Detection of posttransplant donor‐specific anti‐HLA antibodies (DSA) constitutes a risk factor for kidney allograft loss. Together with complement activation, NK‐cell antibody‐dependent cell mediated ...cytotoxicity (ADCC) has been proposed to contribute to the microvascular damage associated to humoral rejection. In the present observational exploratory study, we have tried to find a relationship of circulating donor‐specific and nondonor‐specific anti‐HLA antibodies (DSA and HLA non‐DSA) with peripheral blood NK‐cell subsets and clinical features in 393 renal allograft recipients. Multivariate analysis indicated that retransplantation and pretransplant sensitization were associated with detection of posttransplant DSA. Recipient female gender, DR mismatch and acute rejection were significantly associated with posttransplant DSA compared to HLA non‐DSA. In contrast with patients without detectable anti‐HLA antibodies, DSA and HLA non‐DSA patients displayed lower proportions of NK‐cells, associated with increased CD56bright and NKG2A+ subsets, the latter being more marked in DSA cases. These differences appeared unrelated to retransplantation, previous acute rejection or immunosuppressive therapy. Although preliminary and observational in nature, our results suggest that the assessment of the NK‐cell immunophenotype may contribute to define signatures of alloreactive humoral responses in renal allograft recipients.
This single‐center prospective study of kidney transplant recipients shows that patients with detectable anti‐HLA antibodies display lower proportions of NK cells and increased CD56bright and NKG2A+ subsets than patients without antibodies, the latter being more marked in cases with donor‐specific antibodies.
Patients with end‐stage renal disease have longer survival after kidney transplantation than they would by remaining on dialysis; however, outcome with kidneys from donors aged ≥75 years and the ...survival of recipients of these organs compared with their dialysis counterparts with the same probability of obtaining an organ is unknown. In a longitudinal mortality study, 2040 patients on dialysis were placed on a waiting list, and 389 of them received a first transplant from a deceased donor aged ≥75 years. The adjusted risk of death and survival were calculated by non–proportional hazards analysis with being transplanted as a time‐dependent effect. Projected years of life since placement on the waiting list was almost twofold higher for transplanted patients. Nonproportional adjusted risk of death after transplantation was 0.44 (95% confidence interval CI 0.61–0.32; p < 0.001) in comparison with those that remained on dialysis. Stratifying by age, adjusted hazard ratios for death were 0.17 (95% CI 0.47–0.06; p = 0.001) for those aged <65 years, 0.56 (95% CI 0.92–0.34; p = 0.022) for those aged 65–69 years and 0.82 (95% CI 1.28–0.52; p = 0.389) for those aged ≥70 years. Although kidney transplantation from elderly deceased donors is associated with reduced graft survival, transplanted patients have lower mortality than those remaining on dialysis.
The authors compare the outcomes of kidney transplantation from donors over 75 years old with a time‐dependent survival model with recipients on the waitlist remaining on dialysis, and they find significantly better survival in transplanted patients, especially in those under 65 years old.
Summary
Bone health is assessed by bone mineral density (BMD). Other techniques such as trabecular bone score and microindentation could improve the risk of fracture’s estimation. Our chronic kidney ...disease (CKD) patients presented worse bone health (density, microarchitecture, mechanical properties) than controls. More than BMD should be done to evaluate patients at risk of fracture.
Introduction
BMD measured by dual-energy X-ray absorptiometry (DXA) is used to assess bone health in end-stage renal disease (ESRD) patients. Recently, trabecular bone score (TBS) and microindentation that can measure microarchitectural and mechanical properties of bone have demonstrated better correlation with fractures than DXA in different populations. We aimed to characterize bone health (BMD, TBS, and strength) and calcium/phosphate metabolism in a cohort of 53 ESRD patients undergoing kidney transplantation (KT) and 94 controls with normal renal function.
Methods
Laboratory workout, lumbar spine/hip BMD measurements (using DXA), lumbar spine TBS, and bone strength were carried out. The latter was assessed with an impact microindentation device, standardized as percentage of a reference value, and expressed as bone material strength index (BMSi) units. Multivariable linear regression was used to study differences between cases and controls adjusted by age, gender, and body mass index.
Results
Among cases, serum calcium was 9.6 ± 0.7 mg/dl, phosphorus 4.4 ± 1.2 mg/dl, and intact parathyroid hormone 214 pg/ml 102–390. Fourteen patients (26.4%) had prevalent asymptomatic fractures in spinal X-ray. BMD was significantly lower among ESRD patients compared to controls: lumbar 0.966 ± 0.15 vs 0.982 ± 0.15 (adjusted
p
= 0.037), total hip 0.852 ± 0.15 vs 0.902 ± 0.13 (adjusted
p
< 0.001), and femoral neck 0.733 ± 0.15 vs 0.775 ± 0.12 (adjusted
p
< 0.001), as were TBS (1.20 1.11–1.30 vs 1.31 1.19–1.43 (adjusted
p
< 0.001)) and BMSi (79 71.8–84.2 vs 82. 77.5–88.9 (adjusted
p
= 0.005)).
