Search

This work discusses the effect of sample suspension in radio frequency plasma-enhanced chemical vapor deposition process on properties of the obtained overlays. Silicon nitride (SiN x ) overlays were deposited on flat silicon wafers and cylindrical fused silica optical fibers. The influence of the suspension height and fiber diameter on SiN x deposition rate is investigated. It has been found that thickness of the SiN x overlay significantly increases with suspension height, and the deposition rate depends on fiber dimensions. Moreover, the SiN x overlays were also deposited on long-period gratings (LPGs) induced in optical fiber. Measurements of the LPG spectral response combined with its numerical simulations allowed for a discussion on properties of the deposited overlay. The measurements have proven higher overlay deposition rate on the suspended fiber than on flat Si wafer placed on the electrode. Results of this work are essential for precise tuning of the functional properties of new generations of optical devices such as optical sensors, filters and resonators, which typically are based on optical fibers and require the overlays with well defined properties. [ABSTRACT FROM AUTHOR]

Disturbances in thyroid function are common among patients on renal replacement therapy. The aim of the present study was to compare thyroid stimulating hormone (TSH) and thyroid morphology among patients on hemodialysis (HD), peritoneal dialysis (CAPD), and after kidney transplantation. The study was performed on three groups of patients: 48 transplant recipients (Tx) (receiving cyclosporine, azathioprine, and prednisone); 32 HD, and 26 CAPD patients. The control group included 40 healthy volunteers. Thyroid examinations were performed with a 7.5-MHz probe and the thyroid volume was calculated. Among Tx patients the thyroid volume was 25.16 ± 12.27mL; 21.60 ± 10.33mL in HD; 19.70 ± 8.46 mL in CAPD; and 16.34 ± 5.46mL in the healthy volunteers. Serum TSH was within the normal range in each group. Goiter was diagnosed in the majority of Tx, most HD patients, and some CAPD patients. Single and multiple nodules were found in 21 Tx, 12 HD, and 2 CAPD patients. Moreover, parathyroid glands were visualized on sonography in 10 Tx, 12 HD, and 8 CAPD subjects. In Tx observed correlations were positive between thyroid volume and creatinine, negative between thyroid volume and TSH. The time after transplantation correlated negatively with TSH. No correlation between TSH, thyroid volume, and time on dialysis was observed. The prevalence in patients on renal replacement therapy was higher than that in the general population. These findings suggest that screening for abnormal thyroid morphology should be performed in kidney patients and that iodide supplementation should be considered in Tx patients. [Copyright &y& Elsevier]

Detailed microstructural studies were performed on Ni/Si ohmic contacts to silicon carbide in order to investigate the effect of initial Ni:Si ratio in as-deposited structures on the occurrence of characteristic defects in Ni silicide layers, such as voids, layer discontinuities, rough surface or rough interface. The chosen range of investigated Ni:Si ratios corresponded to δ-Ni 2 Si as a dominant phase after complete annealing sequence. Strong effect of the initial stoichiometry on the ohmic contact's microstructure was observed. The highest Ni concentration significantly lowered the temperature at which roughening of the surface and the interface occurred. The middle value of investigated concentrations resulted in the rough interface after high temperature annealing, while the lowest investigated Ni content preserved smooth interface but introduced large voids and layer discontinuities. After the first annealing step, γ-Ni 31 Si 12 and/or δ-Ni 2 Si phases were detected. In the ohmic contacts (after two-step annealing sequence), beside δ-Ni 2 Si, the metastable, high temperature phase θ-Ni 2 Si was detected (also referred to as Ni 3 Si 2 ·h). This phase can exist within a relatively broad range of Ni:Si stoichiometry. The stoichiometry change toward higher Si content, which occurs during high temperature annealing, was realized through this phase. Superstructures were detected in θ-Ni 2 Si (Ni 3 Si 2 ·h) and in γ-Ni 31 Si 12 grains. The effect of the stoichiometry change on the morphology of the Ni silicide layers is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: BK polyomavirus (BKV) infection and BKV-associated nephropathy (BKVAN) are among the most important problems in renal transplantation. We aimed to determine the incidence of BK viruria, viremia, and BKVAN in renal transplant recipients in the northeastern part of Poland. Methods: Urine and blood samples from 126 cadaveric renal transplant recipients were analyzed for BK viruria and viremia using quantitative real-time polymerase chain reaction and the patients were followed prospectively. The diagnosis of BKVAN was established on the allograft biopsy. Results: Based on the BKV DNA analysis, the patients were divided into three groups: group 1 (n = 89; 70.6%) without viruria or viremia, group 2 (n = 24; 19.1%) with isolated viruria, and group 3 (n = 13; 10.3%) with both viruria and viremia. The presence of BK viremia negatively correlated with time after the transplantation. BK viruria was associated with mycophenolate mofetil daily dose. In group 3 there were four patients (3.2%) with high viremia (>104 genome equivalents [gEq]/mL) and viruria (>107 gEq/mL) loads. Only one patient from this group developed clinical symptoms and had BKVAN in allograft biopsy. In all four cases, the maintenance immunosuppression therapy was based on tacrolimus and steroids. Conclusion: Prevalence of BKV infection in renal transplant recipients in the northeastern part of Poland is similar to that reported by studies from other countries. We confirm that BK viremia could be predicted by the presence of intense viruria. Time after transplantation and the type of immunosuppression strategy are the most important predictors of BK viremia and viruria in patients after renal transplantation. [Copyright &y& Elsevier]

