The toxins of Lyngbya majuscula and their human and ecological health effects

Lyngbya majuscula is a benthic filamentous marine cyanobacterium, which in recent years appears to have been increasing in frequency and size of blooms in Moreton Bay, Queensland. It has a worldwide distribution throughout the tropics and subtropics in water to 30m. It has been found to contain a variety of chemicals that exert a range of biological effects, including skin, eye and respiratory irritation. The toxins lyngbyatoxin A and debromoaplysiatoxin appear to give the most widely witnessed biological effects in relation to humans, and experiments involving these two toxins show the formation of acute dermal lesions. Studies into the epidemiology of the dermatitic, respiratory and eye effects of the toxins of this organism are reviewed and show that Lyngbya induced dermatitis has occurred in a number of locations. The effects of aerosolised Lyngbya in relation to health outcomes were also reported. Differential effects of bathing behaviour after Lyngbya exposure were examined in relation to the severity of health outcomes. The potential for Lyngbya to exhibit differential toxicologies due to the presence of varying proportions of a range of toxins is also examined. This paper reviews the present state of knowledge on the effects of Lyngbya majuscula on human health, ecosystems and human populations during a toxic cyanobacterial bloom. The potential exists for toxins from Lyngbya majuscula affecting ecological health and in particular marine reptiles. (C) 2001 Elsevier Science Ltd. All rights reserved.

Isolation and identification of the toxic peptides from Lophyrotoma zonalis (Pergidae) sawfly larvae

The broad-leaved paper bark tree Melaleuca quinquenervia (Cav) (Myrtaceae) was introduced into Florida (USA) early in this century it has proliferated to such an extent that urgent measures are now required to control it. The sawfly Lophyrotoma zonalis (Pergidae) has been introduced as a possible biological control agent due to its ability to defoliate M. quinquenervia. Because toxic D-amino acid- containing peptides have been isolated from some sawfly species, L. zonalis larvae were processed using the previously reported method for the recovery of these compounds. The toxins lophyrotomin (as the free C-terminal acid) and a mixture of pergidin and Val(4)-pergidin were isolated at 0.36 and 0.43% yield of the dried larvae, respectively. Both compounds when dosed intraperitoneally to C57/B16 male mice were hepatotoxic with lowest lethal doses of 8 and 32 mg/kg, respectively. The pathology of the liver was different for each compound, with the lophyrotomin free acid causing a periportal haemorrhagic necrosis and the pergidin causing a periacinar coagulative necrosis. (C) 2001 Elsevier Science Ltd. All rights reserved.

Too wet to exercise? Leaking urine as a barrier to physical activity in women

Leaking urine Is frequently mentioned (anecdotally) by women as a barrier to physical activity. The aim of this paper was to use results from the Australian Longitudinal Study on Women's Health (ALSWH) to explore the prevalence of leaking urine in Australian women, and to ascertain whether leaking urine might be a barrier to participation for women. More than 41,000 women participated in the baseline surveys of the ALSWH in 1996. More than one third of the mid-age (45-50 years) and older (70-75) women and 13% of the young women (18-23) reported leaking urine. There was a cross-sectional association between leaking urine and physical activity, such that women with more frequent urinary leakage were also more likely to report low levels of physical activity. More than one thousand of those who reported leaking urine at baseline participated in a follow-up study in 1999. Of these, more than 40% of the mid-age women (who were aged 48-53 in 1999), and one in seven of the younger (21-26 years) and older (73-79 years) women reported leaking urine during sport or exercise. More than one third of the mid-age women and more than one quarter of the older women, but only 7% of the younger women said they avoided sporting activities because of leaking urine. The data are highly suggestive that leaking urine may be a barrier to physical activity, especially among mid-age women. As current estimates suggest that fewer than half of all Australian women are adequately active for health benefit, health professionals could be more proactive in raising this issue with women and offering help through non-invasive strategies such as pelvic floor muscle exercises.

SOX9 enhances aggrecan gene promoter/enhancer activity and is up-regulated by retinoic acid in a cartilage-derived cell line, TC6

SOX9 is a transcription factor that plays a key role in chondrogenesis, Aggrecan is one of the major structural components in cartilage; however, the molecular mechanism of aggrecan gene regulation has not yet been fully elucidated, TC6 is a clonal chondrocytic cell line derived from articular cartilage, The purpose of this study was to examine whether SOX9 modulates aggrecan gene expression and to further identify molecules that regulate Sox9 expression in TC6 cells. SOX9 overexpression in TC6 cells enhanced by similar to 3-fold the transcriptional activity of the AgCAT-8 construct containing S-kilobase (kb) promoter/first exon/first intron fragments of the aggrecan gene. SOX9 enhancement of aggrecan promoter activity was lost when we deleted a 4.5-kb fragment from the 3'-end of the 8-kb fragment corresponding to the region including the first intron, In TC6 cells, SOX9 enhanced the transcriptional activity of a reporter construct containing the Sry/Sox consensus sequence >10-fold. SOX9 enhancement of aggrecan gene promoter activity and SOX9 transactivation through the Sry/Sox consensus sequence were not observed in osteoblastic osteosarcoma cells (ROS17/2.8), indicating the dependence on the cellular background. Northern blot analysis indicated that TC6 cells constitutively express Sox9 mRNA at relatively low levels. To examine regulation of Sox9 gene expression, we investigated the effects of calciotropic hormones and cytokines, Among these, retinoic acid (RA) specifically enhanced Sox9 mRNA expression in TC6 cells. The basal levels of Sox9 expression and its enhancement by RA were observed similarly at both permissive (33 degrees C) and nonpermissive (39 degrees C) temperatures. Furthermore, RA treatment enhanced the transcriptional activity of a reporter construct containing the Sry/Sox consensus sequence in TC6 cells. Moreover, RA treatment also enhanced the transcriptional activity of another reporter construct containing the enhancer region of the type II procollagen gene in TC6 cells. These observations indicate that SOX9 enhances aggrecan promoter activity and that its expression is up-regulated by RA in TC6 cells.

