Aspects of the biology of the yabby Trypea australiensis (Dana) (Decapoda : Thalassinidea) and the potential of burrow counts as an indirect measure of population density

The thalassinidean shrimp Trypea australiensis (the yabby) commonly occurs on intertidal sandflats and subtidal regions of sheltered embayments and estuaries along the east coast of Australia and is harvested commercially and recreationally for use as bait by anglers. The potential for counts of burrow openings to provide a reliable indirect estimate of the abundance of yabbies was examined on intertidal sandflats on North Stradbroke Island (Queensland, Australia). The relationship between the number of burrow openings and the abundance of yabbies was generally poor and also varied significantly through time, casting doubt on previous estimates of abundance for this species based on unvalidated hole counts. Spatial and temporal variation in population density, the size at maturity and the reproductive period of the yabby were also assessed. Except for an initial peak in abundance as a result of recruitment, the density of yabbies was constant throughout the study but considerably less than that estimated from a previous study in the same area. Ovigerous females were recorded at 3 mm carapace length (CL) which is smaller than previously recorded for this species and thalassinideans in general. Small ovigerous females were found throughout the study, including the summer months, which is unusual for thalassinideans in the intertidal zone. It was hypothesised that in the intertidal zone, small female yabbies may be able to balance the metabolic demands of reproduction and respiration at higher temperatures than can larger females allowing them to reproduce in the warmer months.

Patterns of co-morbidity between alcohol use and other substance use in the Australian population

The present study describes patterns of co-morbidity between alcohol use and other substance use problems in the Australian population using data from the 1997 National Survey of Mental Health and Well-Being. Multiple regression analyses examined whether the observed associations between alcohol and other drug use disorders were explained by other variables, including demographic characteristics and neuroticism. We also assessed whether the presence of co-morbid substance use disorders affected treatment seeking for a mental health problem. Alcohol use was related strongly to the use of other substances. Those who did not report alcohol use within the past 12 months were less likely to report using tobacco, cannabis, sedatives, stimulants or opiates. Higher rates again were observed among those with alcohol use disorders: half (51%) of those who were alcohol-dependent were regular tobacco smokers, one-third had used cannabis (32%); 15% reported other drug use; 15% met criteria for a cannabis use disorder and 7% met criteria for another drug use disorder. These associations were not accounted for by the demographic and other variables considered here. Co-morbid substance use disorders (sedatives, stimulants or opioids) predicted a high likelihood of seeking treatment for a mental health problem among alcohol-dependent people.

Flexibility revealed by the 1.85 angstrom crystal structure of the beta sliding-clamp subunit of Escherichia coli DNA polymerase III

The beta subunit of the Escherichia coli replicative DNA polymerase III holoenzyme is the sliding clamp that interacts with the alpha (polymerase) subunit to maintain the high processivity of the enzyme. The beta protein is a ring-shaped dimer of 40.6 kDa subunits whose structure has previously been determined at a resolution of 2.5 Angstrom [Kong et al. (1992), Cell, 69, 425-437]. Here, the construction of a new plasmid that directs overproduction of beta to very high levels and a simple procedure for large-scale purification of the protein are described. Crystals grown under slightly modified conditions diffracted to beyond 1.9 Angstrom at 100 K at a synchrotron source. The structure of the beta dimer solved at 1.85 Angstrom resolution shows some differences from that reported previously. In particular, it was possible at this resolution to identify residues that differed in position between the two subunits in the unit cell; side chains of these and some other residues were found to occupy alternate conformations. This suggests that these residues are likely to be relatively mobile in solution. Some implications of this flexibility for the function of beta are discussed.

Can metal complexes serve as hypoxia activated prodrugs? Investigations of a Co(III) complex of the MMP inhibitor marimastat

For many years proof that the hypoxic nature of malignant tumours can be used to selectively target anticancer drugs has been sought. Several classes of potential redox activated anticancer drugs have been developed to take advantage of the reducing environment resulting from the hypoxia. Drug complexes with redox active metal centres as carriers have been investigated, but have largely been employed with cytotoxic drugs that require release of the drug intracellularly, complicating the design of such complexes. MMP inhibitors, a new class of anticancer drug, conversely act in the extracellular environment and we have investigated inhibitor complexes with several redox active transition metals. Marimastat is an MMP inhibitor with potent in-vitro antimetastatic activity and was recently in Phase III clinical trials for a variety of cancer types. We have synthesised a Co(II1) complex of marimastat incorporating the tetradentate ligand tpa (tris(2-methylpyridyl)amine) as a carrier ligand. The complex was structurally characterised in the solid state by single crystal X-ray diffraction, the first example of a crystal structure containing marimastat. 2D COSY and NOESY NMR spectra showed that the complex exists in two isomeric forms in solution, corresponding to the cis and trans isomers yet only crystallises in one of these forms. Biological testing of the complex in mice with 4T1.2 tumours showed interesting and unexpected outcomes. Initial results of the tumour growth inhibition study showed that a significant inhibition of growth was exhibited by the complex over the free inhibitor and the control. However, the metastatic potential of both free marimastat and the complex were higher than the control indicating likely problems with the experimental protocol. Further experiments are needed to determine the potential of such complexes as hypoxia activated prodrugs but there appears at least to be some promise.

