Seasonal Variation of Vitamin D Status in Long-Term Kidney Transplant Recipients.

BACKGROUND: There is little information about circannual rhythm of vitamin D level in kidney transplantation (KTx) patients. MATERIAL AND METHODS: In 71 patients (27 females; 44 males) in the long term after KTx (5.5 ± 2.6 years) during the winter and summer months plasma concentration of 25-hydroxyvitamin D (25(OH)D), 1,25-hydroxyvitamin D, parathormone (PTH), fibroblast growth factor 23 (FGF-23), calcium, and phosphorus were assessed. Vitamin D status was classified according to 25(OH)D level (ie, insufficiency, ≤30 ng/mL; deficiency, <15 ng/mL). RESULTS: In this study, 96% of KTx patients had vitamin D insufficiency including 37% deficiency during winter and 89% of KTx patients had vitamin D insufficiency and 24% had vitamin D deficiency, respectively, during summer. Mean 25(OH)D level during winter was lower than in summer (17.4 ± 7.1 vs 20.2 ± 7.2 ng/mL; P = .02), similar to calcitriol (163.6 ± 37.4 vs 284.5 ± 77.8 pmol/L; P = .001). There were no significant differences in winter and summer levels of calcium, phosphorus, and PTH. The 25(OH)D level was significantly higher in patients with estimated glomerular filtration rate (eGFR) ≥45 mL/min/1.73 m2 compared with those with lower eGFR (21.6 ± 7.5 vs 17.6 ± 6.0; P = .02) only in the summer time. CONCLUSIONS: Most of the KTx patients have vitamin D insufficiency during both winter and summer with higher concentration of vitamin D metabolites in summer. Other factors than graft function may have an impact on vitamin D levels in KTx patients.

Perfusion disturbances of kidney graft parenchyma evaluated with contrast-enhanced ultrasonography in the immediate period following kidney transplantation.

PURPOSE: Graft parenchyma perfusion disturbances (GPPD) in transplanted kidneys are common in the early postoperative period. Rapid and accurate diagnosis can guide proper treatment, preventing graft dysfunction. METHODS: One hundred and eighty patients, who underwent kidney transplantation (KTx), were examined in the immediate postoperative period using real-time ultrasonography (B-mode) with color and power Doppler (US-CD/PD) and B-flow ultrasound, as well as with an additional protocol of contrast-enhanced ultrasonography (CE-US). Regions of GPPD were localized and measured. The number and size of these areas were compared between the two acquisition techniques. Follow-up examinations were carried out 6 months postoperatively. RESULTS: CE-US revealed more GPPDs and showed them more precisely than the B+US-CD/PD/B-flow technique. Moreover, in the CE-US examination, ischemic foci had statistically significant higher echogenicity in comparison to normal parenchyma, were larger and better visualized (better circumscribed) than in B+US-CD/PD/B-flow. CONCLUSION: CE-US allows the visualization of GPPD caused by occlusion of small arteries. It is a noninvasive, safe, real-time method, which has many advantages over standard B+US-CD/PD/B-flow examinations, and we recommend it as a routine diagnostic procedure in the early postoperative period following KTx.

The diagnostic value of contrast-enhanced ultrasonography in the assessment of perirenal hematomas in the early post-operative period after kidney transplantation.

BACKGROUND: Routine B-mode ultrasound examination (rB-US) is a current standard for the assessment of the transplanted kidney(KTx) in the early post-operative period. The alteration of perirenal hematoma (PH) echostructure over time limits their detectability and size assessment with rB-US. The aim of this study was to evaluate the diagnostic value of contrast-enhanced ultrasound (CE-US) in diagnosing PH of KTx in the early post-operative period. METHOD: Routine B-US and CE-US of KTx, performed in 102 patients in the early post-operative period, were analyzed. CE-US was performed after intravenous administration of 2.4 mL of sulfur hexafluoride solution. The data were analyzed with respect to the occurrence and thickness of PH. RESULT: The difference in echogenicity between PH and kidney parenchyma was modest in rB-US (mean of 5.7 dB). However, in CE-US, the difference in echogenicity was significantly increased (mean of 31.4 dB). Routine B-US did not allow PH to be recognized in 18 patients. The application of CE-US results in a twofold increase in PH detection when compared with rB-US (33.3% vs. 15.7%). CONCLUSION: US-CE examination is a valuable method for detection and assessment of PH size. Compared with rB-US, this technique may substantially increase the detectability of hemorrhagic complications in the direct post-operative period.

