Status of estrogen receptor expression and epigenetic methylation in Leydig cells after exposure to metalloestrogen - selenium

The trace element selenium (Se) is essential for the maintenance of spermatogenesis and fertility. A growing volume of evidence shows that Se is necessary for testosterone synthesis, and Se can stimulate Leydig cell proliferation. However, Se can also act as a metalloestrogen, which can mimic estrogen and activate the estrogen receptors. This study aimed to investigate Se effect on estrogen signaling and the epigenetic status of Leydig cells. Mouse Leydig cells (MA-10) were cultured in a medium supplemented with different Se concentrations (4, 8µM) for 24hours. Next, cells were assessed for morphological and molecular (qRT PCR, western blot, immunofluorescence) analyses. Immunofluorescence revealed strong immunosignal for 5-methylcytosine in both control and treated cells, with a stronger signal in the 8μM treated group. qRT-PCR confirmed an increased expression of methyltransferase 3β (Dnmt3b) in 8μM cells. Analysis of the expression of γH2AX (a marker for double-stranded DNA breaks) revealed an increase in the DNA breaks in cells exposed to 8μM Se. Selenium exposure did not affect the expression of canonical estrogen receptors (ERα and ERβ), however, an increase in membrane estrogen receptor G-protein coupled (GPER) protein expression was observed. To sum up, in a high concentration (8μM) Se affects GPER expression (non-genomic estrogen signaling) in Leydig cells possibly via acting on receptor protein and/or its binding. This causes DNA breaks and induces changes in Leydig cell methylation status, especially in de novo methylation which is mediated by Dnmt3b.

Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS) spectra of salivary glands carcinoma, tumor and healthy tissues and their homogenates analyzed by chemometry: Towards development of the novel tool for clinical diagnosis

In this study, two approaches to salivary glands studies are presented: Raman imaging (RI) of tissue cross-section and surface-enhanced Raman spectroscopy (SERS) of tissue homogenates prepared according to elaborated protocol. Collected and analyzed data demonstrate the significant potential of SERS combined with multivariate analysis for distinguishing carcinoma or tumor from the normal salivary gland tissues as a rapid, label-free tool in cancer detection in oncological diagnostics. Raman imaging allows a detailed analysis of the cell wall's chemical composition; thus, the compound's distribution can be semi-quantitatively analyzed, while SERS of tissue homogenates allow for detailed analysis of all moieties forming these tissues. In this sense, SERS is more sensitive and reliable to study any changes in the area of infected tissues. Principal component analysis (PCA), as an unsupervised pattern recognition method, was used to identify the differences in the SERS salivary glands homogenates. The partial least squares-discriminant analysis (PLS-DA), the supervised pattern classification technique, was also used to strengthen further the computed model based on the latent variables in the SERS spectra. Moreover, the chemometric quantification of obtained data was analyzed using principal component regression (PCR) multivariate calibration. The presented data prove that the PCA algorithm allows for 91% in seven following components and the determination between healthy and tumor salivary gland homogenates. The PCR and PLS-DA methods predict 90% and 95% of the variance between the studied groups (in 6 components and 4 factors, respectively). Moreover, according to calculated RMSEC (RMSEP), R2C (R2P) values and correlation accuracy (based on the ROC curve), the PLS-DA model fits better for the studied data. Thus, SERS methods combined with PLS-DA analysis can be used to differentiate healthy, neoplastic, and mixed tissues as a competitive tool in relation to the commonly used method of histopathological staining of tumor tissue.

Performance assessment of the 2 γpositronium imaging with the total-body PET scanners

Purpose

In living organisms, the positron-electron annihilation (occurring during the PET imaging) proceeds in about 30% via creation of a metastable ortho-positronium atom. In the tissue, due to the pick-off and conversion processes, over 98% of ortho-positronia annihilate into two 511 keV photons. In this article, we assess the feasibility for reconstruction of the mean ortho-positronium lifetime image based on annihilations into two photons. The main objectives of this work include the (i) estimation of the sensitivity of the total-body PET scanners for the ortho-positronium mean lifetime imaging using 2γ annihilations and (ii) estimation of the spatial and time resolution of the ortho-positronium image as a function of the coincidence resolving time (CRT) of the scanner.

