Increased risk of non-fatal overdose associated with non-prescribed benzodiazepine use in Scotland, UK

BACKGROUND

Drug-related deaths (DRDs) in Scotland increased for seven years in a row between 2014 and 2020, consolidating Scotland's place at the top of the United Kingdom and European drug-related mortality charts. One of the defining features of this recent and rapid rise has been the role of benzodiazepines, which are now involved in the majority of all DRDs. These deaths are linked to use of non-prescribed, benzodiazepine-type novel psychoactive substances (NPS) which have been identified by the United Nations as a global threat to public health. This study aimed to estimate the prevalence and determinants of non-prescribed benzodiazepine use and its association with recent non-fatal overdose among a national sample of people who inject drugs (PWID).

METHODS

Data from the 2019-20 Needle Exchange Surveillance Initiative (NESI) was analysed using logistic regression. NESI is a voluntary, anonymous, biennial, cross-sectional, bio-behavioural survey of PWID attending community-based services providing injecting equipment in mainland Scotland.

RESULTS

Prevalence of non-prescribed benzodiazepine use in the past six months was 52% and significantly associated with age (aOR 0.97, 0.96-0.98), frequent incarceration (aOR 1.29, 1.07-1.57), recent public injecting (aOR 3.25, 2.33-4.55), a recent methadone prescription (aOR 1.87, 1.51-2.33), and a history of benzodiazepine prescription (aOR 1.92, 1.47-2.52). In addition, non-prescribed benzodiazepine use was significantly associated with non-fatal overdose in the past year among PWID (aOR 2.47, 1.90-3.21).

CONCLUSION

This study found a high prevalence of non-prescribed benzodiazepine use among a national sample of PWID in Scotland. Prevalence was highest among populations known to be at increased risk of drug-related death and use was strongly associated with overdose. These novel findings highlight the scale of the non-prescribed benzodiazepine issue Scotland faces, and the urgency required to expand its harm reduction infrastructure to address this unique element of its overdose crisis.

National increase in the community supply of take-home naloxone associated with a mass media campaign in Scotland: a segmented time series analysis

BACKGROUND

Take-home naloxone (THN) programmes have been associated with reductions in opioid-related mortality. In response to high rates of drug-related deaths in Scotland, the Scottish Government commissioned the 'How to save a life' (HTSAL) mass media campaign to: (1) increase awareness of drug-related deaths and how to respond to an overdose, and (2) increase the supply of THN. The aim of this study was to assess the effect of the campaign on the supply of THN.

METHODS

We used an interrupted time series design to assess the effect of the HTSAL mass media campaign on the national community supply of THN. The study time period was August 2020-December 2021. We modelled two key dates: the start of the campaign (week beginning (w/b) 30th of August 2021) and after the end of the main campaign (w/b 25th of October 2021).

RESULTS

The total number of THN kits distributed in the community in Scotland during the study period was 27,064. The mean number of THN kits distributed per week (relative to the pre-campaign period), increased by 126% during the campaign and 57% post-campaign. In segmented regression analyses, the pre-campaign trend in the number of THN kits supplied was increasing by an average of 1% each week (RR=1.01, 95% CI 1.01 to 1.01, p<0.001). Once the campaign started, a significant change in level was observed, and the number of kits increased by 75% (RR=1.75, 95% CI 1.29 to 2.40, p<0.001). The trend during the campaign was stable (i.e. not increasing or decreasing) but a significant change in level was observed when the campaign ended, and the number of THN kits supplied decreased by 32% (RR=0.68, 95% CI 0.46 to 0.98, p = 0.042). The trend during the post-campaign period was stable.

CONCLUSIONS

The HTSAL campaign had a short term, but large and significant impact, on the community supply of THN in Scotland. Mass media campaigns could be combined with other interventions and strategies to maintain the increased uptake of THN outside of campaign periods.

How to save a life: Public awareness of a national mass media take home naloxone campaign, and effects of exposure to campaign components on overdose knowledge and responses

BACKGROUND

Take home naloxone (THN) programmes are effective at reducing opioid related mortality, but require high levels of distribution, including to the general public. Mass media campaigns can be effective in improving public understanding of a topic and encouraging behavior change. Whilst mass media campaigns focusing on naloxone have been developed internationally, there is a lack of research on their potential impact. We investigated the effects of components of a recent national mass media campaign (Scotland, UK) designed to improve public awareness of drug related deaths, and readiness to intervene.

METHODS

We undertook a cross-sectional online experimental study with a randomized design, conducted with a nationally representative sample. Participants (N = 1551; 52.6% female; age 46.1±16.5 years) were assessed on overdose knowledge and readiness to intervene after presentation of eight combinations of campaign components.

