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Biomedical subjects

W J Xia

Publications and source records attributed to W J Xia.

17 recordsLinked to original sources
PubMed2001

[Investigation on quality difference between Cordyceps of Sichuan and those of Xizang].

OBJECT: The quality difference among the Cordyceps specimens which grew in various micro-ecological environment and between those from Kangding of sichuan and those from Naqu of Xizang was compared and analyzed. METHOD: The specimens from various spots in field were collected, their appearance properties were analyzed, content of adenosine was assayed, and their difference on ecological hereditary variation was discussed. RESULT: The biggest values of quality difference among the Cordyceps specimens from various micro-ecological environment can surpass that between specimen of Sichuan and specimen of Xizang. CONCLUSION: The effect of the micro-ecological environment on the quality of the Cordyceps might exceed that of extensive climates and region differences at times.

Adenosine↗
PubMed2001

[Pattern recognition of stereoscopic features of the leaves epidermis of medicinal Curcuma plants in China by image analysis].

OBJECTIVE: To provide new ways for classifying and identifying medicinal curcuma plants. METHOD: Based on classical taxonomy, the microscopic features of the epidermis of Curcuma plants in China were scored quantitatively by stereology and image analysis. RESULT: It showed that there were a lot of differences in density, size and shape of the epidermic cells among the medicinal Curcuma plants in China; that the average perimeter of the upper epidermic cells, average sectional area of the lower epidermis, stoma density and trichoma distribution of the upper and lower epidermis, etc. could be considered to be the main evidences for the microscopic identification of leaves of Curcuma. The 21 materials which belong to 11 species of Curcuma in China were systematized into 6 species, 1 species complex, 2 cultivated varieties. CONCLUSION: It can be concluded that stereology, and image analysis are advanced and feasible in pharmacognosy and taxonomy especially in the authentication of the relative and easily confused species.

Curcuma↗
PubMed2000

Effects of pH and dose on nasal absorption of scopolamine hydrobromide in human subjects.

PURPOSE: The present study was conducted to evaluate the effects of formulation pH and dose on nasal absorption of scopolamine hydrobromide, the single most effective drug available for the prevention of nausea and vomiting induced by motion sickness. METHODS: Human subjects received scopolamine nasally at a dose of 0.2 mg/0.05 mL or 0.4 mg/0.10 mL, blood samples were collected at different time points, and plasma scopolamine concentrations were determined by LC-MS/MS. RESULTS: Following administration of a 0.2 mg dose, the average Cmax values were found to be 262+/-118, 419+/-161, and 488+/-331 pg/ mL for pH 4.0, 7.0, and 9.0 formulations, respectively. At the 0.4 mg dose the average Cmax values were found to be 503+/-199, 933+/-449, and 1,308+/-473 pg/mL for pH 4.0, 7.0, and 9.0 formulations, respectively. At a 0.2 mg dose, the AUC values were found to be 23,208+/-6,824, 29,145+/-9,225, and 25,721+/-5,294 pg x min/mL for formulation pH 4.0, 7.0, and 9.0, respectively. At a 0.4 mg dose, the average AUC value was found to be high for pH 9.0 formulation (70,740+/-29,381 pg x min/mL) as compared to those of pH 4.0 (59,573+/-13,700 pg x min/mL) and pH 7.0 (55,298+/-17,305 pg x min/mL) formulations. Both the Cmax and AUC values were almost doubled with doubling the dose. On the other hand, the average Tmax, values decreased linearly with a decrease in formulation pH at both doses. For example, at a 0.4 mg dose, the average Tmax values were 26.7+/-5.8, 15.0+/-10.0, and 8.8+/-2.5 minutes at formulation pH 4.0, 7.0, and 9.0, respectively. CONCLUSIONS: Nasal absorption of scopolamine hydrobromide in human subjects increased substantially with increases in formulation pH and dose.

Absorption↗
PubMed2000

Mechanistic studies on surfactant-induced membrane permeability enhancement.