Methods

Simulations are conducted assuming that radiopharmaceutical is labeled with ⁴⁴Sc isotope emitting one positron and one prompt gamma. The image is reconstructed on the basis of triple coincidence events. The ortho-positronium lifetime spectrum is determined for each voxel of the image. Calculations were performed for cases of total-body detectors build of (i) LYSO scintillators as used in the EXPLORER PET and (ii) plastic scintillators as anticipated for the cost-effective total-body J-PET scanner. To assess the spatial and time resolution, the four cases were considered assuming that CRT is equal to 500 ps, 140 ps, 50 ps, and 10 ps.

Results

The estimated total-body PET sensitivity for the registration and selection of image forming triple coincidences (2γ+γ_prompt) is larger by a factor of 13.5 (for LYSO PET) and by factor of 5.2 (for plastic PET) with respect to the sensitivity for the standard 2γ imaging by LYSO PET scanners with AFOV = 20 cm. The spatial resolution of the ortho-positronium image is comparable with the resolution achievable when using TOF-FBP algorithms already for CRT = 50 ps. For the 20-min scan, the resolution better than 20 ps is expected for the mean ortho-positronium lifetime image determination.

Conclusions

Ortho-positronium mean lifetime imaging based on the annihilations into two photons and prompt gamma is shown to be feasible with the advent of the high sensitivity total-body PET systems and time resolution of the order of tens of picoseconds.

Surface-enhanced Raman scattering as a discrimination method of Streptococcus spp. and alternative approach for identifying capsular types of S. pneumoniae isolates

The surface-enhanced Raman spectroscopy (SERS) is a method known for its effectiveness in detecting and identifying microorganisms, that was employed to differentiate various bacterial strains both at genus and species level. In this work, we have examined five species belonging to Streptococcus genus, namely S. pneumoniae, S. suis, S. pseudopneumoniae, S. oralis, and S. mitis. Additionally, we conducted SERS experiments on ten S. pneumoniae strains, representing different capsular types. In all of cases we obtained unique SERS signals being spectroscopic fingerprints of bacterial strains tested. Moreover, the principal component analysis (PCA) was performed in order to prove that the spectra of all studied strains can be well separated into five (in case of streptococcal strains) or ten (in case of pneumococcal serotypes) groups. In both investigated situations, the separation at the level of 95% was achieved, proving that SERS-PCA-based method can be used for reliable and fast identification of different strains belonging to the Streptococcus genus, including encapsulated pneumococcal isolates.

Notch signaling regulates nuclear androgen receptor AR and membrane androgen receptor ZIP9 in mouse Sertoli cells

BACKGROUND

Notch signaling pathway is involved in contact-dependent communication between the cells of seminiferous epithelium, and its proper activity is important for undisturbed spermatogenesis.

OBJECTIVES

The aim was to assess the effect of Notch pathway inhibition on the expression of nuclear (AR) and membrane (ZIP9) androgen receptors and androgen-regulated genes, claudin-5 and claudin-11, in TM4 mouse Sertoli cell line.

MATERIALS AND METHODS

DAPT (γ-secretase inhibitor) treatment and recombination signal binding protein silencing were employed to reduce Notch signaling, whereas immobilized ligands were used to activate Notch pathway in TM4 cells. To reveal specific effect of each androgen receptor, AR or ZIP9 silencing was performed.

RESULTS

Notch pathway inhibition increased the expression of AR and ZIP9 mRNA and proteins (p < 0.01; p < 0.05) in TM4 cells, whereas incubation with Notch ligands, rDLL1 or rJAG1, reduced AR (p < 0.01; p < 0.001) and ZIP9 (p < 0.05; p < 0.01) expressions, respectively. Testosterone enhanced the expression of both receptors (p < 0.05; p < 0.01). Androgen-regulated claudin-5 and claudin-11 (p < 0.01; p < 0.001) and cAMP (p < 0.001) were elevated in Notch-inhibited cells, while activation of Notch signaling by DLL1 or JAG1 reduced claudin-11 or claudin-5 level (p < 0.01; p < 0.001), respectively.

DISCUSSION

Our findings indicate opposite effect of Notch and androgen signaling on the expression of androgen receptors in TM4 cells. We demonstrated that AR expression is regulated by DLL1-mediated Notch signaling, whereas JAG1 is involved in the regulation of ZIP9. The expression of both claudins and cAMP production is under inhibitory influence of Notch pathway. The effects of Notch signaling on claudin-5 and claudin-11 expression are mediated by ZIP9 and AR, respectively.