RESULTS

Compared to a basic campaign description, exposure to all types of campaign component were associated with higher overdose knowledge (p < .001), but not knowledge of what to do in response to an overdose (p = .374), or readiness to intervene (p= .286). The greatest effects were associated with a media rich audio-visual resource (animated video with a popular song on the soundtrack, and narrated by a well-known actor).

CONCLUSION

Our data suggest that harm reduction is an appropriate topic for large-scale mass media campaigns. However, effects may be limited to knowledge and awareness raising in the general public, and may be related to the types of media used. Audience segmentation is important and more general messaging about drug related deaths may be more appropriate for the majority of audiences.

Impact of COVID-19 & Response Measures on HIV-HCV Prevention Services and Social Determinants in People Who Inject Drugs in 13 Sites with Recent HIV Outbreaks in Europe, North America and Israel

HIV/HCV prevention among people who inject drugs (PWID) is of key public health importance. We aimed to assess the impact of COVID-19 and associated response measures on HIV/HCV prevention services and socio-economic status of PWID in high-HIV-risk sites. Sites with recent (2011-2019) HIV outbreaks among PWID in Europe North America and Israel, that had been previously identified, were contacted early May 2020. Out of 17 sites invited to participate, 13 accepted. Semi-structured qualitative site reports were prepared covering data from March to May 2020, analyzed/coded and confirmed with a structured questionnaire, in which all sites explicitly responded to all 103 issues reported in the qualitative reports. Opioid maintenance treatment, needle/syringe programs and antiretroviral treatment /hepatitis C treatment continued, but with important reductions and operational changes. Increases in overdoses, widespread difficulties with food and hygiene needs, disruptions in drug supply, and increased homelessness were reported. Service programs rapidly reformed long established, and politically entrenched, restrictive service delivery policies. Future epidemic control measures should include mitigation of negative side-effects on service provision and socio-economic determinants in PWID.

Increasing drug-related mortality rates over the last decade in Scotland are not just due to an ageing cohort: A retrospective longitudinal cohort study

BACKGROUND

In Europe, North America, and Australia, mortality due to drug-related (DR) causes amongst people who inject drugs (PWID) is a major issue. Our objective was to characterise temporal trends in DR mortality rates in a large cohort of PWID in Scotland over the past decade, all of whom had been diagnosed with hepatitis C virus (HCV) infection, and to investigate factors associated with DR mortality.

METHODS

Retrospective longitudinal cohort study linking Scotland's national HCV Diagnosis Database and deaths registry. The study cohort consisted of all individuals with likely injection drug use-related route of HCV acquisition, who had been diagnosed with HCV between 1991 and 2018, and were alive and aged under 65 years on 1 January 2009. We used Lexis expansion to adjust for ageing cohort effects and calculated the mortality rate from an underlying/contributing DR cause over the period 2009-2018. We fitted Poisson regression models to estimate the temporal trend adjusting for attained age, sex, referral setting, region, and viraemic status at baseline.

RESULTS

Amongst the study population (n = 35,065; 236,914 person-years), a total of 1900 DR deaths occurred; the DR mortality rate increased from 5.6/1000 [101 deaths] in 2009 to 12.4/1000 [342] person-years in 2018. Increasing trends were observed for all age-groups except 55-64 years. The overall DR mortality rate was highest for referrals for HCV testing from prison (11.0/1000) and hospital settings (10.0/1000). Mortality increased with calendar time period, with significantly raised adjusted rate ratios (RRs) from 2015 (RR=1.40, 95% CI:1.16-1.69) to 2018 (RR=2.23, 95% CI:1.88-2.64), compared with 2011-2012, for older age (35-44: RR=1.37, 95% CI:1.20-1.56; 45-54: RR=1.32, CI:1.14-1.53) compared with <35 years, for persons diagnosed with HCV since 2009 (RR=1.34, 95% CI:1.21-1.49), and for prison and hospital referrals (RRs of 1.30, 1.37) compared with GP referrals.

CONCLUSION

Increasing DR mortality rates in Scotland over the past decade are not just due to an ageing cohort. Harm reduction services will likely need to expand and adapt to reverse the recent upward trends in DR mortality in PWID.

National population prevalence of antibodies to SARS-CoV-2 among pregnant women in Scotland during the second wave of the COVID-19 pandemic: a prospective national serosurvey

OBJECTIVES

This study aimed to determine SARS-CoV-2 seroprevalence among pregnant women in the Scottish population during the second wave of the COVID-19 pandemic.

STUDY DESIGN

Prospective national serosurvey.

METHODS

We tested 13,428 residual samples retrieved from pregnant women participating in the first trimester combined ultrasound and biochemical screening for fetal trisomy across Scotland for SARS-CoV-2 antibodies over a 6-month period from November 2020 to April 2021. Seroprevalence estimates were adjusted for the sensitivity and specificity of the assays and weighted to reference populations.

