and the detection limit is 30 ng/ml plasma. The procedure is simple and automatic.
Capillary chromatography was applied to studying the contents of gamma-aminobutyric acid (GABA) and glutamic acid (Glu) in brain affected by coriaria lactone. The results showed that there was a significant increase in the content of Glu whereas no significant change in the content of GABA was noted. The precisions for GABA and Glu were 3.3% and 4.98% and the recoveries of them were 80.5% and 85.2%, respectively. Capillary chromatography is a good method for determining the contents of GABA and Glu in brain, which has the characteristics of rapid and high sensitivity.
This paper reports a reversed phase high performance liquid chromatography method to determine berberine hydrochloride in Coptis chinensis Franch and in the traditional Chinese medicine containing Coptis chinensis Franch. The result shows that the mobile phase of 0.4mol/L ammonium nitratemethanol (52:48) can give a satisfactory separation. The extraction of sample with 1% H2SO4 solution using the ultrasonic vibration method is simple and easy to operate.
An automated clean up and concentration method by column switching is described for the assay of mitoxantrone, an antitumour drug in plasma. The system uses a YWG-CN short precolumn for on-line clean up and concentration and a Shimpack CLC-ODS analytical column for separation. Water is used as pretreat mobile phase and 48% methanol in ammonium acetate (0.2 mol/L pH 1.9) is used as analytical mobile phase. The plasma sample is treated with methanol and ultrasonated for 10 min. The supernatant of treated sample is directly injected to precolumn. The recovery of clean up is 85%. The wavelength used for detection is 658 nm and the concentration of detection limit is 6 ng/ml in plasma. The procedure is simple and the method is sensitive.
An automated high performance liquid chromatographic switching system is described for the analysis of famotidine, an H2-receptor antagonist in plasma. The system used YWG-C18 short precolumn for on-line sample clean-up and a Shimpack CLC-ODS analytical column for separation. A solution of 0.2 mol/L acetic acid was used as pretreatment mobile phase and 14% (v/v) methanol in ammonium acetate (0.2 mol/L) was used as analytical mobile phase. The detection was at 267 nm and the detection limit was 12 ng/ml plasma. Plasma sample was diluted with acetic acid (0.2 mol/L) and injected directly on the HPLC system. The procedure of clean-up is simple and automatic. The recovery of clean-up is 84.1%.
We have made an investigation on the botanical origins of 6 species and 2 varieties of the traditional Chinese drug Caowu produced in Sichuan, and found out that the main species available on the market are Aconitum hemsleyanum and A. hemsleyanum var. leucanthum, while A. legendrei comes second. A key for their identification is presented in this paper.
Mitoxantrone (DHAQ) is a new anti-cancer agent. The ion-pair HPLC method to determine mitoxantrone hydrochloride injection was proposed. Mitoxantrone can be separated on Zorbax-ODS column with methanol-water-formic acid (450:50:1.5) containing 3.605g SDS as mobile phase. The pH of mobile phase was adjusted to 2.7. The flow rate was 1.0 ml/min and detection was at wavelength of 254 nm, providing a detection limit of 1ng (r/n, 3:1) of DHAQ. DHAQ was determined by peak area measurement with ametantrone as internal standard. The rectilinear calibration graph in the range of 1-10 micrograms of DHAQ was obtained (r = 0.999 2). The average recovery was 99.62 +/- 2.36% (n = 10), and the results were not interfered by the other ingredients in the injection.
NBT-PABA test was performed in 72 subjects with simultaneous determination of the plasma PABA time-concentration curve. The curve in 25 controls after oral administration of N-benzoyl-L-tyrosyl-P-aminobenzoic acid (NBT-PABA) peaked (3.88 +/- 0.78 micrograms/ml, M +/- SD) at the third hour. In patients with chronic pancreatitis (24) and pancreatic carcinoma (6), the curves were flattened, and peaked at the fifth hour (2.7 +/- 1.4 micrograms/ml, M +/- SD), and fourth hour (3.14 +/- 2.26 micrograms/ml, M +/- SD), respectively. The discrimination between the controls and patients with chronic pancreatitis was most significant in the third-hour plasma PABA concentration (P less than 0.0001). This study shows that determination of the third-hour plasma PABA concentration is better in sensitivity and specificity than the 6-hour urinary excretion of PABA, suggesting that the third-hour plasma PABA concentration after oral administration of NBT-PABA might be a sensitive index of exocrine pancreatic function test.
