Dying with behavioral and psychological symptoms of dementia in Australian nursing homes: a retrospective case-control study

Objectives

To identify predictors of mortality in people with active and challenging behavioral and psychological symptoms of dementia (BPSD).

Design

A retrospective case-control study was designed to compare those referred to Dementia Support Australia (DSA) who died in the 12 months to November 2016, with an equal number of controls who did not die. An audit tool was designed after literature review and expert opinion from the service. Odds ratio calculations and the Mann-Whitney U test were used to assess for difference.

Setting

Residents of Australian residential aged care facilities with BPSD referred to the DSA service.

Participants

Of 476 patients referred to DSA during the study period, 44 died. 44 controls were randomly selected from those remaining matched for age and sex.

Results

Significant differences included higher rates of benzodiazepine use, drowsiness, delirium, reduced oral intake and discussions about goals of care in those who died. Those who died were referred to the service for a shorter period and had more frequent contact between DSA and nurses at the nursing homes. Increase in opioid use and loss of skin integrity in those who died approached significance. The overall end of life course demonstrated a complex set of needs with frequent delirium, pain and frailty.

Conclusion

Further study is required to determine the optimal care for those with BPSD at the end of their lives. This study would indicate complex end of life care needs and point to a role for palliative care support.

Fourier transform infrared spectroscopy as a non-destructive method for analysing herbarium specimens

Dried plant specimens stored in herbaria are an untapped treasure chest of information on environmental conditions, plant evolution and change over many hundreds of years. Owing to their delicate nature and irreplaceability, there is limited access for analysis to these sensitive samples, particularly where chemical data are obtained using destructive techniques. Fourier transform infrared (FTIR) spectroscopy is a chemical analysis technique which can be applied non-destructively to understand chemical bonding information and, therefore, functional groups within the sample. This provides the potential for understanding geographical, spatial and species-specific variation in plant biochemistry. Here, we demonstrate the use of mid-FTIR microspectroscopy for the chemical analysis of Drosera rotundifolia herbarium specimens, which were collected 100 years apart from different locations. Principal component and hierarchical clustering analysis enabled differentiation between three main regions on the plant (lamina, tentacle stalk and tentacle head), and between the different specimens. Lipids and protein spectral regions were particularly sensitive differentiators of plant tissues. Differences between the different sets of specimens were smaller. This study demonstrates that relevant information can be extracted from herbarium specimens using FTIR, with little impact on the specimens. FTIR, therefore, has the potential to be a powerful tool to unlock historic information within herbaria.

Acrylamide-based hydrogels with distinct osteogenic and chondrogenic differentiation potential

Regeneration solutions for the osteochondral interface depth are limited, where multi-material implants have the potential to delaminate affecting the regeneration process and impacting the final integrity of tissue interface. Here we explore regionally mixed hydrogel networks, presenting distinct chemical features to determine their compatibility in supporting osteogenic or chondrogenic cell behaviour and differentiation. Poly(N-isopropylacrylamide) (pNIPAM) and poly(N-tert-butylacrylamide) (pNTBAM) hydrogels were assessed in terms of their chemical differences, mechanical strength, internal architecture, porosity and capacity to support cell viability, migration, and differentiation. pNTBAM polymerized with a Young’s modulus of up to 371 ± 31 kPa compared to the more flexible pNIPAM, 16.5 ± 0.6 kPa. Viability testing revealed biocompatibility of both hydrogels with significantly increased cell numbers observed in pNTBAM (500 ± 95 viable cells/mm²) than in pNIPAM (60 ± 3 viable cells/mm²) (P ≤ 0.05). Mineralization determined through alkaline phosphatase (ALP) activity, calcium ion and annexin A2 markers of mineralization) and osteogenic behaviour (collagen I expression) were supported in both hydrogels, but to a greater extent in pNTBAM. pNTBAM supported significantly elevated levels of chondrogenic markers as evidenced by collagen II and glycosaminoglycan expression in comparison to little or no evidence in pNIPAM (P ≤ 0.05). In conclusion, structurally similar, chemically distinct, acrylamide hydrogels display variable capacities in supporting osteochondral cell behaviours. These systems demonstrate spatial control of cell interaction through simple changes in monomer chemistry. Fine control over chemical presentation during the fabrication of biomaterial implants could lead to greater efficacy and targeted regeneration of semi-complex tissues.

Impact of type-1 collagen hydrogel density on integrin-linked morphogenic response of SH-SY5Y neuronal cells

Cellular metabolism and behaviour is closely linked to cytoskeletal tension and scaffold mechanics. In the developing nervous system functional connectivity is controlled by the interplay between chemical and mechanical cues that initiate programs of cell behaviour. Replication of functional connectivity in neuronal populations in vitro has proven a technical challenge due to the absence of many systems of biomechanical regulation that control directional outgrowth in vivo. Here, a 3D culture system is explored by dilution of a type I collagen hydrogel to produce variation in gel stiffness. Hydrogel scaffold remodelling was found to be linked to gel collagen concentration, with a greater degree of gel contraction occurring at lower concentrations. Gel mechanics were found to evolve over the culture period according to collagen concentration. Less concentrated gels reduced in stiffness, whilst a biphasic pattern of increasing and then decreasing stiffness was observed at higher concentrations. Analysis of these cultures by PCR revealed a program of shifting integrin expression and highly variable activity in key morphogenic signal pathways, such as mitogen-associated protein kinase, indicating genetic impact of biomaterial interactions via mechano-regulation. Gel contraction at lower concentrations was also found to be accompanied by an increase in average collagen fibre diameter. Minor changes in biomaterial mechanics result in significant changes in programmed cell behaviour, resulting in adoption of markedly different cell morphologies and ability to remodel the scaffold. Advanced understanding of cell-biomaterial interactions, over short and long-term culture, is of critical importance in the development of novel tissue engineering strategies for the fabrication of biomimetic 3D neuro-tissue constructs. Simple methods of tailoring the initial mechanical environment presented to SH-SY5Y populations in 3D can lead to significantly different programs of network development over time.