Tacrolimus dose and blood concentration variability in kidney transplant recipients undergoing conversion from twice daily to once daily modified release tacrolimus.

INTRODUCTION: Maintenance of the target blood levels of immunosuppressive drugs is one of the main factors determining transplant function. The aim of this study was to assess the effect of the conversion of tacrolimus from twice daily (Tc) to the prolonged release form administered once daily (Tc-pr) including the variability of blood concentrations and glomerular filtration rates in kidney transplantation patients. MATERIALS AND METHODS: This retrospective analysis evaluated 52 patients including 23 females, and 29 males with established grafts who underwent a scheduled change of treatment from Tc to Tc-pr. We examined data from six consecutive visits before and six visits after conversion. RESULTS: The average daily dose of Tc was 3.8±2.6 mg/24 h, whereas mean coefficient of variation (CoV) calculated from the visits before conversion was 68%. After the conversion, the mean total daily dose of Tc-pr was not significantly lower (3.2±1.8 mg), as was the mean CoV at six subsequent visits 57% (P=ns). Blood concentrations in both analyzed periods remained in the target range (Tc-pr 6.7±2.9 ng/mL versus Tc-pr 5.0±1.11) with a lower CoV in the case of Tc-pr compared to Tc (22% versus 44%; P<.001). There was no difference in graft function in the analyzed periods. After conversion, lower blood glucose levels were observed: 103.4±28.3 mg/dL versus 95±25.9 mg/dL (P<.03). CONCLUSIONS: The slow-release form of tacrolimus provided greater stability of drug blood concentrations compared with the standard form administered twice daily. The change of the tacrolimus treatment from Tc to Tc-pr dosing did not effect organ function but seemed to improve glycemic control.

Disturbances of kidney graft perfusion as indicators of acute renal vein thrombosis in contrast-enhanced ultrasonography.

INTRODUCTION: The aim of this study was to evaluate the usefulness of contrast-enhanced ultrasound (US-CE) to diagnose acute renal vein thrombosis (ARVT), acute rejection episodes (ARE), or acute tubular necrosis (ATN) in kidney grafts. MATERIALS AND METHODS: We analyzed 171 US-CE among kidney transplantation patients in the early postoperative period. Patients underwent US-CE following a standard diagnostic protocol including real-time ultrasound (B-mode) and color Doppler ultrasound with spectral flow analysis. Tissue perfusion was analyzed based upon time-intensity curves for two regions: the renal cortex and the renal pyramids. RESULTS: Of 14 patients, in whom standard ultrasound showed high resistance parameters in the renal artery, three showed ARVT and 11 had ATN or ARE, which were confirmed by biopsy. Among patients with ARVT, the US-CE showed a lack of contrast perfusion into the cortex and renal pyramids. Patients with ARE/ATN showed slower contrast inflow into the parenchyma with reduced but still present perfusion. The differences in mean signal intensity values were significant for both the cortex and the renal pyramids: cortex: -53.8±5.4 dB versus -35.0±3.5 dB (P<.05) and pyramids: -54.8±5.4 dB versus -37.0±3.5 dB (P<.05). CONCLUSION: US-CE is a noninvasive method that provides easy, reliable differentiation of ARVT from ARE/ATN.

Contrast-enhanced sonography of postbiopsy arteriovenous fistulas in kidney grafts.

