Review Paper: Materials and Techniques for<i>In Vivo</i>pH Monitoring

Korostynska, O.; Arshak, K.; Gill, E.; Arshak, A.

doi:10.1109/jsen.2007.912522

Cited by 95 publications

(55 citation statements)

References 51 publications

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“…37,38 The lack of comparable clinical monitor further clinical studies are impossible, until a new reliable and clinically approved method of continuous in vivo pH bt monitoring in humans is available. Several groups are working on development of such tool [39][40][41] and it may be possible in future to resume clinical pH bt monitoring.…”

Section: Discussionmentioning

confidence: 99%

Extracellular Brain Ph with or without Hypoxia is a Marker of Profound Metabolic Derangement and Increased Mortality after Traumatic Brain Injury

Timofeev

Nortje

Al-Rawi

et al. 2012

J Cereb Blood Flow Metab

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Cerebral hypoxia and acidosis can follow traumatic brain injury (TBI) and are associated with increased mortality. This study aimed to evaluate a relationship between reduced pH bt and disturbances of cerebral metabolism. Prospective data from 56 patients with TBI, receiving microdialysis and Neurotrend monitoring, were analyzed. Four tissue states were defined based on pH bt and P bt O 2 : 1-low P bt O 2 /pH bt , 2-low pH bt /normal P bt O 2 , 3-normal pH bt /low P bt O 2 , and 4-normal pH bt /P bt O 2 ). Microdialysis values were compared between the groups. The relationship between P bt O 2 and lactate/pyruvate (LP) ratio was evaluated at different pH bt levels. Proportional contribution of each state was evaluated against mortality. As compared with the state 4, the state 3 was not different, the state 2 exhibited higher levels of lactate, LP, and glucose and the state 1-higher LP and reduced glucose (Po0.001). A significant negative correlation between LP and P bt O 2 (rho ¼ À 0.159, Po0.001) was stronger at low pH bt (rho ¼ À 0.201, Po0.001) and nonsignificant at normal pH bt (P ¼ 0.993). The state 2 was a significant discriminator of mortality categories (P ¼ 0.031). Decreased pH bt is associated with impaired metabolism. Measuring pH bt with P bt O 2 is a more robust way of detecting metabolic derangements.

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Section: Discussionmentioning

confidence: 99%

Extracellular Brain Ph with or without Hypoxia is a Marker of Profound Metabolic Derangement and Increased Mortality after Traumatic Brain Injury

Timofeev

Nortje

Al-Rawi

et al. 2012

J Cereb Blood Flow Metab

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“…It has been said to be difficult to evaluate rapidly μe-pH near the surface of implants in vivo [18]. The techniques used for pH detection in vivo are of three kinds [19]: electrochemical (e.g.…”

Section: Introductionmentioning

confidence: 99%

Alkaline biodegradable implants for osteoporotic bone defects—importance of microenvironment pH

et al. 2015

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Change of microenvironment pH by biodegradable implants may ameliorate unbalanced osteoporotic bone remodeling. The present work demonstrated that a weak alkaline condition stimulated osteoblasts differentiation while suppressed osteoclast generation. In vivo, implants with an alkaline microenvironment pH (monitored by a pH microelectrode) exhibited a promising healing effect for the repair of osteoporotic bone defects. Introduction Under osteoporotic conditions, the response of the bone microenvironment to an endosseous implant is significantly impaired, and this substantially increases the risk of fracture, non-union and aseptic implant loosening. Acid-base equilibrium is an important factor influencing bone cell behaviour. The present purpose was to study the effect of a series of alkaline biodegradable implant materials on regeneration of osteoporotic bone defect, monitoring the microenvironment pH (μe-pH) over time.Methods The proliferation and differentiation potential of osteoporotic rat bone marrow stromal cells and RAW 264.7 cells were examined under various pH conditions. Ovariectomized rat bone defects were filled with specific biodegradable materials, and μe-pH was measured by pH microelectrode. New osteoid and tartrate-resistant acid phosphatase-positive osteoclast-like cells were examined by Goldner's trichrome and TRAP staining, respectively. The intermediate layer between implants and new bone were studied using energy-dispersive X-ray spectroscopy (EDX) linear scanning. Results In vitro, weak alkaline conditions stimulated osteoporotic rat bone marrow stromal cells (oBMSC) differentiation, while inhibiting the formation of osteoclasts. In vivo, μe-pH differs from that of the homogeneous peripheral blood and exhibits variations over time particular to each material. Higher initial μe-pH was associated with more new bone formation, late response of TRAP-positive osteoclast-like cells and the development of an intermediate 'apatitic' layer in vivo. EDX suggested that residual material may influence μe-pH even 9 weeks post-surgery. Conclusion The pH microelectrode is suitable for in vivo μe-pH detection. Alkaline biodegradable materials generate an in vivo microenvironmental pH which is higher than the normal physiological value and show promising healing effects in the context of osteoporotic bone defects.

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“…According to the Korostynska's et al [16] comprehensive review of pH sensors, the most promising option for in-vivo pH monitoring is a potentiometric pH sensor. Potentiometric pH sensor has two electrodes: one of them is fabricated from an inert metal and is used as a reference electrode (usually made from Ag/AgCl), while the other electrode has a pHsensitive layer deposited onto it.…”

Section: B Types Of Suitable Ph and Temperature Sensorsmentioning

confidence: 99%

Design Concepts and Operation Principles for Smart Intra-Vaginal Health Monitoring Devices

Lewandowski

Chao

Niżański

2016

2016 IEEE 13th International Conference on E-Business Engineering (ICEBE)

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Abstract-The proposed work is the conception of a novel intra-body sensor device capable of measuring and gathering long-term intra-vaginal pH and temperature. At its early stage this project focuses on the analysis of different design concepts and operation principles of such intra vaginal sensor device. Traditional methods of intra-vaginal pH sampling, which rely on analysis of vaginal secretions or discharge from lateral vaginal walls, are difficult in long-term and often fraught with the potential for errors. Therefore this paper focuses on the analysis of such sensor's shape, form, size and fabric in order to enable precise, continuous acquisition of females' and animals' intra-vaginal pH and temperature at the right place inside the vagina. The aim is to set such operation principles, which will enable convenient collection and analysis of continuous vaginal pH and temperature samples for the purpose of further study. The objective is to achieve at least as accurate results as with the discrete analysis of clinicallyobtained intra-vaginal specimens, if not better. The data obtained with such sensors could enable a development of insemination prediction and gynaecological disorders detection models, which deployed to, for example smartphone devices, will help to attain high conception rate for animals and eventually improve the control of the vaginal health for women.

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Review Paper: Materials and Techniques forIn VivopH Monitoring

Cited by 95 publications

References 51 publications

Extracellular Brain Ph with or without Hypoxia is a Marker of Profound Metabolic Derangement and Increased Mortality after Traumatic Brain Injury

Extracellular Brain Ph with or without Hypoxia is a Marker of Profound Metabolic Derangement and Increased Mortality after Traumatic Brain Injury

Alkaline biodegradable implants for osteoporotic bone defects—importance of microenvironment pH

Design Concepts and Operation Principles for Smart Intra-Vaginal Health Monitoring Devices

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