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1.
Using a model of acute zymosan‐induced paw edema in NMRI mice, we test the hypothesis that anti‐inflammatory effects of extremely high‐frequency electromagnetic radiation (EHF EMR) can be essentially modified by application of pulse modulation with certain frequencies. It has been revealed that a single exposure of animals to continuous EHF EMR for 20 min reduced the exudative edema of inflamed paw on average by 19% at intensities of 0.1–0.7 mW/cm2 and frequencies from the range of 42.2–42.6 GHz. At fixed effective carrier frequency of 42.2 GHz, the anti‐inflammatory effect of EHF EMR did not depend on modulation frequencies, that is, application of different modulation frequencies from the range of 0.03–100 Hz did not lead to considerable changes in the effect level. On the contrary, at “ineffective” carrier frequencies of 43.0 and 61.22 GHz, the use of modulation frequencies of 0.07–0.1 and 20–30 Hz has allowed us to restore the effect up to a maximal level. The results obtained show the critical dependence of anti‐inflammatory action of low‐intensity EHF EMR on carrier and modulation frequencies. Within the framework of this study, the possibility of changing the level of expected biological effect of modulated EMR by a special selection of combination of carrier and modulation frequencies is confirmed. Bioelectromagnetics 30:454–461, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

2.
To permit epi‐illuminated, high‐resolution optical microscopy of cells in monolayer culture during unperturbed W‐band (75–110 GHz) irradiation, a new class of applicator has been developed based upon WR10 rectangular waveguide components: the cells are normally plated onto the underside of a coverslip which is then placed against the under side of a waveguide flange and receives a roughly circular exposure pattern, with the ±1 dB central spot roughly 1 mm in diameter. Constructed and tested with 94 GHz millimeter waves, water‐immersion optics, and free‐convection cooling, the applicator works robustly and permits SARs at the cell layer as high as 4500 W/kg before the steady‐state temperature rise at the cell layer exceeds 0.5 K. Bioelectromagnetics 31:140–149, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

3.
The multi‐spectral imaging technique has been used for distant mapping of in‐vivo skin chromophores by analyzing spectral data at each reflected image pixel and constructing 2‐D maps of the relative concentrations of oxy‐/deoxy‐haemoglobin and melanin. Instead of using a broad visible‐NIR spectral range, this study focuses on narrowed spectral band 500–700 nm, speeding‐up the signal processing procedure. Regression analysis confirmed that superposition of three Gaussians is optimal analytic approximation for the oxy‐haemoglobin absorption tabular spectrum in this spectral band, while superposition of two Gaussians fits well for deoxy‐haemoglobin absorption and exponential function – for melanin absorption. The proposed approach was clinically tested for three types of in‐vivo skin provocations: ultraviolet irradiance, chemical reaction with vinegar essence and finger arterial occlusion. Spectral range 500–700 nm provided better sensitivity to oxy‐haemoglobin changes and higher response stability to melanin than two reduced ranges 500–600 nm and 530–620 nm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

4.
The present study was designed to evaluate whether gestational exposure to an EMF targeting the head region, similar to that from cellular phones, might affect embryogenesis in rats. A 1.95‐GHz wide‐band code division multiple access (W‐CDMA) signal, which is one applied for the International Mobile Telecommunication 2000 (IMT‐2000) system and used for the freedom of mobile multimedia access (FOMA), was employed for exposure to the heads of four groups of pregnant CD(SD) IGS rats (20 per group) for gestational days 7–17. The exposure was performed for 90 min/day in the morning. The spatial average specific absorption rate (SAR) for individual brains was designed to be 0.67 and 2.0 W/kg with peak brain SARs of 3.1 and 7.0 W/kg for low (group 3) and high (group 4) exposures, respectively, and a whole‐body average SAR less than 0.4 W/kg so as not to cause thermal effects due to temperature elevation. Control and sham exposure groups were also included. At gestational day 20, all dams were killed and fetuses were taken out by cesarean section. There were no differences in maternal body weight gain. No adverse effects of EMF exposure were observed on any reproductive and embryotoxic parameters such as number of live (243–271 fetuses), dead or resorbed embryos, placental weights, sex ratios, weights or external, visceral or skeletal abnormalities of live fetuses. Bioelectromagnetics 30:205–212, 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

