Population‐based analysis of health care contacts among suicide decedents: identifying opportunities for more targeted suicide prevention strategies

The objective of this study was to detail the nature and correlates of mental health and non‐mental health care contacts prior to suicide death. We conducted a systematic extraction of data from records at the Office of the Chief Coroner of Ontario of each person who died by suicide in the city of Toronto from 1998 to 2011. Data on 2,835 suicide deaths were linked with provincial health administrative data to identify health care contacts during the 12 months prior to suicide. Sub‐populations of suicide decedents based on the presence and type of mental health care contact were described and compared across socio‐demographic, clinical and suicide‐specific variables. Time periods from last mental health contact to date of death were calculated and a Cox proportional hazards model examined covariates. Among suicide decedents, 91.7% had some type of past‐year health care contact prior to death, 66.4% had a mental health care contact, and 25.3% had only non‐mental health contacts. The most common type of mental health contact was an outpatient primary care visit (54.0%), followed by an outpatient psychiatric visit (39.8%), an emergency department visit (31.1%), and a psychiatric hospitalization (21.0%). The median time from last mental health contact to death was 18 days (interquartile range 5‐63). Mental health contact was significantly associated with female gender, age 25‐64, absence of a psychosocial stressor, diagnosis of schizophrenia or bipolar disorder, past suicide attempt, self‐poisoning method and absence of a suicide note. Significant differences between sub‐populations of suicide decedents based on the presence and nature of their health care contacts suggest the need for targeting of community and clinical‐based suicide prevention strategies. The predominance of ambulatory mental health care contacts, often close to the time of death, reinforce the importance of concentrating efforts on embedding risk assessment and care pathways into all routine primary and specialty clinical care, and not only acute care settings.     

A review of the occurrence of inter‐colony segregation of seabird foraging areas and the implications for marine environmental impact assessment

Understanding the determinants of species’ distributions is a fundamental aim in ecology and a prerequisite for conservation but is particularly challenging in the marine environment. Advances in bio‐logging technology have resulted in a rapid increase in studies of seabird movement and distribution in recent years. Multi‐colony studies examining the effects of intra‐ and inter‐colony competition on distribution have found that several species exhibit inter‐colony segregation of foraging areas, rather than overlapping distributions. These findings are timely given the increasing rate of human exploitation of marine resources and the need to make robust assessments of likely impacts of proposed marine developments on biodiversity. Here we review the occurrence of foraging area segregation reported by published tracking studies in relation to the density‐dependent hinterland (DDH) model, which predicts that segregation occurs in response to inter‐colony competition, itself a function of colony size, distance from the colony and prey distribution. We found that inter‐colony foraging area segregation occurred in 79% of 39 studies. The frequency of occurrence was similar across the four seabird orders for which data were available, and included species with both smaller (10–100 km) and larger (100–1000 km) foraging ranges. Many predictions of the DDH model were confirmed, with examples of segregation in response to high levels of inter‐colony competition related to colony size and proximity, and enclosed landform restricting the extent of available habitat. Moreover, as predicted by the DDH model, inter‐colony overlap tended to occur where birds aggregated in highly productive areas, often remote from all colonies. The apparent prevalence of inter‐colony foraging segregation has important implications for assessment of impacts of marine development on protected seabird colonies. If a development area is accessible from multiple colonies, it may impact those colonies much more asymmetrically than previously supposed. Current impact assessment approaches that do not consider spatial inter‐colony segregation will therefore be subject to error. We recommend the collection of tracking data from multiple colonies and modelling of inter‐colony interactions to predict colony‐specific distributions.     

Magnesium increases the curvature of duplex DNA that contains dA tracts

Distinct structural features of DNA, such as the curvature of dA tracts, are important in the recognition, packaging, and regulation of DNA. Physiologically relevant concentrations of magnesium have been found to enhance the curvature of dA tract DNAs, as monitored by solution-state NMR, indicating that the structure of DNA depends on the cations present in solution. A model is presented which accounts for the sequence-dependent effects of magnesium on DNA curvature as well as for the previously known sequence-independent effect on DNA flexibility.     

