The effect of proximity on open-loop accommodation responses measured with pinholes.

Open-loop accommodation levels were measured in 41 healthy, young subjects using a Shin-Nippon SRW-5000 autorefractor in the three viewing conditions: a small physical pinhole pupil (SP), an optically projected pinhole in Maxwellian view (MV) and in the dark (DF). The target viewed through the pinholes was a high-contrast letter presented at 0 D vergence in a +5 D Badal lens system. Overall, results showed that SP open-loop accommodation levels were significantly higher than MV and DF levels. Subjects could be divided into two distinct subgroups according to their response behaviour: responders to the proximal effect of the small physical pinhole (SP accommodation > MV accommodation) and non-responders to the proximal effect of the small physical pinhole (SP accommodation approximately MV accommodation). Correlation analysis demonstrated that open-loop accommodation for both pinhole conditions was correlated with DF for the responders, while for the non-responders SP and MV accommodation were correlated, but were not related to DF accommodation. This suggests that under open-loop conditions some individuals' accommodation levels are mainly affected by proximal and cognitive factors (responders) while others are guided primarily by the presence of the more distal target (non-responders). In conclusion, MV reduces the proximal effect of the physical pinhole and produces open-loop accommodation responses which are more consistent than SP and DF responses.

Sources of methylmercury to a wetland-dominated lake in northern Wisconsin.

Several lines of evidence suggest that wetlands may be a major source of methylmercury (MeHg) to receiving waters, perhaps explaining the strong correlation between concentrations of waterborne MeHg and dissolved organic carbon (DOC) in regions such as northern Wisconsin. We evaluated the relative importance of wetland export in the MeHg budget of a wetland-dominated lake in northern Wisconsin using mass balance. Channelized runoff from a large headwater wetland was the major source of water and total mercury (HgT) to the lake during the study period. The wetland also exported MeHg in high concentrations (0.2-0.8 ng L(-1)), resulting in an export rate similar to those reported for other northern wetlands (ca. 0.3 microg MeHg m(-2) y(-1)). Yet, based on intensive sampling during 2002, the mass of MeHg that accumulated in the lake during summer was an order of magnitude greater than the export of MeHg from the wetland to the lake. Hence, a large in-lake source of MeHg is inferred from the mass balance. Most of the accumulated MeHg built-up in anoxic hypolimnetic waters; and the build-up was roughly balanced by losses of inorganic Hg (Hg(II)) implying a chemical transformation within the anoxic water column. An abundance of sulfate-reducing bacteria (SRB) in hypolimnetic waters, established by DNA analysis of the pelagic microbial community, along with a previous report documenting high methylation rates in the hypolimnion of this lake (ca. 10% d(-1)), suggest that this transformation was microbially mediated. These findings indicate that the direct effect of wetland runoff may be outweighed by indirect effects on the lacustrine MeHg cycle, enhancing the load of Hg(II), the activity of SRB, and the retention of MeHg, especially in northern lakes with flushing times longer than six months.

Predicting violent behavior in stalkers: a preliminary investigation of Canadian cases in criminal harassment.

This study examined the factors associated with violent/aggressive behavior in stalkers using a sample of 100 Canadian cases of persons charged with criminal harassment (more commonly known as stalking). Results revealed that the typical profile of a "simple obsessional" type of stalker was a middle-aged male, single or separated/estranged, with a history of emotional and/or anger management problems. The most common initial strategies used by the victims to cope with the stalkers were oriented towards legal resources. Initial legal remedies, including court orders or police warnings, seemed to be ineffective as a strategy to stop stalking given that most stalkers chose to ignore them. The study also provided partial support for a preliminary model of predictors of violent/aggressive behavior in stalkers. Stalkers with previous violent behaviors, strong negative emotions. and obsessional tendencies toward the victim may be most at risk of future violent and aggressive acts.

Nonsteroidal anti-inflammatory-induced pseudoporphyria: is there an alternative drug?

Drug-induced pseudoporphyria cutanea tarda has been attributed to many different medications including several nonsteroidal anti-inflammatory drugs (NSAIDs). Often the patients taking these anti-inflammatory medications became part of a treatment dilemma when one of the drugs is deemed the cause of a blistering disease. We present a prototypical case of NSAID-induced pseudoporphyria cutanea tarda and suggest alternative NSAIDs that may be safely used in these patients.

Bioaccumulation of mercury in pelagic freshwater food webs.