5.
South‐East Australia has recently been subjected to two of the worst droughts in the historical record (Millennium Drought, 2000–2009 and Big Dry, 2017–2019). Unfortunately, a lack of forest monitoring has made it difficult to determine whether widespread tree mortality has resulted from these droughts. Anecdotal observations suggest the Big Dry may have led to more significant tree mortality than the Millennium drought. Critically, to be able to robustly project future expected climate change effects on Australian vegetation, we need to assess the vulnerability of Australian trees to drought. Here we implemented a model of plant hydraulics into the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model. We parameterized the drought response behaviour of five broad vegetation types, based on a common garden dry‐down experiment with species originating across a rainfall gradient (188–1,125 mm/year) across South‐East Australia. The new hydraulics model significantly improved (~35%–45% reduction in root mean square error) CABLE’s previous predictions of latent heat fluxes during periods of water stress at two eddy covariance sites in Australia. Landscape‐scale predictions of the greatest percentage loss of hydraulic conductivity (PLC) of about 40%–60%, were broadly consistent with satellite estimates of regions of the greatest change in both droughts. In neither drought did CABLE predict that trees would have reached critical PLC in widespread areas (i.e. it projected a low mortality risk), although the model highlighted critical levels near the desert regions of South‐East Australia where few trees live. Overall, our experimentally constrained model results imply significant resilience to drought conferred by hydraulic function, but also highlight critical data and scientific gaps. Our approach presents a promising avenue to integrate experimental data and make regional‐scale predictions of potential drought‐induced hydraulic failure.  相似文献   

6.
MicroRNAs (miRNAs) regulate gene expression with emerging data suggesting miRNAs play a role in skeletal muscle biology. We sought to examine the association of miRNAs with grip strength in a community‐based sample. Framingham Heart Study Offspring and Generation 3 participants (n = 5668 54% women, mean age 55 years, range 24, 90 years) underwent grip strength measurement and miRNA profiling using whole blood from fasting morning samples. Linear mixed‐effects regression modeling of grip strength (kg) versus continuous miRNA ‘Cq’ values and versus binary miRNA expression was performed. We conducted an integrative miRNA–mRNA coexpression analysis and examined the enrichment of biologic pathways for the top miRNAs associated with grip strength. Grip strength was lower in women than in men and declined with age with a mean 44.7 (10.0) kg in men and 26.5 (6.3) kg in women. Among 299 miRNAs interrogated for association with grip strength, 93 (31%) had FDR q value < 0.05, 54 (18%) had an FDR q value < 0.01, and 15 (5%) had FDR q value < 0.001. For almost all miRNA–grip strength associations, increasing miRNA concentration is associated with increasing grip strength. miR‐20a‐5p (FDR q 1.8 × 10?6) had the most significant association and several among the top 15 miRNAs had links to skeletal muscle including miR‐126‐3p, miR‐30a‐5p, and miR‐30d‐5p. The top associated biologic pathways included metabolism, chemokine signaling, and ubiquitin‐mediated proteolysis. Our comprehensive assessment in a community‐based sample of miRNAs in blood associated with grip strength provides a framework to further our understanding of the biology of muscle strength.  相似文献   

7.
《Journal of morphology》2017,278(1):119-130
During tail regeneration in lizards, the stratified regenerating epidermis progressively gives rise to neogenic scales that form a new epidermal generation. Initially, a soft, un‐scaled, pliable, and extensible epidermis is formed that is progressively replaced by a resistant but non‐extensible scaled epidermis. This suggests that the initial corneous proteins are later replaced with harder corneous proteins. Using PCR and immunocytochemistry, the present study shows an upregulation in the synthesis of low‐cysteine type I and II alpha‐keratins and of corneous beta‐proteins with a medium cysteine content and a low content in glycine (formerly termed beta‐keratins) produced at the beginning of epidermal regeneration. Quantitative PCR indicates upregulation in the production of alpha‐keratin mRNAs, particularly of type I, between normal and the thicker regenerating epidermis. PCR‐data also indicate a higher upregulation for cysteine‐rich corneous beta‐proteins and a high but less intense upregulation of low glycine corneous protein mRNAs at the beginning of scale regeneration. Immunolabeling confirms the localization of these proteins, and in particular of beta‐proteins with a medium content in cysteine initially formed in the wound epidermis and later in the differentiating corneous layers of regenerating scales. It is concluded that the wound epidermis initially contains alpha‐keratins and corneous beta‐proteins with a lower cysteine content than more specialized beta‐proteins later formed in the mature scales. These initial corneous proteins are likely related to the pliability of the wound epidermis while more specialized alpha‐keratins and beta‐proteins richer in glycine and cysteine are synthesized later in the mature and inflexible scales. J. Morphol. 278:119–130, 2017. ©© 2016 Wiley Periodicals,Inc.  相似文献   

