Nutrition-related status and granulation tissue colour of pressure ulcers evaluated by digital image analysis in older patients.

OBJECTIVE: Granulation tissue colour may be an indicator for nutritional assessment in pressure ulcer (PU) care. This study evaluated the relationship between nutritional status, anaemia and diabetes, and granulation tissue colour of PUs by colour analysis of digital photographs in the clinical setting. METHOD: The cross-sectional study included 42 older patients with 51 full-thickness PUs from 10 institutions. Patient demographics, wound status, nutritional status and dietary intakes were obtained from medical charts. From a wound image, the granulation red index was processed by computer software and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) was calculated. RESULTS: Haemoglobin levels were positively associated with %GRI80 levels (p=0.007) in the crude model, but not in the adjusted model (p=0.260). The interaction term between diabetes and protein intake was significantly associated with %GRI80 levels in the adjusted models (p=0.010). At protein intakes of 0.95 g/kg or higher, diabetic wounds exhibited lower %GRI80 levels than non-diabetic wounds (p=0.002). At protein intakes of less than 0.95 g/kg, %GRI80 levels did not differ between diabetic and non-diabetic patients (p=0.247). Protein intakes of 0.95 g/kg or higher were associated with higher %GRI80 levels in non-diabetic patients (p=0.015), but not in diabetic patients (p=0.127). CONCLUSION: Granulation tissue colour, evaluated by the objective and quantitative analysis of digital photography, is related to haemoglobin level, diabetes and dietary intakes in clinical settings.

Physiological and appearance characteristics of skin maceration in elderly women with incontinence.

OBJECTIVE: To identify the physiological and appearance characteristics of skin maceration caused by urine and/or faeces and determine their suitability as risk indicators for incontinence-associated dermatitis. METHOD: This cross-sectional, comparative study involved sixty-nine elderly women with urinary and/or faecal incontinence who provided informed consent to participate. Exclusion criteria included serious medical problems, acute illness and the presence of damaged skin on the buttocks. The physiological and appearance characteristics of macerated skin on the buttocks of the patients were examined. Stratum corneum and dermis hydration levels, transepidermal water loss and skin pH were used to assess skin condition. Skin morphology (sulcus cutis) was confirmed using images at x15 magnification. The erythema index and white index were used to evaluate colour in the macerated skin areas. RESULTS: Forty-four patients exhibited skin maceration. Stratum corneum and dermis hydration levels were significantly greater in the maceration group than in the non-maceration group, as were transepidermal water loss, skin pH and differences in sulcus cutis interval between the buttock of interest and the subumbilical region. Furthermore, differences in the erythema and white indices between these two regions were significantly higher and lower, respectively, in the maceration group than in the non-maceration group. CONCLUSION: To our knowledge, this is the first report to note that there are interesting changes not only in the epidermal layer but also in the dermis layer in patients with skin maceration. This finding confirmed that skin maceration caused by incontinence is a severe condition. Moreover, the erythema index was the best index for identifying skin maceration caused by incontinence, indicating that it can be used for precise and easy identification of the condition in clinical practice.

Quantitative estimation of exudate volume for full-thickness pressure ulcers: the ESTimation method.

OBJECTIVE: To develop an equation for the estimation of exudate volume in millilitres, for full-thickness pressure ulcers, according to wound characteristics. METHOD: In a cross-sectional study, 41 patients aged >60 years with 58 full-thickness pressure ulcers were evaluated. Exudate was collected by covering each wound with a transparent occlusive dressing and the accumulated volume was measured to estimate volume per day. The overall severity of each wound was evaluated by the DESIGN-R tool; a model was then developed to estimate the volume of exudate based on these experimental values. Linear regression analyses were performed to evaluate the precision and accuracy of the model. RESULTS: The model, including exudate score, size score, and total score, showed a higher adjusted coefficient of determination (R²=0.66) than the model with only a traditional exudate score (R²=0.57). After adjustment for age, inclusion of interaction terms, and modification of bias, a model with continuous parameters was finally developed: exudate volume per day (ml/day) = exp([0.86×exudate score]+ [0.21×size score]+[0.12×total score]-[0.013×size score×total score]-[0.04×age]-3.60). Furthermore, a categorical model was developed for clinical simplicity of use. The adjusted R2 was increased to 0.73 for the continuous model and to 0.77 for the categorical model. There were no apparent biases (p>0.05) and no correlations between residuals and measured value (p>0.05) in these models. CONCLUSION: The equation, including the exudate score, size score and total score of DESIGN-R, as well as age, is called the ESTimation method. It will be useful for clinicians to predict the absolute volume of exudate and to select appropriate dressings for full-thickness pressure ulcers. DECLARATION OF INTEREST: The authors have nothing to declare.

