Exploring the mechanism of BK polyomavirus-associated nephropathy through consensus gene network approach.

BK polyomavirus-associated nephropathy occurs in kidney transplant recipients under immunosuppressive treatment. BK polyomavirus is implicated in cancer development and invasion, and case reports of renal cell carcinoma and urothelial carcinoma possibly associated with BK polyomavirus has been reported. Further, it has been suggested that the immune responses of KT-related diseases could play a role in the pathogenesis and progression of renal cell carcinoma. Thus, we thought to examine the relationship between BK polyomavirus-associated nephropathy and renal cell carcinoma in terms of gene expression. To identify the common and specific immune responses involved in kidney transplantation-related diseases with a specific focus on BK polyomavirus-associated nephropathy, we performed consensus weighted gene co-expression network analysis on gene profile datasets of renal biopsy samples from different institutions. After the identification of gene modules and validation of the obtained network by immunohistochemistry of the marker across kidney transplantation-related diseases, the relationship between prognosis of renal cell carcinoma and modules was assessed. We included the data from 248 patients and identified the 14 gene clusters across the datasets. We revealed that one cluster related to the translation regulating process and DNA damage response was specifically upregulated in BK polyomavirus-associated nephropathy. There was a significant association between the expression value of hub genes of the identified cluster including those related to cGAS-STING pathway and DNA damage response, and the prognosis of renal cell carcinoma. The study suggested the potential link between kidney transplantation-related diseases, especially specific transcriptomic signature of BK polyomavirus associated nephropathy and renal cell carcinoma.

Impact of prior bevacizumab therapy on the incidence of ramucirumab-induced proteinuria in colorectal cancer: a multi-institutional cohort study.

BACKGROUND: The association between prior bevacizumab (BEV) therapy and ramucirumab (RAM)-induced proteinuria is not known. We aimed to investigate this association in patients with metastatic colorectal cancer (mCRC). METHODS: mCRC patients who received folinic acid, fluorouracil, and irinotecan (FOLFIRI) plus RAM were divided into with and without prior BEV treatment groups. The cumulative incidence of grade 2-3 proteinuria and rate of RAM discontinuation within 6 months (6M) after RAM initiation were compared between the two groups. RESULTS: We evaluated 245 patients. In the Fine-Gray subdistribution hazard model including prior BEV, age, sex, comorbidities, eGFR, proteinuria ≥ 2 + at baseline, and later line of RAM, prior BEV treatment contributed to proteinuria onset (P < 0.01). A shorter interval between final BEV and initial RAM increased the proteinuria risk; the adjusted odds ratios (95% confidence intervals) for the intervals of < 28 days, 28-55 days, and > 55 days (referring to prior BEV absence) were 2.60 (1.23-5.51), 1.51 (1.01-2.27), and 1.04 (0.76-1.44), respectively. The rate of RAM discontinuation for ≤ 6M due to anti-VEGF toxicities was significantly higher in the prior BEV treatment group compared with that in the no prior BEV treatment group (18% vs. 6%, P = 0.02). Second-line RAM discontinuation for ≤ 6M without progression resulted in shorter overall survival of 132 patients with prior BEV treatment (P < 0.01). CONCLUSION: Sequential FOLFIRI plus RAM after BEV failure, especially within 55 days, may exacerbate proteinuria. Its escalated anti-VEGF toxicity may negatively impact the overall survival.

Effect of Low-Density Lipoprotein Apheresis on Quality of Life in Patients with Diabetes, Proteinuria, and Hypercholesterolemia.

INTRODUCTION: Treating diabetic nephropathy with low-density lipoprotein (LDL) apheresis reduces proteinuria and improves prognosis. However, its impact on patients' quality of life (QoL) is unclear. This study evaluated the effect of LDL apheresis on QoL in patients with diabetes, proteinuria, and hypercholesterolemia. METHODS: In this nationwide multicenter prospective study, we enrolled 40 patients with diabetes. Inclusion criteria were proteinuria (defined as an albumin/creatinine ratio ≥3 g/g), serum creatinine levels <2 mg/dL, and serum LDL ≥120 mg/dL despite drug treatment. LDL apheresis was performed 6-12 times within 12 weeks. The 36-item Short Form Health Survey (SF-36) was used to analyze QoL. RESULTS: The study enrolled 35 patients (27 men and 8 women; mean age 58.9 ± 11.9 years). A comparison of baseline SF-36 values with those at the end of the course of apheresis found an improvement in the mean physical component summary (37.9 ± 11.4 vs. 40.6 ± 10.5, p = 0.051) and a significant increase in the mean mental component summary (MCS) (49.4 ± 8.4 vs. 52.5 ± 10.9, p = 0.026). A multivariable linear regression analysis revealed a history of coronary heart disease negatively correlated with the MCS increase at the end of the course of apheresis (ß coefficient -6.935, 95% confidence interval, 13.313 to-0.556, p = 0.034). CONCLUSION: Our results suggest that LDL apheresis may improve the mental and physical QoL in patients with diabetes, proteinuria, and hypercholesterolemia.