Conclusions
ESRD patients undergoing transplant surgery have damaged bone health parameters (density, microarchitecture, and mechanical properties) despite acceptably controlled hyperparathyroidism. Detecting these abnormalities may assist in identifying patients at high risk of post-transplantation fractures.
Thermal radiative emissivity is related to the optical and electrical properties of materials, and it is a key parameter required in a large number of industrial applications. In the case of ...Ti-6Al-4V, spectral emissivity experimental data are not available for the range of temperatures between 400 and 1200 K, where almost all industrial applications take place. The experimental results in this paper show that the normal spectral emissivity decreases with wavelength from a value of about 0.35 at 2.5 Amm to about 0.10 at 22 Amm. At the same time, the spectral emissivity shows a slight linear increase with temperature between 500 and 1150 K, with approximately the same slope for all wavelengths. Additionally, the influence of the samples thermal history on the emissivity is studied. A strong decrease in the emissivity values appears due to the effect of surface stress relaxation processes. This means that the radiative properties of this alloy strongly depend on the surface stress state. A thermal treatment to relieve the surface stress should be carried out to achieve a steady state of the radiative properties. In addition, a good qualitative agreement is found between the temperature dependence of the electrical resistivity obtained using conventional measurements and the one obtained from the emissivity experimental results by using the Hagen-Rubens equation.
The prognostic factors and optimal therapy for invasive pulmonary aspergillosis (IPA) after kidney transplantation (KT) remain poorly studied. We included in this multinational retrospective study ...112 recipients diagnosed with probable (75.0% of cases) or proven (25.0%) IPA between 2000 and 2013. The median interval from transplantation to diagnosis was 230 days. Cough, fever, and expectoration were the most common symptoms at presentation. Bilateral pulmonary involvement was observed in 63.6% of cases. Positivity rates for the galactomannan assay in serum and bronchoalveolar lavage samples were 61.3% and 57.1%, respectively. Aspergillus fumigatus was the most commonly identified species. Six‐ and 12‐week survival rates were 68.8% and 60.7%, respectively, and 22.1% of survivors experienced graft loss. Occurrence of IPA within the first 6 months (hazard ratio HR: 2.29; p‐value = 0.027) and bilateral involvement at diagnosis (HR: 3.00; p‐value = 0.017) were independent predictors for 6‐week all‐cause mortality, whereas the initial use of a voriconazole‐based regimen showed a protective effect (HR: 0.34; p‐value = 0.007). The administration of antifungal combination therapy had no apparent impact on outcome. In conclusion, IPA entails a dismal prognosis among KT recipients. Maintaining a low clinical suspicion threshold is key to achieve a prompt diagnosis and to initiate voriconazole therapy.
Invasive pulmonary aspergillosis presents a high mortality rate in kidney transplant recipients, with diagnosis within the first 6 months posttransplantation and bilateral lung involvement as independent risk factors for mortality.
Bovine mastitis is one of the most economically deleterious diseases affecting dairy herds and results from an infection of the udder by pathogenic microorganisms such as Staphylococcus aureus, ...Streptococcus uberis, and Escherichia coli. The mammary gland is capable of preventing and combating bacterial infection by means of a complex network of innate and adaptive immune mechanisms. Lactoferrin is an 86-kDa protein with antibacterial activity that plays a role in the mammary gland's defense against infection. β-Lactoglobulin (β-LG) is an 18-kDa protein that is present in most mammals but is notably absent in humans, rodents, and lagomorphs. Different genetic variants of this protein exist, with β-LG A and β-LG B being the most common. In spite of being well studied, the biological function of β-LG is not thoroughly understood, and most noticeably, no reports exist on the effects of the native protein on bacterial growth. Hence, the objective of this study was to assess the potential antibacterial activity of β-LG against mastitis agents. To do this, we purified β-LG from normal bovine milk using a mild, nondenaturing method and performed in vitro growth inhibition assays with Staph. aureus, E. coli, and Strep. uberis. β-Lactoglobulin inhibited the growth of Staph. aureus and Strep. uberis but had no effect on E. coli. The antimicrobial activity against Staph. aureus and Strep. uberis was concentration dependent and was elicited by the intact protein because Tricine-sodium dodecyl sulfate-PAGE and analytical gel filtration chromatography did not reveal the presence of short degradation peptides. Analysis of the genetic variants of β-LG showed that β-LG A has higher inhibitory activity against Staph. aureus and Strep. uberis than β-LG B. Coincubation of β-LG and lactoferrin resulted in an augmented antibacterial activity against Staph. aureus, suggesting an additive effect of the proteins. This result, along with the proteins’ complementary spectrum of action, suggests that β-LG and lactoferrin may complement each other in the mammary gland's defenses against bacterial infection.