PURPOSE: To assess the usefulness of contrast-enhanced ultrasonography (CE-US) in the visualization of a kidney graft following a biopsy that was complicated by an arteriovenous fistula (AVF). METHODS: Four postrenal transplant patients who had developed AVFs following graft biopsy were examined using standard US and CE-US. Additionally, follow-up examinations were conducted using CE-US, at 4-6 weeks and 10-12 weeks following fistula closure. RESULTS: The fistulas were detected using color Doppler US, Power Doppler US, and B-flow technique. Reduced parenchymal flow was only detected in one case using standard flow visualization techniques. CE-US allowed for the visualization of regions of disturbed parenchymal perfusion that were not visible in the standard examinations. At follow-up, B-mode ultrasound and standard flow examinations appeared normal. However, all contrast-enhanced images showed clearly demarcated residual regions of reduced parenchymal perfusion, in areas where the fistulas had been previously present. CONCLUSIONS: A posttraumatic AVF reduces parenchymal perfusion in the affected region. CE-US examination may help in monitoring fistulas during the active phase and following spontaneous closure.

Anti-inflammatory effects of somatostatin analogs on zymosan-induced earlobe inflammation in mice: comparison with dexamethasone and ketoprofen.

The aim of the present study was the estimation of the anti-inflammatory effects of the somatostatin analogs, octreotide (OCT) and vapreotide (RC-160), in zymosan-induced mice ear inflammation and to compare their effects with those of the glucocorticoid dexamethasone (DX) and the non-steroid anti-inflammatory drug ketoprofen (KP), which are the well-known and potent suppressors of the inflammatory reaction. The inflammation was induced by injecting 20 microl of 1% suspension of zymosan intradermally into one of the earlobes of the mouse. The control animals received a vehicle 0.9% NaCl. The zymosan-treated animals were injected subcutaneously with one of the following substances: 0.9% NaCl, OCT, RC-160, DX, KP or with OCT plus DX and OCT plus KP. The edema of earlobes, the area of inflammatory focus and the area of vascular profiles in the inflamed tissues were estimated. A reduction of the ear edema in the mice treated with OCT, DX, KP, OCT + DX and OCT + KP was observed. The administration of all drugs caused the decrease of the area of the inflammatory focus and of the area of vascular profiles. The antiphlogistic activity was more pronounced in the OCT-treated animals in comparison to those treated with RC-160. The joint treatment with either OCT plus DX or OCT plus KP almost totally inhibited the zymosan-induced inflammatory reaction. In summary, the somatostatin analog OCT possesses antiphlogistic activity roughly comparable with classical anti-inflammatory drugs such as DX and KP. The somatostatin analogs may constitute a new promising group of anti-inflammatory agents.

Correlation between PCNA expression and AgNOR dots in pituitary adenomas.

Nucleolar organizer regions are segments of DNA associated with argyrophilic proteins (AgNORs). Our previous findings showed that the number, the area, and the intranuclear localization of AgNOR dots differ according to tumor aggressiveness and to the hormone-immunopositivity of pituitary adenomas. Proliferating cell nuclear antigen (PCNA) is a nuclear protein, whose expression is correlated with cell proliferation. The aim of the present paper was to examine PCNA-labeling indexes in pituitary adenomas and to correlate them with AgNOR dots in various immunohistochemical types of the tumors. Histological slides from 32 pituitary tumors and one normal pituitary were silver-stained and analyzed with a computerized system for microscopic image analysis. We found that the percentage of PCNA-positive cells did not differ significantly among examined groups of monohormonal adenomas. However, tumors immunopositive for alpha-subunit (alpha-SU) showed a significantly higher (p < 0.05) PCNA index than adenomas immunonegative for that unit. PCNA index in recurrent tumors was significantly higher than in primary adenomas. There was a moderate positive correlation between the PCNA index and the mean area of AgNOR dots and a similar correlation between the PCNA index and the area of the biggest dot in the nucleus. The obtained results reveal that the PCNA indexes and estimated parameters of AgNOR dots differ according to tumor aggressiveness.