RESULTS

Seroprevalence rates in the antenatal samples significantly increased from 5.5% (95% confidence interval [CI] 4.7%-6.5%) in the 5-week period up to and including International Organization for Standardization (ISO) Week 51 (w/b Monday 14 December 2020) to 11.3% (95% CI 10.1%-12.6%) in the 5-week period up to and including ISO Week 14 (w/b Monday 5 April 2021). Increasing seroprevalence trends across the second wave were observed among all age groups.

CONCLUSIONS

By the end of the second wave of the COVID-19 pandemic, approximately one in 10 women tested around the end of the first trimester of pregnancy had antibodies to SARS-CoV-2, suggesting that the vast majority were still susceptible to COVID-19 as they progressed to the later stages of pregnancy, when risks from infection are elevated for both mother and baby.

Increased case-finding and uptake of direct-acting antiviral treatment essential for micro-elimination of hepatitis C among people living with HIV: a national record linkage study

OBJECTIVES

Micro-elimination of hepatitis C virus (HCV) in people living with HIV (PLHIV) and co-infected with HCV has been proposed as a key contribution to the overall goal of HCV elimination. While other studies have examined micro-elimination in HIV-treated cohorts, few have considered HCV micro-elimination among those not treated for HIV or at a national level.

METHODS

Through data linkage of national and sentinel surveillance data, we examined the extent of HCV testing, diagnosis and treatment among a cohort of PLHIV in Scotland identified through the national database of HIV-diagnosed individuals, up to the end of 2017.

RESULTS

Of 5018 PLHIV, an estimated 797 (15%) had never been tested for HCV and 70 (9%) of these had undiagnosed chronic HCV. The odds of never having been tested for HCV were the highest in those not on HIV treatment [adjusted odds ratio (aOR) = 7.21, 95% confidence interval (CI): 5.15-10.10). Overall HCV antibody positivity was 11%, and it was at its highest among people who inject drugs (49%). Most of those with chronic HCV (91%) had attended an HCV treatment clinic but only half had been successfully treated (54% for those on HIV treatment, 12% for those not) by the end of 2017. The odds of never having been treated for HCV were the highest in those not on HIV treatment (aOR = 3.60, 95% CI: 1.59-8.15).

CONCLUSIONS

Our data demonstrate that micro-elimination of HCV in PLHIV is achievable but progress will require increased effort to engage and treat those co-infected, including those not being treated for their HIV.

Enhanced surveillance of COVID-19 in Scotland: population-based seroprevalence surveillance for SARS-CoV-2 during the first wave of the epidemic

Objectives

The impact of the COVID-19 pandemic in Scotland has been amongst the most severe in Europe. Serological surveillance is critical to determine the overall extent of infection across populations and to inform the public health response. This study aimed to estimate the proportion of people who have antibodies to SARS-CoV-2 (‘seroprevalence’) in the general population of Scotland and to see if this changes over time.

Study design/Methods

Between International Organization for Standardization (ISO) week 17 (i.e. week commencing 20th April) and ISO week 25 (week commencing 15 June), 4751 residual blood samples were obtained from regional biochemistry laboratories in six participating regional health authority areas covering approximately 75% of the Scottish population. Samples were tested for the presence of anti-SARS-CoV-2 IgG antibodies using the LIAISON®SARS-CoV-2 S1/S2 IgG assay (DiaSorin, Italy). Seroprevalence rates were adjusted for the sensitivity and specificity of the assay using Bayesian methods.

Results

The combined adjusted seroprevalence across the study period was 4.3% (95% confidence interval: 4.2%–4.5%). The proportion varied each week between 1.9% and 6.8% with no difference in antibody positivity by age, sex or geographical area.

Conclusions

At the end of the first wave of the COVID-19 pandemic, only a small fraction of the Scottish population had antibodies to SARS-CoV-2. Control of COVID-19 requires the ability to detect asymptomatic and mild infections that would otherwise remain undetected through existing surveillance systems. This is important to determine the true number of infections within the general population which, in turn, can help to understand transmission, inform control measures and provide a denominator for the estimation of severity measures such as the proportion of infected people who have been hospitalised and/or have died.

Effects of messaging on public support for drug consumption rooms in scotland, UK

BACKGROUND

There is evidence to suggest that medically supervised drug consumption rooms (DCRs) may form part of responses to reduce drug-related harm. Although DCRs have been established globally, they are perceived by some to be a controversial approach in the UK, and Government has repeatedly rejected proposals to establish one in Glasgow, Scotland. As public support is an important component of policy development and enactment, we sought to investigate the effects of different types of message framing on public support for DCR.