8.
The helical nature of human sweat ducts, combined with the morphological and dielectric properties of skin, suggests electromagnetic activity in the sub-THz frequency band. A detailed electromagnetic simulation model of the skin, with embedded sweat ducts, was created. The model includes realistic dielectric properties based on the measured water content of each layer of skin, derived from Raman Spectroscopy. The model was verified by comparing it to measurements of the reflection coefficient of the palms of 13 volunteers in the frequency band 350–410 GHz. They were subjected to a measurement protocol intended to induce mental stress, thereby also activating the sweat glands. The Galvanic Skin Response was concurrently measured. Using the simulation model the optimal ac-conductivity for each measurement was found. The range of variation for all subjects was found to be from 100 S/m to a maximum value of 6000 S/m with averages of 1000 S/m. These are one order of magnitude increase from the accepted values for water at these frequencies (~100 s/m at 100 GHz). Considering the known biochemical mechanism for inducing perspiration, we conclude that these ac-conductivity levels are probably valid, even though the real time measurements of sweat ac-conductivity levels inside the duct are inaccessible.  相似文献   

9.
Despite the increase in obesity among women of reproductive ages, few studies have considered maternal obesity as a risk factor for breast‐feeding success. We tested the hypothesis that women who are obese (BMI = 30–34.9) and very obese (BMI ≥35) before pregnancy are less likely to initiate and maintain breast‐feeding than are their normal‐weight counterparts (BMI = 18.5–24.9) among white and black women. Data from 2000 to 2005 South Carolina Pregnancy Risk Assessment Monitoring System (PRAMS) were used. The overall response rate was 71.0%; there were 3,517 white and 2,846 black respondents. Black women were less likely to initiate breast‐feeding and breast‐fed their babies for a shorter duration than white women. Compared to normal‐weight white women, very obese white women were less likely to initiate breast‐feeding (odds ratio: 0.63; 95% confidence interval (CI) = 0.42, 0.94) and more likely to discontinue breast‐feeding within the first 6 months (hazard ratio (HR) = 1.89; 95% CI: 1.39, 2.58). Among black women, prepregnancy BMI was neither associated with breast‐feeding initiation nor with breast‐feeding continuation within the first 6 months. Because very obese white women are less likely to initiate or continue breast‐feeding than other white women, health professionals should be aware that very obese white women need additional breast‐feeding support. Lower rates of breast‐feeding among black women suggest that they should continue to be the focus of the programs and policies aimed at breast‐feeding promotion in the United States.  相似文献   

10.
A framework for the combination of near‐field (NF) and far‐field (FF) radio frequency electromagnetic exposure sources to the average organ and whole‐body specific absorption rates (SARs) is presented. As a reference case, values based on numerically derived SARs for whole‐body and individual organs and tissues are combined with realistic exposure data, which have been collected using personal exposure meters during the Swiss Qualifex study. The framework presented can be applied to any study region where exposure data is collected by appropriate measurement equipment. Based on results derived from the data for the region of Basel, Switzerland, the relative importance of NF and FF sources to the personal exposure is examined for three different study groups. The results show that a 24‐h whole‐body averaged exposure of a typical mobile phone user is dominated by the use of his or her own mobile phone when a Global System for Mobile Communications (GSM) 900 or GSM 1800 phone is used. If only Universal Mobile Telecommunications System (UMTS) phones are used, the user would experience a lower exposure level on average caused by the lower average output power of UMTS phones. Data presented clearly indicate the necessity of collecting band‐selective exposure data in epidemiological studies related to electromagnetic fields. Bioelectromagnetics 34:366–374, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

