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Biomedical subjects

Stephen P Myers

Publications and source records attributed to Stephen P Myers.

18 recordsLinked to original sources
PubMed2006

Essential oil composition of diploid and tetraploid clones of ginger (Zingiber officinale Roscoe) grown in Australia.

Ginger oil, obtained by steam distillation of the rhizome of Zingiber officinale Roscoe, is used in the beverage and fragrance industries. Ginger oil displays considerable compositional diversity, but is typically characterized by a high content of sesquiterpene hydrocarbons, including zingiberene, ar-curcumene, beta-bisabolene, and beta-sesquiphellandrene. Australian ginger oil has a reputation for possessing a particular "lemony" aroma, due to its high content of the isomers neral and geranial, often collectively referred to as citral. Fresh rhizomes of 17 clones of Australian ginger, including commercial cultivars and experimental tetraploid clones, were steam distilled 7 weeks post-harvest, and the resulting oils were analyzed by GC-MS. The essential oils of 16 of the 17 clones, including the tetraploid clones and their parent cultivar, were found to be of substantially similar composition. These oils were characterized by very high citral levels (51-71%) and relatively low levels of the sesquiterpene hydrocarbons typical of ginger oil. The citral levels of most of these oils exceeded those previously reported for ginger oils. The neral-to-geranial ratio was shown to be remarkably constant (0.61 +/- 0.01) across all 17 clones. One clone, the cultivar "Jamaican", yielded oil with a substantially different composition, lower citral content and higher levels of sesquiterpene hydrocarbons. Because this cultivar also contains significantly higher concentrations of pungent gingerols, it possesses unique aroma and flavor characteristics, which should be of commercial interest.

Acyclic Monoterpenes↗
PubMed2006

The continuing use of complementary and alternative medicine in South Australia: costs and beliefs in 2004.

OBJECTIVE: To survey the use, cost, beliefs and quality of life of users of complementary and alternative medicine (CAM). DESIGN: A representative population survey conducted in 2004 with longitudinal comparison to similar 1993 and 2000 surveys. PARTICIPANTS: 3015 South Australian respondents over the age of 15 years (71.7% participation). RESULTS: In 2004, CAMs were used by 52.2% of the population. Greatest use was in women aged 25-34 years, with higher income and education levels. CAM therapists had been visited by 26.5% of the population. In those with children, 29.9% administered CAMs to them and 17.5% of the children had visited CAM therapists. The total extrapolated cost in Australia of CAMs and CAM therapists in 2004 was AUD$1.8 billion, which was a decrease from AUD$2.3 billion in 2000. CAMs were used mostly to maintain general health. The users of CAM had lower quality-of-life scores than non-users. Among CAM users, 49.7% used conventional medicines on the same day and 57.2% did not report the use of CAMs to their doctor. About half of the respondents assumed that CAMs were independently tested by a government agency; of these, 74.8% believed they were tested for quality and safety, 21.8% for what they claimed, and 17.9% for efficacy. CONCLUSIONS: Australians continue to use high levels of CAMs and CAM therapists. The public is often unaware that CAMs are not tested by the Therapeutic Goods Administration for efficacy or safety.

Adolescent↗
PubMed2005

Inhibition of COXs and 5-LOX and activation of PPARs by Australian Clematis species (Ranunculaceae).

The species of Clematis (Ranunculaceae) have been traditionally used for inflammatory conditions by indigenous Australians. We have previously reported that the ethanol extract of Clematis pickeringii inhibited COX-1. In this study, we examined the ethanol extracts and fractions of three Clematis species, Clematis pickeringii, Clematis glycinoides and Clematis microphylla, on cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). We further examined the activating effects on the protein expression of peroxisome proliferator-activated receptor alpha (PPARalpha) and gamma (PPARgamma) in HepG2 cells. The ethanol extracts of three Clematis species inhibited the activities of COX-1, COX-2 and 5-LOX in the different extents. The stem extract of Clematis pickeringii showed the highest inhibitory activities among the three species on COX-1, COX-2 and 5-LOX with the IC(50) values of 73.5, 101.2 and 29.3 microg/mL. One of its fractions also significantly elevated PPARalpha expression by 173, 280 and 435% and PPARgamma expression by 140, 228 and 296% at 4, 8 and 16 microg/mL, respectively.

