Applications of chromatographic techniques to medicinal plants and Chinese traditional medicines are outlined in this review. Areas involved are quantitation of active principles or index or principal components; quality evaluation of crude drugs; identification, characterization and preparative isolation of new compounds for medical use from plants; analysis of pharmaceutical preparations of plant origin and pharmacokinetic and pharmacological studies of herbal drugs and their preparations.

Drugs, Chinese Herbal↗

PubMedDate not supplied

Production of superoxide anion, lipid peroxidation and DNA damage in the hepatic and brain tissues of rats after subchronic exposure to mixtures of TCDD and its congeners.

In this study the induction of oxidative stress in the hepatic and brain tissues of rats after subchronic exposure to various mixtures of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and two of its congeners, namely 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) and 3,3',4,4',5-pentachlorobiphenyl (PCB 126) was investigated. Four mixtures of TCDD and its congeners, corresponding to 10, 22, 46 and 100 ng of toxic equivalence (TEQ) kg(-1) day(-1), were administered to groups of rats for 13 weeks. The animals were sacrificed at the end of the exposure period and the biomarkers of oxidative stress, including the production of superoxide anion, lipid peroxidation and DNA single-strand breaks (SSBs), were determined in the hepatic and brain tissues. All mixtures caused dose-dependent increases in the production of superoxide anion, lipid peroxidation and DNA SSBs in both tissues, with significantly higher damage in the hepatic compared with the brain tissues. The 22 ng TEQ dose level (TEQ = 22) contains TCDD, PeCDF and PCB 126 at levels that correspond to 7.3, 14.5 and 73.3 ng kg(-1) day(-1), respectively, and it produced effects that correspond to ca. 50% of the maximal production of superoxide anion, lipid peroxidation and DNA SSBs in the hepatic and brain tissues of those animals. Relative to the doses that are required to produce 50% of the maximal production of the biomarkers of oxidative stress by the individual congeners in hepatic and brain tissues of rats, the concentrations of the congeners in TEQ = 22 did result in significant interactivity, probably in the form of additive effects in the hepatic but not in brain tissues.

Animals↗

PubMedDate not supplied

Cloning by functional complementation in Trypanosoma brucei.

A procyclic Trypanosoma brucei double-knockout mutant lacking the ornithine decarboxylase (ODC) gene was transfected with a T. brucei genomic library in the expression vector pTSO-HYG4, which utilizes the PARP promoter and replicates extrachromosomally by virtue of a minicircle origin of replication. Transfectants which grew in the absence of exogenous putrescine, the product of the ODC-catalyzed reaction, were obtained at a frequency of 1.6 x 10(-7) and shown to restore ODC protein synthesis and enzymatic activity. Restriction enzyme patterns and Southern blot analysis of plasmids recovered from these cells and propagated in E. coli showed that the inserts contained a single copy of the T. brucei ODC gene. These results demonstrate for the first time the feasibility of identifying novel T. brucei genes by direct complementation of mutant T. brucei cell lines.

Animals↗

PubMedDate not supplied

Met-enkephalin-induced vasoconstriction in the microcirculation of rat striated muscle.

Sprague-Dawley rats were anesthetized with pentobarbital (50 mg/kg) and the arterioles of the cremaster muscle were observed using television microscopy. Methionine (Met)-enkephalin was added to give bath concentrations of 10(-11) to 10(-7) M. Met-enkephalin caused a decrease in the diameter of first-order (127 +/- 7 microns), second-order (57 +/- 7 microns), and third-order (18 +/- 2 microns) arterioles, with the third-order arterioles showing the greatest reactivity. The effects of Met-enkephalin were attenuated by the opiate antagonist, naloxone, by the alpha-adrenergic receptor antagonists, phentolamine and prazosin, and by chemical sympathectomy with 6-hydroxydopamine. These results suggest that Met-enkephalin causes vasoconstriction in the striated muscle microcirculation by stimulating norepinephrine release from local nerve terminals.

Animals↗

PubMedDate not supplied

Hematopoietic differentiation of rhesus monkey embryonic stem cells.