Modification of the surface nanotopography of implant devices: A translational perspective

There is an increasing need for the development of superior, safe, and more sophisticated implants, especially as our society historically has been moving towards an increasingly aging population. Currently, most research is being focused on the next generation of advanced medical implants, that are not only biocompatible but have modified surfaces that direct specific immunomodulation at cellular level. While there is a plethora of information on cell-surface interaction and how surfaces can be nanofabricated at research level, less is known about how the academic knowledge has been translated into clinical trials and commercial technologies. In this review, we provide a clinical translational perspective on the use of controlled physical surface modification of medical implants, presenting an analysis of data acquired from clinical trials and commercial products. We also evaluate the state-of-the-art of nanofabrication techniques that are being applied for implant surface modification at a clinical level. Finally, we identify some current challenges in the field, including the need of more advanced nanopatterning techniques, the comparatively small number of clinical trials and comment on future avenues to be explored for a successful clinical translation.

Glycogenin is Dispensable for Glycogen Synthesis in Human Muscle, and Glycogenin Deficiency Causes Polyglucosan Storage

CONTEXT

Glycogenin is considered to be an essential primer for glycogen biosynthesis. Nevertheless, patients with glycogenin-1 deficiency due to biallelic GYG1 (NM_004130.3) mutations can store glycogen in muscle. Glycogenin-2 has been suggested as an alternative primer for glycogen synthesis in patients with glycogenin-1 deficiency.

OBJECTIVE

The objective of this article is to investigate the importance of glycogenin-1 and glycogenin-2 for glycogen synthesis in skeletal and cardiac muscle.

DESIGN, SETTING, AND PATIENTS

Glycogenin-1 and glycogenin-2 expression was analyzed by Western blot, mass spectrometry, and immunohistochemistry in liver, heart, and skeletal muscle from controls and in skeletal and cardiac muscle from patients with glycogenin-1 deficiency.

RESULTS

Glycogenin-1 and glycogenin-2 both were found to be expressed in the liver, but only glycogenin-1 was identified in heart and skeletal muscle from controls. In patients with truncating GYG1 mutations, neither glycogenin-1 nor glycogenin-2 was expressed in skeletal muscle. However, nonfunctional glycogenin-1 but not glycogenin-2 was identified in cardiac muscle from patients with cardiomyopathy due to GYG1 missense mutations. By immunohistochemistry, the mutated glycogenin-1 colocalized with the storage of glycogen and polyglucosan in cardiomyocytes.

CONCLUSIONS

Glycogen can be synthesized in the absence of glycogenin, and glycogenin-1 deficiency is not compensated for by upregulation of functional glycogenin-2. Absence of glycogenin-1 leads to the focal accumulation of glycogen and polyglucosan in skeletal muscle fibers. Expression of mutated glycogenin-1 in the heart is deleterious, and it leads to storage of abnormal glycogen and cardiomyopathy.

A micro-fabricated in vitro complex neuronal circuit platform

Developments in micro-manufacture as well as biofabrication technologies are driving our ability to create complex tissue models such as ‘organ-on-a-chip’ devices. The complexity of neural tissue, however, requires precisely specific cellular connectivity across many neuronal populations, and thus there have been limited reports of complex ‘brain-on-a-chip’ technologies modelling specific cellular circuit function. Here we describe the development of a model of in vitro brain circuitry designed to accurately reproduce part of the complex circuitry involved in neurodegenerative diseases; using segregated co-culture of specific basal ganglia (BG) neuronal subtypes to model central nervous system circuitry. Lithographic methods and chemical modification were used to form structured micro-channels, which were populated by specifically cultured neuronal sub-types to represent parts of the inter-communicating neural circuit. Cell morphological assessment and immunostaining showed connectivity, which was supported by electrophysiology measurements. Electrical activity of cells was measured using patch-clamp, showing voltage dependant Na⁺ and K⁺ currents, and blocking of Na⁺ current by TTX, and calcium imaging showing TTX-sensitive slow Ca²⁺ oscillations resulting from action potentials. Monitoring cells across connected ports post-TTX addition demonstrated both upstream and downstream changes in activity, indicating network connectivity. The model developed herein provides a platform technology that could be used to better understand neurological function and dysfunction, contributing to a growing urgency for better treatments of neurodegenerative disease. We anticipate the use of this advancing technology for the assessment of pharmaceutical and cellular therapies as a means of pre-clinical assessment, and further for the advancement of neural engineering approaches for tissue engineering.

'It's nice to have something to do': early-onset dementia and maintaining purposeful activity

As the global focus on dementia care increases due to the demand on health, social, legal and financial services, it is imperative to further understand the experience of those living with a diagnosis of dementia. There is a particular lack of research focused on younger people (under the age of 65 years) with dementia and virtually none focuses on the experience of the family unit. The literature suggests that periods of transition place significant stressors on families living with dementia. One such transition is the transition out of perceived purposeful activity, be this employment or voluntary work. This transition was explored during the course of a qualitative repeated interview study with younger people with dementia and their families. Nine families (20 participants) took part in semi-structured research interviews that were transcribed and analyzed using a Framework approach to qualitative analysis. Meaningful Activity emerged as a major theme through this analysis. Two subthemes also emerged: (1) the traumatic cessation of work; and (2) the need for purposeful activity. These themes have significant clinical implications as maintaining a purposeful role through high-quality, age-specific dementia services may decrease the direct and indirect costs of dementia to global economies.

