The relationship between plasma lactate parameters, W-peak and 1-h cycling performance in women

Purpose: The relationship between six descriptors of lactate increase, peak (V) over dot O-2,W-peak, and 1-h cycling performance were compared in 24 trained, female cyclists (peak (V) over dot O-2 = 48.11 +/- 6.32 mL . kg(-1) . min(-1)). Methods: The six descriptors of lactate increase were: 1) lactate threshold (LT; the power output at which plasma lactate concentration begins to increase above the resting level during an incremental exercise test), 2) LT1 (the power output at which plasma lactate increases by 1 mM or more), 3) LTD (the lactate threshold calculated by the D-max method), 4) LTMOD (the lactate threshold calculated by a modified D-max method), 5) L4 (the power output at which plasma lactate reaches a concentration of 4 mmol-L-1), and 6) LTLOG (the power output at which plasma lactate concentration begins to increase when the log([La-]) is plotted against the log (power output)). Subjects first completed a peak (V) over dot O-2 test on a cycle ergometer. Finger-tip capillary blood was sampled within 30 s of the end of each 3-min stage for analysis of plasma lactate. Endurance performance was assessed 7 d later using a 1-h cycle test (OHT) in which subjects were directed to achieve the highest possible average power output. Results: The mean power output (W) for the OHT (+/- SD) was 183.01 +/- 18.88, and for each lactate variable was: LT (138.54 +/- 46.61), LT1 (179.17 +/- 27.25), LTLOG (143.97 +/- 45.74), L4 (198.09 +/- 33.84), LTD (178.79 +/- 24.07), LTMOD (212.28 +/- 31.75). Average power output during the OHT was more strongly correlated with all plasma lactate parameters (0.61 < r < 0.84) and W-peak (r = 0.81) than with peak (V) over dot O-2 (r = 0.55). The six lactate parameters were strongly correlated with each other (0.54 < r < 0.91) and of the six lactate parameters, LTD correlated best with endurance performance (r = 0.84). Conclusions: It was concluded that plasma lactate parameters and W-peak provide better indices of endurance performance than peak (V) over dot O-2 and that, of the six descriptors of lactate increase measured in this study, LTD is most strongly related to 1-h cycling performance in trained, female cyclists.

Health-related quality of life in Australian children with asthma: lessons for the cross-cultural use of quality of life instruments

The development of Australian forms of the Childhood Asthma Questionnaires (CAQs) is reported. Focus group methods and psychometric analyses were used to establish the conceptual, semantic and technical equivalence of these forms with the UK versions. Both versions also provide for data collection from non-asthmatic youngsters. The internal consistency was found to be acceptable (Cronbach's alpha 0.52-0.90) and the health-related quality of life (HRQoL) scores were found to vary with asthma severity (p < 0.05). Comparison with the UK data revealed that the non-asthmatic scores were higher for Australian than British children (p < 0.001) but that the scores for children with asthma did not differ between the two countries. It was only In the Australian sample that the group with asthma reported impaired HRQoL when compared to their healthy peers. These findings were interpreted in the context of cultural expectations of life quality and conclusions are presented regarding the importance of the gap between experience and expectations. The difficulties raised by the developmental and cultural issues inherent in paediatric HRQoL research were discussed. Qual. Life Res. 7:409-419 (C) 1998 Kluwer Academic Publishers

A pyruvated carrageenan from Australian specimens of the red alga Sarconema filiforme

The carrageenan from two Australian specimens of the red alga Sarconema filiforme was shown by a combination of compositional analyses, linkage analysis, and Fourier transform infrared and C-13 nuclear magnetic resonance spectroscopy to be composed predominantly of a hybrid or mixture of carrabiose 2-sulfate (the repeating unit of alpha-carrageenan), carrabiose 2,4'-disulfate (the repeating unit of iota-carrageenan), and the pyruvated unit 4',6'-O-(1-carboxyethylidene)carrabiose 2-sulfate. (C) 1998 Elsevier Science Ltd. All rights reserved.

The epidemiology of Parkinson's disease in an Australian population

A prevalence study of Parkinson's disease (PD) was conducted in the rural town of Nambour, Australia. There were 5 cases of PD in a study population of 1207, yielding a crude prevalence ratio of 414 per 100,000 (95% confidence interval; 53-775). We performed a separate case-control study involving 224 patients with FD and 310 controls from South East Queensland and Central West New South Wales, to determine which factors increase the risk for PD in Australia. A positive family history of PD was the strongest risk factor for the development of the disease (odds ratio = 3.4; p < 0.001). In addition, rural residency was a significant risk factor for PD (odds ratio = 1.8, p < 0.001). Hypertension, stroke and well water ingestion were inversely correlated with the development of PD. There was no significant difference between patients and controls for exposure to herbicides and pesticides, head injury, smoking or depression. The high prevalence of PD in Nambour may be explained by rural residency. However, the most significant risk factor for PD was a positive family history. This demonstrates the need for improved understanding of the genetic nature of the disease.