Several lines of embryonic stem cells (ESC) have been established from rhesus monkey blastocysts. We have examined two of these cell lines for their potential for generating hematopoietic progenitors in cell culture, and we identified culture conditions, including supplementation with bone morphogenetic proteins (BMP), that result in hematopoietic differentiation of rhesus ESC with high efficiency. We have also characterized the resulting hematopoietic progenitor cells for their patterns of gene expression, as compared to those of hematopoietic progenitor cells harvested from rhesus monkey bone marrow. Of more than 60 genes examined in this manner, CD34+/CD38- cells derived from embryonic stem cells and those obtained from bone marrow demonstrated very similar patterns of gene expression. However, with integrin alphaL, IL-6 receptor, and flt-3 gene expression was greatly diminished or absent in CD34+/CD38- cells derived from the ESC, whereas the bone marrow-derived progenitors showed substantial expression of all of these genes. When the same type of comparison was done with mouse (D3 and CCE) as well as human (H1) embryonic stem cells, in each case comparing ESC-derived hematopoietic progenitors with those harvested from bone marrow, the only consistent deficiency of gene expression was that of flt-3. In hematopoietic precursors derived from mouse ESC, globin-gene expression has previously been shown to be a useful index of the embryological maturity of the cells, and we also examined globin-gene expression in rhesus monkey ESC-derived hematopoietic precursor cells, using a semiquantitative technique. CD34+/CD38- cells demonstrated expression of the epsilon- and gamma-globin genes, but negligible levels of beta globin, suggesting that these cells were at the developmental stage in which the yolk sac and fetal liver are the primary sites of hematopoiesis.

Animals↗

PubMedDate not supplied

Low-molecular-weight peptides derived from extracellular matrix as chemoattractants for primary endothelial cells.

The development of synthetic and naturally occurring scaffolds for tissue engineering applications has included strategies to promote attachment of specific cell types, control the rate of scaffold degradation, encourage angiogenesis, or otherwise modulate the host response. We have reported that bioscaffolds developed from porcine small intestinal submucosa (SIS) facilitate the constructive remodeling of tissues and recruit marrow-derived cells that persist long after the acute inflammatory stages have resolved. We have not yet determined which cells are recruited, the eventual fate of these cells, or via what mechanisms the events occur. We now have analyzed various molecular weight fractions of acid-hydrolyzed SIS by both functional and morphologic methods and have determined that fraction 4 (5 to 16 kDa) possesses chemoattractant activity for primary murine adult liver, heart, and kidney endothelial cells in vitro. Addition of fraction 4 to Matrigel plugs promoted in vivo vascularization when the plugs were implanted subcutaneously in mice. These results indicate that small-molecular-weight peptides derived from the degradation of porcine SIS are biologically active in the recruitment of murine endothelial cells in vitro and in vivo.

Angiogenesis Inducing Agents↗

PubMedDate not supplied

Breast cancer resistance protein-mediated topotecan resistance in ovarian cancer cells.

Overexpression of breast cancer resistance protein (BCRP) and mitoxantrone (MX) resistance protein can confer resistance to a variety of cytostatic drugs, such as MX, topotecan (TPT), doxorubicin, and daunorubicin. This study investigates the role of BCRP in resistance of ovarian cancer to TPT treatment. We have developed TPT-resistant human ovarian cancer cell line. Intracellular concentration of fluorescent dye rhodamine 123 (Rh123) was measured by flow cytometry. The expression of several membrane transporter proteins including P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), and BCRP were determined by reverse transcription-polymerase chain reaction and Western blotting. The Rh123 concentration in parental cells was approximately three times of those in TPT-resistant cells. In contrast to undetectable level of P-gp messenger RNA (mRNA) and minimal level of MRP1 expression in TPT-resistant cells, overexpression of both the BCRP mRNA and the protein was detected in these cells. Introduction of antisense-phosphorothioate oligonucleotide derived from BCRP mRNA into TPT-resistant cells resulted in a significant increase in the concentration of intracellular Rh123. These results suggested a novel mechanism in which a reduced intracellular drug concentration may be mediated by BCRP gene products in human ovarian cancer cells.