Animals↗
PubMed2005

Is Lactobacillus rhamnosus GG effective in preventing the onset of antibiotic-associated diarrhoea: a systematic review.

OBJECTIVE: To evaluate the efficacy of Lactobacillus rhamnosus GG in the prevention of antibiotic-associated diarrhoea. DATA SOURCES: A computer-based search of MEDLINE, CINAHL, AMED, the Cochrane Controlled Trials Register and the Cochrane Database of Systematic Reviews was conducted. A hand-search of the bibliographies of relevant papers and previous meta-analyses was undertaken. REVIEW METHODS: Trials were included in the review if they compared the effects of L. rhamnosus GG and placebo and listed diarrhoea as a primary end-point. Studies were excluded if they were not placebo-controlled or utilised other probiotic strains. RESULTS: Six trials were found that met all eligibility requirements. Significant statistical heterogeneity of the trials precluded meta-analysis. Four of the six trials found a significant reduction in the risk of antibiotic-associated diarrhoea with co-administration of Lactobacillus GG. One of the trials found a reduced number of days with antibiotic-induced diarrhoea with Lactobacillus GG administration, whilst the final trial found no benefit of Lactobacillus GG supplementation. CONCLUSION: Additional research is needed to further clarify the effectiveness of Lactobacillus GG in the prevention of antibiotic-associated diarrhoea.

Anti-Bacterial Agents↗
PubMed2005

Gingerol content of diploid and tetraploid clones of ginger (Zingiber officinale Roscoe).

Ginger (Zingiber officinale Roscoe), a monocotyledonous, sterile cultigen, is widely used as a spice, flavoring agent, and herbal medicine. The pungency of fresh ginger is due to a series of homologous phenolic ketones of which [6]-gingerol is the major one. The gingerols are thermally unstable and can be converted to their corresponding shogaols, which are present in dried ginger. Fresh rhizomes of 17 clones of Australian ginger, including commercial cultivars and experimental tetraploid clones, were assayed by HPLC for gingerols and shogaols. [6]-Gingerol was identified as the major pungent phenolic compound in all samples, while [8]- and [10]-gingerol occurred in lower concentrations. One cultivar known as "Jamaican" contained the highest concentrations of all three gingerols and was the most pungent of the clones analyzed. Gingerols were stable in ethanolic solution over a 5-month period when stored at 4 degrees C. Shogaols were not identified in the extracts prepared from fresh rhizomes at ambient temperature, confirming that these compounds are not native constituents of fresh ginger. In contrast to previous findings, this study did not find significant differences in gingerol concentrations between the tetraploid clones and their parent diploid cultivar.

Australia↗
PubMed2004

An adaptogenic role for omega-3 fatty acids in stress; a randomised placebo controlled double blind intervention study (pilot) [ISRCTN22569553].

BACKGROUND: There is evidence for an adaptive role of the omega -3 fatty acid, docosahexaenoic acid (DHA) during stress. Mechanisms of action may involve regulation of stress mediators, such as the catecholamines and proinflammatory cytokines. Prevention of stress-induced aggression and hostility were demonstrated in a series of clinical trials. This study investigates whether perceived stress is ameliorated by DHA in stressed university staff. METHODS: Subjects that scored > or = 17 on the Perceived Stress Scale were randomised into a 6-week pilot intervention study. The diet reactive group was supplemented with 6 g of fish oil containing 1.5 g per day DHA, while the placebo group was supplemented with 6 g a day of olive oil. The groups were compared with each other and a wider cross sectional study population that did not receive either active or placebo intervention. RESULTS: There was a significant reduction in perceived stress in both the fish oil and the placebo group from baseline. There was also a significant between-group difference between the fish oil group and the no-treatment controls in the rate of stress reduction (p < 0.05). However, there was not a significant between-group difference between the fish oil and the placebo group, nor the placebo group and the control group. These results are discussed in the context of several methodological limitations. The significant stress reductions in both the fish oil and the placebo group are considered in view of statistical regression, an effect likely to have been exaggerated by the time course of the study, a large placebo effect and the possibility of an active effect from the placebo. CONCLUSION: There were significant differences (p < 0.05) in the fish oil group compared with no-treatment controls. This effect was not demonstrated in the placebo group. As a pilot study, it was not sufficiently powered to find the difference between the fish oil group and the placebo group significant. Further work needs to be undertaken to conclusively demonstrate these data trends. However, the findings from this research support the literature in finding a protective or 'adaptogenic' role for omega-3 fatty acids in stress.