PURPOSE: To gain some mechanistic understanding of surfactant-induced membrane permeabilization and identify a surfactant physical property that can be used as a predictor for intestinal membrane permeability enhancement. METHODS: The maximum surface pressures (piCMC) of series of anionic and non-ionic surfactants as indicators of surface activity were determined using a bubble surface tensiometer, and related to in vivo intestinal membrane permeability and acute damage data of the same surfactants from a previous work. Phospholipid bilayers with constant surface pressures and monolayers with different surface pressures were used as model membranes to systematically study membrane permeability enhancement and membrane penetration of surfactants at different concentrations. RESULTS: Surfactants that did not permeabilize or acutely damage the intestinal wall generally exhibited a piCMC < 25 dyne/cm. Permeability enhancement and acute damage increased as piCMC increased beyond 25 dyne/cm. This critical threshold value at around 25 dynes/cm was also observed with in vitro experiments using phospholipid vesicles and monolayers. Data support the hypothesis that the threshold phenomenon originates from the interfacial tension at the membrane/water interface, which controls the surface adsorption process of surfactant molecules onto the membrane. CONCLUSIONS: For a surfactant to permeabilize and acutely damage the intestinal wall, it must exhibit a surface pressure of greater than 25 dynes/cm. This threshold value is related to an intrinsic property, surface pressure, of the phospholipid membranes. Since the surfactant surface pressure is a property of the surfactant monomer, partition of the surfactant monomer, not the micelle, into the membrane is an obligate step in membrane permeabilization. Above the surfactant critical micelle concentration, CMC, micelles may act as a depot to continuously replace aqueous surfactant monomers taken up by the membrane. For some surfactants above CMC, sufficient number of monomers can partition into the membrane to cause solubilization of membrane lipids in surfactant micelles.

Fluoresceins↗
PubMed1997

[A model atlas of the crude drug Radix Ophiopogonis in tri-dimensional computer reconstraction from their serial transections].

In this paper, the tri-dimensional computer reconstruction and animated display from the serial transections of the crude drugs Radix Ophiopogonis and Radix Liriopes have been achieved. Accordingly, some tri-dimensional image techniques and information for the computer aided teaching and identification of pharmacognosy have been offered.

Imaging, Three-Dimensional↗
PubMed1995

Study on in vivo release of levonorgestrel-containing silicon capsule.

The in vivo release rate of levonorgestrel-containing silicon capsule (in vitro releasing rate: 6 micrograms/d) placed in rabbits was determined. The results showed that the average release per year was 8.32 micrograms with r being 0.96000. The release pattern of the levonorgestrel-containing silicon capsule system was proved to be zero-order release. Our study provided some experimental data for clinical use of the system for birth control.

Animals↗
PubMed1991

Cytokine administration alters the distribution of activated lymphocytes to the lung.

The effects of intraperitoneal injections of recombinant interleukin-1 alpha (IL-1; 250,000 U/day), interleukin-2 (IL-2; 50,000 units/day), interferon-gamma (IFN-gamma; 50,000 U/day) and tumor necrosis factor-alpha (TNF; 100,000 U/day), on the biodistribution of concanavalin A (Con A)-activated, indium-111-labeled lymphocytes were evaluated in BALB/c mice. Syngeneic spleen cells were activated for 48 h in medium with Con A (5 micrograms/ml) and maintained in culture for 72 h in IL-2 (1,000 U/ml). Groups of 12 mice were treated for 4 days with either one of the cytokines or saline. On day 4, mice received 10(7) lymphocytes (3-5 mu Ci) intravenously. Mice were sacrificed at 4 and 24 h following injection and the percent of administered dose per organ was determined. TNF and IL-1 produced a significant increase in lung uptake of radiolabeled lymphocytes at 4 and 24 h, whereas IL-2 and IFN-gamma decreased uptake at both time points. IL-1 increased uptake by liver at 4 and 24 h while IL-2 increased uptake only at 4 h. We conclude that the distribution of activated lymphocytes following adoptive transfer is altered by cytokines. This finding may have important implications for cell delivery during adoptive immunotherapy.

