Nef binds p6* in gagpol during replication of human immunodeficiency virus type 1

The atypical Nef protein (NefF12) from human immunodeficiency virus type 1 strain F12 (HIV-1F12) interferes with virion production and infectivity via a mysterious mechanism. The correlation of these effects with the unusual perinuclear subcellular localization of NefF12 suggested that the wild-type Nef protein could bind to assembly intermediates in late stages of viral replication. To test this hypothesis, Nef from HIV-1NL4-3 was fused to an endoplasmic reticulum (ER) retention signal (NefKKXX). This mutant NefKKXX protein recapitulated fully the effects of NefF12 on Gag processing and virion production, either alone or as a CD8 fusion protein. Importantly, the mutant NefKKXX protein also localized to the intermediate compartment, between the ER and the trans-Golgi network. Furthermore, Nef bound the GagPol polyprotein in vitro and in vivo. This binding mapped to the C-terminal flexible loop in Nef and the transframe p6* protein in GagPol. The significance of this interaction was demonstrated by a genetic assay in which the release of a mutant HIV-1 provirus lacking the PTAP motif in the late domain that no longer binds Tsg101 was rescued by a Nef.Tsg101 chimera. Importantly, this rescue as well as incorporation of Nef into HIV-1 virions correlated with the ability of Nef to interact with GagPol. Our data demonstrate that the retention of Nef in the intermediate compartment interferes with viral replication and suggest a new role for Nef in the production of HIV-1.

The raft-promoting property of virion-associated cholesterol, but not the presence of virion-associated brij 98 rafts, is a determinant of human immunodeficiency virus type 1 infectivity

Lipid rafts are enriched in cholesterol and sphingomyelin and are isolated on the basis of insolubility in detergents, such as Brij 98 and Triton X-100. Recent work by Holm et al. has shown that rafts insoluble in Brig 98 can be found in human immunodeficiency virus type 1 (HIV-1) virus-like particles, although it is not known whether raft-like structures are present in authentic HIV-1 and it is unclear whether a virion-associated raft-like structure is required for HIV replication. Independently, it was previously reported that virion-associated cholesterol is critical for HIV-1 infectivity, although the specific requirement of virion cholesterol in HIV-1 was not examined. In the present study, we have demonstrated that infectious wild-type HIV-1 contains Brij 98 rafts but only minimal amounts of Triton X-100 rafts. To directly assess the functional requirement of virion-associated rafts and various features of cholesterol on HIV-1 replication, we replaced virion cholesterol with exogenous cholesterol analogues that have demonstrated either raft-promoting or -inhibiting capacity in model membranes. We observed that variable concentrations of exogenous analogues are required to replace a defined amount of virion-associated cholesterol, showing that structurally diverse cholesterol analogues have various affinities toward HIV-1. We found that replacement of 50% of virion cholesterol with these exogenous cholesterol analogues did not eliminate the presence of Brij 98 rafts in HIV-1. However, the infectivity levels of the lipid-modified HIV-1s directly correlate with the raft-promoting capacities of these cholesterol analogues. Our data provide the first direct assessment of virion-associated Brij 98 rafts in retroviral replication and illustrate the importance of the raft-promoting property of virion-associated cholesterol in HIV-1 replication.

Mutations that abrogate human immunodeficiency virus type 1 reverse transcriptase dimerization affect maturation of the reverse transcriptase heterodimer