Lepocreadiidae (Digenea) of Australian coastal fishes: new species of Opechona Looss, 1907, Lepotrema Ozaki, 1932 and Bianium Stunkard, 1930 and comments on other species reported for the first time or poorly known in Australian waters

Opechona austrobacillaris n, sp. is described from Pomatomus saltatrix from marine sites off Western Australia and New South Wales, Australia. It differs from O. bacillaris in its elongate outline, small ventral sucker, longer pseudoesophagus (relative to the oesophagus), relatively shorter ventral sucker to ovary distance and the relatively longer post-testicular region. Lepotrema monile n. sp. is described from Pomacentrus wardi from Heron Island, Queensland. It differs from its congeners in the sphincter around the distal metraterm and the more-or-less oval ovary. Bianium spongiosum n. sp, is described from Ostracion cubicus from Lizard Island, Queensland. It differs from its congeners in lacking lateral flaps in the forebody, but in having large, internal spongiform patches in the lateral forebody. The following species are redescribed from Australian sites: Lepocreadium oyabitcha from Abudefduf whitleyi, Lizard Island; Clavogalea trachinoti from Trachinotus botla, Heron Island and T. coppingeri, New South Wales, Stradbroke Island, Queensland and Heron Island; Myzoxenus insolens from Notolabrus parilus, Western Australia; Bulbocirrus aulostomi from Aulostomus chinensis, Heron Island; Lepocreadioides orientalis [new synonyms: Bicaudum interruptum Bilqees, 1973; Lepocreadioides interruptum (Bilqees, 1973) Madhavi, Narasimhulu & Shameem, 1986; Lepocreadioides discum Wang, 1986; Lepocreadioides sp. of Karyakarte & Yadav (1976)] from Cynoglossus bilineata, Moreton Bay, Queensland; Hypocreadium patellare from Sufflamen chrysopterus, Heron Island; Echeneidocoelium indicum from Echeneis naucrates, Heron Island; Multitestis pyriformis from Epinephelus cyanopodus, Heron Island; Pseudopisthogonoporus vitellosus from Naso brevirostris, Heron Island; and Bianium hispidum from Torquigener whitleyi and T. pleurogramma, southern Queensland. Only M. solens and M. pyriformis have been reported from Australian waters before; both are new host records.

Novel nano-organisms from Australian sandstones

We report the detection of living colonies of nano-organisms (nanobes) on Triassic and Jurassic sandstones and other substrates. Nanobes have cellular structures that are strikingly similar in morphology to Actinomycetes and fungi (spores, filaments, and fruiting bodies) with the exception that they are up to 10 times smaller in diameter (20 nm to 1.0 mu m). Nanobes are noncrystalline structures that are composed of C, O, and N. Ultra thin sections of nanobes show the existence of an outer layer or membrane that may represent a cell wall. This outer layer surrounds an electron dense region interpreted to be the cytoplasm and a less electron dense central region that may represent a nuclear area. Nanobes show a positive reaction to three DNA stains, [4',6-diamidino-2 phenylindole (DAPI), Acridine Orange, and Feulgen], which strongly suggests that nanobes contain DNA. Nanobes are communicable and grow in aerobic conditions at atmospheric pressure and ambient temperatures. While morphologically distinct, nanobes are in the same size range as the controversial fossil nannobacteria described by others in various rock types and in the Martian meteorite ALH84001.

Factors controlling the origin of gas in Australian Bowen Basin coals

Open system pyrolysis (heating rate 10 degrees C/min) of coal maturity (vitrinite reflectance, VR) sequence (0.5%, 0.8% and 1.4% VR) demonstrates that there are two stages of thermogenic methane generation from Bowen Basin coals. The first and major stage shows a steady increase in methane generation maximising at 570 degrees C, corresponding to a VR of 2-2.5%. This is followed by a less intense methane generation which has not as yet maximised by 800 degrees C (equivalent to VR of 5%). Heavier (C2+) hydrocarbons are generated up to 570 degrees C after which only the C-1 (CH4, CO and CO2) gases are produced. The main phase of heavy hydrocarbon generation occurs between 420 and 510 degrees C. Over this temperature range,methane generation accounts for only a minor component, whereas the wet gases (C-2-C-5) are either in equal abundance or are more abundant by a factor of two than the liquid hydrocarbons. The yields of non-hydrocarbon gases CO2 and CO are greater then methane during the early stages of gas generation from an immature coal, subordinate to methane during the main phase of methane generation after which they are again dominant. Compositional data for desorbed and produced coal seam gases from the Bowen show that CO2 and wet gases are a minor component. This discrepancy between the proportion of wet gas components produced during open system pyrolysis and that observed in naturally matured coals may be the result of preferential migration of wet gas components, by dilution of methane generated during secondary cracking of bitumen, or kinetic effects associated with different activations for production of individual hydrocarbon gases. Extrapolation of results of artificial pyrolysis of the main organic components in coal to geological significant heating rates suggests that isotopically light methane to delta(13)C of -50 parts per thousand can be generated. Carbon isotope depletions in C-13 are further enhanced, however, as a result of trapping of gases over selected rank levels (instantaneous generation) which is a probable explanation for the range of delta(13)C values we have recorded in methane desorbed from Bowen Basin coals (-51 +/- 9 parts per thousand). Pervasive carbonate-rich veins in Bowen Basin coals are the product of magmatism-related hydrothermal activity. Furthermore, the pyrolysis results suggest an additional organic carbon source front CO2 released at any stage during the maturation history could mix in varying proportions with CO2 from the other sources. This interpretation is supported by C and O isotopic ratios, of carbonates that indicate mixing between magmatic and meteoric fluids. Also, the steep slope of the C and O isotope correlation trend suggests that the carbonates were deposited over a very narrow temperature interval basin-wide, or at relatively high temperatures (i.e., greater than 150 degrees C) where mineral-fluid oxygen isotope fractionations are small. These temperatures are high enough for catagenic production of methane and higher hydrocarbons from the coal and coal-derived bitumen. The results suggests that a combination of thermogenic generation of methane and thermodynamic processes associated with CH4/CO2 equilibria are the two most important factors that control the primary isotope and molecular composition of coal seam gases in the Bowen Basin. Biological process are regionally subordinate but may be locally significant. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Volatile solvent use among western Australian adolescents

