Role of duodenal iron transporters and hepcidin in patients with alcoholic liver disease

Patients with alcoholic liver disease (ALD) often display disturbed iron indices. Hepcidin, a key regulator of iron metabolism, has been shown to be down-regulated by alcohol in cell lines and animal models. This down-regulation led to increased duodenal iron transport and absorption in animals. In this study, we investigated gene expression of duodenal iron transport molecules and hepcidin in three groups of patients with ALD (with anaemia, with iron overload and without iron overload) and controls. Expression of DMT1, FPN1, DCYTB, HEPH, HFE and TFR1 was measured in duodenal biopsies by using real-time PCR and Western blot. Serum hepcidin levels were measured by using ELISA. Serum hepcidin was decreased in patients with ALD. At the mRNA level, expressions of DMT1, FPN1 and TFR1 genes were significantly increased in ALD. This pattern was even more pronounced in the subgroups of patients without iron overload and with anaemia. Protein expression of FPN1 paralleled the increase at the mRNA level in the group of patients with ALD. Serum ferritin was negatively correlated with DMT1 mRNA. The down-regulation of hepcidin expression leading to up-regulation of iron transporters expression in the duodenum seems to explain iron metabolism disturbances in ALD. Alcohol consumption very probably causes suppression of hepcidin expression in patients with ALD.

Fabrication of biodegradable textile scaffold based on hydrophobized hyaluronic acid

In this work, we report on the preparation of a novel biodegradable textile scaffold made of palmitoyl-hyaluronan (palHA). Monofilament fibres of palHA with a diameter of 120μm were prepared by wet spinning. The wet-spun fibres were subsequently processed into a warp-knitted textile. To find a compromise between swelling in water and degradability of the final textile scaffold, a series of palHA derivatives with different degrees of substitution of the palmitoyl chain was synthesized. Freeze-drying not only provided shape fixation, but also speeded up scaffold degradation in vitro. Fibronectin, fibrinogen, laminin and collagen IV were physically adsorbed on the textile surface to enhance cell adhesion on the material. The highest amount of adsorbed cell-adhesive proteins was achieved with fibronectin (89%), followed by fibrinogen (81%). Finally, textiles modified with fibronectin or fibrinogen both supported the adhesion and proliferation of normal human fibroblasts in vitro, proving to be a useful cellular scaffold for tissue engineering.

Incidence of cutaneous malignant melanoma in the Czech Republic: the risks of sun exposure for adolescents

The Czech Republic reported one of the highest incidence rate in cutaneous melanoma (CM) in Europe and because this incidence has been increasing, mainly among young people, the main goal of our study was to establish sun exposure behavior risk factors for CM formation and to evaluate whether the young generation of Czechs is exposed to a higher risk of CM than the older generation. A questionnaire-based case-control study was conducted. We obtained 978 completed questionnaires: 216 from patients with CM and 762 from healthy respondents. The healthy individuals were further divided to adolescents (n = 460) and older respondents (n = 302). Three logistic regression models were developed: 1. patients with CM vs. healthy older respondents, 2. adolescents vs. healthy older respondents, and 3. patients with CM vs. adolescents. The main risk factors for all three models were the number of sunburn episodes and the use of the sunscreen in the childhood. The most alarming results for adolescents included: all day sun exposure, including times of maximum risk (11 AM to 3 PM), inadequate use of sunscreen in adulthood, and frequent mountain holidays. Our results show that sun-safety in the young generation is satisfactory, when the responsibility for sun exposure behavior is in the hands of their parents; however, when children become adolescents, they become immune to sun-safety and risk prevention campaigns and their behavior becomes much more risky. Our results further suggest the sun-safety campaigns need to be modified in such a way as to have greater impact and influence on adolescent sun-risk behaviors.

Improvements in colorectal cancer screening programmes - quantitative immunochemical faecal occult blood testing - how to set the cut-off for a particular population

OBJECTIVE

The aim of the study was to determine the optimum cut-off value of the quantitative immunochemical test (q-FIT) OC-Sensor for colorectal cancer and advanced adenomatous polyps in a particular population.

METHODS

815 patients were referred for colonoscopy and were offered two q-FIT examinations at two different colonoscopy centers. The patients were classified according to the colonoscopic findings. Test sensitivity, specificity, and accuracy were statistically evaluated using one test and two tests at the levels of 50, 75, 100, 125, and 150 ng/mL of faecal hemoglobin in those patients with advanced polyps and colorectal cancer. The optimum cut-off test level for clinically significant neoplasia was determined using one test.