The specific impact of mutations that abrogate human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) dimerization on virus replication is not known, as mutations shown previously to inhibit RT dimerization also impact Gag-Pol stability, resulting in pleiotropic effects on HIV-1 replication. We have previously characterized mutations at codon 401 in the HIV-1 RT tryptophan repeat motif that abrogate RT dimerization in vitro, leading to a loss in polymerase activity. The introduction of the RT dimerization-inhibiting mutations W401L and W401A into HIV-1 resulted in the formation of noninfectious viruses with reduced levels of both virion-associated and intracellular RT activity compared to the wild-type virus and the W401F mutant, which does not inhibit RT dimerization in vitro. Steady-state levels of the p66 and p51 RT subunits in viral lysates of the W401L and W401A mutants were reduced, but no significant decrease in Gag-Pol was observed compared to the wild type. In contrast, there was a decrease in processing of p66 to p51 in cell lysates for the dimerization-defective mutants compared to the wild type. The treatment of transfected cells with indinavir suggested that the HIV-1 protease contributed to the degradation of virion-associated RT subunits. These data demonstrate that mutations near the RT dimer interface that abrogate RT dimerization in vitro result in the production of replication-impaired viruses without detectable effects on Gag-Pol stability or virion incorporation. The inhibition of RT activity is most likely due to a defect in RT maturation, suggesting that RT dimerization represents a valid drug target for chemotherapeutic intervention.

Mature reverse transcriptase (p66/p51) is responsible for low levels of viral DNA found in human immunodeficiency virus type 1 (HIV-1)

Reverse transcription of the HIV RNA genome is thought to occur in the host cell cytoplasm after viral adsorption. However, viral DNA has been isolated in cell-free virus particles. We have quantitated by polymerase chain reaction (PCR) amplification the amount of viral DNA in virions as compared to RNA. Virus produced by proviral DNA transfections of cos-7 cells or by chronically-infected H9 cells; neither of which express the cell surface CD4 receptor, contained at least 1000 times more viral RNA than DNA. In contrast, only 60 times more RNA than DNA was present in virus particles produced by transfection of Jurkat cells, which were CD4-positive and thus potentially susceptible to superinfection. Protease-defective virus, carrying only the precursor of reverse transcriptase (RT) p160gag-pol, contained virtually no detectable DNA. These results indicate that only mature RT (p66/p51) and not its precursor (p160gag-pol) is responsible for the presence of viral DNA in HIV.

Transition to motherhood in type 1 diabetes : design of the pregnancy and postnatal well-being in transition questionnaires

Background : Life transitions are associated with high levels of stress affecting health behaviours among people with Type 1 diabetes. Transition to motherhood is a major transition with potential complications accelerated by pregnancy with risks of adverse childbirth outcomes and added anxiety and worries about pregnancy outcomes. Further, preparing and going through pregnancy requires vigilant attention to a diabetes management regimen and detailed planning of everyday activities with added stress on women. Psychological and social well-being during and after pregnancy are integral for good pregnancy outcomes for both mother and baby. The aim of this study is to establish the face and content validity of two novel measures assessing the well-being of women with type 1 diabetes in their transition to motherhood, 1) during pregnancy and 2) during the postnatal period.

Methods : The approach to the development of the Pregnancy and Postnatal Well-being in T1DM Transition questionnaires was based on a four-stage pre-testing process; systematic overview of literature, items development, piloting testing of questionnaire and refinement of questionnaire. The questionnaire was reviewed at every stage by expert clinicians, researchers and representatives from consumer groups. The cognitive debriefing approach confirmed relevance of issues and identified additional items.

Results : The literature review and interviews identified three main areas impacting on the women’s postnatal self-management; (1) psychological well-being; (2) social environment, (3) physical (maternal and fetal) well-being. The cognitive debriefing in pilot testing of the questionnaire identified that immediate postnatal period was difficult, particularly when the women were breastfeeding and felt depressed.

Conclusions : The questionnaires fill an important gap by systematically assessing the psychosocial needs of women with type 1 diabetes during pregnancy and in the immediate postnatal period. The questionnaires can be used in larger data collection to establish psychometric properties. The questionnaires potentially play a key role in prospective research to determine the self-management and psychological needs of women with type 1 diabetes transitioning to motherhood and to evaluate health education interventions.

Linguistic and psychometric validation of the diabetes-specific quality-of-life scale in U. K. english for adults with type 1 diabetes

OBJECTIVE To develop a linguistically and psychometrically validated U.K. English (U.K./Ireland) version of the Diabetes-Specific Quality-of-Life Scale (DSQOLS) for adults with type 1 diabetes.