Structural characterisation of a polyphosphate kinase

When deprived of nutrients bacteria undergo what is referred to as the `stringent response'. During the stringent response, the cell induces the expression of genes to cope with stress and starvation and diverts resources away from cell growth and division. This involves altering the cellular levels of the signalling molecules: ppGpp, pppGpp and inorganic polyphosphate (polyP)[1]. This is controlled by four enzymes; Polyphosphate kinase (Ppk), Exopolyphosphatase (Ppx), RelA and SpoT. Therefore, modulation of these enzymes is an attractive method for targeting pathogenic bacteria such as Francisella tularensis (F. tularensis), the causative agent of tularemia. FtPpk transfers phosphate from polyP to ADP to generate ATP, a reaction that is fully reversible. The importance of FtPpk in infection has been demonstrated in knockout mutants which resulted in defective growth of F. tularensis in macrophages[2]. Mutagenesis in other pathogenic bacteria has yielded attenuated mutants, suggesting an important role for Ppk in a broad spectrum of bacterial species[3]. To maximise our understanding of FtPpk, our aim was to obtain co-crystals of the enzyme and substrates. Isothermal Titration Calorimetry (ITC) was used to measure the binding of polyP and ADP to FtPpk as independent substrates. FtPpk binds ADP very weakly or not at all in the absence of polyP. FtPpk binds polyP in an exothermic reaction with a relatively high affinity (0.385 µM) in the absence of ADP. Co-crystals of FtPpk with polyP and ADP have been obtained and optimised to diffract to 2.0 Å, identifying a potential binding site for polyP. A non-hydrolysable analogue of ATP has been chemically synthesised to allow co-crystallisation experiments.

Sterol regulatory element-binding protein-1 (SREBP-1) is required to regulate glycogen synthesis and gluconeogenic gene expression in mouse liver

Sterol regulatory element-binding protein-1 (SREBP-1) is a key transcription factor that regulates genes in the de novo lipogenesis and glycolysis pathways. The levels of SREBP-1 are significantly elevated in obese patients and in animal models of obesity and type 2 diabetes, and a vast number of studies have implicated this transcription factor as a contributor to hepatic lipid accumulation and insulin resistance. However, its role in regulating carbohydrate metabolism is poorly understood. Here we have addressed whether SREBP-1 is needed for regulating glucose homeostasis. Using RNAi and a new generation of adenoviral vector, we have silenced hepatic SREBP-1 in normal and obese mice. In normal animals, SREBP-1 deficiency increased Pck1 and reduced glycogen deposition during fed conditions, providing evidence that SREBP-1 is necessary to regulate carbohydrate metabolism during the fed state. Knocking SREBP-1 down in db/db mice resulted in a significant reduction in triglyceride accumulation, as anticipated. However, mice remained hyperglycemic, which was associated with up-regulation of gluconeogenesis gene expression as well as decreased glycolysis and glycogen synthesis gene expression. Furthermore, glycogen synthase activity and glycogen accumulation were significantly reduced. In conclusion, silencing both isoforms of SREBP-1 leads to significant changes in carbohydrate metabolism and does not improve insulin resistance despite reducing steatosis in an animal model of obesity and type 2 diabetes.

Superhydrophobicity for antifouling microfluidic surfaces

Fouling of surfaces is often problematic in microfluidic devices, particularly when using protein or -enzymatic solutions. Various coating methods have been investigated to reduce the tendency for protein molecules to adsorb, mostly relying on hydrophobic surface chemistry or the antifouling ability of -polyethylene glycol. Here we present the potential use of superhydrophobic surfaces to not only reduce the amount of surface contamination but also to induce self-cleaning under flow conditions. The methodology is presented in order to prepare superhydrophobic surface coatings having micro- and nanoscale feature dimensions, as well as a step-by-step guide to quantify adsorbed protein down to nanogram levels. The fabrication of these surfaces as coatings via silica sol-gel and copper nano-hair growth is presented, which can be applied within microfluidic devices manufactured from various materials.

Surface treatments for microfluidic biocompatibility

Microfluidic systems allow small volumes of liquids to be manipulated, either by being passed through channels or moved around as liquid droplets. Such systems have been developed to separate, purify, analyze, and deliver molecules to reaction zones. Although volumes are small, reaction rates, catalysis, mixing, and heat transfer can be high, enabling the accurate sensing of tiny quantities of agents and the synthesis of novel products. The incorporation of multiple components, such as pumps, valves, mixers, and heaters, onto a single microfluidic platform has brought about the field of lab-on-a-chip devices or micro total analysis systems (μTAS). Although used in the research laboratory for numerous years, few of these devices have made it into the commercial market, due to their complexity of fabrication and limited choice of material. As the dimensions of these systems become smaller, interfacial interactions begin to dominate in terms of device performance. Appropriate selection of bulk materials, or the application of surface coatings, can allow control over surface properties, such as the adsorption of (bio)molecules. Here we review current microfluidic technology in terms of biocompatibility issues, examining the use of modification strategies to improve device longevity and performance.

'It's easier just to separate them': practice constructions in the mental health care and support of younger people with dementia and their families

There is no standard model of specialist care for younger people with dementia (onset before the age of 65 years) and specialist service provision varies widely throughout the UK. In order to gain a clearer picture about ways in which clinical staff work with younger people with dementia, semi-structured interviews were conducted with dementia care staff working in the north-west of England. Interviews focused on exploring daily working practices and the meaning placed on clinical decision making when involving family/carers in routine practice. Content analysis generated three core themes: (1) Maintaining Separation: how clinical staff conceptualize the meaning of 'family' in the provision of dementia care services; (2) Providing Practical Help: the focus in care provision on assisting families with aspects of daily life such as finances, education and physical care; and (3) Acknowledging the Family Context: how staff understand and interact with family members in an attempt to initiate care, utilizing biographically informed practice. By understanding how staff view their role in providing younger people with dementia with effective, high-quality dementia care, it is anticipated that a more family-centred approach can be integrated into already established patterns of working that more holistically meet the needs of this group.