RESULTS

The optimum cut-off value of q-FIT OC-Sensor for the detection of clinically significant neoplasia in our particular population was determined as 75 ng/mL using one test. This value provides an optimum proportion of 73% sensitivity (±95% CI 60.3% - 83.4%) and 90% specificity (±95% CI 86.8% - 92.8%), PPV and NPV were determined as 54.76% and 95.43% respectively.

CONCLUSIONS

The first step in the implementation of q-FIT test in the screening program in our country is to determine the optimum cut-off level for a population, and to estimate the number of tests performed with respect to the optimum cost effectiveness and economical climate. Using one test, the optimum level of q-FIT OC-Sensor® in the Czech Republic was determined as 75 ng/mL. This study could serve as a model for further studies in other countries, where screening does not yet exist.

The evolution of rectal and urinary toxicity and immune response in prostate cancer patients treated with two three-dimensional conformal radiotherapy techniques

Background

Our research compared whole pelvic (WP) and prostate-only (PO) 3-dimensional conformal radiotherapy (3DCRT) techniques in terms of the incidence and evolution of acute and late toxicity of the rectum and urinary bladder, and identified the PTV-parameters influencing these damages and changes in antitumor immune response.

Methods

We analyzed 197 prostate cancer patients undergoing 3DCRT for gastrointestinal (GI) and genitourinary (GU) toxicities, and conducted a pilot immunological study including flow cytometry and an NK cell cytotoxicity assay. Acute and late toxicities were recorded according to the RTOG and the LENT-SOMA scales, respectively. Univariate and multivariate analyses were conducted for factors associated with toxicity.

Results

In the WP group, an increase of acute rectal toxicity was observed. A higher incidence of late GI/GU toxicity appeared in the PO group. Only 18 patients (WP-7.76% and PO-11.11%) suffered severe late GI toxicity, and 26 patients (WP-11.21% and PO-16.05%) severe late GU toxicity. In the majority of acute toxicity suffering patients, the diminution of late GI/GU toxicity to grade 1 or to no toxicity after radiotherapy was observed. The 3DCRT technique itself, patient age, T stage of TNM classification, surgical intervention, and some dose-volume parameters emerged as important factors in the probability of developing acute and late GI/GU toxicity. The proportion and differentiation of NK cells positively correlated during 3DCRT and negatively so after its completion with dose-volumes of the rectum and urinary bladder. T and NKT cells were down-regulated throughout the whole period. We found a negative correlation between leukocyte numbers and bone marrow irradiated by 44-54 Gy and a positive one for NK cell proportion and doses of 5-25 Gy. The acute GU, late GU, and GI toxicities up-regulated the T cell (CTL) numbers and NK cytotoxicity.

Conclusion

Our study demonstrates the association of acute and late damage of the urinary bladder and rectum, with clinical and treatment related factors. The 3DCRT itself does not induce the late GI or GU toxicity and rather reduces the risk of transition from acute to late toxicity. We have described for the first time the correlation between organs at risk, dose-volume parameters, and the immunological profile.

Duodenal expression of iron transport molecules in patients with hereditary hemochromatosis or iron deficiency

Disturbances of iron metabolism are observed in chronic liver diseases. In the present study, we examined gene expression of duodenal iron transport molecules and hepcidin in patients with hereditary hemochromatosis (HHC) (treated and untreated), involving various genotypes (genotypes which represent risk for HHC were examined), and in patients with iron deficiency anaemia (IDA). Gene expressions of DMT1, ferroportin, Dcytb, hephaestin, HFE and TFR1 were measured in duodenal biopsies using real-time PCR and Western blot. Serum hepcidin levels were measured using ELISA. DMT1, ferroportin and TFR1 mRNA levels were significantly increased in post-phlebotomized hemochromatics relative to controls. mRNAs of all tested molecules were significantly increased in patients with IDA compared to controls. The protein expression of ferroportin was increased in both groups of patients but not significantly. Spearman rank correlations showed that DMT1 versus ferroportin, Dcytb versus hephaestin and DMT1 versus TFR1 mRNAs were positively correlated regardless of the underlying cause, similarly to protein levels of ferroportin versus Dcytb and ferroportin versus hephaestin. Serum ferritin was negatively correlated with DMT1 mRNA in investigated groups of patients, except for HHC group. A decrease of serum hepcidin was observed in IDA patients, but this was not statistically significant. Our data showed that although untreated HHC patients do not have increased mRNA levels of iron transport molecules when compared to normal subjects, the expression is relatively increased in relation to body iron stores. On the other hand, post-phlebotomized HHC patients had increased DMT1 and ferroportin mRNA levels possibly due to stimulated erythropoiesis after phlebotomy.