A Systematic Review of the Literature on Chronic Kidney Disease Following Liver Transplantation.

Chronic kidney disease (CKD) is a serious comorbidity affecting liver transplant recipients (LTRs). Calcineurin inhibitor dosing minimization protocols and everolimus use purportedly increased from 2010, potentially impacting CKD development. This systematic literature review was designed to identify CKD incidence in adult LTRs, focusing on studies published from 2010 onwards. PubMed, Embase, and the Cochrane Database of Systematic Reviews were searched for papers reporting -renal function (glomerular filtration rate [GFR]; estimated GFR [eGFR] or Chronic Kidney Disease Epidemiology Collaboration) for adult LTRs ≥6 months after transplantation. Primary outcome: renal function ≥6 months -after transplantation, with CKD stage. Bias was assessed using the Cochrane Collaboration bias tool and by -reviewing disclosures/industry funding. Of 3960 records identified, 14 publications were included. In at least 1 study arm, mean GFR/eGFR remained stable/improved temporally in 4 and decreased in 8 publications. Where GFR/eGFR decreased, mean eGFR was 71.4-119.6 mL/min/1.73 m² (CKD stage 2-stage 1) across studies at baseline, and was 77.2 and 79.1 mL/min/1.73 m² (stage 2) at 12 months. The proportion of patients with CKD increased between baseline and follow-up; 23.2-36.8% of patients had CKD stage 3a or higher at 12 months (2 studies). Rates ranged from 85.7-100% (6 months) for patient survival, 81.0% (12 months) to 100.0% (17 months) for graft survival, and 0-40% (12 months) for acute rejection. Most studies carried risk of bias. Evidence of temporal renal function decline highlights the need for continuous renal monitoring of LTRs, particularly regarding potential CKD development/progression.

Effects of LDL apheresis on proteinuria in patients with diabetes mellitus, severe proteinuria, and dyslipidemia.

BACKGROUND: Patients with diabetes mellitus and severe proteinuria present with poor renal prognoses, despite improvements in diabetes and kidney disease therapies. In this study, we designed a low-density lipoprotein (LDL)-cholesterol apheresis treatment for patients with diabetic nephropathy (DN)/diabetic kidney disease and severe proteinuria. This was a multicenter prospective LICENSE study to confirm the impact of LDL apheresis on proteinuria that exhibited hyporesponsiveness to treatment. In addition, we sought to determine the efficacy and safety of LDL apheresis by comparing the outcomes to those of historical controls in patients with diabetes, refractory hypercholesterolemia, and severe proteinuria. METHODS: This was a prospective, multicenter study, including 40 patients with diabetes, severe proteinuria, and dyslipidemia. LDL apheresis was performed 6-12 times over a 12-week period. The primary endpoint was the proportion of patients with a decrease in proteinuria excretion of at least 30% in the 6 months after starting therapy. The secondary endpoints included serum creatinine levels and laboratory variables, which were evaluated 4, 6, 12, 18, and 24 months after therapy initiation. RESULTS: LDL apheresis was performed on 40 registered patients with diabetes. The proportion of cases in which proteinuria decreased by 30% or more after 6 months of LDL apheresis was 25%, which was similar to that of historical controls. The overall survival and end-stage kidney disease-free survival rates were significantly higher in the LICENSE group compared to those in historical controls. CONCLUSION: Our results suggest that LDL apheresis may be effective and safe for patients with diabetes, proteinuria, and dyslipidemia. TRIAL REGISTRATION: Trial registration number: jRCTs042180076.