Clinical Trial↗
PubMed2004

The other side of the coin: safety of complementary and alternative medicine.

Most consumers consider complementary and alternative medicine (CAM) products inherently safe. The growing simultaneous use of CAM products and pharmaceutical drugs by Australian consumers increases the risk of CAM-drug interactions. The Therapeutic Goods Administration (TGA) has a two-tier, risk-based regulatory system for therapeutic goods - CAM products are regulated as low risk products and are assessed for quality and safety; and sponsors of products must hold the evidence for any claim of efficacy made about them. Adverse reactions to CAM products can be classified as intrinsic (innate to the product), or extrinsic (where the risk is not related to the product itself, but results from the failure of good manufacturing practice). Adverse reactions to CAM practices can be classified as risks of commission (which includes removal of medical therapy) and risks of omission (which includes failure to refer when appropriate). While few systematic studies of adverse events with CAM exist, and under-reporting is likely, most CAM products and practices do not appear to present a high risk; their safety needs to be put into the perspective of wider safety issues. A priority for research is to rigorously define the risks associated with both CAM products and practices so that their potential impact on public health can be assessed.

Acupuncture Therapy↗
PubMed2004

Anti-inflammatory activity, cytotoxicity and active compounds of Tinospora smilacina Benth.

Tinospora smilacina Benth. has been used in Australian indigenous medicine for the treatment of headache, rheumatoid arthritis and other inflammatory disorders. As part of an investigation into the anti-inflammatory potential of plants using an ethnopharmacological approach, the present study sought to evaluate the efficacy and safety of Tinospora smilacina. An ethanol extract of this plant was evaluated in vitro for anti-inflammatory activities on cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LO) and phospholipase A(2) (PA(2)). The ethanol extract of Tinospora smilacina showed inhibitory activities on COX-1, COX-2, 5-LO and PA(2) with the IC(50) values of 63.5, 81.2, 92.1 and 30.5 micro g/mL respectively. Cytotoxic effect of the extracts of Tinospora smilacina was investigated in vitro using ATP-based luminescence assay and the results showed no cytotoxic effect on cell lines of skin fibroblasts (1BR3), human Caucasian hepatocyte carcinoma (Hep G2) and human Caucasian promyelocytic leukaemia (HL-60). This paper also describes the results of fractionations and bioassay guided chemical studies, suggesting that the anti-inflammatory activity is due to triterpene-fatty acid esters and free fatty acids.

Animals↗
PubMed2004

A new anti-inflammatory glucoside from Ficus racemosa L.

Bioassay-guided fractionation of the ethanol extract of Ficus racemosa resulted in the identification of a new compound (rel)-4,6-dihydroxy-5-[3-methyl-(E)-propenoic acid-3-yl]-7-beta-glucopyranosyl-[2alpha,3beta-dihydrobenzofuran]-(3,2: b)-[4alpha,5beta-dihydroxy-6alpha-hydroxymethyltetrahydropyran] (racemosic acid). Racemosic acid showed potent inhibitory activity against COX-1 and 5-LOX in vitro with IC50 values of 90 and 18 microM, respectively. Racemosic acid also demonstrated a strong antioxidant activity to scavenge ABTS free radical cations with an IC50 value of 19 microM. In addition, cytotoxic effects of the extracts of F. racemosa were investigated in vitro using the ATP-based luminescence assay and results showed no cytotoxicity on the cell lines skin fibroblasts (1BR3), human Caucasian hepatocyte carcinoma (Hep G2) and human Caucasian promyelocytic leukaemia (HL-60). Bergenin was also isolated from the same active fraction.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

A rapid microtitre plate screening method for in vitro assessment of fibrinolysis: a preliminary report.