Expression of selected proteins in breast cancer brain metastases

The aim of the study was to assess the immunohistochemical (IHC) profiles of SRC3, Pax2, ER, PgR, Her2, EGFR, CK5/6, and Ki67 proteins in breast-cancer brain metastasis. The study utilized tumor samples from 30 metastatic patients and calculated correlations between all IHC variables. In fourteen cases, primary breast cancers paired with secondary deposits were analyzed. We evaluated the association between IHC status in the primary and secondary deposits, grade, and histotype of the tumors. The examination of the metastatic deposits in all 30 patients resulted in positive detection in the following cases: SRC3 in 20 cases (66.6%), Pax2 in 22 (73.3%), ER in 22 (73.3%), PgR in 25 (83.3%), Her2 in 10 (33.3%), EGFR in 12 (40%), CK5/6 in 7 (23.3%), and Ki67 in 23 (76.6%). Grade 2 was found in 13.3% of all patients, and grade 3 in 86.7%. SRC3 and Pax2 were positive in both G2 and G3. Invasive lobular carcinoma and invasive ductal carcinoma were diagnosed in 23.3% and 76.7% of cases, respectively. There were no differences between the IHC expression of the studied proteins in either grading or histotype of the tumors. In the IHC profiles, which included SRC3, Pax2, ER, PgR, Her2, CK5/6, Ki67, and EGFR, we found no statistically significant differences between the primary cancer and the brain metastasis. In our study of metastatic breast carcinoma deposits, there was no correlation between SRC3, Pax2 status and histotype, and tumor grade. The IHC status of the paired primary and metastatic deposits did not differ in a statistically significant manner.

Vascular supply of the anterior interventricular epicardial nerves and ventricular Purkinje fibers in the porcine hearts

The aim of this study was to perform a pilot histological and quantitative analysis of the blood vessels accompanying the epicardial nerves (vasa nervorum) in the porcine hearts. Twenty healthy porcine hearts were used in this study. The blood vessels were analyzed by light microscopy using four different staining techniques in transverse sections taken from the upper, middle, and lower segments of the anterior part of the interventricular region and the adjacent parts of the right and left ventricles containing epicardial nerves and the endocardial peripheral parts of the Purkinje fibers. In total, 317 epicardial nerves were detected. The vasa nervorum were present in 75.7% of these nerves. The vasa nervorum resembled arterioles and postcapillary and collecting venules. One hundred and forty nine epicardial nerves were perivascular, located in the adventitia of the anterior interventricular artery and vein. The remaining 168 nerves ran freely through the epicardial interstitium. The presence of the vasa nervorum was not related to topographical location or nerve diameter. Additionally, from a total of 33 analyzed ventricular complexes of Purkinje fibers small blood vessels located in their proximity were identified in only two cases. It can be concluded that the majority of the anterior epicardial nerves of porcine heart possess well-developed vasa nervorum. In contrast, similar blood vessels are rarely present in the vicinity of the Purkinje fibers. The data obtained contribute to a better understanding of the nutrition of the cardiac nerves.

Dynamics of fertility in patients on waiting list for kidney transplantation

OBJECTIVES

To evaluate the presence of hormonal abnormalities and fertility disorders in patients with chronic kidney disease (CKD) awaiting renal transplantation.

METHODS

From September 2009 to April 2011 all male patients with CKD awaiting kidney transplantation were investigated. The following tests were performed: semen analysis, serum concentration of testosterone, SHBG, LH, FSH and prolactin. Differences in hormone levels and sperm count parameters were statistically evaluated between the control group and the patient group.

RESULTS

The group of patients consisted of 74 and the control group of 41 men. Average testosterone levels were lower in patients compared to control group. In patients significantly higher levels of SHBG, LH, FSH and PRL were found, and statistically significantly lower ejaculate volume, total sperm count, sperm concentration, total and progressive sperm motility and sperm morphology than in the control group. Within the group of patients a negative correlation between testosterone and PRL was found and a positive correlation between testosterone and total sperm motility and morphology. A negative correlation was detected between the duration of haemodialysis and testosterone, sperm concentration, total and progressive motility and sperm morphology.