A simulation model for analysing patient activity in dermatology

We developed a general model to assess patient activity within the primary and secondary health-care sectors following a dermatology outpatient consultation. Based on observed variables from the UK teledermatology trial, the model showed that up to 11 doctor-patient interactions occurred before a patient was ultimately discharged from care. In a cohort of 1000 patients, the average number of health-care visits was 2.4 (range 1-11). Simulation analysis suggested that the most important parameter affecting the total number of doctor-patient Interactions is patient discharge from care following the initial consultation. This implies that resources should be concentrated in this area. The introduction of teledermatology (either realtime or store and forward) changes the values of the model parameters. The model provides a quantitative tool for planning the future provision of dermatology health-care.

Seedling responses of three Australian tree species to toxic concentrations of zinc in solution culture

A frequently desired outcome when rehabilitating Zn toxic sites in Australia is to establish a self-sustaining native ecosystem. Hence, it is important to understand the tolerance of Australian native plants to high concentrations of Zn. Very little is known about the responses of Australian native plants, and trees in particular, to toxic concentrations of Zn. Acacia holosericea, Eucalyptus camaldulensis and Melaleuca leucadendra plants were grown in dilute solution culture for 10 weeks. The seedlings (42 days old) were exposed to six Zn treatments viz., 0.5, 5, 10, 25, 50 and 100 muM. The order of tolerance to toxic concentrations of Zn was E. camaldulensis > A. holosericea > M. leucadendra, the critical external concentrations being approximately 20, 12 and 1.5 muM, respectively. Tissue Zn concentrations increased as solution Zn increased for all species. Root tissue concentrations were higher than shoot tissue concentrations at all solution Zn concentrations. The critical tissue Zn concentrations were approximately 85 and 110 mug g(-1) DM for M. leucadendra, 115 and 155 mug g(-1) DM for A. holosericea and 415 and 370 mug g(-1) DM for E. camaldulensis for the youngest fully expanded leaf and total shoots, respectively. The results from this paper provide the first comprehensive combination of growth responses, critical external concentrations, critical tissue concentrations and plant toxicity symptoms for three important Australian genera, viz., Eucalyptus, Acacia and Melaleuca, for use in the rehabilitation of potentially Zn toxic sites.

Associations involving delays (particularly long delays) between certain weather parameters and geomagnetic activity

Four sunspot-minimum periods (1963-1966, 1971-1977, 1983-1987 and 1992-1997) have been examined for the results which are presented. Using several different weather parameters, tropospheric gravity waves, enhanced cold fronts and two rainfall data sets in Eastern Australia, associations at reasonably high levels of significance have been found with enhanced geomagnetic activity (EGA). Statistically this EGA involved either short delays of several days or long delays of about 20 days. The geomagnetic parameters used were (a) the AE index (b) the hourly H component for a number of stations and (c) the daily K-P-sum value. The K-P-sum analyses have shown that the EGA associated with the delays form part of four or five cycles of recurrent geomagnetic activity for 27-day periodicities. Furthermore statistically two recurrent cycles are found to exist concurrently, one apparently related to the short delays and the other to the long delays. Periodicities of 13.5 days are created because the two sets are displaced from each other by approximately this interval. A brief reference is made to the 13.5 periodicity known to exist for geomagnetic activity and the evidence in the literature for active regions on the sun to be displaced by 180 degrees of solar longitude.

Microbial interactions with tannins: Nutritional consequences for ruminants

Polyphenolics are widely distributed in the plant kingdom and are often present in the diet of herbivores. The two major groups of plant polyphenolic compounds other than lignin are condensed and hydrolysable tannins. These compounds can have toxic and/or antinutritional effects on the animal. It is well established that tannins complex with dietary proteins can reduce nitrogen supply to the animal, but the ability of gastrointestinal microorganisms to metabolise these compounds and their effects on microbial populations have received little attention. In this paper, we review recent literature on the topic as well as present research from our laboratories on the effect of condensed tannins on rumen microbial ecology and rumen metabolism. Interactions of tannins with dietary components and endogenous protein in the rumen and post-ruminally, and their impact on the nutrition of the animal are considered. (C) 2001 Elsevier Science B.V. All rights reserved.

The use of perineal ultrasound to quantify levator activity and teach pelvic floor muscle exercises

Perineal ultrasound was used to detect and quantify levator activity by measuring the displacement of the internal urethral meatus against the inferoposterior margin of the symphysis pubis, Women who had previously been instructed in pelvic floor muscle exercises were more likely to contract the levator muscle when asked to do so than were those without previous instruction (P