A novel and precise assay that facilitates high-throughput screening of fibrinolytic agents was developed based on the automated assessment of the euglobulin clot lysis time in microtitre plates. Euglobulin fractions from fresh plasma samples were assessed over 28 days to determine the inter-assay and intra-assay precision. The intra-assay (coefficient of variation range, 0.7-2.6%) and inter-assay precision (coefficient of variation range, 6.8-12.1%) was found to be well within limits required by the Food and Drug Administration. On day 1 and day 28, the results of the microtitre plate euglobulin clot lysis time method were compared with tissue plasminogen activator activity, plasminogen activator inhibitor activity and results produced on fibrin plates. All comparisons were found to correlate significantly. The validity of this method for assaying fibrinolytic agents was assessed by comparing dose-response curves for streptokinase produced using fibrin plates and this method. The critical influence of ambient temperature on the inter-assay reproducibility of this method was established by testing samples over a range of temperatures between 20 degrees C and 40 degrees C.

Adult↗
PubMed2004

The comprehensive osteoarthritis test: a simple index for measurement of treatment effects in clinical trials.

OBJECTIVE: To assess the measurement properties of a simple index of symptom severity in osteoarthritis (OA) of the hips and knees. METHODS: Both the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the proposed new Comprehensive Osteoarthritis Test (COAT) instrument were completed weekly by 125 subjects in the context of a randomized, 12-week, 3 parallel-arm clinical trial. The reliabilities of the various scales were assessed on a weekly basis by use of Cronbach's alpha coefficients. The validity of the COAT total scale was assessed by correlation with the WOMAC total scale on a weekly basis with correlation coefficients, and in terms of the correlations between subject-level intercepts and slopes over time. The relative responsiveness of the WOMAC and COAT total scales was assessed using a multilevel (longitudinal) multivariate (WOMAC, COAT) linear model. RESULTS: The WOMAC and COAT total scales were highly reliable (mean over weeks: WOMAC alpha = 0.98; COAT alpha = 0.97). The correlations between the WOMAC and COAT scales were very high (mean over weeks = 0.92; subject-level intercepts = 0.91, slopes = 0.88). The COAT total scale was significantly more responsive than the WOMAC total scale in the active treatment (34.8% improvement vs 26.8%; p = 0.002). CONCLUSION: The COAT total scale is simple to administer, reliable, valid, and responsive to treatment effects.

Antirheumatic Agents↗
PubMed2004

The causes of intestinal dysbiosis: a review.

Alterations in the bowel flora and its activities are now believed to be contributing factors to many chronic and degenerative diseases. Irritable bowel syndrome, inflammatory bowel disease, rheumatoid arthritis, and ankylosing spondylitis have all been linked to alterations in the intestinal microflora. The intestinal dysbiosis hypothesis suggests a number of factors associated with modern Western living have a detrimental impact on the microflora of the gastrointestinal tract. Factors such as antibiotics, psychological and physical stress, and certain dietary components have been found to contribute to intestinal dysbiosis. If these causes can be eliminated or at least attenuated then treatments aimed at manipulating the microflora may be more successful

Anti-Bacterial Agents↗
PubMed2003

A cross-cultural study: anti-inflammatory activity of Australian and Chinese plants.