Expression and purification of hexahistidine-tagged human glutathione S-transferase P1-1 in Escherichia coli

The bacterial expression and purification of human pi class glutathione S-transferase (hGST P1-1) as a hexahistidine-tagged polypeptide was performed. The expression plasmid for hGST P1-1 was constructed by ligation of the cDNA which codes for the protein into the expression vector pET-15b. The expressed protein was purified by either glutathione or metal (Co(2+)) affinity column chromatography, which produced the pure and fully active enzyme in one step with a yield of more than 30 mg/liter culture. The activity of the purified protein was 130 units mg(-1) from the GSH affinity column and 112 units mg(-1) from the Co(2+) affinity column chromatography. The purity of the protein was assessed by electrospray ionization mass spectrometry and size-exclusion chromatography. It showed that the real molecular weight of the hexahistidine-tagged hGST P1-1 polypeptide chain agreed with the calculated value and that the purified protein eluted as an apparent homodimer on the gel filtration column. Our expression system allows the expression and purification of active hexahistidine-tagged hGST P1-1 in high yield with no need of removal of the hexahistidine tag and gives pure protein in one purification step allowing further study of this enzyme.     

Mechanisms of calcium signaling in smooth muscle cells explored with fluorescence confocal imaging

A rise in the intracellular concentration of ionized calcium ([Ca²⁺]_i) is a primary signal for contraction in all types of muscles. Recent progress in the development of imaging techniques, with special accent on fluorescence confocal microscopy, and new achievements in the synthesis of organelle- and ion-specific fluorochromes provide an experimental basis for studying the relationship between the structural organization of living smooth muscle cells (SMCs) and features of calcium signaling at the subcellular level. Applying fluorescent confocal imaging, patch-clamp recording, immunostaining, and flash photolysis techniques to freshly isolated SMCs, we have demonstrated that: (i) Ca²⁺ sparks are mediated by spontaneous clustered opening of ryanodine receptors (RyRs) and occur at the highest rate at preferred sites (frequent discharge sites, FDSs), the number of which depends on SMC type; (ii) FDSs are associated with sub-plasmalemmal sarcoplasmic reticulum (SR) elements, but not with polarized mitochondria; (iii) Ca²⁺ spark frequency increases with membrane depolarization in voltage-clamped SMCs or following neurotransmitter application to SMCs, in which the membrane potential was not controlled, leading to spark summation and resulting in a cell-wide increase in [Ca²⁺]_i and myocyte contraction; (iv) cross-talk between RyRs and inositol trisphosphate receptors (IP₃Rs) is an important determinant of the [Ca²⁺]_i dynamics and recruits neighboring Ca²⁺-release sites to generate [Ca²⁺]_i waves; (v) [Ca²⁺]_i waves induced by depolarization of the plasma membrane or by noradrenaline or caffeine, but not by carbachol (CCh), originate at FDSs; (vi) Ca²⁺-dependent K⁺ and Cl^- channels sense the local changes in [Ca²⁺]_i during a Ca²⁺ spark and thereby may couple changes in [Ca²⁺]_i within a microdomain to changes in the membrane potential, thus affecting the cell excitability; (vii) the muscarinic cation current (mI _cat) does not mirror changes in [Ca²⁺]_i, thus reflecting the complexity of [Ca²⁺]_i — muscarinic cationic channel coupling; (viii) RyR-mediated Ca²⁺ release, either spontaneous or caffeine-induced, does not augment mI _cat; (ix) intracellular flash release of Ca²⁺ is less effective in augmentation of mI _cat than flash release of IP₃, suggesting that IP₃ may sensitize muscarinic cationic channels to Ca²⁺; (x) intracellular flash release of IP₃ fails to augment mI _cat in SMCs, in which [Ca²⁺]_i was strongly buffered, suggesting that IP₃ exerts no direct effect on muscarinic cationic channel gating, and that these channels sense an increase in [Ca²⁺]_i rather than depletion of the IP₃-dependent Ca²⁺ store; and (xi) predominant expression of IP₃R type 1 in the peripheral SR provides a structural basis for a tight functional coupling between IP₃R-mediated Ca²⁺ release and muscarinic cationic channel opening.Neirofiziologiya/Neurophysiology, Vol. 36, Nos. 5/6, pp. 455–465, September–December, 2004.This revised version was published online in April 2005 with a corrected cover date and copyright year.     

Solid-phase synthesis and SAR of 4-carboxy-2-azetidinone mechanism-based tryptase inhibitors

A series of nonguanidine N1-activated C4-carboxy azetidinone tryptase inhibitors was prepared by solid-phase methodology to quickly assess the SAR associated with distal functionality on the N1-activating group. From these studies, potent inhibitors with improved specificity were discovered.     