Evaluation of the Quality of Life and Health-Related Quality of Life of Patients With End-Stage Kidney Disease Resulting From Kidney Transplantation Using the Kidney Disease Quality of Life-Short Form and EuroQOL-5 Dimension-5 Level Questionnaires.

BACKGROUND: Renal transplantation improves the quality of life (QOL) of end-stage renal disease (ESRD) patients with renal failure. However, it remains unclear which renal disease-specific QOL aspects determine general health-related QOL of ESRD patients. This study aimed to identify these QOL items by examining the QOL of ESRD patients using the Kidney Disease Quality of Life-Short Form (KDQOL-SF), version 1.3, and EuroQoL-5 dimension-5 levels (EQ-5D-5L) questionnaires. METHODS: We conducted QOL surveys with 67 renal transplant recipients at our hospital. EQ-5D-5L, which evaluates general health-related QOL, was the response variable, and KDQOL-SF, which includes the renal disease-specific instrument and general health-related QOL SF-36 instrument, was the explanatory variable. We analyzed the effects of each KDQOL-SF domain on EQ-5D-5L using Pearson correlation coefficient. RESULTS: Regarding the general health-related QOL assessed by SF-36, physical health aspects, such as physical functioning (R = 0.749) and daily functioning physical (R = 0.603), showed a strong correlation with EQ-5D-5L, and the domains related to the psychological and social aspects of QOL showed a limited correlation. Regarding kidney disease-specific scales, symptoms/problems related to physical function showed a good correlation (R = 0.691) with EQ-5D-5L, whereas other scales, including burden of kidney disease (R = 0.168), quality of social interaction (R = 0.284), and those related to the mental and social aspects of QOL showed a low correlation with EQ-5D-5L. CONCLUSION: Among kidney transplant recipients, the physical health aspects of QOL, such as symptoms/problems, were the major factors influencing overall QOL as assessed by EQ-5D-5L.

[Simultaneous Hepatorenal Transplantation from a Brain-Dead Donor for Graft Dysfunction and Renal Insufficiency in a Liver Transplant Recipient : A Case Report].

We report a case of lethal hepatorenal insufficiency in a 52-year-old man who received successful simultaneous hepatorenal transplantation from a deceased donor. The patient had undergone live-donor liver transplantation for type-C hepatitis and liver cirrhosis 11 years before he developed graft liver dysfunction due to recurrent viral hepatitis and cirrhosis. At that instance, he also developed end-stage renal dysfunction due to calcineurin inhibitor nephropathy and hepatorenal syndrome. Although he needed three open hemostases and abundant blood transfusion, he was withdrawn from continuous hemodiafiltration on the 55th day and discharged from the hospital on the 272nd day postoperatively. Simultaneous hepatorenal transplantation was reported to be associated with more favorable outcomes of graft function, lower rejection rates, but higher perioperative complication rates compared with liver transplantation alone in patients on hemodialysis. Particularly, close attention should be paid for hemostasis since patients have a hemorrhagic tendency until the recovery of graft liver function.

Dietary Sodium Restriction Reduces Nocturnal Urine Volume and Nocturnal Polyuria Index in Renal Allograft Recipients With Nocturnal Polyuria.

OBJECTIVE: To investigate whether sodium restriction alters the nocturnal urine volume (NUV) and the ratio of NUV to 24-hour urine of renal allograft recipients (RARs). MATERIALS AND METHODS: This prospective, single-center study analyzed 38 of the 59 RARs who were followed up for more than 6 months in our hospital. All patients underwent 3 sessions of dietary counseling performed by a board-certified dietitian. Before and after these 3 sessions, 24-hour urine samples were collected, along with voiding frequency volume charts. RESULTS: Of the 38 included RARs, 23 (60.5%) were diagnosed as having nocturnal polyuria (NP, NUV >10 mL/kg). After counseling the RARs with NP, their 24-hour sodium excretion was reduced from 169.5 to 125.6 mEq (P = .0066), their NUV from 862 to 709 mL (P = .021), and the ratio of NUV to 24-hour urine volume from 38.9% to 33.0% (P = .023). In contrast, these parameters were not significantly changed by dietary counseling in RARs without NP. Reduced sodium excretion and decreased NUV were significantly correlated (Spearman rho = 0.45, P = .005). CONCLUSION: Excess intake of sodium is considered a cause of NP in RARs. Dietary counseling on sodium restriction is effective in reducing NUV in RARs. Prospective studies are needed to evaluate the general population with NP.