The folic acid endophenotype and depression in an elderly population

OBJECTIVES

Folate status and/or genes have been linked to depression in a number of studies. This may be via a direct action (or actions) on neuronal membranes or indirect effects through the metabolism of methyl groups involved in neurotransmitter synthesis. This study examines folate and related thiol metabolism that might underpin either phenomenon.

DESIGN

Cohort study describing the relationship between several genetic and nutritional aspects of folic acid homeostasis and depression assessed by the HADS psychometric index in an elderly cohort.

SETTING

New South Wales (Australia) retirement village.

PARTICIPANTS

118 elderly participants (age 65-90 years).

RESULTS

Stepwise multiple regression was used to determine the best statistical model to predict depression; C677T-MTHFR (p=0.0103) was found to be positively associated with depression, while the thiol dipeptide Cys-Gly was negatively associated (p=0.0403). The statistical models used accounted for the major folate related indices (genetic and biochemical) that are most often evaluated in the context of health and disease. When only genetic data were examined for interactions, C677T-MTHFR was found to be negatively associated with the HADS Depression Index Score (p=0.0191).

CONCLUSION

The potential influence of Cys-Gly on this phenotype is novel, and of considerable interest given that it has been linked to altered spontaneous activity and sedation in an animal model. Cys-Gly is a recognised ligand at the N-methyl-D-aspartatic acid (NMDA) subclass of glutamate receptor, a system associated with depression. In addition, the C677T-MTHFR association adds further support to existing findings underscoring the potential role of folate in depression.

Historical interrelated variations of mercury and aquatic organic matter in lake sediment cores from a subArctic lake in Yukon, Canada: further evidence toward the algal-mercury scavenging hypothesis

This study investigates the role of climate-driven aquatic productivity increases in conrolling the sedimentary accumulation of mercury (Hg) in Kusawa Lake, Yukon, Canada. Organic geochemistry data reveals a significant link between the increasing trends of Hg and of labile algal-derived organic matter (OM) over the centuries and in particular over recent decades. Sedimentary Hg accumulation rates continue to increase even though atmospheric concentrations of Hg have remained the same or even declined. Together, these findings indicate that the significant rise in Hg content recorded in the sediments since the early 1950s may not be representative of increasing atmospheric Hg levels but are strongly influenced by elevated concentrations of algal-derived OM in the water-column. These likely increase the scavenging rate of "available" Hg from the water column. Therefore, recent increases in algal productivity may result in overestimation of the historical rates of atmospheric Hg deposition recorded in the sediments. This study confirms earlier published findings from two High Arctic lakes, and shows that the Hg-OM scavenging hypothesis may also apply to sub-Arctic lakes.

Predictors and confounders of unprotected sex: A UK web-based study

OBJECTIVES

To evaluate the effects of gender, sex orientation, age, relationship status, age at first sex education, age at first sex, frequency of sex and number of sexual partners on the likelihood of unprotected sex in the United Kingdom (UK).

METHODS

A web-based survey was conducted in the UK in 2004 with 10,138 respondents. Eight variables were chosen as potential predictors of unprotected sex. Responses from sexually active participants were combined and crude/adjusted odds ratios (AORs) were calculated for binary/categorical variables.

RESULTS

No differences were found in AOR for gender, sex orientation, relationship status and frequency of sex. Differences were found in AOR for age, sex education, age at first sex and number of sexual partners, e.g. AOR 21-24 years of age versus under 16 (1.92, CI 1.38-2.68; p-value < 0.001); AOR sex education never received versus first sex education under 10 years of age (1.45, CI 1.12-1.87; p-value < 0.01); AOR first sex at 20 years versus at 14 years (0.56, CI 0.40-0.79; p-value < 0.01); and AOR 11-20 partners versus one partner (24.91, CI 20.02-30.98; p-value < 0.001). The association of sex orientation and relationship status with unprotected sex is confounded by the number of sexual partners.

CONCLUSIONS

UK health and education authorities should develop strategies to provide sex education starting in primary school and continuing throughout secondary school. Prevention programs and policies should focus on particular sexual behaviours. Furthermore, an understanding of sexual diversity and reducing stigmatisation of sexual orientation is necessary.

Nano-scale superhydrophobicity: suppression of protein adsorption and promotion of flow-induced detachment

Wall adsorption is a common problem in microfluidic devices, particularly when proteins are used. Here we show how superhydrophobic surfaces can be used to reduce protein adsorption and to promote desorption. Hydrophobic surfaces, both smooth and having high surface roughness of varying length scales (to generate superhydrophobicity), were incubated in protein solution. The samples were then exposed to flow shear in a device designed to simulate a microfluidic environment. Results show that a similar amount of protein adsorbed onto smooth and nanometer-scale rough surfaces, although a greater amount was found to adsorb onto superhydrophobic surfaces with micrometer scale roughness. Exposure to flow shear removed a considerably larger proportion of adsorbed protein from the superhydrophobic surfaces than from the smooth ones, with almost all of the protein being removed from some nanoscale surfaces. This type of surface may therefore be useful in environments, such as microfluidics, where protein sticking is a problem and fluid flow is present. Possible mechanisms that explain the behaviour are discussed, including decreased contact between protein and surface and greater shear stress due to interfacial slip between the superhydrophobic surface and the liquid.