Stromal decidualization of endometriosis in the rhesus macaque (Macaca mulatta): a case report

During exploratory laparotomy, a 10-year-old female rhesus macaque was found to have a 6.0 x 9.5 x 2.0-cm multichambered, yellow, cystic mass cranial to the uterus, from which large amounts of opaque, white fluid were discharged into the abdominal cavity. The animal was euthanized, and the body was submitted for gross and histologic evaluation. Sections of the mass examined microscopically consisted of sheets of polygonal to round cells, with well defined cell borders and moderate amounts of eosinophilic cytoplasm. Scattered throughout these cells were few, variably sized glandular structures composed of columnar to cuboidal epithelium. Glandular epithelial cells were positive for keratin, and the sheets of polygonal cells were positive for vimentin and negative for keratin and CD 68. Gross and histologic appearance, immunohistochemical findings, and history of medroxyprogesterone acetate injections were compatible with a diagnosis of stromal decidualization of endometriosis. Subsequent biopsies of similar lesions in other rhesus macaques in the colony being treated with medroxyprogesterone acetate for endometriosis revealed comparable histologic findings.     

Survival of Escherichia coli O157:H7 in farm water: its role as a vector in the transmission of the organism within herds

AIMS: The study aimed to investigate the survival characteristics of Escherichia coli O157:H7 in farm water (FW), and in sterile distilled municipal water (SDW), stored outdoors under field conditions, with or without the addition of faeces (1% w/v), in a farmyard shed and the laboratory at 15 degrees C. METHODS AND RESULTS: Water samples were inoculated with E. coli O157:H7 at 10(3) and 10(6) ml(-1), and sampled over a 31-day period. In FW stored outdoors in a field, E. coli O157:H7 survived for 14 days at temperatures <15 degrees C, at both inoculation levels, while in the laboratory at 15 degrees C, the organism was still detectable at low levels (<1 log10 cfu ml(-1)) after 31 days. The addition of bovine faeces to water outdoors (1% w/v) resulted in survival for 24 days. In SDW inoculated at 10(6) ml(-1) and stored in the laboratory (15 degrees C), only a 2.5 log reduction was observed after 31 days, while the organism could not be detected after 17 days in the field. Preliminary screening of water samples stored outdoors isolated a bacterium which exhibited antimicrobial activity towards E. coli O157:H7. CONCLUSIONS: The survival of E. coli O157:H7 observed in this study illustrates the potential of farm water to act as a vehicle in the transfer of the organism across a herd. SIGNIFICANCE AND IMPACT OF THE STUDY: The difficulty in extrapolating results from controlled laboratory situations to on-farm conditions is also highlighted in this study.     

A real-time PCR assay for the detection of Campylobacter jejuni in foods after enrichment culture

A real-time PCR assay was developed for the quantitative detection of Campylobacter jejuni in foods after enrichment culture. The specificity of the assay for C. jejuni was demonstrated with a diverse range of Campylobacter species, related organisms, and unrelated genera. The assay had a linear range of quantification over six orders of magnitude, and the limit of detection was approximately 12 genome equivalents. The assay was used to detect C. jejuni in both naturally and artificially contaminated food samples. Ninety-seven foods, including raw poultry meat, offal, raw shellfish, and milk samples, were enriched in blood-free Campylobacter enrichment broth at 37 degrees C for 24 h, followed by 42 degrees C for 24 h. Enrichment cultures were subcultured to Campylobacter charcoal-cefoperazone-deoxycholate blood-free selective agar, and presumptive Campylobacter isolates were identified with phenotypic methods. DNA was extracted from enrichment cultures with a rapid lysis method and used as the template in the real-time PCR assay. A total of 66 samples were positive for C. jejuni by either method, with 57 samples positive for C. jejuni by subculture to selective agar medium and 63 samples positive in the real-time PCR assay. The results of both methods were concordant for 84 of the samples. The total time taken for detection from enrichment broth samples was approximately 3 h for the real-time PCR assay, with the results being available immediately at the end of PCR cycling, compared to 48 h for subculture to selective agar. This assay significantly reduces the total time taken for the detection of C. jejuni in foods and is an important model for other food-borne pathogens.