Abstract: Background: Many factors affect long-term graft and patient survival. Compliance with lifestyle recommendation may be an important factor. Lifestyle modifications may play a therapeutic and protective role against graft failure and possible death. Methods: The aim of this work was to assess compliance with lifestyle recommendations among 110 kidney allograft recipients. All patients were asked to complete a questionnaire regarding life style, frequency of outpatient visits, self-control, diet, physical activity and addictions. Results: The mean age of the population was 48.79 ± 13.18 years, and their mean time after transplantation was 69 ± 44.5 years with a mean serum creatinine value of 1.45 ± 0.7 mg/dL. Physicians were the major source of information (40%) for patients while in the hospital; nurses informed patients in only 5.5% of cases. The majority of patients (97.5%) attended regular outpatient clinic visits. A similar percentage of subjects regularly measured their blood pressure at home. One-fifth of the patient wrote a self-control diary. Only 55.5% of patients knew the immunosuppressive regimen, including the doses of the medications. An overweight condition was diagnosed in 39%, with obesity in 22%; 16% of the patients were smokers; one-fourth of the patients drank alcohol at least several times a month; 85.3% of patients did not change their diet after kidney transplantation; and one-half of the patients (64.2%) were not aware of dietary recommendations after kidney transplantation. Conclusions: The majority of patients regularly attended the outpatient clinic and ingested immunosuppressive medications. However, their knowledge regarding diet, cancer prophylaxis, and self-control was insufficient. Therefore, there is a need to introduce more intense organizational and educational activities to improve patient knowledge. [Copyright &y& Elsevier]

Abstract: Introduction: Both anemia and erythrocytosis frequently occur after kidney transplantation. The aim of this study was to analyze the influence of both anemia and erythrocytosis on kidney graft function and long-term patient outcomes following kidney transplantation. Patients and Methods: Three hundred eight-five consecutive patients with at least 12 months of follow-up after successful kidney transplantation were enrolled into this study. Of the total, 88.3% of patients completed a 5-year follow-up. Anemia occurred in 30.4% of patients (with 17.7% showing a hemoglobin concentration (Hb) <11.0 g/dL), whereas erythrocytosis was observed in 19.0% of patients, including 9.6% with hematocrit (HTC) >55%. We also analyzed graft function every 6 months after transplantation for the impact of anemia or erythrocytosis on the 5-year risk of patient death or graft loss. Results: In 57.3% of anemia patients the Hb did not reach the normal range during the observation time. The mean eGFR–Modification of Diet in Renal Disease (MDRD) at 12 months after transplantation was significantly lower among patients with anemia: 43.9 mL/min/1.73 m2 (39.5–48.4) vs 55.3 mL/min/1.73 m2 (53.0–57.6; P < .001). Better 12-month graft function was observed among patients with erythrocytosis, namely, 57.7 mL/min/1.73 m2 (53.5–62.0). Anemia but not erythrocytosis was associated with an increased risk of graft loss (hazard ratio [HR] = 4.11 [95% confidence interval (CI) 2.02–8.37]; P < .001). Conclusion: Anemia after transplantation was associated with worse kidney graft function and was a strong predictor of graft loss. Erythrocytosis occurs among patients with excellent allograft function; when properly treated it did not increase the risk of graft loss or death. [Copyright &y& Elsevier]

Abstract: Background: Thyroid hormones could affect renal function, and, on the other hand, renal dysfunction may affect thyroid function. Disturbances of concentrations of thyroid hormones are often associated with thyroid gland enlargement. The aim of the study was to assess the function and morphology of the thyroid (volume and hormones concentration) and kidney function after transplantation (creatinine concentration and resistance index [RI] of transplant artery). Material and Methods: The group included 13 females, 19 males; aged 19–69 years, mean 44.75 ± 14.8 years after transplantation with stable graft function. Thyroid volume, renal artery RI, creatinine concentration, and concentrations of T3, rT3, FT3, FT4, and TSH were estimated the day before surgery, and at 1, 3, 6, and 10 days after transplantation. Results: The statistical analysis revealed a negative correlation between delta RI (difference between RI at 3 and 6 days after transplantation) and serum creatinine concentration, 10 days after transplantation (r = −0.63; P < 0.01). We also observed a negative correlation between creatinine serum concentration at 10 days after transplantation and delta thyroid volume (Δ Vol; r = − 0.48; p < .05), a positive correlation between delta FT4 (Δ FT4) serum concentration, and delta creatinine (Δ Crea; r = 0.73; P < .001). Conclusions: The dynamics of RI changes in the transplant kidney artery between 3 and 6 days after transplantation may predict graft function. Together with improved kidney function at 10 days after transplantation, we observed a regression of goiter. [Copyright &y& Elsevier]