11.
《Journal of morphology》2017,278(2):228-235
Axolotls (Ambystoma mexicanum ) may heal their skin wounds scar‐free in both paedomorphs and metamorphs. In previous studies on small punch skin wounds, rapid re‐epithelialisation was noted in these two axolotl morphs. However, large wound size in mammals may affect wound healing. In this study, large circumferential full thickness excision wounds on the hind limbs were created on juvenile paedomorphic and metamorphic axolotls. The results showed re‐epithelialisation was more quickly initiated in paedomorphs than in metamorphs after wounding. The migrating rate of epidermis on the wound bed was faster in paedomorphs than in metamorphs and thus completion of re‐epithelialisation was faster in paedomorphs than in metamorphs. Within these re‐epithelialisation periods, neither basement membrane nor dermis was reformed. Epidermal cell proliferation was detected by EdU‐labelling technique. In the normal unwounded skin, epidermal proliferation rate was higher in paedomorphs than in metamorphs. After wounding, the epidermal proliferation rate was significantly lower in the migrating front on the wound bed than in the normal skin in paedomorphs. The EdU‐labelling rate between normal skin and migration front was not different in metamorphs. Lacking of more proliferating epidermal cells on the wound bed indicated that the new epidermis here derived rather from migrating epidermal cells than from cell proliferation in situ. In conclusion, re‐epithelialisation in the large wound might be fully completed in both morphs despite it was initiated earlier and with faster rate in paedomorphs than in metamorphs. The new epidermis on the wound bed derived mainly from cell migration than by cell proliferation in the re‐epithelialisation period. J. Morphol. 278:228–235, 2017. © 2016 Wiley Periodicals,Inc.  相似文献   

12.
To biosynthesize the (3R,5S)‐CDHH in an industrial scale, a newly synthesized stereoselective short chain carbonyl reductase (SCR) was successfully cloned and expressed in Escherichia coli. The fermentation of recombinant E. coli harboring SCR was carried out in 500 L and 5000 L fermenters, with biomass and specific activity of 9.7 g DCW/L, 15749.95 U/g DCW, and 10.97 g DCW/L, 19210.12 U/g DCW, respectively. The recombinant SCR was successfully applied for efficient production of (3R,5S)‐CDHH. The scale‐up synthesis of (3R,5S)‐CDHH was performed in 5000 L bioreactor with 400 g/L of (S)‐CHOH at 30°C, resulting in a space‐time yield of 13.7 mM/h/g DCW, which was the highest ever reported. After isolation and purification, the yield and d.e. of (3R,5S)‐CDHH reached 97.5% and 99.5%, respectively. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:612–620, 2017  相似文献   

13.
Recent studies have reported that three‐dimensionally cultured cells have more physiologically relevant functions than two‐dimensionally cultured cells. Cells are three‐dimensionally surrounded by the extracellular matrix (ECM) in complex in vivo microenvironments and interact with the ECM and neighboring cells. Therefore, replicating the ECM environment is key to the successful cell culture models. Various natural and synthetic hydrogels have been used to mimic ECM environments based on their physical, chemical, and biological characteristics, such as biocompatibility, biodegradability, and biochemical functional groups. Because of these characteristics, hydrogels have been combined with microtechnologies and used in organ‐on‐a‐chip applications to more closely recapitulate the in vivo microenvironment. Therefore, appropriate hydrogels should be selected depending on the cell types and applications. The porosity of the selected hydrogel should be controlled to facilitate the movement of nutrients and oxygen. In this review, we describe various types of hydrogels, external stimulation‐based gelation of hydrogels, and control of their porosity. Then, we introduce applications of hydrogels for organ‐on‐a‐chip. Last, we also discuss the challenges of hydrogel‐based three‐dimensional cell culture techniques and propose future directions. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:580–589, 2017  相似文献   

14.
The interaction between electromagnetic fields and biological media, particularly regarding very high power, short pulses as in radar signals, is not a fully understood phenomenon. In the past few years, many in vitro, cellular communications‐oriented exposure studies have been carried out. This article presents a high‐power waveguide exposure system capable of dealing with monochromatic, multicarrier or pulsed signals between 1.8 and 3.2 GHz (L‐ and S‐band) with a pulse duration as low as 90 ns, minimum pulse repetition of 100 Hz, and maximum instantaneous power of 100 W. The setup is currently being used with a 2.2 GHz carrier modulated by 5 µs pulses with a 100 Hz repetition period and approximately 30 W of instantaneous power. After a worst‐case temperature analysis, which does not account for conduction and convection thermal effects, the experiment's exposure is considered sub‐thermal. Evaluation of the results through the specific absorption rate distribution is not considered sufficient enough in these cases. An electromagnetic field distribution analysis is needed. For monochromatic signals, the representation of the modulus of the electric and magnetic field components is proposed as a suitable method of assessment. Bioelectromagnetics 31:479–487, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