METHODS

We undertook a cross-sectional online study with a randomised design, conducted with a nationally representative sample. Participants were randomised to one of six message conditions comprising combinations of four components. All conditions included i) a basic description of a DCR, and conditions included combinations of ii) factual information; iii) pre-emptive refutation of common public concerns about DCR; and/or iv) a sympathetic narrative describing a mother whose son died from a heroin overdose. After reading each message, participants completed a bespoke measure assessing support for DCR. Data were analysed using ANCOVA.

RESULTS

Complete data were obtained from 1591 participants (50.3% Female; mean age 44.9 ± 16.1 years). Compared to reading a basic description of DCR alone, there was greater support for DCR in participants receiving the refutation (p < .001); sympathetic + factual (p < .05); and sympathetic + factual + refutation (p < .001) message conditions. Presenting factual or sympathetic messages alone were not associated with increased support.

CONCLUSION

Our findings suggest that public support for DCRs is not improved through communication of factual statements outlining potential benefits of the intervention alone. Advocates seeking to foster public support, and thus influence policy making, should also consider communication campaigns that address common concerns that the public might have about DCRs, and present the intervention in relation to potential benefits that they hold for people indirectly affected by drug-related harm.

Influence of sorbitol on protein crowding in solution and freeze-concentrated phases

Small-angle neutron scattering was employed to study protein crowding under freezing conditions that mimic those used in pharmaceutical processing. The results demonstrate that, although there is an increase in heterogeneity as the temperature is reduced, sorbitol reduces protein crowding in both solution and freeze-concentrated phases, thus protecting the protein from forming oligomers or irreversible aggregates.

Effect of manufacturing process parameters on virus inactivation by dry heat treatment at 80 degrees C in factor VIII

BACKGROUND AND OBJECTIVES

Dry heat treatment at 80 degrees C for 72 h is used as a virus inactivation step for some coagulation factor concentrates such as Bio Products Laboratory's (BPL) factor VIII 8Y. In the current study, the effect of this process has been tested on a range of viruses. In addition the effect of various manufacturing process parameters on virus inactivation has been investigated.

MATERIALS AND METHODS

Samples of product intermediate were obtained from manufacturing, spiked with virus and subjected to freeze drying and dry heat treatment. Virus inactivation was determined by infectivity assay.

RESULTS

Freeze drying followed by dry heat treatment was effective for inactivating a wide range of enveloped and nonenveloped viruses. Sucrose or protein concentration had no effect on virus inactivation. Product presentation or the interruption of heat treatment also had no effect. The inactivation of some of the viruses was greater at higher residual water content but under such conditions the stability of the product was reduced.

CONCLUSION

This virus inactivation step was effective for a wide range of viruses and over the range of process conditions encountered in manufacturing. This demonstrates the robustness of this process step.

The synthesis and characterization of the pendant-armed ligand N,N′-bis(2′-pyridylmethyl)-1,7-dithia-4,11-diazacyclotetradecane (L4) and crystal structures of L4 and the copper(II) complex [Cu(L4)](ClO4)2 — Crystal structure of the nickel(II) complex of N-(2′-pyridylmethyl)-1,4,7-trithia-11-azacyclotetradecane (L2), [Ni(L2)(CH3CN)](ClO4)2·CH3CN

The synthesis and characterization of the mixed donor ligand N,N′-bis(2′-pyridylmethyl)-1,7-dithia-4,11-diazacyclotetradecane (L4) containing two pendant pyridine arms is described. The macrocycle formation involves reaction of N-tosylbis(2-bromoethyl)amine with N-tosylbis(3-mercaptopropyl)amine at high dilution followed by detosylation at the nitrogen atoms using LiAlH4 in view of the presence of the thioether groups. An X-ray study of the ligand shows the sulphur atoms lie exo to the macrocyclic ring. The nickel(II) and copper(II) complexes of L4 have been characterized and the X-ray structure of the Cu(II) ion exhibits a five-coordinate copper ion despite the presence of six available donor atoms. In the case of ligand N-(2-pyridylmethyl)-1,4,7-trithia-11-azacyclotetradecane (L2), with a single pendant N donor, the Ni(II) complex is distorted octahedral with a molecule of acetonitrile in the sixth site. Details of UV–vis, ESR spectra, and electrochemical studies on the complexes are presented.Key words: synthesis, pendant-armed, mixed donor S,N macrocycles, copper, nickel.