Current paradigms regarding the bioaccumulation of mercury are rooted in observations that monomethyl mercury (meHg) biomagnifies along pelagic food chains. However, mechanisms regulating the formation of meHg, its initial incorporation at the base of pelagic food chains, and its subsequent trophic transfer remain controversial. Here we use field data from 15 northern Wisconsin lakes, equilibrium aqueous speciation modeling, and statistical modeling to revisit several hypotheses about the uptake, distribution, and fate of inorganic Hg (HgII) and meHg in aquatic biota. Our field data comprise determinations of total Hg (HgT) and meHg in surface waters, sediments, microseston, zooplankton, and small fish in each of the study lakes. For these lake waters, strong positive correlations between DOC and aqueous concentrations of mercury along with negative correlations between DOC and the seston-water partitioning of mercury indicate that organic ligands bind HgII and meHg strongly enough to dominate their apparent aqueous speciation. In the microseston, zooplankton and fish, meHg concentrations and bioaccumulation factors (BAFs) increased with increasing trophic level while biotic concentrations of HgII decreased--indicating that meHg was indeed the biomagnified species of mercury. For all trophic levels, meHg concentrations varied positively with the calculated aqueous concentration of meHg+ (free ion), especially when coupled with pH, or meHgOH (hydroxide) species but not with meHgCl0, the neutral chloride complex. These findings suggest that: (1) the passive uptake of meHg does not control bioaccumulation at the base of aquatic food webs in nature (i.e. phyto- and bacterioplankton); (2) correlation with pH and DOC largely reflect the supply and bioavailability of meHg to lower trophic levels; and (3) meHg concentrations at higher trophic levels reflect uptake at low trophic levels and other factors, such as diet and growth. Low concentrations of meHg in surficial sediments indicate that the fates of biotic HgII and meHg are different. Most biotic meHg is demethylated rather than buried in lake sediments.

Alternative pathways of angiotensin II production in the human saphenous vein.

1. The aim of our study was to demonstrate the existence, location and functional importance of an alternative angiotensin II-forming pathway other than angiotensin converting enzyme (ACE) in the human saphenous vein (SV). 2. Vascular reactivity studies using an in vitro organ bath technique showed that the SV (n=20) produced similar maximum contractions in response to angiotensin I (41.5+/-5.4 mN) compared to those observed to angiotensin II (46.7+/-10.9 mN). The response to angiotensin I could be significantly inhibited (P<0.05) by incubation with the AT1 receptor antagonist losartan (1 microM). 3. Prior incubation of segments of SV with either captopril (1 microM) (n=6), quinaprilat (1 microM) (n=7), or the chymase inhibitor soya bean trypsin inhibitor (SBTI) (10 microM) (n=7) singularly failed to have any inhibitory effect on the response to angiotensin I. However when vessel segments (n=7) were co-incubated with quinaprilat (1 microM) and SBTI (10 microM), the SV exhibited a rightward shift in curve profile to angiotensin I and a markedly reduced maximum response 12.5+/-2.4 mN, when compared to control (30.4+/-7.6 mN), quinaprilat (24.5+/-9.4 mN), and SBTI (31.6+/-10.7 mN) on their own. 4. An immunohistochemical technique employing streptavidin biotin peroxidase localised ACE to both endothelial cells and smooth muscle cells while chymase was confined to mast cells in the adventitia of the vessel wall. 5. In conclusion, our results demonstrate the existence of an alternative angiotensin I converting pathway to that of ACE, involving chymase. Therefore, there is the capacity for a continuation of angiotensin II formation, in the presence of ACE inhibition.

Personality correlates of the Five-Factor Model for a sample of business owners/managers: associations with scores on Self-Monitoring, Type A Behavior, Locus of Control, and Subjective Well-being.

Bivariate relationships were examined between scores on the Five-Factor Model of personality and four personality dimensions including Self-monitoring, Locus of Control, Type A Behavior, and Subjective Well-being. Data were collected from 307 franchise business owner/managers from four different industries. Scores for Self-monitoring were positively related to those on Extraversion; Self-monitoring was the only personality measure significantly correlated with scores on Openness to Experience. Scores for Type A Behavior, measured by the Jenkins Activity Survey, were negatively correlated with Agreeableness and positively correlated with those for Extraversion. Somewhat surprisingly, the score for Type A Behavior had a relatively low correlation with the score for Conscientiousness. Scores for Subjective Well-being and Locus of Control were most strongly correlated with the positive pole of Neuroticism (Emotional Stability), Conscientiousness, and Extraversion. Possible explanations for the observed relationships are discussed.