In this study, in vitro inhibitory effects of 33 ethanol extracts obtained from 24 plant species (representing 11 different families) on cyclooxygenase-1 (COX-1) were evaluated. The plant materials selected for this study have been used in aboriginal medicine in Australia and traditional medicine in China for the treatment of various diseases that are considered as inflammation in nature, e.g. asthma, arthritis, rheumatism, fever, edema, infections, snakebite and related inflammatory diseases. All of the selected plants, with one exception, showed inhibitory activity against COX-1, which supports their traditional uses. The most potent COX-1 inhibition were observed from the extracts of Acacia ancistrocarpa leaves (IC(50)=23 microg/ml). Ficus racemosa bark, Clematis pickeringii stem, Acacia adsurgens leaves, Tinospora smilacina stem and Morinda citrifolia fruit powder exhibited inhibition of COX-1 with the IC(50) of 100, 141, 144, 158 and 163 microg/ml, respectively. Aspirin and indomethacin used as the reference COX-1 inhibitors in this study inhibited COX-1 with IC(50) of 241 and 1.2 microg/ml, respectively. The findings of this study may explain at least in part why these plants have been traditionally used for the treatment of inflammatory conditions in Australian aboriginal medicine and traditional Chinese medicine.

Anti-Inflammatory Agents↗
PubMed2003

Anti-inflammatory activity of Chinese medicinal vine plants.

Anti-inflammatory activities of ethanol extracts from nine vine plants used in traditional Chinese medicine to treat inflammatory conditions were evaluated against a panel of key enzymes relating to inflammation. The enzymes included cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), phospholipase A(2) (PLA(2)), 5-lipoxygenase (5-LO) and 12-lipoxygenase (12-LO). The vine plants studied were: the stem of Spatholobus suberectus Dunn, the stem of Trachelospermum jasminoides Lem., the root from Tripterygium wilfordii Hook. f., the stem of Sinomenium acutum Rehder and Wilson, the stem of Piper kadsura (Choisy) Ohwi, the stem of Polygonum multiflorum Thunb., the root and stem from Tinospora sagittata Gagnep., the root of Tinospora sinensis (Lour.) Merrill, and the stem of Clematis chinensis Osbeck. All of the plant extracts showed inhibitory activities against at least one of the enzymes in various percentages depending upon the concentrations. The extract from S. suberectus was found to be active against all enzymes except COX-2. Its IC(50) values were 158, 54, 31 and 35 microg/ml in COX-1, PLA(2), 5-LO and 12-LO assays, respectively. T. jasminoides showed potent inhibitory activities against both COX-1 (IC(50) 35 microg/ml) and PLA(2) (IC(50) 33 microg/ml). The most potent COX-1, COX-2 and 5-LO inhibition was observed in the extract of T. wilfordii with the IC(50) values of 27, 125 and 22 microg/ml, respectively. The findings of this study may partly explain the use of these vine plants in traditional Chinese medicine for the treatment of inflammatory conditions.

Anti-Inflammatory Agents↗
PubMed2002

Development of a Chinese herbal medicine toxicology database.

BACKGROUND: Use of Chinese herbal medicine has increased steadily in the West and adverse reactions have been reported. However, information is not readily available on the toxicity of the herbs and the management of poisoning. The goals of this project were to retrieve and evaluate scientific evidence on the toxicity of Chinese herbal medicine, to grade the toxicity of individual herbs, and to summarize relevant herb data via a searchable electronic database. METHODS: English and Chinese primary studies were systematically retrieved via journal abstracting databases and key toxicity texts. Partial translation of published research was achieved via an audited process utilizing data extraction forms. Methods for grading herb toxicity (in therapeutic use or overdose) were developed based on a combination of the quality of reports, severity of adverse reaction, supporting animal studies, extrapolation from pharmacology and empirical evidence. RESULTS: Good quality studies on the toxicity of Chinese herbs are lacking. In some cases there is insufficient scientific evidence to create an evidence-based grading of the toxicity of individual herbs. Available data have been summarized into detailed monographs. Twelve herb monographs (with a full toxicity profile and grading) have been completed and summary data for all adequate quality papers used in the grading are linked to the monographs. CONCLUSIONS: The resultant database and monographs represent the first reviews specifically on the toxicity of individual Chinese herbs with toxicological grades based on the evidence of published studies. The database and monographs should assist in promoting the safe and effective use of Chinese herbal medicine.

Databases, Factual↗