Renal osteodystrophy is a common complication of chronic renal failure and renal replacement therapy. Successful kidney transplantation reverses many of these abnormalities, but the improvement is often incomplete. The evaluation of renal osteodystrophy in everyday practice is based on noninvasive measurements. Taking this into consideration the aim of the present study was to assess new markers of bone metabolism: serum CrossLaps degradation products of C-terminal telopeptides of type I collagen tartrate-resistant acid phosphatase (TRAP) and bone-specific alkaline phosphatase (bALP), as well as their correlations with bone mineral disease (BMD) in kidney transplant recipients. Twenty-six patients (aged 26 to 54 years) receiving a triple immunosuppressive regimen with stable graft function were enrolled in the study. Serum parathormone (PTH) osteocalcin type collagen C-terminal peptides (ICTP), and procollagen type I carboxyterminal extension peptide (PICP) concentrations were measured by radioimmunoassay (RIA), Serum CrossLaps, bALP, β2-microglobulin, TRAP 5b by enzyme-linked immunoassay (ELISA), and deoxypyridinoline (DPD) in urine immunochemiluminescence. BMD, as measured by dual-energy X-ray absorptiometry (DEXA), correlated negatively with markers of bone formation (bALP, osteoclacin, and PICP) and resorption (TRAP, ICTP, and β2-microglobulin). The only positive correlation was between urine DPD and BMD at the femoral neck. Interestingly, BMD correlated negatively with CsA concentration. TRAP 5b correlated positively with serum creatinine, ALP, bALP, osteocalcin, iPTH, ICTP, and serum β2-microglobulin, and negatively with CsA concentration, and azathioprine and prednisone dose. DPD did not correlate with any parameters. Serum CrossLaps correlated with markers of both bone formation and resorption. Because TRAP and serum CrossLaps correlated with markers of both bone formation and or resorption, additional studies are needed to establish the value of these markers of bone resorption to assess renal osteodystrophy. [Copyright &y& Elsevier]

Abstract: Background: Cytomegalovirus (CMV) infection is a common complication of renal transplantation. It can be diagnosed serologically, mainly based on seroconversion or by the detection of viral antigen via CMV-DNA amplification (polymerase chain reaction [PCR]). Aim: We sought diagnosis of an active CMV infection in renal transplant patients comparing serologic assays of CMV-IgM antibodies with CMV-DNA amplification. Methods: We retrospectively studied renal transplant recipients 26 (including 15 women) hospitalized with clinical suspicion of CMV disease. The diagnosis of CMV infection was suspected on the basis of nonspecific symptoms, including fever, leukopenia, hyperbilirubinemia, and alanine aminotransferase elevation, alone or in combination. At the time of admission, all patients were screened for CMV-IgM antibody (immunoassays AxSYM/IMx) and CMV-DNA (qualitative PCR). Results: The confirmation of CMV infection by the two methods (immunoassay and PCR) was obtained in only three patients (11.5%), its unambiguous exclusion—in four cases (15.4%). Nineteen patients (73.1%) were positive for CMV-IgM and negative for CMV-DNA. Conclusion: Detection of CMV-IgM antibodies by various immunoassays is not sensitive enough for diagnosis and cannot be used for monitoring during the active period in renal transplant recipients. This observation supported the prolonged presence of IgM antibodies after recent CMV infection in this patient group. [Copyright &y& Elsevier]

Abstract: Background: Renal allograft survival depends on a number of factors, however, no reliable simple parameter has been shown to predict long-term outcome after transplantation. Ultrasound is recognized and relatively inexpensive, providing information about renal location, contour, and size. Doppler ultrasonography shows kidney morphology and hemodynamics. The aim of this study was the evaluation of whether Doppler ultrasound of renal arteries performed in the early stage after transplantation was a valuable predictor for long-term-outcomes. Material and Methods: The study included 17 female and 24 male patients, aged 17–69 years with stable graft function. The Doppler ultrasound of renal flow was done on the 1st and 3rd day after transplantaion, and estimated glomerular filtration rate (eGFR) on the 20th day. The measured indices were as follows: maximum blood flow velocity (Vmax), minimum blood flow velocity (Vmin), resistive index (RI), and pulsatile index (PI). The creatinine concentration was evaluated, and eGFR calculated. Results: Mean renal and intrarenal artery RI increased to day 3 after transplantation, and then reduced. The mean renal and intrarenal Vmax at day 3 correlated positively with eGFR (r = 0.38; P = .015); (r = 0.45; P = .003, respectively). Mean renal and intrarenal Vmin correlated positively with eGFR (r = 0.50; P = .001; r = 0.41; P = .008, respectively). The mean renal and intrarenal Vmax and Vmin on day 1 did not correlate with eGFR. Conclusions: Early Doppler Ultrasonography of renal graft hemodynamics may be a valuable predictor of graft survival and long-term outcomes. Blood flow velocity within renal arteries seemed to be an important factor. [Copyright &y& Elsevier]