Semistructured interviews were conducted with 40 adolescents who reported inhaling volatile solvents. Their average age was 14.2 years, and they used a range of substances. All were aware of the short-term health risks involved in volatile solvent use, and most reported experiencing ill effects, such as headaches and vomiting. Users were found to be organized into groups and peer networks, which often were involved in theft, prostitution, and other risk-taking behaviors. More chronic users had higher status within the group. Suggestions pertaining to intervention were obtained, and these are discussed in light of the findings.

Insufficiently active Australian college students: Perceived personal, social, and environmental influences

Background. A sustainable pattern of participation in physical activity is important in the maintenance of health and prevention of disease, College students are in transition from an active youth to a more sedentary adult behavior pattern. Methods. We assessed self-reported physical activity and other characteristics in a sample of 2,729 male and female students (median age was 20 years) recruited from representative courses and year levels at four Australian College campuses. They were categorized as sufficiently or insufficiently active, using estimates of energy expenditure (kcal/week) derived from self-reported physical activity, Personal factors (self-efficacy, job status, enjoyment), social factors (social support from family/friends), and environmental factors (awareness of facilities, gym membership) were also assessed. Results. Forty-seven percent of females and 32% of males were insufficiently active. For females, the significant independent predictors of being insufficiently active were lower social support from family and friends, lower enjoyment of activity, and not working. For males, predictors were lower social support from family and friends, lower enjoyment of activity, and being older. Conclusions. Factors associated with physical activity participation (particularly social support from family and friends) can inform physical activity strategies directed at young adults in the college setting. (C) 1999 American Health Foundation and Academic Press.

A H-1 MRS study of probable Alzheimer's disease and normal aging: Implications for longitudinal monitoring of dementia progression

In order to evaluate the capability of H-1 MRS to monitor longitudinal changes in subjects with probable Alzheimer's disease (AD), the temporal stability of the metabolite measures N-acetylaspartate and N-acetylas-partylglutamate (NA), total Creatine (Cr), myo-Inositol (mI), total Choline (Chol), NA/Cr, mI/Cr, Chol/Cr and NA/mI were investigated in a cohort of normal older adults. Only the metabolite measures NA, mi, Cr, NA/Cr, mI/Cr, and NA/mI were found to be stable after a mean interval of 260 days. Relative and absolute metabolite measures from a cohort of patients with probable AD were subsequently compared with data from a sample of normal older adult control subjects, and correlated with mental status and the degree of atrophy in the localized voxel. Concentrations of NA, NA/Cr, and NA/mI were significantly reduced in the AD group with concomitant significant increases in mi and mI/Cr. There were no differences between the two groups in measures of Cr, Chol, or Chol/Cr. Significant correlations between mental status as measured by the Mini-Mental State Examination and NA/mI, mI/Cr and NA were found. These metabolite measures were also significantly correlated with the extent of atrophy (as measured by CSF and GM composition) in the spectroscopy voxel. (C) 1999 Elsevier Science Inc.

Asymmetry and duration dependence in Australian GDP and unemployment

The per iodic structure of business cycles suggests that significant asymmetries are present over different phases of the cycle. This paper uses markov regime-switching models with fixed and duration dependent transition probabilities to directly model expansions, contractions and durations in Australian GDP growth and unemployment growth. Evidence is found of significant asymmetry in growth rates across expansions and contractions for both series. GDP contractions exhibit duration dependence implying that as output recessions age the likelihood of switching into an expansion phase increases. Unemployment growth does not exhibit duration dependence in either phase. Evidence is also presented that non-linearities in unemployment growth are well explained by the asymmetries in the GDP growth cycle. The analysis suggests that recessions are periods of rapid and intense job destruction, that Australian unemployment tends to ratchet up in recessionary periods and, in contrast to US and UK studies, that shocks to Australian unemployment growth are more persistent in recessions than expansions. [E37 C5 C41].