Decoupling of the liquid response of a superhydrophobic quartz crystal microbalance

Recent reports using particle image velocimetry and cone-and-plate rheometers have suggested that a simple Newtonian liquid flowing across a superhydrophobic surface demonstrates a finite slip length. Slippage on a superhydrophobic surface indicates that the combination of topography and hydrophobicity may have consequences for the coupling at the solid--liquid interface observed using the high-frequency shear-mode oscillation of a quartz crystal microbalance (QCM). In this work, we report on the response of a 5 MHz QCM possessing a superhydrophobic surface to immersion in water--glycerol mixtures. QCM surfaces were prepared with a layer of SU-8 photoresist and lithographically patterned to produce square arrays of 5 mum diameter circular cross-section posts spaced 10 microm center-to-center and with heights of 5, 10, 15, and 18 microm. Non-patterned layers were also created for comparison, and both non-hydrophobized and chemically hydrophobized surfaces were investigated. Contact angle measurements confirmed that the hydrophobized post surfaces were superhydrophobic. QCM measurements in water before and after applying pressure to force a Cassie-Baxter (non-penetrating) to Wenzel (penetrating) conversion of state showed a larger frequency decrease and higher dissipation in the Wenzel state. QCM resonance spectra were fitted to a Butterworth-van Dyke model for the full range of water-glycerol mixtures from pure water to (nominally) pure glycerol, thus providing data on both energy storage and dissipation. The data obtained for the post surfaces show a variety of types of behavior, indicating the importance of the surface chemistry in determining the response of the quartz crystal resonance, particularly on topographically structured surfaces; data for hydrophobized post surfaces imply a decoupling of the surface oscillation from the mixtures. In the case of the 15 microm tall hydrophobized post surfaces, crystal resonance spectra become narrower as the viscosity-density product increases, which is contrary to the usual behavior. In the most extreme case of the 18 microm tall hydrophobized post surfaces, both the frequency decrease and bandwidth increase of the resonance spectra are significantly lower than that predicted by the Kanazawa and Gordon model, thus implying a decoupling of the oscillating surface from the liquid, which can be interpreted as interfacial slip.

Comparison of insulin lispro mixture 25/75 with insulin glargine during a 24-h standardized test-meal period in patients with Type 2 diabetes

AIM

To compare insulin lispro mixture (25% insulin lispro and 75% NPL; Mix 25/75) twice-daily plus oral glucose-lowering medications (metformin and/or sulphonylurea) with once-daily insulin glargine plus oral agents with respect to postprandial glycaemic control and other glucose and lipid parameters in patients with Type 2 diabetes inadequately controlled with insulin and/or oral glucose-lowering agents.

METHODS

This was a randomized, open-label, crossover study. Prestudy oral agents were continued and patients not already on oral agents were treated with metformin. Mix 25/75 and insulin glargine were adjusted over 3 months to attain premeal plasma glucose (PG) < 6.0 mmol/l and were then given during a 24-h in-patient test meal period with frequent PG, serum triglyceride (TG) and free fatty acid (FFA) measurements.

RESULTS

Twenty patients (10 F/10 M; mean +/-sd age 54.0 +/- 10.7 years, body mass index 37.0 +/- 8.6 kg/m2, HbA1c 8.4 +/- 1.01%) participated. Mean doses were 23 U before the morning and 37 U before the evening meal for Mix 25/75 and 44 U for insulin glargine. The combined 2-h morning and evening meal postprandial plasma glucose (PPG) was not different between groups (9.2 +/- 2.04 vs. 9.9 +/- 1.66 mmol/l, P = 0.161). Mix 25/75 was associated with a lower mean 2-h PPG for all meals combined (9.0 +/- 1.88 vs. 9.9 +/- 1.80 mmol/l, P < 0.05) and lower mean 24-h PG (6.7 +/- 1.00 vs. 7.5 +/- 1.32 mmol/l, P < 0.01). Eight patients experienced mild hypoglycaemia (PG < 3.5 mmol/l) with Mix 25/75 and 3 with insulin glargine. The endpoint HbA1c was lower with Mix 25/75 (6.9 +/- 0.52% vs. 7.3 +/- 0.81%, P < 0.05).

CONCLUSIONS

In a 24-h test-meal setting in 20 patients, Mix 25/75 insulin plus oral glucose-lowering agents was associated with lower mean PPG and 24-h PG, more mild hypoglycaemia and similar TG, FFA and fasting PG concentrations. HbA1c was lower with Mix 75/25 plus oral agents, although it may not have reached steady state due to ongoing dose adjustment.

Temporal trends of organochlorine contaminants in burbot and lake trout from three selected Yukon lakes

Historical studies have demonstrated that organochlorine (OC) concentrations in top predators can vary considerably from lake to lake within a small geographic region but temporal trends of these contaminants have rarely been monitored in a sub-Arctic area for a long period of time. This study examined OC concentrations, including chlordane (CHL), DDT, hexachlorocyclohexane (HCH), toxaphene (CHB), PCB and chlorinated benzenes (CBz) in lake trout and burbot, from three Yukon lakes (Laberge, Kusawa, Quiet), over a span of 11 years (1992-2003). Temporal and spatial differences continue to exist in the OC concentrations of burbot and lake trout between these lakes. There is strong evidence that these contaminants are declining at various rates in lake trout (Salveninus namaycush) in Laberge, Kusawa and Quiet Lakes. For example, SigmaDDT concentrations have decreased 39%, 85% and 84% in Kusawa, Quiet and Laberge Lakes, respectively. Conversely, no consistent trends were observed in OC concentrations for burbot (Lota lota). For example, there is no evidence of a decline in toxaphene concentrations of Kusawa burbot yet a 58% decrease was observed in Laberge samples. Increases were also observed in the SigmaHCH levels of Kusawa Lake burbot, as well as increases in all OC groups (except SigmaHCH) for the Quiet Lake burbot samples. Decreases in burbot were evident in SigmaHCH and SigmaCHB for Lake Laberge fish and in SigmaCHL for Kusawa Lake samples. Spatial variations in OC levels are quite evident as Lake Laberge trout and burbot continued to maintain the highest levels over the eleven-year period from 1992 to 2003 followed by Kusawa Lake and then Quiet Lake. These differences were related to a variety of factors especially the species morphological characteristics such as log age, log weights and fish lipid content. A decreasing trend in Quiet and Laberge Lake trout lipid content, coupled with fluctuating condition factors and increases in body masses, suggest biotic changes may be occurring within the food webs due to fish population variations related to the cessation of commercial fishing or potentially an increase in lake plankton productivity related to annual climate variation. It is suspected that biotic factors rather than atmospheric inputs are the primary factors affecting the contaminant concentrations in lake trout and burbot in the study lakes.