Animals↗
PubMed1991

Accessory cells of the lung. I. Interferon-gamma increases Ia+ dendritic cells in the lung without augmenting their accessory activities.

Dendritic cells are specifically adapted to provide accessory signals for the growth of T lymphocytes. Ia+ dendritic cells are present within the normal lung; however, little is known concerning their regulation in vivo. Interferon-gamma (IFN-gamma) is a proinflammatory lymphokine that augments the expression of Ia antigens and promotes the accessory activities of a variety of cells. In order to determine whether IFN-gamma regulates pulmonary dendritic cells in vivo, Lewis rats were injected intraperitoneally with recombinant murine IFN-gamma (2 x 10(5) U/rat/day) or with buffered saline for 5 consecutive days. Following sacrifice, the lungs were excised, and the distribution and number of Ia (OX-6)+ cells was determined in situ. Dendritic cells were localized in the mucosal lining of the tracheobronchial tree, in pulmonary capillaries, as well as in the alveolar septal interstitium and subjacent to the pleural surfaces. IFN-gamma yielded a specific increase in Ia+ dendritic cells in alveolar septa and in pulmonary airways. Purified Ia+ dendritic cells from enzymatic digests of lung were excellent accessory cells for the proliferative responses of both antigen-primed and naive T lymphocytes. IFN-gamma did not, however, further augment the expression of Ia antigens or the accessory activities of pulmonary dendritic cells. These results suggest that IFN-gamma may promote pulmonary T cell-mediated inflammatory responses in vivo by increasing the number of Ia+ dendritic accessory cells in the lung.

Animals↗
PubMed1991

Accessory cells of the lung. II. Ia+ pulmonary dendritic cells display cell surface antigen heterogeneity.

In earlier studies, we had determined that class II (Ia) major histocompatibility complex (MHC) antigen expression in the normal rat lung was limited to dendritic cells and type II alveolar cells. In order to characterize the Ia+ pulmonary dendritic cells of the lung parenchyma, Lewis rat lungs were dissected free of their major airways, enzymatically digested, and serially subjected to density centrifugation on bovine serum albumin, overnight adherence, and immunopanning with a murine anti-rat monoclonal antibody (anti-OX-6) that reacts specifically with class II (Ia) MHC antigens. The purified Ia+ pulmonary cells displayed the morphologic and functional features of dendritic accessory cells, including extended cell processes, absence of nonspecific esterase staining, minimal phagocytosis of latex beads, rapid clustering with T lymphocytes, and co-stimulation of T-cell mitogen responses. Detailed immunophenotyping by cytofluorimetry and immunohistology showed that the purified dendritic cells were Ia (OX-6)+, CD45R (OX-1)+, CD45Rb (OX-22)-, ICAM-1+, and OX-43-. As many as 50% of the cells bound heat-aggregated IgG, while a smaller percentage expressed the CD43 sialophorin antigens (W3/13) expressed by a variety of blood-derived cells, and/or the OX-41 and RMA macrophage antigens. We conclude that Ia+ dendritic cells of lung are heterogeneous with respect to their expression of surface membrane differentiation antigens and may prove to be functionally distinct with respect to their accessory activities.

Animals↗
PubMed1991

[Pharmacokinetics and metabolism of artesunate in cows].

The pharmacokinetics of artesunate (AS) was studied in 3 cows, single dose of AS (5 mg/kg) were administered intravenously and the drug concentrations were determined by means of a TLC method developed in our laboratory. The plasma drug concentration-time course of AS, after the treatment with a pharmacokinetic microcomputer program MCPKP edited by Wen-Jiang Xia, was found to be best fitted to a two compartment open model and its pharmacokinetic parameters were as follows, T1/2 alpha = 2.43 min, T1/2 beta = 31.45 min, V1 = 0.124 L/kg, VB = 0.937 L/kg, ClB = 0.0215 L/kg. min, AUC = 236 mg/L.min. Dihydroartemisinine (DHA), the main active metabolite of AS in the bodies, was detected simultaneously. Peak plasma concentration of 3.5 micrograms/ml of DHA was reached at about 3 minutes after dosing and the AUC was 82 mg/L.min.