Embracing ligands. A synthetic strategy towards new nitrogen-thioether multidentate ligands and characterization of the cobalt(III) complexes

The synthesis of the hexadentate ligand 2,2,9,9-tetra(methyleneamine)-4,7-dithiadecane (EtN(4)S(2)amp) is reported. The ligand is of a type in which bifurcations of the chain occur at atoms other than donor atoms. The cobalt(III) complex [Co(EtN(4)S(2)amp)](3+) (1) was isolated and characterized. The synthetic methodology also results in a number of by-products, notably 2,9,9-tris(methyleneamine)-9-methylenehydroxy-4,7-dithiadecane (Et(HO)N(3)S(2)amp) and an eleven-membered pendant arm macrocyclic ligand 6,10-dimethyl-6,10-bis(methyleneamine)-1,4-dithia-8-azaacycloundec-7- ene (dmatue). The complexes [Co(Et(HO)N(3)S(2)amp)](3+) (2), in which the alcohol is coordinated to the metal ion, and [Co(dmatue)Cl](2+) (4) were isolated and characterized. Et(HO)N(3)S(2)amp also undergoes complexation with cobalt(III) to produce two isomers endo-[Co(Et(HO) N(3)S(2)amp)Cl](2+) (endo-3) and exo-[Co(Et(HO) N(3)S(2)amp)Cl](2+) (exo-3), both with an uncoordinated alcohol group. endo- 3 has the alcohol positioned cis, and exo-3 trans, to the sixth metal coordination site. Reaction of 1 with isobutyraldehyde, paraformaldehyde and base in dimethylformamide results in the encapsulated complex [Co(1,5,5,9,13,13-hexamethyl-18,21-dithia-3,7,11,15-tetraazabicyclo[7.7.6]docosa- 3,14-diene)](ClO4)(3) . 2H(2)O ([Co(Me(6)docosadieneN(4)S(2))](3+) ( 5). All complexes have been characterized by single crystal X-ray study. The low-temperature (11 K) absorption spectrum of 1 has been measured in Nafion films with spin-allowed (1)A(1g) --> T-1(1g) and (1)A(1g) --> T-1(2g) and spin forbidden (1)A(1g) --> T-3(1g) and (1)A(1g) --> T-3(2g) bands observed. The octahedral ligand-field parameters were determined (10Dq = 22570 cm(-1), B = 551 cm(-1); C = 3500 cm(-1)). For 5 10Dq and B were determined (20580 cm(-1); 516 cm(-1), respectively) and compared with those for similar expanded cavity complexes [Co(Me(8)tricosatrieneN(6))](3+) and [Co(Me(5)tricosatrieneN(6))](3+).

trans-Cyano(6-methyl-1,4,8,11-tetraazacyclotetradecan-6-amine)cobalt(III) bis(perchlorate) hydrate and trans-hydroxo(6-methyl-1,4,8,11-tetraazacyclotetradecan-6-amine)cobalt(III) bis(perchlorate)

The crystal structures of a pair of closely related macrocyclic cyano- and hydroxopentaaminecobalt(III) complexes, as their perchlorate salts, are reported. Although the two complexes, [Co(CN)(C11H27N5)](ClO4)2.H2O and [Co(OH)(C11H27N5)](ClO4)(2), exhibit similar conformations, significant differences in the Co-N bond lengths arise from the influence of the sixth ligand (cyano as opposed to hydroxo). The ensuing hydrogen-bonding patterns are also distinctly different. Disorder in the perchlorate anions was clearly resolved and this was rationalized on the basis of distinct hydrogen-bonding motifs involving the anion O atoms and the N-H and O-H donors.

Active and passive smoking and the risk of subarachnoid hemorrhage - An international population-based case-control study

Background and Purpose - This study was undertaken to better clarify the risks associated with cigarette smoking and subarachnoid hemorrhage (SAH). Methods - The study included 432 incident cases of SAH frequency matched to 473 community SAH-free controls to determine dose-dependent associations of active and passive smoking ( at home) and smoking cessation with SAH. Results - Compared with never smokers not exposed to passive smoking, the adjusted odds ratio for SAH among current smokers was 5.0 (95% confidence interval [CI], 3.1 to 8.1); for past smokers, 1.2 ( 95% CI, 0.8 to 2.0); and for passive smokers, 0.9 ( 95% CI, 0.6 to 1.5). Current and lifetime exposures showed a clear dose-dependent effect, and risks appeared more prominent in women and for aneurysmal SAH. Approximately 1 in 3 cases of SAH could be attributed to current smoking, but risks decline quickly after smoking cessation, even among heavy smokers. Conclusions - A strong positive association was found between cigarette smoking and SAH, especially for aneurysmal SAH and women, which is virtually eliminated within a few years of smoking cessation. Large opportunities exist for preventing SAH through smoking avoidance and cessation programs.

Brazilian Adaptation of the Woodcock-Johnson III Cognitive Tests

An adaptation of the standard battery of Woodcock-Johnson III Tests of Cognitive Abilities (WJ-III) for Brazilian children and youth was investigated. The sample was composed of 1094 students (54 percent girls), ages 7-17, living in Sao Paulo state (91 percent). Items from Brazilian school books as well as from the WJ-III Spanish version (Bateria-R) were added to comprehension-knowledge tests. Brazilian words were adapted to the auditory tests according to syllabic division and stressed syllables. Items were examined through IRT and age differences through analysis of variance. Results indicated the need to remove items from all WJ-III subtests with the exception of the visual learning test. Analysis of Variance indicated significant age differences (p <= 0.001) for all tests. Thus, the importance of a Brazilian adaptation for the WJ-III was confirmed.