A history of total mercury in edible muscle of fish from lakes in northern Canada

Subsistence fishing has been an important source of food for Native People in northern Canada since prehistoric time. Measurements of the levels of mercury in edible muscle of northern fish have been undertaken for over three decades in efforts to evaluate the risks of consuming northern fish. This report summarizes the data obtained from 7974 fish of 25 species from sites distributed from the Yukon to Labrador. The most abundant species were lake trout, lake whitefish, arctic char, walleye, northern pike and burbot. The question being asked was essentially "Are the fish safe to eat?" The results were used to support decisions on fishing and consumption of fish. They were sorted in several ways, into concentration ranges corresponding to human consumption guidelines, into political jurisdictions and into types of bedrock geology. Overall walleye, northern pike and lake trout, usually exceeded the subsistence consumption guideline of 0.2 microg g-1 total mercury and often exceeded the higher guideline of 0.5 microg g-1 total mercury for commercial sales of fish. Mercury in burbot, another facultative predator, was often lower but several still exceeding a guideline. Arctic char collections were mostly from anadromous populations and these had very low levels of mercury, presumably reflecting marine food sources. Lake whitefish were among the cleanest fish examined with 69 of 81 collections falling in the lowest range. Most collections were from sites in sedimentary rock. However a few sites were in metamorphic, intrusive or volcanic rocks and these, taken together, tended to have a higher proportion of sites in the higher ranges of mercury. These results indicate a widespread problem with mercury in subsistence fisheries for predator species of fish with the problem being most problematic for Nunavut.

A 75% insulin lispro/25% NPL mixture provides a longer duration of insulin activity compared with insulin lispro alone in patients with Type 1 diabetes

AIMS

To compare a new insulin formulation, high mix (HM) [75% lispro (LP) and 25% neutral protamine lispro (NPL)], to regular human insulin (HR) and LP with respect to glucose response and pharmacokinetics following a test meal in patients with Type 1 diabetes.

METHODS

After fasting overnight, patients received an intravenous insulin infusion to standardize blood glucose (BG) to 7.5 mmol/l (135 mg/dl). In a randomised, three-way crossover study, HR was injected 30 min before, and LP or HM was injected immediately before the test meal on three separate occasions. For each patient, LP and HR were administered at identical doses; the HM dose was one and one third times that of HR and LP to maintain the same dose of short or rapid-acting insulin. The insulin infusion was stopped 15 min after the insulin injection. Free insulin and BG concentrations were measured frequently for 7 h following the test meal.

RESULTS

HM and LP resulted in better glycaemic control than HR during the observation period. BG concentrations during the first 4-5 h did not differ between HM and LP. However, HM exhibited prolonged insulin activity relative to LP beyond 5 h, extending the duration of action by approximately 1 h, and resulting in lower overall BG concentrations when the 0-6- and 0-7-h intervals were considered.

CONCLUSIONS

Compared with LP, HM provided similar glycaemic control for up to 5 h and superior glycaemic control from 5 to 7 h following a standard test meal.

Humalog Mix50 before carbohydrate-rich meals in type 2 diabetes mellitus

AIM

To compare pre-meal injection of Humalog Mix50 (Mix50) and Humalog Mix25 (Humalog Mix75/25 in the US; Mix25) with respect to 2 h postprandial (2 h pp) blood glucose (BG) control after a carbohydrate-rich breakfast in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

One hundred and sixteen patients were enrolled in a 16-week crossover trial and received two treatment regimens in a randomized crossover fashion: (i) Mix50 before breakfast and Mix25 before the evening meal (Mix50/Mix25) and (ii) Mix25 before both breakfast and the evening meal (Mix25 twice daily). Insulin doses were adjusted according to stated glycaemic targets. After 6 and 8 weeks of treatment, the patient's usual morning insulin dose was administered, followed immediately by a test breakfast representative of the patient's usual breakfast meal. Fasting and 2 h pp BG concentrations were measured at the time of the test meal. Haemoglobin A1c (A1C) was measured, and information regarding hypoglycaemia (symptoms) was collected at the end of each treatment period.

RESULTS

Insulin doses were similar between treatments (morning = 31-33 U, evening = 26-28 U) at endpoint. Following the test breakfast, the 2 h pp BG was lower (10.9 +/- 0.3 mmol/l vs. 12.4 +/- 0.3 mmol/l, p = 0.0012) and the 2 h pp BG excursion was smaller (1.4 +/- 0.28 mmol/l vs. 3.5 +/- 0.28 mmol/l, p < 0.001) during treatment with Mix50/Mix25 than during treatment with Mix25 twice daily. There was no difference between the treatments with respect to fasting BG (Mix50/Mix25, 9.5 +/- 0.3 mmol/l vs. Mix25 twice daily, 8.9 +/- 0.3 mmol/l; p = NS), A1C (8.14% +/- 1.14% vs. 8.14% +/- 1.07%; p = NS) or the incidence of self-reported hypoglycaemia (34% vs. 23%; p = NS).

CONCLUSIONS

Compared with treatment with Mix25 twice daily, treatment with Mix50 before breakfast and Mix25 before the evening meal resulted in better pp glycaemic control following a carbohydrate-rich meal, and similar fasting BG, A1C and incidence of hypoglycaemia in patients with type 2 diabetes.