Cleaved Form of Osteopontin in Urine as a Clinical Marker of Lupus Nephritis.

We assessed the utility of two forms of osteopontin (OPN), OPN full and its cleaved form (OPN N-half), in plasma and urine as markers of disease activity in lupus nephritis (LN). Samples were collected from patients with systemic lupus erythematosus (SLE) (LN: N = 29, non-LN: N = 27), IgA nephropathy (IgAN) (N = 14), minimal change nephrotic syndrome (MCNS) (N = 5), diabetic nephropathy (DN) (N = 14) and healthy volunteers (HC) (N = 17). While there was no significant difference in urine OPN full concentration between groups, urine OPN N-half concentration was significantly higher in patients with LN than HC (p < 0.05). Moreover, urine OPN N-half was higher in LN patients with overt proteinuria (urine protein/creatinine ratio: P/C > 0.5) than LN patients with minimal proteinuria (P/C < 0.5, p < 0.0001), and also higher than in DN patients with overt proteinuria (P/C > 0.5, p < 0.01). Urine thrombin activity correlated with urine OPN N-half concentration (p < 0.0001), but not with urine OPN full concentration. These results suggest that urine OPN N-half concentration reflects renal inflammation. Thus, urine OPN N-half may be a novel disease activity marker for LN.

The Short-Term Impact of Dietary Counseling on Sodium Intake and Blood Pressure in Renal Allograft Recipients.

BACKGROUND: Sodium retention causes posttransplant hypertension, and sodium restriction is recommended in kidney allograft recipients. However, there have been few studies on the impact of dietary counseling on sodium intake and blood pressure (BP) in this population. OBJECTIVE: To determine the effect of dietary counseling on sodium intake and consequent BP control in kidney allograft recipients. DESIGN, SETTING, AND PARTICIPANTS: A prospective single-arm study to determine the effect of dietary counseling on sodium intake. Enrolled were renal allograft recipients with sodium intake >100 mEq/d, BP >130/80, antihypertensive use, or body mass index >25 kg/m2. Of 53 renal transplant recipients who met the criteria, 48 participated in the present study. Sodium intake was estimated based on 24-hour urinary sodium excretion before and after 3 sessions of dietary counseling by a board-certified dietitian. RESULTS: Sodium intake was significantly decreased after dietary counseling (158.7 vs 129.6 mEq/d; P = .005). Systolic BP was significantly decreased from 124 mm Hg (interquartile range: 122-134) before counseling to 121 mm Hg (interquartile range: 117-128) after counseling ( P < .001). The number of patients with systolic BP >130 mm Hg was decreased by 30% (n = 19-13; P = .07). Among 34 patients on antihypertensive medications, 8 (23.5%) ceased or reduced their drugs due to improvement in BP, whereas 2 increased or changed the drugs due to poor control of BP. CONCLUSION: Dietary counseling showed a short-term efficacy of reducing sodium intake and clinically relevant BP improvement in renal allograft recipients.

Molecular Markers of Tubulointerstitial Fibrosis and Tubular Cell Damage in Patients with Chronic Kidney Disease.

In chronic kidney disease (CKD), progressive nephron loss causes glomerular sclerosis, as well as tubulointerstitial fibrosis and progressive tubular injury. In this study, we aimed to identify molecular changes that reflected the histopathological progression of renal tubulointerstitial fibrosis and tubular cell damage. A discovery set of renal biopsies were obtained from 48 patients with histopathologically confirmed CKD, and gene expression profiles were determined by microarray analysis. The results indicated that hepatitis A virus cellular receptor 1 (also known as Kidney Injury Molecule-1, KIM-1), lipocalin 2 (also known as neutrophil gelatinase-associated lipocalin, NGAL), SRY-box 9, WAP four-disulfide core domain 2, and NK6 homeobox 2 were differentially expressed in CKD. Their expression levels correlated with the extent of tubulointerstitial fibrosis and tubular cell injury, determined by histopathological examination. The expression of these 5 genes was also increased as kidney damage progressed in a rodent unilateral ureteral obstruction model of CKD. We calculated a molecular score using the microarray gene expression profiles of the biopsy specimens. The composite area under the receiver operating characteristics curve plotted using this molecular score showed a high accuracy for diagnosing tubulointerstitial fibrosis and tubular cell damage. The robust sensitivity of this score was confirmed in a validation set of 5 individuals with CKD. These findings identified novel molecular markers with the potential to contribute to the detection of tubular cell damage and tubulointerstitial fibrosis in the kidney.

