Junko Matsuo

Involvement of NADPH oxidase and protein kinase C in endothelin-1-induced superoxide production in retinal microvessels

Redox signaling has been implicated in pathophysiological changes in the vascular system. We examined whether endothelin-1 (ET-1) increases the formation of superoxide anions in retinal microvessels. Freshly isolated retinal microvessels from rats were exposed to ET-1 (100 nM), and the intracellular superoxide formation in the retinal pericytes was assessed semi-quantitatively by time-lapse fluorometric analyses using hydroethidine. The receptor mechanisms were determined by BQ-123 and BQ-788, receptor antagonists for ET(A) and ET(B) receptors, respectively, and also by IRL-1620, a selective agonist for ET(B) receptors. In addition, the changes induced by adding apocynin (10 microM), myr-PKC (1.0 microM), allopurinol (100 microM), rotenone (10 microM), or L-NAME (100 microM) with ET-1 were evaluated. Microvessels were incubated with phorbol 12-myristate 13-acetate (PMA, 10nM), a protein kinase C (PKC) activator. Fluorometric analyses showed ethidium fluorescence-positive regions that coincided well with the location of retinal pericytes. The intracellular superoxide levels were significantly increased after addition of ET-1 (100 nM), and this elevation was suppressed by apocynin or myr-PKC. Other enzyme inhibitors including L-NAME had no effect. The ET-1-induced increase of superoxide was significantly suppressed by BQ-123 (1.0 microM), while effects of adding BQ-788 (1.0 microM) were insignificant. IRL-1620 (100 nM) did not increase superoxide formation significantly. PMA (10nM) mimicked the effect of ET-1. These results suggest that ET-1 increases the formation of superoxides in the retinal microvascular pericytes most likely by activating NADPH oxidase through ET(A) receptors. The activation of PKC may be involved in the mechanism. Thus, ET-1 may augment its vasoconstrictive effects through the formation of superoxide, which may impair the bioavailability of nitric oxide in the retinal microvasculature.

Development and validity of a new model for assessing pressure redistribution properties of support surfaces.

Pressure ulcers are a common problem, especially in older patients. In Japan, most institutionalized older people are malnourished and show extreme bony prominence (EBP). EBP is a significant factor in the development of pressure ulcers due to increased interface pressure concentrated at the skin surface over the EBP. The use of support surfaces is recommended for the prophylaxis of pressure ulcers. However, the present equivocal criteria for evaluating the pressure redistribution of support surfaces are inadequate. Since pressure redistribution is influenced by physique and posture, evaluations using human subjects are limited. For this reason, models that can substitute for humans are necessary. We developed a new EBP model based on the anthropometric measurements, including pelvic inclination, of 100 bedridden elderly people. A comparison between the pressure distribution charts of our model and bedridden elderly subjects demonstrated that maximum contact pressure values, buttock contact pressure values, and bone prominence rates corresponded closely. This indicates that the model provides a good approximation of the features of elderly people with EBP. We subsequently examined the validity of the model through quantitative assessment of pressure redistribution functions consisting of immersion, envelopment, and contact area change. The model was able to detect differences in the hardness of urethane foam, differences in the internal pressure of an air mattress, and sequential changes during the pressure switching mode. These results demonstrate the validity of our new buttock model in evaluating pressure redistribution for a variety of surfaces.

Concurrent validation and reliability of digital image analysis of granulation tissue color for clinical pressure ulcers.

Granulation tissue color is one indicator for pressure ulcer (PU) assessment. However, it entails a subjective evaluation only, and quantitative methods have not been established. We developed color indicators from digital image analysis and investigated their concurrent validity and reliability for clinical PUs. A cross‐sectional study was conducted on 47 patients with 55 full‐thickness PUs. After color calibration, a wound photograph was converted into three images representing red color: erythema index (EI), modified erythema index with additional color calibration (granulation red index [GRI]), and , which represents the artificially created red–green axis of L*a*b* color space. The mean intensity of the granulation tissue region and the percentage of pixels exceeding the optimal cutoff intensity (% intensity) were calculated. Mean GRI (ρ=0.39, p=0.007) and (ρ=0.55, p<0.001), as well as their % intensity indicators, showed positive correlations with a* measured by tristimulus colorimeter, but erythema index did not. They were correlated with hydroxyproline concentration in wound fluid, healthy granulation tissue area, and blood hemoglobin level. Intra‐ and interrater reliability of the indicator calculation using both GRI and had an intraclass correlation coefficient >0.9. GRI and from digital image analysis can quantitatively evaluate granulation tissue color of clinical PUs.