Use of computed tomography pulmonary angiography in the diagnosis of pulmonary embolismin patients with an intermediate probability ventilation/perfusion scan

BACKGROUND

Computed tomography pulmonary -angiography (CTPA) plays an increasingly important role in the diagnosis of pulmonary embolism (PE). Although accurate in the detection of large PE, its accuracy in other patient groups is yet to be defined.

AIM

To compare CTPA with pulmonary angiography as a second-line investigation in patients with a ventilation/perfusion (VQ) scan indicating an intermediate probability of PE.

METHODS

We recruited 25 patients over a 17-month period. Subjects were eligible if they: (i). had clinically suspected PE, (ii). had a VQ scan indicating an intermediate probability of PE and (iii). were referred for pulmonary angiography. Subjects underwent CTPA within 36 h of the VQ scan. CTPA was interpreted without knowledge of the results of the pulmonary angiogram by two of the authors.

RESULTS

PE was prevalent (i.e. embolus detected at pulmonary angiography) in seven of 25 subjects (28%). The sensitivity of CTPA was 57% and the specificity was 94%.

CONCLUSIONS

In the setting of intermediate-probability VQ scanning, CTPA may be used to clarify the diagnosis of PE. However, a negative CTPA cannot -definitely exclude PE. Conventional pulmonary angiography may be necessary to determine the presence of PE if CTPA is negative.

Reductive cleavage of S-adenosylmethionine by biotin synthase from Escherichia coli

Biotin synthase (BioB) catalyzes the insertion of a sulfur atom between the C6 and C9 carbons of dethiobiotin. Reconstituted BioB from Escherichia coli contains a [4Fe-4S](2+/1+) cluster thought to be involved in the reduction and cleavage of S-adenosylmethionine (AdoMet), generating methionine and the reactive 5'-deoxyadenosyl radical responsible for dethiobiotin H-abstraction. Using EPR and Mössbauer spectroscopy as well as methionine quantitation we demonstrate that the reduced S = 1/2 [4Fe-4S](1+) cluster is indeed capable of injecting one electron into AdoMet, generating one equivalent of both methionine and S = 0 [4Fe-4S](2+) cluster. Dethiobiotin is not required for the reaction. Using site-directed mutagenesis we show also that, among the eight cysteines of BioB, only three (Cys-53, Cys-57, Cys-60) are essential for AdoMet reductive cleavage, suggesting that these cysteines are involved in chelation of the [4Fe-4S](2+/1+) cluster.

Tc-99m-labeled RBC scintigraphy and splenic hemangioma

PURPOSE

The aim of this study was to assess the diagnostic value of RBC scintigraphy in the evaluation of possible splenic hemangioma.

MATERIALS AND METHODS

RBC scintigraphy was performed on a patient with an incidental finding of a splenic mass on computed tomographic scanning. Early and delayed planar and SPECT images were obtained.

RESULTS

Delayed images revealed blood pooling of the splenic mass. This finding is similar to the characteristics seen in RBC scintigraphy for hepatic hemangioma.

CONCLUSION

RBC scintigraphy may be useful in the evaluation of possible splenic hemangioma.

Observation of the iron-sulfur cluster in Escherichia coli biotin synthase by nanoflow electrospray mass spectrometry

Biotin synthase from Escherichia coli was analyzed by nanoflow electrospray ionization mass spectrometry. From solution conditions in which the protein is in its native state, a distribution of monomeric, dimeric, and tetrameric species was observed. The distribution of these species was sensitive to changes in ionic strength: in the positive ion spectrum, biotin synthase at low ionic strength (pH 7.0-8.5) yielded less than 10% dimer. The masses of the monomeric species were consistent with the presence of a [2Fe-2S] cluster with a mass difference of 175.3 Da from the apomonomer with one disulfide bond. Despite the molecular mass of the noncovalent dimer (77 kDa), it was possible to observe a dimeric species containing one iron-sulfur cluster in both positive and negative ion spectra. Additionally, observation of a series of charge states assigned to the apodimer indicated that binding of the iron-sulfur cluster was not required to maintain the dimer. Binding of Cu2+ to biotin synthase was also observed; in the presence of excess chelating agent, free metals were removed and the iron-sulfur cluster remained intact. Evidence for the coordination of the iron-sulfur cluster in biotin synthase was obtained in a tandem mass spectrometry experiment. A single charge state containing the cluster at m/z 2416.9 was isolated, and collision-induced dissociation resulted in sequential loss of sulfur and retention of Fe3+.

Improved glycaemic control with the use of self-prepared mixtures of insulin lispro and insulin lispro protamine suspension in patients with types 1 and 2 diabetes

A total of 166 patients (102 type 1, 64 type 2) were randomised to insulin lispro (LP) combined with insulin lispro protamine suspension (NPL), an intermediate-acting formulation of LP, or to regular human insulin (HR) combined with human NPH insulin (NPH) in this open-label, parallel study. Insulin doses were similar at endpoint. Blood glucose (BG) measurements (before and two hours after meals, bedtime, 3 a.m.)(mmol/l) were lower with LP/NPL two hours after breakfast (8.84 +/- 0.32 vs 10.29 +/- 0.41, p < 0.001), before lunch (6.21 +/- 0.20 vs 7.10 +/- 0.31, p = 0.016), two hours after the evening meal (10.18 +/- 0.36 vs 7.86 +/- 0.28, p < 0.0.001), and at bedtime (7.85 +/- 0.28 vs 9.43 +/- 0.40, p = 001). HbA1c was lower for LP/NPL at endpoint (7.54 +/- 0.11% vs 7.92 +/- 0.10%, p = 0.019). There was no difference in hypoglycaemia or insulin antibody levels. LP/NPL resulted in better glycaemic control than HR/NPH without increasing the risk of hypoglycaemia.