CONCLUSION

Notch signaling may be considered as an important pathway controlling Sertoli cell physiology, and its alterations may contribute to disturbed response of Sertoli cells to androgens.

Detection of circulating tumor cells in blood by shell-isolated nanoparticle - enhanced Raman spectroscopy (SHINERS) in microfluidic device

Isolation and detection of circulating tumor cells (CTCs) from human blood plays an important role in non- invasive screening of cancer evolution and in predictive therapeutic treatment. Here, we present the novel tool utilizing: (i) the microfluidic device with (ii) incorporated photovoltaic (PV) based SERS-active platform, and (iii) shell-isolated nanoparticles (SHINs) for simultaneous separation and label-free analysis of circulating tumour cells CTCs in the blood specimens with high specificity and sensitivity. The proposed microfluidic chip enables the efficient size - based inertial separation of circulating cancer cells from the whole blood samples. The SERS-active platform incorporated into the microfluidic device permits the label-free detection and identification of isolated cells through the insight into their molecular and biochemical structure. Additionally, the silver nanoparticles coated with an ultrathin shell of silica (Ag@SiO2) was used to improve the detection accuracy and sensitivity of analysed tumor cells via taking advantages of shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). The empirical analysis of SHINERS spectra revealed that there are some differences among studied (HeLa), renal cell carcinoma (Caki-1), and blood cells. Unique SHINERS features and differences in bands intensities between healthy and cancer cells might be associated with the variations in the quantity and quality of molecules such as lipid, protein, and DNA or their structure during the metastasis cancer formation. To demonstrate the statistical efficiency of the developed method and improve the differentiation for circulating tumors cells detection the principal component analysis (PCA) has been performed for all SHINERS data. PCA method has been applied to recognize the most significant differences in SHINERS data among the three analyzed cells: Caki-1, HeLa, and blood cells. The proposed approach challenges the current multi-steps CTCs detection methods in the terms of simplicity, sensitivity, invasiveness, destructivity, time and cost of analysis, and also prevents the defragmentation/damage of tumor cells and thus leads to improving the accuracy of analysis. The results of this research work show the potential of developed SERS based tool for the separation of tumor cells from whole blood samples in a simple and minimally invasive manner, their detection and molecular characterization using one single technology.

Comment on “Spectroscopic properties and location of the Ce3+ energy levels in Y3Al2Ga3O12 and Y3Ga5O12 at ambient and high hydrostatic pressure” by S. Mahlik, A. Lazarowska, J. Ueda, S. Tanabe and M. Grinberg, Phys. Chem. Chem. Phys., 2016, , 6683

The temperature dependence of the band-gap energy affects the evaluation of the energy positions of rare-earth 4f levels in relation to the vacuum level.

Photovoltaic cells as a highly efficient system for biomedical and electrochemical surface-enhanced Raman spectroscopy analysis

Surface-enhanced Raman scattering (SERS) has been intensively used recently as a highly sensitive, non-destructive, chemical specific, and label-free technique for a variety of studies. Here, we present a novel SERS substrate for: (i) the standard ultra-trace analysis, (ii) detection of whole microorganisms, and (iii) spectroelectrochemical measurements. The integration of electrochemistry and SERS spectroscopy is a powerful approach for in situ investigation of the structural changes of adsorbed molecules, their redox properties, and for studying the intermediates of the reactions. We have developed a conductive SERS platform based on photovoltaic materials (PV) covered with a thin layer of silver, especially useful in electrochemical SERS analysis. These substrates named Ag/PV presented in this study combine crucial spectroscopic features such as high sensitivity, reproducibility, specificity, and chemical/physical stability. The designed substrates permit the label-free identification and differentiation of cancer cells (renal carcinoma) and pathogens (Escherichia coli and Bacillus subtilis). In addition, the developed SERS platform was adopted as the working electrode in an electrochemical SERS approach for p-aminothiophenol (p-ATP) studies. The capability to monitor in real-time the electrochemical changes spectro-electro-chemically has great potential for broadening the application of SERS.

We have developed a conductive SERS platform based on photovoltaic materials (PV) covered with a thin layer of silver, especially useful in electrochemical SERS analysis.