Animals↗
PubMed1990

Anti-RMA: a murine monoclonal antibody that activates rat macrophages. I. Distribution and characterization of the RMA antigen.

Activated macrophages participate in inflammation by eliminating foreign cells, promoting wound healing, and modulating the immune response. A murine monoclonal antibody, designated anti-rat macrophage activator (RMA), was raised against alveolar macrophages (AM) activated with interferon-gamma (IFN-gamma) and phorbol myristate acetate (PMA). The RMA antigen is expressed by resident macrophages but not by other cells. Binding to AM by anti-RMA is not competitively inhibited by the murine monoclonal antibodies MRC OX-41, OX-42, and OX-43. Surface membrane expression of RMA antigens is upregulated by lipopolysaccharide, PMA, and tumor necrosis factor-alpha but not by IFN-gamma. Stimulation of AM with anti-RMA yields distinct ultrastructural alterations, as well as de novo protein and DNA synthesis. Immunoprecipitation of [35S]methionine metabolically labeled AM yields a 120 kD protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) that is not altered by chemical reduction. We conclude that the RMA antigen is macrophage specific and that binding of anti-RMA to AM promotes functional activities in a subset of these cells.

Animals↗
PubMed1987

Pharmacokinetics and metabolism of metioprim in pigs and goats.

The pharmacokinetics and metabolism of metioprim (MTP) have been studied after intravenous administration of a single dose of 5 mg/kg b.wt. to pigs (n = 4) and 10 mg/kg b.wt. to goats (n = 5). Kinetic parameters were calculated using a two-compartment open model. The elimination half-life was much shorter in goats (23 +/- 4 min.) than in pigs (169 +/- 17 min.). The apparent volume of distribution exceeded 1.0 1/kg b.wt. in both species indicating accumulation in tissues. Pigs excreted the major part of the dose (86 +/- 9%) in urine and only a small part (9 +/- 3%) in faeces, while the goats excreted almost equal amounts in urine (55 +/- 5%) and faeces (38 +/- 4%). Metabolism played the major role in elimination of MTP. Of the 80% of the dose excreted in urine within 24 hrs in pigs unchanged MTP made up 8%, metioprim sulfoxide 64% and O-desmethyl-MTP 8%. Metioprim sulfoxide was also the major metabolite in goats, but in this species another demethylated metabolite--metioprim sulfonic acid--was formed. Goats excreted 49 +/- 7% of the dose in urine within 24 hrs of which unchanged MTP made up less than 1%, while metioprim sulfoxide accounted for about 35% and metioprim sulfonic acid for approximately 14%. Metabolites isolated from urine were identified by NMR-spectroscopy combined with EI, FAB or 252Cf plasma desorption mass spectrometry.

Animals↗
PubMed1983

Comparison of pharmacokinetic parameters for two oxytetracycline preparations in pigs.

Pharmacokinetics of oxytetracycline (OTC) were studied in 10 pigs after administration of 20 mg/kg body weight of either a conventional (OTC-C) or a long-acting (OTC-LA) preparation. After intravenous administration of OTC-C the elimination half-life for OTC was 3.75 h, with approximately 75% of the dose being excreted in the urine in 1 week. Intramuscular (i.m.) injection of OTC-C resulted in plasma peak values after 4 h, while OTC-LA after i.m. administration produced the highest plasma levels within 1 h, although these were lower than with OTC-C. For both preparations the bioavailability after i.m. administration was 95-100% and about 70% of the dose was excreted in the urine during the first week. With OTC-C given i.m., plasma concentrations above 0.5 micrograms/ml were maintained for 28 h and with OTC-LA for 35 h indicating a weak retard effect of the latter. Pronounced tissue damage at the injection site was seen 1 and 2 weeks after the administration of OTC-LA, while OTC-C produced very little irritation. OTC could be found at the injection site for 2 weeks, the concentrations being higher for OTC-LA than for OTC-C.

Absorption↗