Synthesis and reactivity of the macrobicyclic complexes (1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane)cobalt(III) perchlorate ([Co(L1)(ClO4)](ClO4)2), [(chloro(1,4,8,11-tetraaza-17-oxabicyclo[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L2)(Cl)](ClO4)2), (4,8-dimethyl-1,4,8,11-tetraaza-17-oxabicyclo[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L3)(ClO4)](ClO4)2), and (5,8-dimethyl-1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane)cobalt(III) perchlorate ([Co(L4)(ClO4)](ClO4)2) — Crystal structure of the L2 complex

The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1,5-diaza-8-oxacyclodecane with either 1,9-dichloro-3,7-diazanonane-2,8-dione, and subsequent reduction of the diamide (3), or with 1,9-dichloro-3,7-(dimethyl)diazanonane-2,8-dione and reduction (L3). A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1,4-diaza-7-oxacyclononane. The Co(III) complexes of these ligands and of 1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane (L1) have been prepared. Spectrophotometric determinations on the L1 complex ion confirm the presence of two hydrogen ion related equilibria, one of which (pK = 2.2 ± 0.2) is associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound to the metal centre and hydrogen bonded to the ether. The species derived from L1 and L2 exhibit remarkable kinetic stability. Studies on the anation of the [Co(L1)(H2O)](ClO4)3 with chloride ions in acidic media are consistent with the reaction of both the proton-related complex and the [Co(L1)(H2O)]3+ ion. Whilst complex ions containing two secondary NH groups maintain the metal–ion coordination in strongly acidic media, corresponding species with ligands containing all four tertiary amine sites are subject to attack by protons leading to a relatively facile demetallation of the complexes. The latter finding is supported by kinetic studies and mass spectrometric fragmentation patterns of the ions. Key words: cobalt(III), macrobicycle, hydrolysis, anation, spectroscopic analysis.

Synthesis of 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1) and a Spectroscopic and Structural Study of [Ni(L1)(ClO4)](ClO4) and of the Macrobicyclic Precursor Diamide Complex, [Ni(HL2)](ClO4); Chloride Substitution Kinetics of the Corresponding [Ni(III)(L1)]3+ Species

The pentadentate ligand 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1) has been synthesized by the high dilution cyclization of 1-oxa-4,8-diazacyclododecane ([10]aneN(2)O) (1) with 1,3-bis(alpha-chloroacetamido)propane (2) and subsequent reduction of the diamide intermediate. The structure [Ni(L1)(ClO(4))](ClO(4)) (P2(1)/c (no. 14), a = 8.608(3), b = 16.618(3), c = 14.924(4) A, beta = 91.53(3) degrees converged at R = 0.050 (R(w) = 0.046) for 307 parameters using 2702 reflections with I > 2sigma(I). For the nickel(II) complex of the (monodeprotonated) precursor diamide ligand 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane-3,9-dione (H(2)L2), [Ni(HL2)](ClO(4)) (Pbca (no. 61), a = 15.1590(3), b = 13.235(2), c = 18.0195(6) A), the structure converged at R = 0.045 (R(w) = 0.038) for 265 parameters using 1703 reflections with I > 3sigma(I). In the reduced system, the cyclam-based ligand adopts a trans-III configuration. The [Ni(L1)(ClO(4))](2+) ion is pseudooctahedral with the Ni-O(ether) 2.094(3) A distance shorter than the Ni-O(perchlorate) 2.252(4) A. The nickel(II) and nickel(III) complexes are six-coordinate in solution. Oxidation of [Ni(L1)(OH(2))](2+) with K(2)S(2)O(8) in aqueous media yielded an axial d(7) Ni(III) species (g( perpendicular) = 2.159 and g( perpendicular) = 2.024 at 77 K). The [Ni(L1)(solv)](2+) ion in CH(3)CN showed two redox waves, Ni(II/I) (an irreversible cathodic peak, E(p,c) = -1.53 V) and Ni(III/II) (E(1/2) = 0.85 V (reversible)) vs Ag/Ag(+). The complex [Ni(HL2)](ClO(4)) displays square-planar geometry with monodeprotonation of the ligand. The ether oxygen is not coordinated. Ni-O(3) = 2.651(6) A and Ni-O(3a) = 2.451(12) A, respectively. The Ni(III/II) oxidation at E(1/2) = 0.24 V (quasi-reversible) vs Ag/Ag(+) is considerably lower than the saturated system. The kinetics of Cl(-) substitution at [Ni(L1)(solv)](3+) are pH dependent. Detachment of the ether oxygen atom is proposed, with insertion of a protonated water molecule which deprotonates at a pK(a) more acidic than in the corresponding cyclam complex. Mechanistic implications are discussed.