CONCLUSION

Significant changes in hormone levels and impaired fertility are found in haemodialyzed patients on a waiting list for kidney transplantation. The dynamics of these changes are dependent on the duration of haemodialysis (Tab. 4, Fig. 2, Ref. 15). Text in PDF www.elis.sk.

¹³C-methacetin breath test in the evaluation of disease severity in patients with liver cirrhosis

AIMS

The non-invasive (13)C-methacetin ((13)C-MBT) breath test has been proposed as a measure of metabolic liver function that improves the diagnostic efficacy of serologic and biochemical tests in assessing hepatic functional capacity and liver disease severity, The goal of this study was to establish the clinical utility of this test in quantifying hepatic metabolic function in patients with liver cirrhosis of varying severity and to compare (13)C-MBT measurements with the AST/ALT ratio, APRI score, and other routine liver tests.

METHODS

Routine liver function tests including serum bilirubin, aspartate aminotransferase activity (AST), alanine aminotransferase (ALT), AST/ALT ratio, the APRI score, the percentage of dose rate (PDR) and cumulative percentage of dose rate (CPDR) of the (13)C-MBT were evaluated in 52 cirrhotic patients of alcohol etiology (Child-Pugh A/B/C 10/28/14) and 37 healthy controls.

RESULTS

The (13)C-MBT differed significantly between healthy controls and cirrhotic patients at all time intervals measured. It also proved the ability to differentiate patients with liver cirrhosis based on severity of hepatic impairment corresponding to the Child-Pugh classification A vs. B vs. C. The ROC curve analysis suggested that the best prediction is provided by time intervals between the 10th - 20th or 10th - 40th minute of PDR.

CONCLUSIONS

The (13)C-MBT offers a reliable means for quantification of hepatic metabolic function over the complete range of functional liver impairment. It is non-invasive, easy to perform and completely safe.

Natriuretic peptide proANP (1-98), a biomarker of ALI/ARDS in burns

INTRODUCTION

Plasma atrial natriuretic peptide levels (proANP (1-98)), a parameter of myocardial dysfunction, have been reported to be increased in critically ill patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). The aim of the study was to examine if proANP is a biomarker of ALI/ARDS as assessed by the Sequential Organ Failure Assessment score (SOFA Lung ≥2) in burn patients, and how it compares to the corresponding values for age, total body surface area percent (TBSA%) and inhalation injury for mortality prediction.

METHODS

A group of 22 burn patients with a mean TBSA of 30% (10-75%) and a mean age of 52 years (25-84 years) was investigated during 2010. Organ dysfunction/failure was classified according to the SOFA score. The criteria for ALI/ARDS were based on SOFA Lung ≥2. ProANP (1-98) concentrations (nmoll(-1)) were measured by commercially available enzyme linked immunosorbent assay (ELISA) immunoassays (Biomedica Austria) on post-burn days 2 and 7.

RESULTS

ProANP levels on day 7 post-burn positively correlated with a SOFA score day 7 post-burn, c=0.91. The receiver operating curve (ROC) analysis proved a sensitivity of 75% and a specificity of 75% for ALI/ARDS at cut-off values >3.35 nmoll(-1). The ROC value of proANP for ALI/ARDS (SOFA Lung ≥2) was significantly larger than that of age, TBSA% and inhalation injury: 0.90, 0.71, 0.74, and 0.69 (p<0.001).

CONCLUSIONS

ProANP levels, as a biomarker of ALI/ARDS, in critically burn patients correlated with SOFA scoring. The inhalation injury did not lead to increase in proANP values.

The size and shape of the human pelvis: a comparative study of modern and medieval age populations

INTRODUCTION

Great variability in shape and size of the bony pelvis can be observed in the current population, but there is not enough data on how long the historical period must elapse to gain changes in pelvic shape and size. The aim of the study was to identify morphological changes in bony pelvis in males and females after a developmentally short period of approximately one thousand years.

MATERIAL AND METHODS

Seventeen defined external dimensions of pelvic bone from 120 adult individuals (two craniocaudal, two ventrodorsal, six mediolateral, three acetabular dimensions, and four dimension of the auricular surface) were measured. The medieval sample of 60 pelvic bones (30 male and 30 female) was obtained from the Great Moravian site of Mikulčice-Valy (9th-10th century), while the modern collection of 60 pelvic bones (30 male and 30 female) dates from the late 19th and first half of the 20th centuries. Obtained results were evaluated using the independent t-test at a 5% level of significance.