Use of ultrasound in assessment of necrotic tissue in pressure ulcers with adjacent undermining.

OBJECTIVE: To reveal the specific ultrasonic imaging findings of non-visible necrotic tissue in pressure ulcers (PUs) with undermining and describe the images objectively. The predictive validity of the specific images of the undermined necrotic tissue was also determined. METHOD: Using digital ultrasonography (12 MHz linear transducer, MyLab25; Hitachi Medical Corporation), we imaged PUs with undermining every 2 weeks. PUs were also monitored by DESIGN-R, a PU assessment tool, at the same time. RESULTS: Ten patients had 11 PUs with undermining and all ulcers were located in the sacral region. The necrotic tissue showed high echogenicity with no layers, unclear borders and an uneven gray level (cloud-like image). Granulation tissue appeared as a low echoic image which had no layers, was of coarse resolution and an even gray level. There were significant differences between the pixel uniformity of the necrotic tissue (84.0) and granulation tissue (53.9) compared with uninjured tissue (65.5; p=0.000 and 0.005, respectively). The sensitivity, specificity, and positive and negative predictive values of cloud-like image were 87.5%, 91.7%, 77.8% and 95.6%, respectively. CONCLUSION: The results suggest that cloud-like image is the most useful diagnostic indicator for non-visible necrotic tissue in PUs with undermining and is the best prognostic indicator for PU healing. DECLARATION OF INTEREST: The authors have no conflicts of interest to declare. There were no external sources of funding for this study.

Does the use of a cleanser on skin surrounding pressure ulcers in older people promote healing?

OBJECTIVE: To determine whether the use of a skin cleanser on the skin surrounding pressure ulcers helps to promote healing. METHOD: The study was conducted over a two-year period in patients with stage II or more pressure ulcers. All subjects were at least 65 years of age and resident in a long-term care hospital. During the first year, skin was cleansed with normal saline. In year two, a pH-balanced cleanser was used. The healing times for the two methods were then compared. RESULTS: Healing time was shorter in the group using the cleanser for every stage of ulcer, with an especially significant difference for stage II ulcers (p=0.002). Analysis using the Cox proportional hazards model found a 1.79-fold improvement in the healing rate of stage II ulcers when the surrounding skin was washed with the cleanser. CONCLUSION: Cleaning the surrounding skin with a cleanser rather than normal saline promotes the healing of pressure ulcers.

Beta-amyloid(1-42)-induced cholinergic lesions in rat nucleus basalis bidirectionally modulate serotonergic innervation of the basal forebrain and cerebral cortex.

Ample experimental evidence suggests that beta-amyloid (A beta), when injected into the rat magnocellular nucleus basalis (MBN), impels excitotoxic injury of cholinergic projection neurons. Whereas learning and memory dysfunction is a hallmark of A beta-induced cholinergic deficits, anxiety, or hypoactivity under novel conditions cannot be attributed to the loss of cholinergic MBN neurons. As mood-related behavioral parameters are primarily influenced by the central serotonergic system, in the present study we investigated whether A beta(1-42) toxicity in the rat MBN leads to an altered serotonergic innervation pattern in the rat basal forebrain and cerebral cortex 7 days postsurgery. A beta infusion into the MBN elicited significant anxiety in the elevated plus maze. A beta toxicity on cholinergic MBN neurons, expressed as the loss of acetylcholinesterase-positive cortical projections, was accompanied by sprouting of serotonergic projection fibers in the MBN. In contrast, the loss of serotonin-positive fiber projections, decreased concentrations of both serotonin and 5-hydroxyindoleacetic acid, and decline of cortical 5-HT(1A) receptor binding sites indicated reduced serotonergic activity in the somatosensory cortex. In conclusion, the A beta-induced primary cholinergic deficit in the MBN and subsequent cortical cholinergic denervation bidirectionally modulate serotonergic parameters in the rat basal forebrain and cerebral cortex. We assume that enhanced serotonin immunoreactivity in the damaged MBN indicates intrinsic processes facilitating neuronal recovery and cellular repair mechanisms, while diminished cortical serotonergic activity correlates with the loss of the subcortical cholinergic input, thereby maintaining the balance of neurotransmitter concentrations in the cerebral cortex.