15.
The combined use of a gas‐exchange system and laser‐based isotope measurement is a tool of growing interest in plant ecophysiological studies, owing to its relevance for assessing isotopic variability in leaf water and/or transpiration under non‐steady‐state (NSS) conditions. However, the current Farquhar & Cernusak (F&C) NSS leaf water model, originally developed for open‐field scenarios, is unsuited for use in a gas‐exchange cuvette environment where isotope composition of water vapour (δv) is intrinsically linked to that of transpiration (δE). Here, we modified the F&C model to make it directly compatible with the δv–δE dynamic characteristic of a typical cuvette setting. The resultant new model suggests a role of ‘net‐flux’ (rather than ‘gross‐flux’ as suggested by the original F&C model)‐based leaf water turnover rate in controlling the time constant (τ) for the approach to steady sate. The validity of the new model was subsequently confirmed in a cuvette experiment involving cotton leaves, for which we demonstrated close agreement between τ values predicted from the model and those measured from NSS variations in isotope enrichment of transpiration. Hence, we recommend that our new model be incorporated into future isotope studies involving a cuvette condition where the transpiration flux directly influences δv. There is an increasing popularity among plant ecophysiologists to use a gas‐exchange system coupled to laser‐based isotope measurement for investigating non‐steady state (NSS) isotopic variability in leaf water (and/or transpiration); however, the current Farquhar & Cernusak (F&C) NSS leaf water model is unsuited for use in a gas‐exchange cuvette environment due to its implicit assumption of isotope composition of water vapor (δv) being constant and independent of that of transpiration (δE). In the present study, we modified the F&C model to make it compatible with the dynamic relationship between δv and δE as is typically associated with a cuvette setting. Using an experiment conducted on cotton leaves, we show that the modified NSS model performed well in predicting the time constant for the exponential approach of leaf water toward steady state under cuvette conditions. Such a result demonstrates the applicability of this new model to gas‐exchange cuvette conditions where the transpiration flux directly influences δv, and therefore suggests the need to incorporate this model into future isotope studies that employ a laser‐cuvette coupled system.  相似文献   

16.
Coral reefs have recently experienced an unprecedented decline as the world's oceans continue to warm. Yet global climate models reveal a heterogeneously warming ocean, which has initiated a search for refuges, where corals may survive in the near future. We hypothesized that some turbid nearshore environments may act as climate‐change refuges, shading corals from the harmful interaction between high sea‐surface temperatures and high irradiance. We took a hierarchical Bayesian approach to determine the expected distribution of 12 coral species in the Indian and Pacific Oceans, between the latitudes 37°N and 37°S, under representative concentration pathway 8.5 (W m?2) by 2100. The turbid nearshore refuges identified in this study were located between latitudes 20–30°N and 15–25°S, where there was a strong coupling between turbidity and tidal fluctuations. Our model predicts that turbidity will mitigate high temperature bleaching for 9% of shallow reef habitat (to 30 m depth) – habitat that was previously considered inhospitable under ocean warming. Our model also predicted that turbidity will protect some coral species more than others from climate‐change‐associated thermal stress. We also identified locations where consistently high turbidity will likely reduce irradiance to <250 μmol m?2 s?1, and predict that 16% of reef‐coral habitat ≤30 m will preclude coral growth and reef development. Thus, protecting the turbid nearshore refuges identified in this study, particularly in the northwestern Hawaiian Islands, the northern Philippines, the Ryukyu Islands (Japan), eastern Vietnam, western and eastern Australia, New Caledonia, the northern Red Sea, and the Arabian Gulf, should become part of a judicious global strategy for reef‐coral persistence under climate change.  相似文献   

17.
Obesity is associated with an increase in chronic, low‐grade inflammation which has been implicated in the development of type 2 diabetes mellitus and cardiovascular disease. The purpose of this study was to determine whether obesity was associated with an elevation of whole blood lipopolysaccharide (LPS)‐stimulated tumor necrosis factor‐α (TNF‐α) production. African‐American women were recruited from a larger study and assigned to one of five groups based on BMI: normal weight (NORM; BMI 20–25, n = 7), overweight (OVER; BMI 25–30, n = 12), class 1 obese (OB1; BMI 30–35, n = 19), class 2 obese (OB2; BMI 35–40, n = 10), or class 3 obese (OB3; BMI >40, n = 17). Body composition was determined via a whole body dual‐energy X‐ray absorptiometry (DXA) scan. Venous blood samples were collected following an overnight fast (>8 h), and stimulated with five doses of LPS (Salmonella enteriditis): 80, 40, 20, 10, and 5 µg/ml for 24 h in a 37 °C, 5% CO2 incubator. Following stimulation, TNF‐α was measured using enzyme‐linked immunosorbent assay. OB3 produced 365% more TNF‐α than NORM at an LPS dose of 20 µg/ml (P < 0.05). When maximal TNF‐α production was assessed regardless of LPS dose, OB3 produced 230% more than NORM and OVER produced 190% more than NW (P = 0.001). Total and trunk fat mass and BMI were significantly correlated with maximal TNF‐α production and LPS = 20 µg/ml. Our findings are consistent with previous reports suggesting a relationship between increased adiposity and inflammatory marker production. This is one of the first studies to focus on African‐American women, who have higher rates of obesity.  相似文献   