Lévy walks with variable waiting time: A ballistic case

The Lévy walk process for a lower interval of an excursion times distribution (α<1) is discussed. The particle rests between the jumps, and the waiting time is position-dependent. Two cases are considered: a rising and diminishing waiting time rate ν(x), which require different approximations of the master equation. The process comprises two phases of the motion: particles at rest and in flight. The density distributions for them are derived, as a solution of corresponding fractional equations. For strongly falling ν(x), the resting particles density assumes the α-stable form (truncated at fronts), and the process resolves itself to the Lévy flights. The diffusion is enhanced for this case but no longer ballistic, in contrast to the case for the rising ν(x). The analytical results are compared with Monte Carlo trajectory simulations. The results qualitatively agree with observed properties of human and animal movements.

Lévy walks in nonhomogeneous environments

The Lévy walk process with rests is discussed. The jumping time is governed by an α-stable distribution with α>1 while a waiting time distribution is Poissonian and involves a position-dependent rate which reflects a nonhomogeneous trap distribution. The master equation is derived and solved in the asymptotic limit for a power-law form of the jumping rate. The relative density of resting and flying particles appears time-dependent, and the asymptotic form of both distributions obeys a stretched-exponential shape at large time. The diffusion properties are discussed, and it is demonstrated that, due to the heterogeneous trap structure, the enhanced diffusion, observed for the homogeneous case, may turn to a subdiffusion. The density distributions and mean squared displacements are also evaluated from Monte Carlo simulations of individual trajectories.

Clinical and Microbiological Efficacy of Levofloxacin Administered three Times a Day for the Treatment of Bacterial Conjunctivitis

Purpose

This randomized, investigator-masked study aimed to compare the clinical and microbiological effectiveness of three times daily administration of levofloxacin 0.5% eyedrops with the classic, more frequent dosing in patients with bacterial conjunctivitis.

Methods

A total of 120 patients with symptoms of bacterial conjunctivitis were enrolled. The patients were randomly assigned to receive 0.5% levofloxacin eyedrops three times daily to each eye for 5 days (experimental dosage group), or every 2 hours on days 1 and 2, and then every 4 hours on days 3–5 (up to four times per day) (classic dosage group). Ocular symptoms and signs were assessed on day 1, days 3 to 4, and 7 ± 1 visits. Conjunctival cultures were obtained at baseline and final visits. Clinical outcomes were based on resolution of cardinal signs. Microbial outcomes were based on culture results.

Results

Eighty-six patients (41 experimental dosage, 45 classic dosage) were evaluated. There was no difference between the groups in frequency of patients with clinical outcome resolved (85.4% in experimental vs 93.3% in classic dosage group, p=0.3). The microbial eradication rates did not differ statistically between the groups (92.7% vs 95.6%, respectively, p=0.67).

Conclusions

There was no statistically significant difference in the efficacy or safety between the two methods of drug administration. Analysis of the results of compliance supported our conclusion that the less frequent method of dosing of 0.5% levofloxacin eyedrops was more convenient for patients and resulted in better adherence to the drug-dosing scheme

Changing phenotypic expression in a patient with a mitochondrial encephalopathy due to 13042G>A de novo mutation--a 5 year follow up

Mutations in NADH dehydrogenase (ND) subunits of complex I lead to mitochondrial encephalomyopathies associated with various phenotypes. This report aims to present the patient's clinical symptomatology in the context of a very rare 13042G>A de novo mutation and with an emphasis on changing phenotypic expression and pronounced, long-standing response to levetiracetam.

Bilirubin is an independent factor inversely associated with glycated hemoglobin level in pediatric patients with type 1 diabetes

OBJECTIVE

Bilirubin is a potent antioxidant, and serum total bilirubin (STB) concentrations correlate negatively with cardiovascular risk. In adult diabetic patients and in healthy adults, a negative correlation between STB and glycated hemoglobin (HbA1c) has been reported. We investigated whether there is such an association in children and adolescents with type 1 diabetes mellitus.

METHODS

The study group included 224 patients with type 1 diabetes duration of more than 12 months. Patients with suspected or confirmed hemolytic anemia or liver dysfunction were excluded.