Mechanisms of beta-amyloid neurotoxicity: perspectives of pharmacotherapy.

One of the characteristic neuropathological hallmarks of Alzheimer's disease (AD) is the extracellular accumulation of beta-amyloid peptides (Abeta) in neuritic plaques. Experimental data indicate that different molecular forms of Abeta affect a wide array of neuronal and glial functions and thereby may lead to neuronal death in the nervous system. Whereas the fatal outcome of Abeta overproduction in transgenic cell lines, and of exogenous Abeta administration in numerous neurotoxicity models, is well established, particular facets of a complex molecular cascade by which Abeta attack neural cells are still elusive. In the present review we summarize recent knowledge on mechanisms of Abeta aggregation, its role in Abeta neurotoxicity, and binding of Abeta peptides to putative neuronal and glial receptors. Additionally, an integrative view on the interactions of Ca2+ -mediated excitotoxicity and free radical-induced oxidative stress in Abeta toxicity is provided. Furthermore, we survey advances of pharmacological investigations attempting to prevent and antagonize Abeta toxicity, or to promote neuronal regeneration following Abeta-induced neurotoxic insults. We distinguish two major classes of therapeutic approaches: conventional pharmacotherapy that employs blockade of known receptors, signal transduction pathways, and re-uptake of neurotransmitters, and direct targeting of neurotoxic Abeta by means of beta-sheet breakers, functional anti-Abeta peptides, and antibodies. Although a clinically relevant neuroprotective strategy is not yet available, sequential combination of drug regimens may provide prospects for effective antagonism of late-life Abeta burden and subsequent development of dementia.

beta-amyloid neurotoxicity is mediated by a glutamate-triggered excitotoxic cascade in rat nucleus basalis.

Whereas a cardinal role for beta-amyloid protein (Abeta) has been postulated as a major trigger of neuronal injury in Alzheimer's disease, the pathogenic mechanism by which Abeta deranges nerve cells remains largely elusive. Here we report correlative in vitro and in vivo evidence that an excitotoxic cascade mediates Abeta neurotoxicity in the rat magnocellular nucleus basalis (MBN). In vitro application of Abeta to astrocytes elicits rapid depolarization of astroglial membranes with a concomitant inhibition of glutamate uptake. In vivo Abeta infusion by way of microdialysis in the MBN revealed peak extracellular concentrations of excitatory amino acid neurotransmitters within 20-30 min. Abeta-triggered extracellular elevation of excitatory amino acids coincided with a significantly enhanced intracellular accumulation of Ca2+ in the Abeta injection area, as was demonstrated by 45Ca2+ autoradiography. In consequence of these acute processes delayed cell death in the MBN and persistent loss of cholinergic fibre projections to the neocortex appear as early as 3 days following the Abeta-induced toxic insult. Such a sequence of Abeta toxicity was effectively antagonized by the N-methyl-D-aspartate (NMDA) receptor ligand dizocilpine maleate (MK-801). Moreover, Abeta toxicity in the MBN decreases with advancing age that may be associated with the age-related loss of NMDA receptor expression in rats. In summary, the present results indicate that Abeta compromises neurons of the rat MBN via an excitotoxic pathway including astroglial depolarization, extracellular glutamate accumulation, NMDA receptor activation and an intracellular Ca2+ overload leading to cell death.

N-Methyl-D-aspartate receptor antagonist MK-801 and radical scavengers protect cholinergic nucleus basalis neurons against beta-amyloid neurotoxicity.