Estimation of Protein Requirements According to Nitrogen Balance for Older Hospitalized Adults with Pressure Ulcers According to Wound Severity in Japan

To estimate protein requirements in older hospitalized adults with pressure ulcers (PrU) according to systemic conditions and wound severity.

Evaluation of nutritional status and skin condition among elderly residents in a long-term care hospital.

ObjectiveThe availability of nutritional screening tools for older adults is limited, depending on their physical characteristics or the setting. We investigated the relationships between various nutritional indicators and skin conditions as possible screening indicators.DesignCross-sectional study.SettingA long-term care hospital in Japan.Participants90 elderly residents who were aged ≥65 years old.MeasurementsThe nutritional status of the residents was assessed by body mass index (BMI), involuntary weight loss, arm muscle area, and serum albumin and prealbumin levels. Leg skin condition was evaluated by: 1) functional factors including pH, hydration and transepidermal water loss; 2) skin color including L*, a*, b* and individual typology angle (ITAo) using a tristimulus colorimetric instrument; and 3) skin morphology. Repeated measures analysis of variance was employed, adjusted for demographic characteristics and room temperature, with measurement site as the repeated variable.ResultsAmong the skin indicators, b* was significantly correlated with BMI (p=0.018), and weight loss over the previous month (p=0.042) and 6 months (p=0.002). Additionally, ITAo was associated with weight loss over 1 month (p=0.013). Both b* and ITAo showed the area under the receiver operating characteristic curve of 0.64 to 0.80 for weight loss >2% over 1 month.ConclusionsResidents with poorer nutritional status had yellower and darker skin color.

Heel Blood Flow During Loading and Off-Loading in Bedridden Older Adults With Low and Normal Ankle–Brachial Pressure Index: A Quasi-Experimental Study

The purpose of this study was to evaluate the differences in heel blood flow during loading and off-loading in bedridden adults older than 65 years. The patients were divided into three groups based on ankle–brachial pressure index (ABI) and transcutaneous oxygen tension (tcPO2): (1) patients with an ABI ≥ 0.8 (Group A); (2) patients with an ABI < 0.8 and heel tcPO2 ≥ 10 mmHg (Group B); and (3) patients with an ABI < 0.8 and heel tcPO2 < 10 mmHg (Group C). Heel blood flow was monitored using tcPO2 sensors. Data were collected with the heel (1) suspended above the bed surface (preload), (2) on the bed surface for 30 min (loading), and (3) again suspended above the bed surface for 60 min (off-loading). Heel blood flow during off-loading was assessed using three parameters: oxygen recovery index (ORI), total tcPO2 for the first 10 min, and change in tcPO2 after 60 min of off-loading. ORI in Group C (n = 8) was significantly shorter than in Groups A (n = 22) and B (n = 15). Total tcPO2 for the first 10 min of off-loading in Group C was significantly less than that in Groups A and B. Change in tcPO2 after 60 min of off-loading in Group C was less than in Group A. Based on these findings, additional preventive care against heel blood flow decrease in older adults with an ABI < 0.8 and heel tcPO2 < 10 mmHg might be necessary after loading.

Non-invasive monitoring of core body temperature rhythms over 72 h in 10 bedridden elderly patients with disorders of consciousness in a Japanese hospital: A pilot study

The purpose of this study was to elucidate the body core temperature rhythms of bedridden elderly patients with disorders of consciousness (DOC) in a Japanese hospital using a simple, non-invasive, deep-body thermometer. We measured body core temperature on the surface of abdomen in 10 bedridden elderly patients with DOC continuously over 72 h. A non-heated core body temperature thermometer was used. The cycle of the body core temperature rhythm was initially derived by using the least squares method. Then, based on that rhythm, the mean, amplitude, and times of day of the highest and lowest body temperatures during the optimum cycle were determined using the cosinor method. We found a 24-h cycle in seven of the 10 patients. One patient had a 6-h, one a 12-h, and one a 63-h cycle. The mean value of the cosine curve in the respective optimum cycles was 36.48 ± 0.34 °C, and the amplitude was 0.22 ± 0.09 °C. Of the seven subjects with 24-h cycles, the highest body temperature occurred between 12:58 and 14:44 h in four. In addition to 24-h cycles of core temperature rhythm, short cycles of 12 and 6-h and a long cycle of 63-h were seen. In order to understand the temperature rhythms of bedridden elderly patients with DOC, it is necessary to monitor their core body temperatures, ideally using a simple, non-invasive device. In the future, it will be important to investigate the relationship of the core temperature rhythm to nursing care and living environment.