ATP Binding Cassette Transporter, Subfamily G, Mem↗

PubMedDate not supplied

Physician asthma management practices in Canada.

OBJECTIVES: To establish national baseline information on asthma management practices of physicians, to compare the reported practices with the Canadian Consensus recommendations and to identify results potentially useful for interventions that improve physician asthma management practices. DESIGN: National, stratified cross-sectional survey. SETTINGS: The 10 provinces and two territories of Canada, from 1996 to 1997. PARTICIPANTS: Questionnaires were sent to 4489 physicians stratified by province/territory and specialty group (family/general practice, respirology, internal medicine, pediatrics and allergy/immunology); 2605 responses were received. OUTCOME MEASURES: Methods for the diagnosis, treatment, education and follow-up of patients with asthma ('asthma management practices'). RESULTS: Significant variations existed among the five specialty groups in asthma management practices. A low use of objective measures of airflow limitation to assist with diagnosis was found among some respondents (mostly family physicians). Up to 40% of physicians regarded the daily fixed dosing (three or four times a day) of inhaled, short acting beta2-agonist as 'first-line therapy' for moderate to severe asthma. A minority of physicians reported using written action plans for patients or referring them to other health professionals for asthma education. Insufficient time during appointments and a perceived lack of appropriate educational materials were frequently cited as reasons for not providing asthma education. The perceived knowledge of the Canadian Consensus recommendations varied among physicians but was lowest among nonspecialists. CONCLUSIONS: The survey showed variations in certain aspects of the management of asthma by physicians. The findings will help to target specific areas for future physician education programs and other behavioural change strategies.

Asthma↗

PubMedDate not supplied

Detection of plasma alpha-granule membrane protein GMP-140 using radiolabeled monoclonal antibodies in thrombotic diseases.

There is an assumption that platelet activation and endothelium damage play a critical role in the pathogenesis of thrombotic disorders. A radioimmunoassay based on using two monoclonal antibodies (MAbs) to different epitopes of alpha-granule membrane protein (GMP-140) was used to determine whether plasma GMP-140 can be detected in patients suffering from acute myocardial infarction (AMI) or cerebral thrombosis and in patients during cardiopulmonary bypass (CPB). MAb SZ-51 was used as a solid phase, and 125I-labeled MAb S12 was used as a fluid phase. The assay is so sensitive that it can detect as little as 1 ng/ml of purified GMP-140. The intra- and interassay coefficients of variation were 4.2% (n = 5) and 7.1% (n = 8), respectively. The concentration of plasma GMP-140 was found to be 10.0 +/- 4.5 ng/ml (mean +/- SD, n = 20) in normal subjects. Ten patients undergoing CPB demonstrated a transient increase in the concentration of plasma GMP-140, especially at 2 h after CPB, and the plasma GMP-140 level was inversely correlated with the decreased platelet counts during bypass (r = -0.81, p < 0.01). It was found that the concentration of plasma GMP-140 increased significantly after AMI. Plasma GMP-140 reached the peak within 3 days and changed with the process of AMI (n = 16) patients. The concentration of plasma GMP-140 increased significantly in patients with cerebral thrombosis in the acute phase but not after relief.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗

PubMedDate not supplied

Biosynthesis of docosahexaenoate-containing glycerolipid molecular species in the retina.

Vertebrate retinas are highly enriched in long-chain polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (22:6n-3, DHA). In the present study, we investigated the role of de novo synthesis in the enrichment of 22:6n-3 in characteristic molecular species of retinal glycerolipids. Following the incubation of fresh dark-adapted retinas with [2-(3)H]-glycerol, individual glycerolipids were isolated and converted into either diacylglycerol acetates (DGAC) or diacylglycerol benzoates (DGBZ), followed by high-performance liquid chromatography (HPLC) and flow-through radioactivity detection. Total lipids from rat retinas incubated with [3H]-glycerol were analyzed. Unlike what was observed with frog retinas, relative larger of amounts of di-22:6 molecular species were synthesized de novo. In both rat and frog retinas, there was synthesis of glycerolipid molecular species containing two PUFA (one of which was 22:6) in larger amounts than predicted by their steady-state mass levels. These results demonstrate that the unique molecular species of retinal glycerolipids are derived only in part through de novo synthesis, but that molecular rearrangement (remodeling) and differential turnover must also play a role in maintaining the high levels of 22:6 found in rod phohtoreceptor outer segments (ROS) membranes.