[A case of successful living related renal transplantation in a patient with end-stage renal disease resulting from sarcoidosis].

We report a case in a 44-year-old man with known past history of sarcoidosis associated with uveitis that was first diagnosed when he was 20 years old. He developed renal dysfunction 6 years after the diagnosis of sarcoidosis. At that time, a renal biopsy revealed non-necrotizing granulomatous interstitial nephritis, typical findings of renal involvement of sarcoidosis. Despite corticosteroid therapy administered soon after the biopsy, the renal dysfunction gradually progressed to end-stage renal disease. The patient underwent kidney transplantation from a living donor and the renal graft has been functioning well with no evidence of recurrence 10 months postoperatively, and with a serum creatinine level between 1.2 and 1.5 mg/dl.

Once-daily oral administration of cyclosporine in a lung transplant patient with a history of renal toxicity of calcineurin inhibitors.

Cyclosporine is usually administered orally in two divided doses every 12 h in transplant patients. However, some patients have difficulty in achieving therapeutic levels after transplantation. In fact, cyclosporine is reportedly administered once daily in renal and liver transplantation cases, but not in lung transplantation cases. We report a patient with a history of calcineurin inhibitor-induced renal toxicity who successfully underwent living-donor lobar lung transplantation (LDLLT) with the novel immunosuppressive strategy of once-daily administration of cyclosporine. An 18-year old man with progressive respiratory insufficiency after bone marrow transplantation was referred to our hospital for lung transplantation. He had a history of renal toxicity due to calcineurin inhibitors. Based on his history of tacrolimus- and cyclosporine-induced renal toxicity, we decided to initiate basiliximab as induction therapy, followed by once-daily cyclosporine administration to obtain high enough blood cyclosporine concentrations at 2 h post-dose (C2) and lowered trough blood concentrations (C0) for protection of renal function as maintenance therapy. LDLLT was successfully performed, and the postoperative course was uneventful and free of rejection episodes. Cyclosporine dosing was adjusted with intensive therapeutic drug monitoring of blood cyclosporine levels. One year after LDLLT, the patient is alive and well with no problems with daily life activities.

Low density lipoprotein apheresis ameliorates interferon-γ production in patients with nephrotic syndrome.

Rapid amelioration of hypercholesterolemia in nephrotic syndrome (NS) using low density lipoprotein-apheresis (LDL-A) sometimes leads to NS remission, along with improvement of impaired biodefense system; however, the mechanism of how LDL-A affects NS is still unknown. We studied IFN-γ production under IL-12 stimulation for 24 h in whole blood from 30 NS patients, 31 non-NS patients, 35 healthy volunteers and another four persistent NS patients due to refractory focal segmental glomerulonephritis and minimal change type nephrotic syndrome. We compared IFN-γ production in whole blood and peripheral blood mononuclear cells (PBMC) from persistent NS patients before and after each of 14 LDL-A procedures. Finally, we studied the effect that persistent NS patients' serum before and after LDL-A had on IFN-γ production in healthy volunteers' PBMC. Whole blood IFN-γ production was significantly lower in NS patients compared with healthy volunteers or non-NS patients. In persistent NS, after LDL-A, IFN-γ production returned to normal levels. IFN-γ production in PBMC varied greatly among these patients and did not show consistent changes after LDL-A. Healthy volunteers PBMC incubated with persistent NS patients' serum obtained after LDLA showed higher IFN-γ production than before LDL-A. IFN-γ production in peripheral blood is impaired if a patient is in a nephrotic state. LDL-A might restore suppressed PBMC function in persistent NS patients, thereby ameliorating the nephrotic state, possibly through removing interfering serum factors.

Application of nilvadipine solid dispersion to tablet formulation and manufacturing using crospovidone and methylcellulose as dispersion carriers.