Theophylline is the drug of choice in the prevention and treatment of asthmatic symptoms. A plasma sample clean up procedure using alumina solid phase to eliminate the interference of plasma impurities and some other drugs and a RP-HPLC method to determine plasma theophylline concentration were developed. The system used a Zorbax-C18 (5 microns) column. The mobile phase consists of a mixture of methanol and sodium acetate (50:50) buffer (pH 3.0). Detection at a wavelength of 254 nm showed no interfering peaks. Caffeine was used as an internal standard. The clean up procedure is simple, rapid and satisfactory. The detection limit of theophylline is 0.2 ng (R/N, 3:1), the minimal detectable concentration of theophylline in plasma is 20 ng/ml. Calibration curve is linear (r = 0.9995) in the concentration range of 4 micrograms/ml to 30/micrograms/ml. Within-day precision and day-to-day precision (CV) were 1.89% and 2.41% respectively. The average recovery of the method is 98.44 +/- 0.89%.
Initiation events in the packaging of bacteriophage phi 29 DNA-gp3 (DNA-gene product 3 complex) were studied in a completely defined in-vitro system that included purified proheads, DNA-gp3 and the DNA packaging protein gp16. In the sequential interactions, gp16 first bound to, and was modified by, the prohead. The prohead-gp16 complex then bound to DNA-gp3, resulting in a second modification of gp16 that permitted binding of ATP. DNA-gp3 aggregates were produced, and the hydrolysis of ATP accompanied DNA-gp3 packaging. Binding and hydrolysis of ATP by gp16 was both prohead- and DNA-gp3-dependent. Interruption of packaging by DNase I addition revealed filled heads but few particles containing partial lengths of DNA, suggesting that following a rate-limiting initiation, the translocation of DNA-gp3 into the prohead was much faster in the defined in-vitro system than in extracts.
The ATPase activity of the DNA packaging protein gp16 (gene product 16) of bacteriophage phi 29 was studied in the completely defined in-vitro assembly system. ATP was hydrolyzed to ADP and Pi in the packaging reaction that included purified proheads, DNA-gp3 and gp16. Approximately one molecule of ATP was used in the packaging of 2 base-pairs of phi 29 DNA, or 9 X 10(3) ATP molecules per virion. The hydrolysis of ATP by gp16 was both prohead and DNA-gp3 dependent. gp16 contained both the "A-type" and the "B-type" ATP-binding consensus sequences (Walker et al., 1982) and the predicted secondary structure for ATP binding. The A-type sequence of gp16 was "basic-hydrophobic region-G-X2-G-X-G-K-S-X7-hydrophobic", and similar sequences were found in the phage DNA packaging proteins gpA of lambda, gp19 of T7 and gp17 of T4. Having both the ATP-binding and potential magnesium-binding domains, all of these proteins probably function as ATPases and may have common prohead-binding capabilities. The phi 29 protein gp3, covalently bound to the DNA, may be analogous in function to proteins gpNul of lambda and gpl of phi 21 that bind the DNA.
The bacteriophage phi 29 DNA-gene product 3 complex (DNA-gp3) has been efficiently packaged into proheads in a completely defined in vitro system. The phi 29 DNA packaging protein gp16, the product of gene 16, was overproduced in Escherichia coli and purified to near homogeneity. The purified gp16 packaged 23% of the DNA-gp3 added to purified proheads in the defined mixture, while gp16 in an extract of phage-infected cells packaged 26% of the DNA-gp3. No host proteins were required in the defined system. ATP-dependent packaging of DNA-gp3 in the defined system was optimal with approximately equal to 100 copies of gp16 per DNA-gp3, an amount similar to the production of gp16 per DNA-gp3 in phi 29-infected cells.
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