Stepwise Complexation of Ni(II) and Cu(II) Ions by 6,6'-C-spirobi(cyclam) (cyclam = 1,4,8,11-Tetraazacyclotetradecane), L(1). Syntheses and Redox Chemistry of [M(H(2)L(1))]X(4) (M = Cu(2+), Ni(2+)), [Cu(2)(L(1))]X(4), and [CuNi(L(1))]X(4) (X = ClO(4)(-)) and the X-ray Crystal Structure of [Cu(2)(L(1))](ClO(4))(4)

In aqueous HClO(4), the cation [H(4)(L(1))](4+) where L(1) is 6,6'-C-spirobi(cyclam) (cyclam = 1,4,8,11-tetraazacyclotetradecane), complexes Cu(2+) and Ni(2+) ions in a stepwise fashion to form [M(H(2)L(1))](ClO(4))(4) (M = Cu(2+) and Ni(2+)) from which [CuNi(L(1))](ClO(4))(4) has been prepared selectively. The preparation and the structure of [Cu(2)(L(1))](ClO(4))(4) (empirical formula, C(19)H(44)N(8)Cu(2)Cl(4)O(16); space group, triclinic; P&onemacr;; a = 8.1815(6) Å, b = 12.6098(9) Å, c = 16.6565(12) Å, alpha = 80.3890(10) degrees, beta = 76.5840(10) degrees, gamma = 87.1750(10) degrees, V = 1647.9(2) Å(3), and Z = 2; of the 9531 total reflections collected, 6779 reflections with I > 2sigma(I) on least-squares refinement provided final R(1) = 0.0657 and wR(2) = 0.1424) are also reported. The cyclic voltammograms (1.0 M NaCl, 0.1 M H(+); Pt electrodes; all E(1/2) vs NHE) of [M(H(2)L(1))](4+) (M = Cu(2+) and Ni(2+)) ions show single waves for the Cu(II)/Cu(III) couple (E(1/2) = 0.79 V, irreversible) and the Ni(II)/Ni(III) couple (E(1/2) = 0.56 V, reversible), respectively. In CH(3)CN (0.1 M Et(4)NClO(4)), the [Cu(2)(L(1))](4+) ion shows a reversible wave for the Cu(II)-Cu(II)/Cu(II)-Cu(III) couple ((1)E(1/2) = 1.120 V) and an irreversible wave for the Cu(II)-Cu(III)/Cu(III)-Cu(III) couple ((2)E(1/2) = 1.430 V). Similarly, a reversible wave for the Cu(II)-Ni(II)/Cu(II) -Ni(III) couple ((1)E(1/2) = 0.750 V) and an irreversible wave for the Ni(III)-Cu(II)/Ni(III)-Cu(III) couple ((2)E(1/2) = 1.20 V) are observed in the case of the [Cu(II)Ni(II)(L(1))](4+) ion. The [Cu(2)(L(1))](4+) ion (g( perpendicular) = 2.120, g( parallel) = 2.256 and 2.196, A( parallel) = 150 G, and D( parallel) = 75 G) and the mixed valent species [Cu(II)Ni(III)(L(1))](5+) (for Cu(2+), g( perpendicular) = 2.060, g( parallel) = 2.219, and A( parallel) = 100 G; for Ni(3+) in sulfate media, g( perpendicular) = 2.204 and g( parallel) = 1.967) and [Cu(II)Cu(III)(L(1))](5+) (g(xx)() = 1.982, g(yy)() = 2.155, g(zz)() = 2.386, A(yy)() = 80 G, and A(zz)() = 120 G) show dipolar-dipolar interaction. In the mixed-valent ions, due to strong electrostatic repulsion from either the Ni(III) or Cu(III) ions, significantly smaller A( parallel) (or A(zz)()) values are observed for the Cu(2+) ion compared to 200 G in the mononuclear ions. Also, the [Cu(II)Ni(II)(L(1))](4+) in aqueous HClO(4) and the [Ni(2)(L(1))](4+) ion in CH(3)NO(2) show a tendency to reduce perchlorate very slowly.

Quenching of Triplet State Tetrakis(&mgr;-pyrophosphito-PP')diplatinate(II) by Nickel(II) Macrocyclic and Tris-diimine Complexes