RESEARCH DESIGN AND METHODS We conducted independent forward and backward translation of the validated German DSQOLS. An iterative interview study with health professionals (n = 3) and adults with type 1 diabetes (n = 8) established linguistic validity. The DSQOLS was included in three Dose Adjustment for Normal Eating (DAFNE) studies (total N = 1,071). Exploratory factor analysis (EFA) was undertaken to examine questionnaire structure. Concurrent and discriminant validity, internal consistency, and reliability were assessed.

RESULTS EFA indicated a six-factor structure for the DSQOLS (social aspects, fear of hypoglycemia, dietary restrictions, physical complaints, anxiety about the future, and daily hassles). High internal consistency reliability was found for these factors and the weighted treatment satisfaction scale (α = 0.85–0.94). All subscales were moderately, positively correlated with the Audit of Diabetes-Dependent Quality-of-Life (ADDQoL) measure, demonstrating evidence of concurrent validity. Lower DSQOLS subscale scores [indicating impaired quality of life (QoL)] were associated with the presence of diabetes-related complications.

CONCLUSIONS The DSQOLS captures the impact of detailed aspects of modern type 1 diabetes management (e.g., carbohydrate counting and flexible insulin dose adjustment) that are now routine in many parts of the U.K. and Ireland. The U.K. English version of the DSQOLS offers a valuable tool for assessing the impact of treatment approaches on QoL in adults with type 1 diabetes.

Young adults' management of type 1 diabetes during life transitions

Aim. To identify life transitions likely to impact diabetes self-care among young adults with Type 1 diabetes and their coping strategies during transition events.

Background. Relationships among psychosocial stress, adjustment, coping and metabolic control affect clinical outcomes and mental health. Life transitions represent major change and are associated with stress that temporarily affects individuals’ problem-solving, coping abilities and blood glucose levels.

Design. A qualitative interpretive inquiry.

Method. Semi-structured interviews were conducted with 20 young adults with Type 1 diabetes and a constant comparative analysis method. Data and analysis was managed using QSR_ NVIVO 7 software.

Results. Participants identified two significant transition groups: life development associated with adolescence, going through the education system, entering new relationships, motherhood and the workforce and relocating. Diabetes-related transitions included being diagnosed, developing diabetes complications, commencing insulin pump treatment and going on diabetes camps. Participants managed transitions using ‘strategic thinking and planning’ with strategies of ‘self-negotiation to minimise risks’; ‘managing diabetes using previous experiences’; ‘connecting with others with diabetes’; ‘actively seeing information to ‘patch’ knowledge gaps’; and ‘putting diabetes into perspective’.

Conclusions. Several strategies are used to manage diabetes during transitions. Thinking and planning strategically was integral to glycaemic control and managing transitions. The impact of transitions on diabetes needs to be explored in larger and longitudinal studies to identify concrete strategies that assist diabetes care during life transitions.

Relevance to clinical practice. It is important for health professionals to understand the emotional, social and cognitive factors operating during transitions to assist young adults with Type 1 diabetes to achieve good health outcomes by prioritising goals and plan flexible, timely, individualised and collaborative treatment.

Structured Type 1 Diabetes education delivered within routine care: impact on glycemic control and diabetes-specific quality of life

OBJECTIVE:
To determine whether improvements in glycemic control and diabetes-specific quality of life (QoL) scores reported in research studies for the type 1 diabetes structured education program Dose Adjustment For Normal Eating (DAFNE) are also found when the intervention is delivered within routine U.K. health care.

RESEARCH DESIGN AND METHODS:
Before and after evaluation of DAFNE to assess impact on glycemic control and QoL among 262 adults with type 1 diabetes.