18.
To elucidate cellular mechanisms of sex‐related differences in fat distribution, we determined body fat distribution (dual‐energy X‐ray absorptiometry and single‐slice abdominal computed tomography (CT)), adipocyte size, adipocyte number, and proportion of early‐differentiated adipocytes (aP2+CD68?) in the stromovascular fraction (SVF) in the upper and lower body of normal‐weight healthy men (n = 12) and premenopausal women (n = 20) (age: 18–49 years, BMI: 18–26 kg/m2). Women had more subcutaneous and less visceral fat than men. The proportion of early differentiated adipocytes in the subcutaneous adipose tissue SVF of women was greater than in men (P = 0.01), especially in the femoral depot, although in vitro adipogenesis, as assessed by peroxisome proliferator activated receptor‐γ (PPARγ) expression, was not increased in femoral preadipocytes cultured from women compared with men. In women, differentiation of femoral preadipocytes was less than that of abdominal subcutaneous preadipocytes (P = 0.04), and femoral subcutaneous preadipocytes tended to be more resistant to tumor necrosis factor‐α (TNFα)–induced apoptosis (P = 0.06). Thus, turnover and utilization of the preadipocyte pool may be reduced in lower vs. the upper‐body fat in women. Collectively, these data indicate that the microenvironment, rather than differences in inherent properties of preadipocytes between genders, may explain the gynoid obesity phenotype and higher percent body fat in women compared to men.  相似文献   

19.
Plant ecologists require spatial information on functional soil properties but are often faced with soil classifications that are not directly interpretable or useful for statistical models. Sand and clay content are important soil properties because they indicate soil water‐holding capacity and nutrient content, yet these data are not available for much of the landscape. Remotely sensed soil radiometric data offer promise for developing statistical models of functional soil properties applicable over large areas. Here, we build models linking radiometric data for an area of 40,000 km2 with soil physicochemical data collected over a period of 30 years and demonstrate a strong relationship between gamma radiometric potassium (40K), thorium (²³²Th), and soil sand and clay content. Our models showed predictive performance of 43% with internal cross‐validation (to held‐out data) and ~30% for external validation to an independent test dataset. This work contributes to broader availability and uptake of remote sensing products for explaining patterns in plant distribution and performance across landscapes.  相似文献   

20.
Platelet‐activating factor (PAF) is an important mediator of anaphylaxis and is therefore an anti‐anaphylactic drug target. We recently reported that synthetic N‐terminally biotinylated peptides (BP4‐BP29) inhibit PAF by directly interacting with PAF and its metabolite/precursor lyso‐PAF. In this study, we investigated whether the biotinylated peptides can inhibit anaphylactic reactions in vivo. In mouse models of anaphylaxis, one of the peptides, BP21, markedly and dose‐dependently inhibited hypothermia with a maximum dose–response within 30 min after administration, even at doses 20 times lesser than doses of the known PAF antagonist CV‐3988. In contrast, the anti‐hypothermic effect of BGP21, in which the Tyr‐Lys‐Asp‐Gly sequence in BP21 was modified to a Gly‐Gly‐Gly‐Gly sequence, was less than that of BP21. The alanine scanning and shuffling the amino acid residues of BP4 (Tyr‐Lys‐Asp‐Gly) demonstrated that the Tyr‐Lys‐Asp‐Gly consensus sequence is important for the inhibitory effect of the peptide on hypothermia. BP21 also suppressed vascular permeability during anaphylaxis with a maximum dose–response within 30 min of administration. In a rat model of hind paw oedema, BP21 significantly inhibited the oedema induced by PAF but not that induced by the other pro‐inflammatory mediators, such as histamine, serotonin, and bradykinin. Tryptophan fluorescence measurements showed that BP21 interacted with PAF, but not with histamine, serotonin, or bradykinin. In contrast, BGP21 did not interact with PAF. These results suggest that biotinylated peptides, especially BP21, can specifically and markedly inhibit anaphylactic reactions in vivo and that this involves direct interaction of its Tyr‐Lys‐Asp‐Gly region with PAF. Therefore, a biotinylated peptide, BP21, can be used as novel potential anti‐anaphylactic drugs targeting PAF. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

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