RESULTS

A statistically significant negative correlation was found between STB and HbA1c (R = -0.15; p = 0.024), which retained its significance in multivariate analysis (β = -0.18, p = 0.005). Patients' age and daily insulin dose were positively correlated with HbA1c levels, whereas other variables included in the multivariate analysis [sex, diabetes duration, insulin regimen, C-peptide, hemoglobin, mean corpuscular hemoglobin concentration (MCHC), alanine transaminase (ALT), and aspartate transaminase (AST)] did not correlate with HbA1c. The mean HbA1c level in patients with STB >1.2 mg/dL (>21 µmol/L; the threshold for clinical diagnosis of Gilbert's syndrome) was lower than in patients with STB ≤1.2 mg/dL (≤21 µmol/L), and the mean difference was 0.63% (6.9 mmol/mol; 95% CI: 0.11-1.16%).

CONCLUSIONS

These results show that in young patients with type 1 diabetes, STB concentration is an independent factor inversely associated with HbA1c level. Further studies should investigate the background and long-term effects of this association.

Muscle pathology in myotonic dystrophy: light and electron microscopic investigation in eighteen patients

Myotonic dystrophy (DM) is the most common muscular dystrophy in adults. Two known genetic subtypes include DM1 (myotonic dystrophy type 1) and DM2 (myotonic dystrophy type 2). Genetic testing is considered as the only reliable diagnostic criterion in myotonic dystrophies. Relatively little is known about DM1 and DM2 myopathology. Thus, the aim of our study was to characterise light and electron microscopic features of DM1 and DM2 in patients with genetically proven types of the disease. We studied 3 DM1 cases and 15 DM2 cases from which muscle biopsies were taken for diagnostic purposes during the period from 1973 to 2006, before genetic testing became available at our hospital. The DM1 group included 3 males (age at biopsy 15-19). The DM2 group included 15 patients (5 men and 10 women, age at biopsy 26-60). The preferential type 1 fibre atrophy was seen in all three DM1 cases in light microscopy, and substantial central nucleation was present in two biopsies. Electron microscopy revealed central nuclei in all three examined muscle biopsies. No other structural or degenerative changes were detected, probably due to the young age of our patients. Central nucleation, prevalence of type 2 muscle fibres, and the presence of pyknotic nuclear clumps were observed in DM2 patients in light microscopy. Among the ultrastructural abnormalities observed in our DM2 group, the presence of internal nuclei, severely atrophied muscle fibres, and lipofuscin accumulation were consistent findings. In addition, a variety of ultrastructural abnormalities were identified by us in DM2. It appears that no single ultrastructural abnormality is characteristic for the DM2 muscle pathology. It seems, however, that certain constellations of morphological changes might be indicative of certain types of myotonic dystrophy.

Spectroscopy of gadolinium gallium garnet crystals doped with Yb(3+) revisited

The optical spectroscopy measurements of gadolinium gallium garnet (GGG) crystals doped with Yb show evidence of the presence of non-equivalent optical centers with very similar radiative decay rates. The energy level schemes of those centers have been determined on the basis of optical absorption, luminescence and Raman experiments. Crystal field fitting resulted in two sets of slightly different crystal field parameters for two non-equivalent Yb centers. Both sets of parameters describe perfectly the experimentally detected Yb(3+) energy levels. Correlation between systematic trends in the experimental energy level schemes and crystal field parameters is discussed.

Lambert-Eaton myasthenic syndrome in childhood

Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder of the neuromuscular junction. LEMS can be associated with a variety of neoplasms. Patients present with proximal muscle weakness and fatigability, often combined with areflexia. Only 5% of reported cases are children. We report a case of 11-year old boy with non-neoplastic Lambert-Eaton myasthenic syndrome. Repetitive nerve stimulation test showed 83% increment after maximal voluntary contraction, presence of antibodies against voltage-gated calcium channels confirmed the diagnosis. The boy responded well to immunosuppressive treatment with prednisone and azathioprine and remains cancer-free for 4 years.

Diffusion equations for a Markovian jumping process

We consider a Markovian jumping process which is defined in terms of the jump-size distribution and the waiting-time distribution with a position-dependent frequency, in the diffusion limit. We assume the power-law form for the frequency. For small steps, we derive the Fokker-Planck equation and show the presence of the normal diffusion, subdiffusion, and superdiffusion. For the Lévy distribution of the step size, we construct a fractional equation, which possesses a variable coefficient, and solve it in the diffusion limit. Then we calculate fractional moments and define the fractional diffusion coefficient as a natural extension to the cases with the divergent variance. We also solve the master equation numerically and demonstrate that there are deviations from the Lévy stable distribution for large wave numbers.