Nilvadipine (NIL) solid dispersion using crospovidone (Cross-linked-N-vinyl-2-pyrolidone, cl-PVP) and methylcellulose (MC) as carriers was applied to tablet formulation. Several grades of cl-PVP and MC were used, and their influence on tablet properties such as hardness, disintegration, dissolution and chemical stability were investigated. The agitation granulation method was used for preparation of solid dispersion granules, and the granules were compressed using a rotary tableting machine, and finally the obtained tablets were coated with film. As the particle size of cl-PVP decreased, hardness and apparent solubility were increased, while dissolution rate was lowered. When a higher viscosity grade of MC was used, hardness and dissolution rate were increased, and apparent solubility did not change. All batches of tablets were chemically stable at 40 degrees C, 75% relative humidity (R.H.) for six months. Finally, tablets with enhanced dissolution properties were obtained by using Polyplasdone XL-10 and Metolose SM-25 as the grades of cl-PVP and MC, respectively. These formulation tablets showed higher solubility and dissolution rate during storage as well as initial indicating good physical stability.

[Stability of nilvadipine solid dispersion tablet with non-packaging condition].

Nilvadipine (NIL) solid-dispersion tablets were stored counter to packaging instructions by exposing them to 40 degrees C, 25 degrees C, 75% relative humidity, and light. The dissolution, stability assay, and tablet properties (weight, thickness and hardness) were then examined. NIL dissolved more than 85% after all storage periods with exposure to high temperature and humidity. Powder X-ray diffraction analysis indicated that NIL was present in an amorphous state as in the initial state. The stability assay of NIL showed that it was more than 99% stable during all storage periods when exposed to temperature, humidity, and light, indicating good stability. Tablet properties were influenced by humidity more than by temperature, and the hardness of tablets decreased with time to 42.9 N after storage of 3 months.

An attempt to stabilize nilvadipine solid dispersion by the use of ternary systems.

Firstly, we investigated the physical stability of nilvadipine (NIL)/crospovidone (cl-PVP) solid dispersion during storage (40 degrees C, 75% relative humidity) with powder x-ray diffraction, differential scanning calorimetry (DSC) and dissolution test. These studies indicated that recrystallization occurred during storage and that the dissolution of NIL greatly decreased, compared with that of the initial finding. Secondly, to improve the amorphous form physical stability of NIL, methylcellulose (MC) was added to NIL/cl-PVP solid dispersions as a dispersion carrier and NIL/cl-PVP/MC ternary solid dispersion systems were obtained by the solvent method. Powder x-ray diffraction and DSC studies indicated that the amorphous form physical stability of NIL clearly improved in the NIL/cl-PVP/MC solid dispersion systems during storage. Moreover, the dissolution properties of NIL/cl-PVP/MC solid dispersion systems were characterized by cl-PVP markedly enhancing the dissolution of NIL and MC inhibiting the change of the dissolution of NIL during storage. Finally, we obtained an ideal solid dispersion that was accompanied by a consistently higher rate of dissolution.

Physicochemical characterization and drug release studies of nilvadipine solid dispersions using water-insoluble polymer as a carrier.

Nilvadipine solid dispersions were prepared by the solvent method using water-insoluble polymers, including low-substituted hydroxypropylcellulose, croscarmellose sodium, carmellose calcium, carmellose, and crospovidone. Differential scanning calorimetry and powder x-ray diffraction analysis showed that nilvadipine was present in an amorphous state in the solid dispersion obtained using crospovidone as a carrier. The degree of crystallinity of nilvadipine was dependent on the ratio of nilvadipine to crospovidone, and nilvadipine was present in an amorphous state when the ratio of nilvadipine to crospovidone was below one-half. Fourier transform infrared studies suggested the presence of hydrogen bonding between nilvadipine and crospovidone in the solid dispersion. Dissolution studies indicated that the maximum percentage of dissolution and dissolution rate constants were markedly increased in nilvadipine with crospovidone solid dispersion, compared with those of pure nilvadipine and physical mixtures. The dissolution rate of nilvadipine solid dispersion with crospovidone could be calculated by the Higuchi square root time equation.

A discrimination method for paper by Fourier transform and cross correlation.

A non-destructive method for discriminating between different types of paper has been proposed, using image analysis, Fourier transformation, and cross-correlation matching. A fast Fourier transform (FFT) is used to extract the periodicity in the structure of paper that results from the manufacturing processes. The light-transmission images of the paper to be Fourier transformed are obtained from a flatbed image scanner. The similarity between the power spectrum of the FFT of the sample and that of a reference is quantified using a cross-correlation matching method. An advantage of using frequency analysis is that periodicity can be detected even if the sample is damaged or is printed on. The technique works on samples as small as 2 cm2.