The excited state of tetrakis(&mgr;-pyrophosphito-PP')diplatinate(II), Pt(2)(pop)(4)(4)(-), has been shown to be reductively quenched by a series of Ni(II) complexes. Steady-state photolysis of Pt(2)(pop)(4)(4)(-) in the presence of Ni(cyclam)(2+) and SO(4)(2)(-) ions was followed by absorption spectroscopy and showed the production of the Ni(III) complex with low efficiency. The Ni(III) yield was enhanced in the presence of oxygen presumably because of scavenging of Pt(2)(pop)(4)(5)(-) from the solvent-caged {Pt(2)(II,I).Ni(III)} primary product pair resulting from electron transfer. Cage escape yields of 0.028 in N(2) saturated solution and 0.054 in aerated solutions were estimated from the data. For a series of complexes with decreasing redox potential, the rate constants for their (3)Pt(2)(pop)(4)(4)(-) phosphorescence lifetime quenching decreased with driving force DeltaG, consistent with Rehm-Weller behavior and leading to a reorganization energy of approximately 60 kJ mol(-)(1). The diffusional rate constant calculated from the Debye-Smoluchowski equation was 1.6 x 10(10) M(-)(1) s(-)(1), in excellent agreement with the observed value of 1.6 x 10(10) M(-)(1) s(-)(1) based on the Rehm-Weller equation. The transmission factor for the electron transfer was estimated at 10(-)(4), in the weakly adiabatic region. Although the Rehm-Weller treatment has been used successfully in reactions involving mainly uncharged organic reactants, in this investigation it leads to an unrealistic ratio for the rate constants for the diffusive separation of the charged reactants and products. An alternative interpretation of the results based on an approach by Meyer and Nagle removes this problem and the observed linear dependence of ln k(q) on the square root of E degrees (Ni(II)/Ni(III)) in the endergonic region shows that the dominant back electron transfer produces ground-state species. The analysis also leads to an estimate of the (3)Pt(2)(pop)(4)(4)(-)/Pt(2)(pop)(4)(5)(-) potential of 1.29 +/- 0.05 V(vs NHE), in excellent agreement with the previous literature value of 1.34 V.

A Novel Mixed Macrocycle Complex of Nickel: Synthesis, Structure, and Redox Chemistry of [Ni(II)([9]aneN(3))([9]aneS(3))](ClO(4))(2).CHCl(3) ([9]aneN(3) = 1,4,7-Triazacyclononane and [9]aneS(3) = 1,4,7-Trithiacyclononane)

The mixed macrocycle cation, [Ni([9]aneN(3))([9]aneS(3))](2+) (where [9]aneN(3) = 1,4,7-triazacyclononane and [9]aneS(3) = 1,4,7-trithiacyclononane), has been prepared by stepwise complexation of [9]aneN(3) and [9]aneS(3), respectively, to Ni(II) cation. The intermediate [Ni([9]aneN(3))(CH(3)NO(2))(3)](2+) has been isolated and characterized by mass spectrometry and UV-visible spectroscopy. Cyclic voltammetry of [Ni([9]aneN(3))(CH(3)NO(2))(3)](2+) shows a quasireversible wave for the Ni(II/III) couple (E(1/2) = 0.73V vs Fc(+/0)), and the Ni(III) species exhibits an axial ESR spectrum (g( perpendicular) = 2.101 and g( parallel) = 1.985). The structure of [Ni([9]aneN(3))([9]aneS(3))](ClO(4))(2).CHCl(3) has been determined. It crystallizes in monoclinic space group P2(1)/c with a = 13.3911(8) Å, b = 14.4430(9) Å, c = 13.6116(8) Å, beta = 107.2090(10) degrees, V = 2514.7(3) Å(3), and Z = 4. Of the 15 047 reflections collected, 5765 reflections (I > 2sigma(I)) were used in the refinement to obtain a final R(w) = 0.0278 and R(F) = 0.0368. In the cation [Ni([9]aneN(3))([9]aneS(3))](2+), the two macrocycles occupy the trigonal faces of the Ni(2+) ion, imposing a distorted octahedral geometry. Cyclic voltammetry of the complex in CH(3)CN (Pt electrodes, 0.1 M n-Bu(4)NClO(4), 500 mV) shows a quasireversible wave for the Ni(II)/Ni(III) couple (E(1/2) = 0.86V vs Fc(+/0)). Chemical oxidation by NOPF(6) of the cation [Ni([9]aneN(3))([9]aneS(3))](2+) generates a Ni(III) species that shows axial ESR spectrum with g( perpendicular) = 2.106 and g( parallel) = 2.063. No characteristic reduction wave was observed in either CH(3)CN or CH(3)NO(2) media.

Platelet activation, epinephrine, and blood pressure in obstructive sleep apnea syndrome

OBJECTIVE

There is an increased risk of patients with obstructive sleep apnea syndrome (OSAS) to have stroke or cardiac infarcts. Besides hypertension, epinephrine-induced platelet activation could be a further reason for the increased cardiovascular morbidity and mortality in OSAS.

METHODS

During a 4-month period (August 1994 to December 1994) we recruited prospectively 76 patients referred for polysomnograms because of a suspected sleep disorder such as OSAS.

RESULTS

Fifty patients had no respiratory events during sleep (non-OSAS), 19 patients had more than five but less than 50 obstructive apneas or hypopneas per hour of total sleep time (mild-to-moderate OSAS group), and seven patients had an apnea hypopnea index of more than 50 per hour of total sleep time (severe OSAS group). Blood pressure, plasma epinephrine levels, and P-selectin expression (as a marker for platelet activation) were measured in every patient at 9 PM and 6 AM (before and after the polysomnogram). There was a significant correlation of the apnea hypopnea index with 9 PM and 6 AM systolic and diastolic blood pressure, with 9 PM platelet activation, and with 6 AM epinephrine levels mainly due to high values in the severe OSAS group.