High-Performance Liquid Chromatography Versus Immunoassay for the Measurement of Sirolimus: Comparison of Two Methods

Sirolimus is an immunosuppressive agent administered as prophylaxis of acute rejection to patients after kidney transplantation. Therapeutic drug monitoring (TDM) of whole blood is an important part of immunosuppressive therapy. At present, two methods of measuring drug concentrations are available: the reference method is high-performance liquid chromatography (HPLC) with ultraviolet (UV) or mass spectrometry (MS) detection and a second technique is the IMx sirolimus assay, which is an enzyme immunoassay using microparticles coated with anti-sirolimus antibodies (MEIA). The objective of this study was to compare the two methods. We examined a group of 42 patients receiving sirolimus after kidney transplantation. Blood was taken during routine ambulatory visits. The drug concentration in blood was performed at the same time by the two methods. To compare the methods, a statistical analysis was performed, yielding: r-value = 0.939 (r(2)); slope = 1.04; intercept = +0.38. The mean concentration of sirolimus was higher in the immunoassay than in the HPLC method namely, 9.7 +/- 6.4 ng/mL versus 8.9 +/- 5.8 ng/mL respectively. The HPLC method showed high sensitivity and specificity, but it was time consuming and labor intensive. The MEIA method is burdened with a high risk of methodologic error, due to its lack of specificity caused by cross-reactions with drug metabolites. We concluded that HPLC with its high sensitivity and analytical specificity is still the reference method; however, MEIA may be a fast method for use in clinical practice.

Congenital myopathy with tubular aggregates and tubulofilamentous IBM-type inclusions

We report on a 16-year-old girl with a unique neuromuscular disorder characterised by progressive proximal muscle weakness and numerous tubular aggregates, intracytoplasmic, as well as intranuclear inclusions of the IBM type in her muscle biopsy. The clinical features of the presented case, as manifested by the early childhood onset of the disease, proximal weakness, lumbar hyperlordosis, and bilateral Achilles tendon contractures, were suggestive of congenital myopathy. To the best of our knowledge, the coexistence of tubular aggregates and tubulofilamentous inclusions of the IBM type in a child has never been described.

Stochastic equation for a jumping process with long-time correlations

A jumping process, defined in terms of the jump size and waiting time distributions, is presented. The jumping rate depends on the process value. The process, which is Markovian and stationary, relaxes to an equilibrium and is characterized by a power-law autocorrelation function. Therefore, it can serve as a model of 1/f noise as well as of the stochastic force in the generalized Langevin equation. This equation is solved for noise correlations approximately 1/t ; the resulting velocity distribution has sharply falling tails. The system preserves memory about the initial condition for a very long time.

Simple jumping process with memory: transport equation and diffusion

We present a stochastic jumping process, defined in terms of jump-size probability density and jumping rate, which is a generalization of the well-known kangaroo process. The definition takes into account two process values: after and before the jump. Therefore, the process is able to preserve memory about its previous values. It possesses a simple stationary limit. Its master equation is interpreted as the kinetic equation with variable collision rate. The process can be easily applied to model systems which relax to distributions other than Maxwellian. The case of a constant jumping rate corresponds to the diffusion process, either normal or ballistic.

Solving the Chapman-Kolmogorov equation for a jumping process

A general solution to the Chapman-Kolmogorov equation for a jumping process called the "kangaroo process" is derived. A special case of algebraic dependences is discussed in detail. In particular, simple asymptotic formulas for probability distribution are presented. It is demonstrated that there are two different classes of limiting stationary distributions. An expression for the covariance is also derived.

Congenital myopathy with abundant ring fibres, rimmed vacuoles and inclusion body myositis-type inclusions

We report a 17-year-old girl with an unusual neuromuscular disorder characterised by slowly progressive proximal muscle weakness whose muscle biopsy showed multiple ring fibres and numerous rimmed vacuoles as well as intracytoplasmic and intranuclear inclusions of the inclusion body myositis-type. The clinical features of the presented case, manifested by the onset of the disease in early childhood, delayed motor development, short stature, lordosis and joint contractures were suggestive of congenital myopathy. The coexistence of ring fibres, rimmed vacuoles and inclusion-body myositis-type inclusions in a child with congenital myopathy has not been previously reported.

