Measuring water contents in animal organ tissues using terahertz spectroscopic imaging

Lee, Kyumin; Jeoung, Kiyong; Kim, Sang Hoon; Ji, Young Bin; Son, Ho‐Young; Choi, Yuna; Huh, Yong Min; Suh, Jin Suck; Oh, Seung Jae

doi:10.1364/boe.9.001582

Cited by 37 publications

(20 citation statements)

References 23 publications

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“…The hydrogel anchors were found to be more effective in liver and kidney tissues compared to fat and muscle. One possible explanation for this is that liver and kidney tissues have relatively higher water content [ 23 ], which may promote hydrogel expansion. Another possible explanation is that these tissues are composed of tightly packed organized functional units (e.g., hepatic lobules in liver and nephrons in the kidney) and are more dense than fat and muscle [ 24 ], which may also contribute to microdevice stability.…”

Section: Discussionmentioning

confidence: 99%

Self-Expanding Anchors for Stabilizing Percutaneously Implanted Microdevices in Biological Tissues

et al. 2021

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Percutaneously implanted miniaturized devices such as fiducial markers, miniaturized sensors, and drug delivery devices have an important and expanding role in diagnosing and treating a variety of diseases. However, there is a need to develop and evaluate anchoring methods to ensure that these microdevices remain secure without dislodgement, as even minimal migration within tissues could result in loss of microdevice functionality or clinical complications. Here we describe two anchoring methods made from biocompatible materials: (1) a self-expanding nitinol mesh anchor and (2) self-expanding hydrogel particles contained within pliable netting. We integrate these anchors into existing drug-screening microdevices and experimentally measure forces required to dislodge them from varying tissues. We report similar dislodgement forces of 738 ± 37, 707 ± 40, 688 ± 29, and 520 ± 28 mN for nitinol-anchored microdevices, and 735 ± 98, 702 ± 46, 457 ± 47, and 459 ± 39 mN for hydrogel-anchored microdevices in liver, kidney, fat, and muscle tissues, respectively—significantly higher compared with 13 ± 2, 15 ± 3, 15 ± 2, and 15 ± 3 mN for non-anchored microdevices (p < 0.001 in all tissues). The anchoring methods increased resistance to dislodgement by a factor of 30–50× in all tissues, did not increase the required needle gauge for insertion, and were compatible with percutaneous implantation and removal. These results indicate that anchoring significantly improves microdevice stability and should reduce migration risk in a variety of biological tissues.

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Section: Discussionmentioning

confidence: 99%

Self-Expanding Anchors for Stabilizing Percutaneously Implanted Microdevices in Biological Tissues

et al. 2021

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“…However, coincident with moult, birds undergo hypertrophy of thymus glands (Höhn 1956;Ward and d'Cruz 1968;Anderson 1970) and spleen (Silverin et al 1999), both of which will increase protein and energy demands. Based on published masses for these organs during moult (Höhn 1956;Anderson 1970;Silverin et al 1999) and accounting for their water content (Corper 1912;Boyd et al 1956;Lee et al 2018), the dry mass of these two organs would be about 2% of dry feather mass of White-crowned Sparrows and would therefore place inconsequential demands on daily protein synthesis during moult. Flight muscle mass has been found to vary in some species during moult, but pectoral muscle scores of House Sparrows, although a qualitative estimate of actual muscle mass, are unaffected by moult (Buttemer et al 2019).…”

Section: Discussionmentioning

confidence: 99%

The energy cost of feather replacement is not intrinsically inefficient

2020

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Feathers serve a diversity of functions in birds and their continuous use and exposure to the environment requires a scheduled moult to maintain their full functionality. As feathers represent about 25% of a bird’s protein content, moult is expected to impose substantial energy and nutrient demands, but perhaps not to the extent reported. Energy conversion efficiencies for feather formation are among the lowest for any biological structure examined, but this assumes that increases in maintenance energy requirements (minimum resting metabolic rate (RMRmin)) during moult are predominately due to feather synthetic costs. We tested this assumption by comparing the RMRmin and protein turnover rates of House Sparrows (Passer domesticus (Linnaeus, 1758)) during peak moult and in a non-moulting cohort before and 12 days after having a similar amount of feathers plucked. Replacement of plucked feathers had no effect on metabolic rate, whereas RMRmin was 28% higher in moulting than in non-moulting House Sparrows. Protein turnover rates were lowest in non-moulting birds, but rate differences between non-moulting and moulting birds were threefold higher than those between non-moulting and plucked House Sparrows. Thus, the energy inefficiencies reported for feather replacement are mainly due to costs associated with coincident processes rather than being a direct cost of feather synthesis per se.

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“…Liver samples from hispid cotton rats and deer were digested by microwave in 8 mL nitric acid (MARS 6; One Touch Animal Tissue Method; CEM, Mathews, North Carolina, USA) to assay minerals by atomic emission spectroscopy against an internal standard of beef liver (486 ± 74 mg/kg Cu, 165 ± 29 mg/kg Fe, and 93 ± 22 mg/kg Zn, dry weight). Hispid cotton rat liver mineral deficiencies reported on a wet weight basis were converted from dry weight using the total moisture content of liver tissue samples (75.3 ± 1.9%), which was similar to liver moisture content in laboratory rats [ 40 ]. White-tailed deer liver deficiencies reported on a wet weight basis were converted from dry weight using the calculated moisture content from the lipid content of individual deer (69.9 ± 2.6%).…”

Section: Methodsmentioning

confidence: 99%

Trace mineral supplies for populations of little and large herbivores

et al. 2021

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Copper (Cu), iron (Fe), and zinc (Zn) are essential trace minerals for the reproduction, growth, and immunity of mammalian herbivore populations. We examined the relationships between Cu, Fe, and Zn in soils, common plants, and hepatic stores of two wild herbivores to assess the effects of weather, sex, and population density on the transfer of trace minerals from soils to mammals during the growing season. Soils, grasses, woody browse, hispid cotton rats (Sigmodon hispidus), and white-tailed deer (Odocoileus virginianus) were sampled across 19 sites. Concentrations of Cu, Fe, and Zn in grasses and browse species were not correlated with concentrations of those minerals in soils sampled from the same areas. Leaves of woody browse were higher in Cu, lower in Fe, and similar in Zn when compared with grasses. Available concentrations of soils were positively related to liver Cu and Zn in hispid cotton rats, which was consistent with the short lives and high productivity of these small mammals that rely on grass seed heads. Interactions between soil concentrations and weather also affected liver Cu and Fe in deer, which reflected the greater complexity of trophic transfers in large, long-lived, browsing herbivores. Population density was correlated with liver concentrations of Cu, Fe, and Zn in hispid cotton rats, and concentrations of Cu and Fe in deer. Liver Cu was < 5 mg/kg wet weight in at least 5% of animals at two of eight sites for hispid cotton rats and < 3.8 mg/kg wet weight in at least 5% of animals at three of 12 sites for deer, which could indicate regional limitation of Cu for populations of mammalian herbivores. Our data indicate that supplies of trace minerals may contribute to density dependence of herbivore populations. Local population density may therefore influence the prevalence of deficiency states and disease outbreak that exacerbate population cycles in wild mammals.

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Measuring water contents in animal organ tissues using terahertz spectroscopic imaging

Cited by 37 publications

References 23 publications

Self-Expanding Anchors for Stabilizing Percutaneously Implanted Microdevices in Biological Tissues

Self-Expanding Anchors for Stabilizing Percutaneously Implanted Microdevices in Biological Tissues

The energy cost of feather replacement is not intrinsically inefficient

Trace mineral supplies for populations of little and large herbivores

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