RESULTS

A comparison of male and female pelvic dimensions within a single population yielded expected results: the mean male values were greater. In modern population, male pelvis mean values were greater in 15 of defined parameters, while in medieval population, male dimensions were larger in 16 variables. A comparison of modern and medieval female pelvic bones found 11 variables to be greater in medieval sample (one determining the craniocaudal dimension, five the mediolateral, all three the acetabular, and two determining the auricular surface dimensions), but only two were significant (two dimensions determining the mediolateral dimensions). In modern female samples, there were five variables greater (one determining the craniocaudal dimension, one the ventrodorsal, one the mediolateral, and two determining the auricular surface dimensions), but only two were significant as well (one determining the craniocaudal and one the ventrodorsal dimensions). A comparison of male pelvic bones found 13 variables to be greater in medieval pelvis (one determining the craniocaudal dimension, all six the mediolateral, one the ventrodorsal, all three the acetabular, and two determining the auricular surface dimensions), but only four were significant as well (all determining the mediolateral dimensions). In modern male sample, there were only four variables greater (one determining the craniocaudal dimension, one the ventrodorsal, and two determining the auricular surface dimensions), but only one was significant (determining the craniocaudal dimension).

CONCLUSION

Unexpectedly, our study did not find the early medieval population to have a smaller pelvis compared to the modern population. While pelvic bones of the former were somewhat lower, but wider, those of the latter population were a bit higher and narrower. The study allows a very careful statement that one millennium is a time period long enough for measurable morphological deviations of the pelvic bones shape and size to occur.

25-gauge vitrectomy and gas for the management of rhegmatogenous retinal detachment

AIMS

To evaluate the anatomical and functional results in patients with rhegmatogenous retinal detachment (RRD) who underwent 25-gauge pars plana vitrectomy (PPV) with gas tamponade.

MATERIALS AND METHODS

A retrospective evaluation of 126 eyes of 126 patients (79 men, 47 women) with RRD who underwent 25-gauge PPV with gas tamponade (13% C3F8 in 87 eyes, 20% SF6 in 39 eyes). 113 patients (89.7%), were operated on under local anaesthesia, 13 patients (10.3%) under general anaesthesia. Macula was detached in 85 eyes (67.5%). 53 eyes had pseudophakic RRD, 73 eyes were phakic. Anatomical success of the primary intervention, change in best corrected visual acuity (BCVA) and incidence of complications were assessed. An average follow-up period is 7.2 months (6-15).

RESULTS

With single operation, retinal attachment was achieved in 125 eyes (99.2%); the final anatomical success was 100%. The initial mean BCVA was 0.89 logMar (2.00 to 0.00); at the end of the follow-up period, it improved to 0.23logMAR (1.00 to -0.10), P < 0,0001. During the first post-intervention day, hypotony of the eye below 10 mmHg was observed in 1 patient (0.8%); on the contrary, intraocular pressure was temporarily increased to 25 mmHg and more in 36 patients (28.6%).

CONCLUSION

The surgical treatment of RRD using 25-gauge PPV with expansive gas tamponade renders excellent anatomical results and improvement in BCVA. The incidence of complications and necessity of sclerotomy suturing are low.

The Efficacy of Fibrin Sealant in Sutureless Deep Sclerectomy-Preliminary Outcomes

PRCIS

Deep sclerectomy (DS) with fibrin adhesive can constitute a safe alternative to the classic procedure using sutures, providing nonallergenic, nontoxic, and secure adhesion with no sign of aqueous humor outflow obstruction postoperatively.

OBJECTIVE

To evaluate short and medium-term postoperative results of DS with a fibrin sealant.

PATIENTS AND METHODS

This prospective, noncomparative, interventional case series involves 12 eyes of 12 patients with uncontrolled open angle glaucoma who underwent DS with Esnoper (Clip or V2000) implant between February 2021 and March 2022. A novel method of wound closure (sclera, Tenon fascia, and conjunctiva) employing fibrin glue was used instead of classic sutures. Surgical outcomes assessed include: intraocular pressure and glaucoma therapy reduction, best-corrected visual acuity changes, and number of complications registered peri and postoperatively. All measurements were performed preoperatively, as well as at 1 day, at 1 and 2 weeks, and at 1, 2, 3, 6, 9, and 12 months after surgery.