Excitation energy transport and trapping in concentrated solid solutions of flavomononucleotide

Excitation energy transport and trapping is studied for monomer-fluorescent dimer system of flavomononucleotide (FMN) in polyvinyl alcohol films (PVA). It is shown that the theory neglecting reverse energy transfer (RET) from dimers to monomers does not allow for the explanation of concentration quenching and concentration depolarization results presented herein. Much better agreement has been obtained using generalized energy transport theory in which fluorescent dimers are treated as imperfect traps for excitation energy. Such parameters like the dimer quantum yield and its emission anisotropy are estimated.

Hepatobiliary scanning in the diagnosis of biliary atresia

Early diagnosis is vital in the neonatal cholestasis. The aim of this study was to assess the usefulness of hepatobiliary scanning in the diagnosis of biliary atresia. 33 hepatobiliary scannings performed in 30 children with cholestasis over the last two years were analysed. The mean age at the diagnosis was 6.6 weeks. The investigation was carried out with Multispect camera using intravenous infusion of 99mTc-MBrIDA. In 23 patients there was no passage of the radiolabelled substance into the intestinal tract. In 18 patients biliary atresia was diagnosed. One patient with a clinical suspicion of Alagille syndrome had two scannings performed at the interval of two weeks. In 1 child a common biliary tract cyst with total obstruction of extrahepatic biliary tree was diagnosed. In 18 children with biliary atresia the diagnosis was confirmed during the operation and Kasai procedure was performed. In 2 children the second scanning showed bile drainage. In 3 children intrahepatic cholestasis was diagnosed in addition to the bile passage failure. Hepatobiliary scanning in the diagnosis of neonatal cholestasis was characterised by high sensitivity (100%) but lower specificity (75%). In difficult cases the final diagnosis should be made on a basis of complex clinical, biochemical and radiological techniques and, if necessary, it should be verified by intraoperative cholangiography.

Scintiscanning in diagnostics of hepatopulmonary syndrome in children

BACKGROUND

Arterial blood oxygenation disturbances accompanying liver cirrhosis are referred to as hepatopulmonary syndrome (HPS). HPS develops due to the formation of intrapulmonary arteriovenous shunts and dilatation of the vascular bed. The aim of the study was to assess the incidence of arteriovenous shunts in children with hepatic cirrhosis and HPS suspected on the basis of clinical signs, qualified for liver transplantation.

MATERIAL AND METHODS

The study was carried out in a group of 21 children aged from 1.2 to 17.7 years (mean age 8.4); 8 girls and 13 boys. The patients were diagnosed as follows: biliary cirrhosis due to extrahepatic bile duct impatency--12, post-inflammatory liver cirrhosis due to infection with HVB--2, autoimmune hepatitis--2, fibrosis of the liver--2, alpha 1-antitrypsin deficiency--1, progressive familial intrahepatic cholestasis--1, cystic fibrosis--1. The presence of arteriovenous anastomoses in the lungs was detected by scintiscanning utilizing microspheres (albumin macroaggregates). Under physiologic conditions, technetium-labeled microspheres injected i.v. are accumulated in pulmonary capillaries. Radioactivity detected in other organs (kidneys, brain) indicates the presence of pathologic shunts omitting the alveoli. A percentage ratio of radioactivity detected in the brain to that present in the lungs serves as the index of blood flow through the anastomosis (SI--shunt index). According to Grimon, the mean SI value for healthy children amounts to 0.43%, the values ranging from 1% to 2% are regarded as borderline ones, and those above 2% allow unequivocal diagnosis of HPS.

RESULTS

The SI values obtained in the study ranged from 0.06 to 51%. In 7 patients SI exceeded 1%, reaching 1.23% in one, and over 3% in the remaining 6 patients. No correlations were found either between SI value and the etiology of cirrhosis, or between the index and clinical condition of the patient assessed according to Child-Pugh scale.

CONCLUSIONS

1. Scintiscanning revealed the presence of arteriovenous shunts in the lungs of 6/21 (28.6%) investigated patients. 2. No correlation was found between the severity of HPS and the etiology and stage of the underlying disease.