Previous experimental data indicate the involvement of Ca(2+)-related excitotoxic processes, possibly mediated by N-Methyl-D-Aspartate (NMDA) receptors, in beta-amyloid (beta A) neurotoxicity. On the other hand, other lines of evidence support the view that free radical generation is a critical step in the beta A-induced neurodegenerative cascade. In the present study, therefore, a neuroprotective strategy was applied to explore the contributions of each of these pathways in beta A toxicity. beta A(1-42) was injected into the magnocellular nucleus basalis of rats, while neuroprotection was achieved by either single or combined administration of the NMDA receptor antagonist MK-801 (2.5 mg/kg) and/or a vitamin E and C complex (150 mg/kg). The degree of neurodegeneration was determined by testing the animals in consecutive series of behavioral tasks, including elevated plus maze, passive avoidance learning, small open-field and open-field paradigms, followed by acetylcholinesterase (AChE), choline-acetyltransferase (ChAT), and superoxide dismutase (SOD) biochemistry. beta A injected in the nucleus basalis elicited significant anxiety in the elevated plus maze, derangement of passive avoidance learning, and altered spontaneous behaviors in both open-field tasks. A significant decrease in both AChE and ChAT accompanied by a similar decrement of MnSOD, but not of Cu/ZnSOD provided neurochemical substrates for the behavioral changes. Each of the single drug administrations protected against the neurotoxic events, whereas the combined treatment failed to ameliorate beta A toxicity.

Neuroprotective approaches in experimental models of beta-amyloid neurotoxicity: relevance to Alzheimer's disease.

1. beta-Amyloid peptides (A beta s) accumulate abundantly in the Alzheimer's disease (AD) brain in areas subserving information acquisition and processing, and memory formation. A beta fragments are produced in a process of abnormal proteolytic cleavage of their precursor, the amyloid precursor protein (APP). While conflicting data exist in the literature on the roles of A beta s in the brain, and particularly in AD, recent studies have provided firm experimental evidence for the direct neurotoxic properties of A beta. 2. Sequence analysis of A beta s revealed a high degree of evolutionary conservation and inter-species homology of the A beta amino acid sequence. In contrast, synthetic A beta fragments, even if modified fluorescent or isotope-labeled derivatives, are pharmacological candidates for in vitro and in vivo modeling of their cellular actions. During the past decade, acute injection, prolonged mini-osmotic brain perfusion approaches or A beta infusions into the blood circulation were developed in order to investigate the effects of synthetic A beta s, whereas transgenic models provided insight into the distinct molecular steps of pathological APP cleavage. 3. The hippocampus, caudate putamen, amygdala and neocortex all formed primary targets of acute neurotoxicity screening, but functional consequences of A beta infusions were primarily demonstrated following either intracerebroventricular or basal forebrain (medial septum or magnocellular basal nucleus (MBN)) infusions of A beta fragments. 4. In vivo investigations confirmed that, while the active core of A beta is located within the beta(25-35) sequence, the flanking peptide regions influence not only the folding properties of the A beta fragments, but also their in vivo neurotoxic potentials. 5. It has recently been established that A beta administration deranges neuron-glia signaling, affects the glial glutamate uptake and thereby induces noxious glutamatergic stimulation of nerve cells. In fact, a critical role for N-methyl-D-aspartate (NMDA) receptors was postulated in the neurotoxic processes. Additionally, A beta s might become internalized, either after their selective binding to cell-surface receptors or after membrane association in consequence of their highly lipophilic nature, and induce free radical generation and subsequent oxidative injury. Ca(2+)-mediated neurotoxic events and generation of oxygen free radicals may indeed potentiate each other, or even converge to the same neurotoxic events, leading to cell death. 6. Neuroprotection against A beta toxicity was achieved by both pre- and post-treatment with NMDA receptor channel antagonists. Moreover, direct radical-scavengers, such as vitamin E or vitamin C, attenuated A beta toxicity with high efficacy. Interestingly, combined drug treatments did not necessarily result in additive enhanced neuroprotection. 7. Similarly to the blockade of NMDA receptors, the neurotoxic action of A beta s could be markedly decreased by pharmacological manipulation of voltage-dependent Ca(2+)-channels, serotonergic IA or adenosine A1 receptors, and by drugs eliciting membrane hyperpolarization or indirect blockade of Ca(2+)-mediated intracellular consequences of intracerebral A beta infusions. 8. A beta neurotoxicity might be dose-dependently modulated by trace metals. In spite of the fact that zinc (Zn) may act as a potent inhibitor of the NMDA receptor channel, high Zn doses accelerate A beta fibril formation, stabilize the beta-sheet conformation and thereby potentiate A beta neurotoxicity. Combined trace element supplementation with Se, Mn, or Mg, which prevails over the expression of detoxifying enzymes or counteracts intracellular elevations of Ca2+, may reduce the neurotoxic impact of A beta s. 9. Alterations in the regulatory functions of the hypothalamo-pituitary-adrenal axis may contribute significantly to neurodegenerative changes in the brain. Furthermore, AD patients exhibit substantially increased circadia