Iron-sulfur center of biotin synthase and lipoate synthase

Biotin synthase and lipoate synthase are homodimers that are required for the C-S bond formation at nonactivated carbon in the biosynthesis of biotin and lipoic acid, respectively. Aerobically isolated monomers were previously shown to contain a (2Fe-2S) cluster, however, after incubation with dithionite one (4Fe-4S) cluster per dimer was obtained, suggesting that two (2Fe-2S) clusters had combined at the interface of the subunits to form the (4Fe-4S) cluster. Here we report Mössbauer studies of (57)Fe-reconstituted biotin synthase showing that anaerobically prepared enzyme can accommodate two (4Fe-4S) clusters per dimer. The (4Fe-4S) cluster is quantitatively converted into a (2Fe-2S)(2+) cluster upon exposure to air. Reduction of the air-exposed enzyme with dithionite or photoreduced deazaflavin yields again (4Fe-4S) clusters. The (4Fe-4S) cluster is stable in both the 2+ and 1+ oxidation states. The Mössbauer and EPR parameters were DeltaE(q) = 1.13 mm/s and delta = 0.44 mm/s for the diamagnetic (4Fe-4S)(2+) and DeltaE(q) = 0.51 mm/s, delta = 0.85 mm/s, g(par) = 2.035, and g(perp) = 1.93 for the S = (1)/(2) state of (4Fe-4S)(1+). Considering that we find two (4Fe-4S) clusters per dimer, our studies argue against the early proposal that the enzyme contains one (4Fe-4S) cluster bridging the two subunits. Our study of lipoate synthase gave results similar to those obtained for BS: under strict anaerobiosis, lipoate synthase can accommodate a (4Fe-4S) cluster per subunit [DeltaE(q) = 1.20 mm/s and delta = 0.44 mm/s for the diamagnetic (4Fe-4S)(2+) and g(par) = 2.039 and g(perp) = 1.93 for the S = (1)/(2) state of (4Fe-4S)(1+)], which reacts with oxygen to generate a (2Fe-2S)(2+) center.

Nosocomial transmission of tuberculosis (TB) associated with care of an infant with peritoneal TB

Nosocomial transmission of tuberculosis (TB) after exposure to infected peritoneal fluid has not been described. We report the exposure of 111 healthcare workers to infected dialysate from an infant with TB peritonitis. Two (5%) of 39 primary-care nurses, but no doctors or environmental service workers, had apparent tuberculin skin test conversions, raising the concern that patients with peritoneal TB may be a source for nosocomial transmission of TB.

Effects of menopause and hormone replacement therapy on plasma lipids, lipoproteins and LDL-receptor activity

A cross-sectional study of ninety six women was conducted to examine the effect of menopause and hormone replacement therapy (HRT) on plasma lipids, lipoproteins and oxidation of low density lipoproteins. The sample consisted of 26 premenopausal women, 26 postmenopausal women taking no replacement hormones and 43 postmenopausal women on hormone replacement therapy. Postmenopausal women not taking replacement hormones had significantly higher plasma cholesterol, low density lipoprotein (LDL) cholesterol and lipoprotein[a] (Lp[a]) levels compared to premenopausal women or postmenopausal women on HRT [6.00 +/- 0.15, 5.36 +/- 0.17 (P < 0.01), 5.63 +/- 0.13 (P < 0.05) mmol/l, respectively for total cholesterol; 4.13 +/- 0.15, 3.64 +/- 0.15 (P < 0.05), 3.82 +/- 0.12 (P < 0.05) mmol/l, respectively for LDL-cholesterol; 48.19 +/- 9.90, 26.59 +/- 5.53 (P < 0.03), 25.12 +/- 4.62 (P < 0.03) mg/dl, respectively for Lp[a]]. The differences in LDL cholesterol concentrations were inversely related to changes in LDL receptor activity (r = -0.27, P < 0.01). HRT use was found to be associated with a significantly smaller LDL particle size. Plasma triglyceride was significantly higher in women on HRT (1.16 +/- 0.07 mmol/l) than in the premenopausal group (0.96 +/- 0.07) or postmenopausal group not using HRT (0.87 +/- 0.06). There were no differences in LDL oxidation between the groups when LDL was oxidised in the presence of copper. Nor was there any difference in the uptake of copper-oxidised or macrophage-modified LDL into J774 macrophages. These results confirm the effect of menopause and exogenous hormones on plasma lipids and lipoproteins, and suggest that HRT modifies the activity of the LDL receptor. Hormone replacement did not appear to protect LDL from oxidation.

Improved postprandial glycemic control during treatment with Humalog Mix25, a novel protamine-based insulin lispro formulation. Humalog Mix25 Study Group

OBJECTIVE

Humalog Mix25 is a manufactured premixed insulin formulation containing insulin lispro and a novel insulin lispro-protamine formulation (NPL) in a ratio of 25:75%. The objective of this study was to compare Humalog Mix25 to human insulin 30/70 (30% regular insulin/70% NPH) with respect to glycemic control.

RESEARCH DESIGN AND METHODS

Humalog Mix25 was compared with human insulin 30/70 in 89 individuals with type 2 diabetes during a 6-month randomized open-label two-period crossover study. Each insulin was administered twice daily, before the morning and evening meals. Information regarding self-monitored blood glucose (BG), hypoglycemic episodes (hypoglycemic signs or symptoms or BG < or = 3.0 mmol/l), insulin dose, and HbA1c was collected.

RESULTS

Treatment with Humalog Mix25 resulted in better postprandial glycemic control after the morning and evening meals compared with treatment with human insulin 30/70. Overall glycemic control and the incidence of hypoglycemia were comparable between the treatments.

CONCLUSIONS

In comparison to treatment with human insulin 30/70, twice daily administration of Humalog Mix25 resulted in improved postprandial glycemic control, similar overall glycemic control, and the convenience of dosing immediately before meals.