Risk factors for invasive pulmonary aspergillosis (IPA) after kidney transplantation have been poorly explored. We performed a multinational case–control study that included 51 kidney transplant (KT) ...recipients diagnosed with early (first 180 posttransplant days) IPA at 19 institutions between 2000 and 2013. Control recipients were matched (1:1 ratio) by center and date of transplantation. Overall mortality among cases was 60.8%, and 25.0% of living recipients experienced graft loss. Pretransplant diagnosis of chronic pulmonary obstructive disease (COPD; odds ratio OR: 9.96; 95% confidence interval CI: 1.09–90.58; p = 0.041) and delayed graft function (OR: 3.40; 95% CI: 1.08–10.73; p = 0.037) were identified as independent risk factors for IPA among those variables already available in the immediate peritransplant period. The development of bloodstream infection (OR: 18.76; 95% CI: 1.04–339.37; p = 0.047) and acute graft rejection (OR: 40.73, 95% CI: 3.63–456.98; p = 0.003) within the 3 mo prior to the diagnosis of IPA acted as risk factors during the subsequent period. In conclusion, pretransplant COPD, impaired graft function and the occurrence of serious posttransplant infections may be useful to identify KT recipients at the highest risk of early IPA. Future studies should explore the potential benefit of antimold prophylaxis in this group.
A multinational case‐control study in kidney transplant recipients finds that pretransplant diagnosis of chronic obstructive pulmonary disease, delayed graft function, bloodstream infection and acute graft rejection identify patients at the highest risk for early invasive pulmonary aspergillosis.
To assess the risk factors for development of late-onset invasive pulmonary aspergillosis (IPA) after kidney transplantation (KT).
We performed a multinational case-control study that retrospectively ...recruited 112 KT recipients diagnosed with IPA between 2000 and 2013. Controls were matched (1:1 ratio) by centre and date of transplantation. Immunosuppression-related events (IREs) included the occurrence of non-ventilator-associated pneumonia, tuberculosis, cytomegalovirus disease, and/or de novo malignancy.
We identified 61 cases of late (>180 days after transplantation) IPA from 24 participating centres (accounting for 54.5% (61/112) of all cases included in the overall study). Most diagnoses (54.1% (33/61)) were established within the first 36 post-transplant months, although five cases occurred more than 10 years after transplantation. Overall mortality among cases was 47.5% (29/61). Compared with controls, cases were significantly older (p 0.010) and more likely to have pre-transplant chronic obstructive pulmonary disease (p 0.001) and a diagnosis of bloodstream infection (p 0.016) and IRE (p <0.001) within the 6 months prior to the onset of late IPA. After multivariate adjustment, previous occurrence of IRE (OR 19.26; 95% CI 2.07–179.46; p 0.009) was identified as an independent risk factor for late IPA.
More than half of IPA cases after KT occur beyond the sixth month, with some of them presenting very late. Late IPA entails a poor prognosis. We identified some risk factors that could help the clinician to delimit the subgroup of KT recipients at the highest risk for late IPA.
► Emittance of Inconel 718 coated with plasma sprayed yttria stabilized zirconia. ► The coating is opaque for
λ
>
9
μm and semi-transparent for
λ
<
9
μm. ► In the semi-transparent region the ...emittance decreases with coating thickness. ► 300
μm thick coatings are still semi-transparent. ► In the opaque region the surface roughness determines the emittance level.
Knowledge of the radiative behaviour of the yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) is needed to perform radiative heat transfer calculations in industrial applications. In this paper, normal spectral emittance experimental data of atmospheric plasma sprayed (PS) YSZ films layered on Inconel 718 substrates are shown. The spectral emittance was measured between 2.5 and 22
μm on samples with film thicknesses ranging from 20 to 280
μm. The samples were heated in a controlled environment, and the emittance was measured for several temperatures between 330 and 730
°C. The dependence of the spectral emittance with film thickness, surface roughness and temperature has been studied and compared with the available results for YSZ TBCs obtained by electron-beam physical vapour deposition. The PS-TBC samples show a Christiansen point at
λ
=
12.8
μm. The films are semi-transparent for
λ
<
9
μm, and opaque for
λ
>
9
μm. In the semi-transparent region, the contribution of the radiation emitted by the Inconel 718 substrate to the global emittance of the samples is analysed. In addition, the influence of the roughness in the emittance values in the opaque spectral region is discussed. Finally, the total normal emittance is obtained as a function of the TBC thickness.
Emissivity measurements on aeronautical alloys del Campo, L.; Pérez-Sáez, R.B.; González-Fernández, L. ...
Journal of alloys and compounds,
01/2010, Letnik:
489, Številka:
2
Journal Article
Recenzirano
The emissivity of three Ni and Co based aeronautical alloys is analyzed in this paper. These alloys are employed in high temperature environments whenever good corrosion resistance, high temperature ...resistance and high strength are essential. Thus, apart from the aeronautical industry, these alloys are also used in other technological applications, as for example, aerospace, nuclear reactors, and tooling. The results in this paper extend the emissivity data for these alloys available in the literature. Emissivity dependence on the radiation wavelength (2–22
μm), sample temperature (200–650
°C) and emission angle (0–85°) has been investigated. In addition, the effect of surface finish and oxidation has also been taken into consideration. The data in this paper have several applications, as temperature measurement of a target by pyrometry, low observability of airplanes and thermal radiation heat transfer simulation in airplane nozzles or furnaces.
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