NADPH Oxidase–Mediated ROS Production Determines Insulin's Action on the Retinal Microvasculature

PURPOSE To determine whether insulin induces nitric oxide (NO) formation in retinal microvessels and to examine the effects of high glucose on the formation of NO. METHODS Freshly isolated rat retinal microvessels were incubated in normal (5.5 mM) or high (20 mM) glucose with or without insulin (100 nM). The levels of insulin-induced NO and reactive oxygen species (ROS) in the retinal microvessels were determined semiquantitatively using fluorescent probes, 4,5-diaminofluorescein diacetate, and hydroethidine, respectively, and a laser scanning confocal microscope. The insulin-induced changes of NO in rat retinal endothelial cells and pericytes cultured at different glucose concentrations (5.5 and 25 mM) were determined using flow cytometry. Nitric oxide synthase (NOS) protein levels were determined by Western blot analysis; intracellular levels of ROS were determined using fluorescence-activated cell sorting (FACS) analysis of ethidium fluorescence; and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase RNA expression was quantified using real-time PCR. RESULTS Exposure of microvessels to insulin under normal glucose conditions led to a significant increase in NO levels; however, this increase was significantly suppressed when the microvessels were incubated under high glucose conditions. Intracellular levels of ROS were significantly increased in both retinal microvessels and cultured microvascular cells under high glucose conditions. The expression of NOS and NADPH oxidase were significantly increased in endothelial cells and pericytes under high glucose conditions. CONCLUSIONS The increased formation of NO by insulin and its suppression by high glucose conditions suggests that ROS production mediated by NADPH oxidase is important by insulins effect on the retinal microvasculature.

Using an extreme bony prominence anatomical model to examine the influence of bed sheet materials and bed making methods on the distribution of pressure on the support surface

Bed sheets generate high surface tension across the support surface and increase pressure to the body through a process known as the hammock effect. Using an anatomical model and a loading device characterized by extreme bony prominences, the present study compared pressure distributions on support surfaces across different bed making methods and bed sheet materials to determine the factors that influence pressure distribution. The model was placed on a pressure mapping system (CONFORMat; NITTA Corp., Osaka, Japan), and interface pressure was measured. Bed sheet elasticity and friction between the support surface and the bed sheets were also measured. For maximum interface pressure, the relative values of the following methods were higher than those of the control method, which did not use any bed sheets: cotton sheets with hospital corners (1.28, p = 0.02), polyester with no corners (1.29, p = 0.01), cotton with no corners (1.31, p = 0.003), and fitted polyester sheets (1.35, p = 0.002). Stepwise multiple regression analysis indicated that maximum interface pressure was negatively correlated with bed sheet elasticity (R(2) = 0.74). A statistically significant negative correlation was observed between maximum interface pressure and immersion depth, which was measured using the loading device (r = -0.40 and p = 0.04). We found that several combinations of bed making methods and bed sheet materials induced maximum interface pressures greater than those observed for the control method. Bed sheet materials influenced maximum interface pressure, and bed sheet elasticity was particularly important in reducing maximum interface pressure.

A case of eosinophilic chronic rhinosinusitis associated with optic neuropathy

We report a case of eosinophilic chronic rhinosinusitis (ECRS) associated with optic neuropathy. The visual acuity in the right eye was suddenly reduced to no light perception on awakening in the morning. Fundus examination of both eyes on the same day showed no remarkable changes. Emergency computed tomography showed pan-sinusitis bilaterally and a partial defect of the sphenoid bone on the right side. From the clinical findings, the case was diagnosed as optic neuropathy associated with chronic sinusitis. Endoscopic sinus surgery (ESS) was performed on the same day, and all of the major sinuses were found to be filled with highly viscous fluid. Part of the optic canal had a defect probably due to inflammatory invasion from the adjacent sphenoid bone. Steroid therapy was started immediately postoperatively. Histopathological examination of excised polyps showed that numerous eosinophils had invaded the polyps but no hyphae were present. The patient reported that he had bronchial asthma and had had nasal polypectomy. Six months after the ESS and steroid therapy, the patient had a recurrence of the sinusitis. At that time, laboratory examination showed an elevation of total IgE and eosinophil numbers. From the clinical findings and course, this case was diagnosed as ECRS accompanied by optic neuropathy. Although ECRS rarely has ocular complications, the inflammation can spread and the optic nerve can be affected.