RESULTS:
There were significant improvements in HbA_1c from baseline to 6 and 12 months (from 9.1 to 8.6 and 8.8%, respectively) in a subgroup with suboptimal control. QoL was significantly improved by 3 months and maintained at both follow-up points.

CONCLUSIONS:
Longer-term improved glycemic control and QoL is achievable among adults with type 1 diabetes through delivery of structured education in routine care, albeit with smaller effect sizes than reported in trials.

Diabetes care provision: barriers, enablers and service needs of young adults with Type 1 diabetes from a region of social disadvantage

AIMS:
To determine the barriers to and enablers of engaging with specialist diabetes care and the service requirements of young adults with Type 1 diabetes mellitus from a low socio-economic, multicultural region.

METHODS:
A cross-sectional survey targeted 357 young adults with Type 1 diabetes, aged 18-30 years. Participants completed questions about barriers/enablers to accessing diabetes care and service preferences, self-reported HbA(1c), plus measures of diabetes-related distress (Problem Areas in Diabetes), depression/anxiety (Hospital Anxiety and Depression Scale), and illness perceptions (Brief Illness Perceptions Questionnaire).

RESULTS:
Eighty-six (24%) responses were received [55 (64%) female; mean ± sd age 24 ± 4 years; diabetes duration 12 ± 7 years; HbA(1c) 68 ± 16 mmol/mol (8.4 ± 1.5%)]. Logistical barriers to attending diabetes care were reported; for example, time constraints (30%), transportation (26%) and cost (21%). However, 'a previous unsatisfactory diabetes health experience' was cited as a barrier by 27%. Enablers were largely matched to overcoming these barriers. Over 90% preferred a multidisciplinary team environment, close to home, with after-hours appointment times. Forty per cent reported severe diabetes-related distress, 19% reported moderate-to-severe depressive symptoms and 50% reported moderate-to-severe anxiety.

CONCLUSIONS:
Among these young adults with Type 1 diabetes, glycaemic control was suboptimal and emotional distress common. They had identifiable logistical barriers to accessing and maintaining contact with diabetes care services, which can be addressed with flexible service provision. A substantial minority were discouraged by previous unsatisfactory experiences, suggesting health providers need to improve their interactions with young adults. This research will inform the design of life-stage-appropriate diabetes services targeting optimal engagement, access, attendance and ultimately improved healthcare outcomes in this vulnerable population.

The cost-effectiveness of the Dose Adjustment for Normal Eating (DAFNE) structured education programme: an update using the Sheffield Type 1 Diabetes policy model

AIMS: 
To estimate the cost-effectiveness of training in flexible intensive insulin therapy [as provided in the Dose Adjustment for Normal Eating (DAFNE) structured education programme] compared with no training for adults with Type 1 diabetes mellitus in the UK using the Sheffield Type 1 Diabetes Policy Model.

METHODS: 
The Sheffield Type 1 Diabetes Policy Model was used to simulate the development of long-term microvascular and macrovascular diabetes-related complications and the occurrence of diabetes-related adverse events in 5000 adults with Type 1 diabetes. Total costs and quality-adjusted life years were estimated from a National Health Service perspective over a lifetime horizon, discounted at a rate of 3.5%. The treatment effectiveness of DAFNE was modelled as a reduction in HbA1c that affected the risk of developing long-term diabetes-related complications. Probabilistic and structural sensitivity analyses were conducted.

RESULTS:
DAFNE resulted in greater life expectancy and reduced incidence of some diabetes-related complications compared with no DAFNE. DAFNE was found to generate an average of 0.0294 additional quality-adjusted life years for an additional cost of £426 per patient, leading to an incremental cost-effectiveness ratio of £14 400 compared with no DAFNE. There was a 54% probability that DAFNE would be cost-effective at a willingness-to-pay threshold of £20 000 per quality-adjusted life year.

CONCLUSIONS: 
The results of this study suggest that DAFNE is a cost-effective structured education programme for people with Type 1 diabetes and support its provision by the National Health Service in the UK.