RESULTS

The mean intraocular pressure decreased from 24.0 ± 9.1 mm Hg to 13.8 ± 6.3 mm Hg at 1 year postoperatively ( P < 0.001). Kaplan-Meier survival analysis revealed complete and qualified success rates of 83.3% and 91.7%. The mean glaucoma therapy decreased from 3.2 ± 1.1 to 0.8 ± 1.3 drugs 12 months after surgery ( P < 0.001). Nd:YAG goniopunture was performed in 2 eyes at 1 and 12 months postoperatively. No significant best-corrected visual acuity changes were registered. Perioperatively, we noted a trabeculo-descemet microperforation in 1 eye, transient hypotony in 5 eyes, and mild hyphema in 2 eyes.

CONCLUSIONS

Fibrin adhesive provided an effective closure in sutureless DS in the patients included in our study. This modification of classical DS may simplify the surgical technique, ensure secure wound adaptation, optimize healing, and lower the risk of inflammation and fibrosis postoperatively.

Association of biomarkers of cardiac remodeling, myocardial fibrosis and inflammation with parameters of heart function and structure in patients with arterial hypertension

BACKROUND AND AIMS

Early evaluation of cardiac remodeling may be useful in predicting heart failure in patients with arterial hypertension. The identification of biomarkers as useful clinical tools in this regard is ongoing. The aim of this study was to evaluate the association of selected cardiac biomarkers levels with parameters of cardiac structure and function in patients with arterial hypertension.

PATIENTS AND METHODS

Included in the study were patients with arterial hypertension with normal left ventricular ejection fraction (LV EF) and absence of signs of heart failure. The levels of selected biomarkers: NT-proBNP, sST2, Galectin-3, GDF-15, Cystatin C, TIMP-1 and ceruloplasmin were measured and assessed together with other biochemical and echocardiographic parameters.

RESULTS

A total of 92 patients (61% men) mean age 61.5 years were included. Mean LV EF was 64.7% and mean LV mass index was 91.7 g/m2. NT-proBNP level correlated significantly with the parameters of LV diastolic function: velocity of E wave (r=0.377, P<0.002), and with E/A ratio, (r=0.455, P<0.0001), with E lat (r=-0.354, P=0.006), E/E' ratio, r=0.393, P<0.002, with ePAP (r=0.390, P=0.014), and with age (r=0.384, P<0.0001). Statistically significant correlations for GDF-15 were as follows: with age (r=0.426, P<0.0001) and left atrial diameter (LA) (r=0.401, P<0.0001), for Cystatin C there are statistically significant correlation with age (r=0.288, P=0.006) and LA (r=0.329, P=0.004). Only sST2 level correlated significantly with parameters of cardiac structure: with LV mass (r=0.290, P<0.01) and LV mass index (r=0.307, P=0.012) and with posterior wall thickness PW (r=0.380, P<0.001). No other observed variables including Galectin-3 and TIMP-1, correlated significantly with age or echocardiographic variables. In a comparison of patients with and without left ventricular hypertrophy, statistically significant differences were found only in LA (P<0.0001) and sST2 (P=0.004). In a multivariate logistic regression, sST2 and TIMP were independent predictors of left ventricular hypertrophy.

CONCLUSION

NT-proBNP level as a biomarker of cardiac remodeling correlated with parameters of LV diastolic function in patients with arterial hypertension. Soluble ST2 correlated with parameters of cardiac structure. Biomarkers sST2 and TIMP-1 were associated with left ventricular hypertrophy.

Widefield imaging of upconverting nanoparticles on epifluorescence microscopes adapted for laser illumination with top-hat profile

We describe a modification of epifluorescence microscopes that allows quantitative widefield imaging of samples labeled by upconverting nanoparticles (UCNP). A top-hat illumination profile on the sample was achieved with a 980-nm laser diode by using tandem microlens arrays, a moving diffuser and a telescope, which adjusts the top-hat area to the field of view. Illumination homogeneity is a critical factor for imaging of UCNP since the intensity of their luminescence typically scales with the second power of the excitation intensity. Our illuminator is combined with the epifluorescence attachment of the microscope, allowing easy switching between observation of UCNP and traditional fluorescent dyes. Illumination profile homogeneity of about 98% was measured for objectives with magnification from 4× to 100×, and the top-hat profile was also obtained with phase contrast objectives. We demonstrate capability of the illuminator by evaluating in vitro uptake of UCNP encapsulated in oleyl-hyaluronan micelles into breast cancer cells. Micelles bearing the targeting peptide were about an order of magnitude more efficient than nontargeted micelles.