Animals↗

PubMedDate not supplied

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part I--General considerations and summary of results.

Recurrent plantar ulceration is a common and serious complication occurring consequent to impairment of the tibial nerve in leprosy patients. In spite of many therapies and long therapeutic course, it is extremely difficult to abolish this complication in many cases because of extensive skin and soft tissue cushion loss due to repeated infection. Since the early 70's we have been using microscopic surgical techniques to reconstruct the ulcerated area using eight types of the flaps. In this series of papers we review our experience (76 patients). Post-operatively, the flaps survived in all cases, the long-term results have proved satisfactory, and recurrent ulceration occurred in only three patients.

Adult↗

PubMedDate not supplied

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part II--First toe web and dorsal foot flaps.

The first toe web flap consists of the skin and subcutaneous tissues of the contiguous sides between the great and second toes. It is based on the first dorsal metatarsal artery or the common plantar digital artery. This flap was used as artery pedicled island graft to reconstruct losses of skin and soft tissue cushion in the ball of the foot in the first and second metatarsal head region in 16 cases. Follow-up examination revealed that ulceration had recurred in one case due to dehiscence of the flap margin 12 months post-operatively. The other 15 patients have done well without recurrence at 48 to 124 months follow-up examination. The dorsal flap of the foot based on the dorsalis pedis artery, the corresponding veins and the deep peroneal nerve was designed in 1974 to resurface skin and soft tissue defects in the sole of the foot. This flap was used in 30 cases of leprosy with excellent results. During follow-up 36 to 120 months after surgery the plantar ulcer had recurred in only one case. All the others have done well. The long-term curative effect has thus proved satisfactory.

Foot Ulcer↗

PubMedDate not supplied

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part III. Use of plantar skin or musculocutaneous flaps and anterior leg flap.

Anatomical studies suggest that five types of plantar flaps namely, the lateral and medial plantar flaps, the Abductor hallucis-, the Flexor digitorum brevis-, and the Abductor digiti minimi-myocutaneous flaps, can be incised from the central section of the sole. The advantages of a plantar flap are recognizable neurovascular bundles of the sole, wide calibre of constantly located blood vessels, identical histological structure of the donor and the recipient sites, hidden donor site and absence of functional deficit. We have used the plantar flaps in seven cases. There has been no recurrence of ulceration in any of them during the follow-up period of 12 to 108 months. An anterior leg flap based on the cutaneous branches of the anterior tibial artery, with firmly anchored vessels, a long pedicle with wide vessels may be used not only as a free flap graft for reconstruction of moderate degree distant defects but also as a retrograde island flap graft for the reconstruction of adjacent tissue defect. We have used the retrograde island flap graft based on the anterior tibial artery in five cases of plantar ulceration with satisfactory results. There was no recurrence of ulceration during the follow-up period of 48 to 72 months.

Foot↗

PubMedDate not supplied

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part IV. Use of medial leg flap and medial knee flap.

The medial leg flap, based on the cutaneous branches of the posterior tibial artery is raised from the middle and lower regions of the medial aspect of the leg. It has a long pedicle, and it can be used as a free flap to reconstruct the distant soft tissue defects and also as an island flap. We have used this retrograde island flap for surfacing ulcerated areas in six leprosy patients. The flap survived in all cases. At 24 to 60 months follow-up examination, ulceration had not recurred in any of them. The medial knee flap consisting of the skin and subcutaneous tissue of the lower part of the medial side of the thigh and the upper part of the leg, is suitable for covering soft tissue cushion defects of the extremities because of the constant vessels, long pedicle, wide diameter, well-recognizable sensory nerves and less subcutaneous fat. We have used the medial knee flap for the resurfacing sizeable raw areas due to ulceration in three leprosy patients. The flap survived in all cases and there was no recurrence of ulceration during the 70-148 months follow-up period.

Foot Ulcer↗