CONCLUSIONS

Our results suggest that platelet activation, epinephrine, and high blood pressure play a role in the high prevalence of cerebrovascular and cardiovascular events in patients with OSAS.

Mental disorder among a homeless population in Belfast: an exploratory survey

This study aimed to identify the prevalence of mental disorder in hostels for the homeless in Belfast, Northern Ireland. In addition, it attempted to assess the facilities and support offered from both the hostels and the Health Service to homeless people who have a mental disorder. Lastly it sought to determine whether or not psychiatric hospital bed closure had any influence on the prevalence of homelessness among these persons in Belfast. An exploratory approach was adopted, using semi-structured interviews as the method of data collection. The sample consisted of 12 hostels for the homeless with a total occupancy of 250 residents. Officers in charge were surveyed. The results obtained indicated that approximately 25% of the homeless in Belfast hostels have a diagnosed mental disorder and that hospital closure has had a direct effect on the size of this percentage. In addition, it was found that the hostels generally are not able to offer the levels of therapy and support given in hospital or in designated hostels for people with mental health problems. Responses also suggest that support from Health Service personnel is less than satisfactory. While the findings in this study do not look at the entire homeless population in Northern Ireland, interesting and useful information emerged that has implications for policy and further areas of study elsewhere.

Crystal and solution structure of a pendant-armed macrocyclic complex of palladium(II)

The synthesis and X-ray crystal structure of [Pd)py2[9]aneN2S)](BF4)2 (py2[9]aneN2S = 1-thia-4,7-bis(pyridylmethyl)diaza-cyclononane) (P21/n,a = 10.233(4) Å, b = 11.484(5) Å, c = 19.913(6) Å, β = 94.03(4)°, V = 2334(2) Å3, R = 0.0705, Rw = 0.0759 ) are presented. The crystal structure indicates a long range interaction (2.92 Å) between the planar palladium and the apical sulphur atom. Although this distance is longer than the value for a Pd—S bond observed normally there is evidence for a net positive interaction provided by the solution structure as determined by NMR spectroscopy. Comparative analysis of the structural features exhibited by this complex with similar nine-membered chelating ligands emphasizes the presence of an axial Pd—S bond.

X-ray crystal structure of [Ni(III)(cyclam)(NO3)2](ClO4) and electron transfer reactions of the Ni(III)/Ni(II) couple

The synthesis and crystal structure of [Ni(cyclam)(NO3)2](ClO4) are described (P1, a = 8.347(4) Å, b = 15.960(7) Å, c = 7.656(3) Å, α = 90.33(6)°, β = 110.97(4)°, γ = 104.45(5)°, V = 917.0(7) Å3, R = 0.0425, Rw = 0.0384). The crystal contains two unique Ni(III) cations within the unit cell, with a network of hydrogen bonding interactions linking one of the cations into a stacked configuration while the other cation contains a strong internal hydrogen bond. This provides an interesting inorganic example of multi-site cooperative binding involving a metal complex cation. By use of electron transfer data from known outer-sphere redox reagents, measurement of the cross-reactions with [Ni(cyclam)]3+/2+ in 3 M nitrate media yielded a self-exchange rate constant of 1.4 × 105 M−1 s−1. The structural data have been utilized to obtain a calculated estimate of the self-exchange rate constant (1.0 × 108 M−1 s−1) for this couple. The relationship between these two values is explored. The lack of adiabaticity is reflected in a value ≈0.01 for κeI not only for this couple but also for other related cyclam complexes.

Synthesis and crystal structure of an octahedral nickel(II) complex derived from pentaerythrityl tetraamine

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Synthesis and crystal structure of an octahedral nickel(II) complex derived from pentaerythrityl tetraamine

The Ni(II) complex, Ni(Htam)24+ (tam = pentaerythrityl tetraamine), has been prepared under controlled conditions. In this ion, three of the four amino groups of each ligand are coordinated to yield an octahedral structure which shows tetragonal and trigonal distortion. The fourth amino group is protonated in each case and binds strongly to the counter ion SO42−. The crystal structure (triclinic, [Formula: see text], a = 8.913(3), b = 9.775(2), c = 7.505(3), α = 102.61(4)°, β = 106.28(4)°, γ = 96.40(3)°) has been refined, converging to final values of R = 0.0347 and Rw = 0.0386. The three dimensional nature of the hydrogen bonding in the crystal structure has been described. Differences in Ni—N bond lengths are observed. A transient nickel(III) species is generated chemically or electrochemically. The esr spectrum is consistent with a low spin d7 centre and is axial in nature. Keywords: nickel, pentaerythrityl tetraamine, hydrogen bonding, oxidation.