[Results of the treatment of pre-urolithiasis state in children with recurrent urinary tract infections]

Urolithiasis often coexists with recurrent urinary tract infections (RUTI). The aim of the study was to determine the correlation of preurolithiasis state (PS) and recurrent urinary tract infections and to establish an effect of the treatment UTI recurrence incidence. PS was found in 202(21.1%) children, most frequently: hyperoxaluria--in 61/202 (30.2%), hypercalciuria--in 32/202 (15.8%), and hyperuricosuria--in 30/202 (14.9%) children. Complex metabolic abnormality was observed in 62/202 (30.7%) patients. Therapeutic management comprised of: antibacterial prophylaxis, high fluid intake, proper diet, correction of urine pH, and pharmacological treatment if necessary. Disappearance of RUTI and PS in 88/202 (43.6%) children, disappearance of RUTI in spite of persistent PS in 36/202 (17.8%), and decrease of RUTI in 54/202 (26.7%) patients were method. In 110/202 (54.5) children PS disappeared.

[Results of ESWL treatment in children with urolithiasis: own experience]

Actually extracorporeal shock wave lithotripsy (ESWL) is the most frequent method in the treatment of urolithiasis in children. The aim of the study was to estimate the results of ESWL in children with urolithiasis. Between 1991 and 1999 y, in our Department 260 "reno-ureteral units" in 203 children were treated by lithotripsy. Totally of 518 ESWL procedures were performed. In general efficacy of ESWL was 88.08%, in children with single stone in kidney--97.80%., with multiple stones in kidneys--78.65%, in ureterolithiasis--71.88%. For complete recovery in patients mean 1.99 ESWL procedures were performed on 1 "reno-ureteral unit" on the average diameter of the stone/stones 13.3 mm.

[Hypocitraturia in children with urolithiasis]

Inhibitors of crystallization process play an important role in renal-stone forming patients. One of well-known inhibitor is citrate. The aim of the study was to define the type of metabolic abnormality in children with nephrolithiasis and the role of urinary citrate excretion. 52 children with nephrolithiasis were examined. Hypocitraturia was observed in 42.3% of patients, most frequently in children with hypercalciuria, hyperoxaluria, and hyperoxaluria with hyperuricosuria. Low urinary citrate excretion found in patients with nephrolithiasis may play an important role in the pathogenesis of the disease. Urinary citrate excretion should be examined in patients with nephrolithiasis.

[A form of premorbid condition of urolithiasis and urinary stone composition in children with urolithiasis]

In diagnosis, monitoring and prophylaxis of urolithiasis it is important to use simple, non-invasive tests. The aim of the study was to define the value of crystallizing ratios in urine in correlation with chemical stone composition in presumptive diagnosis and monitoring patients with urolithiasis. The study involved 102 children. An analysis of chemical stone composition was carried out in 62 cases. A correlation between values of crystallizing ratios in the urine, indicating the kind of preurolithiasis state and chemical stone composition has been found.

[The role of environmental factors in the formation of kidney calculi]

Various endo- and exogenous factors play a role in the urinary stones formation tract. The aim of the study was to define the type and frequency of hyperexcretion of lithogenic substances in school children population and to determine an influence of risk factors on hyperexcretion of crystallizing substances. The study included 220 school children. Preurolithiasis state (PS) was found in 30% children. The most frequently hyperoxaluria, hyperuricosuria and hypercalciuria were diagnosed and it may be connected with abnormal nutritional habits, excessive application of multivitamins, vitamin D and calcium, disturbances in drinking water chemical composition (higher amount of calcium, smaller amount of magnesium, abnormal pH). Urinary tract infections, particularly in children with obstructive uropathy are an important risk factor in the examined population. Positive familial history of urolithiasis in 43.3% children may indicate for the important role of the genetic factor in the pathogenesis of the disease.

[Etiology of nephrolithiasis in children: own observation]

Recurrent formation of renal calculi may be prevented by selective medical therapy designed to correct underlying metabolic disturbances in urine biochemistry. The aim of the study was to estimate potential risk factors of urolithiasis in 102 children before ESWL treatment. Metabolic disturbances followed by anatomical malformations of urinary tract, recurrent urinary tract infections caused by urease-induced microorganisms are the most frequent risk factors. In single cases possible risk factors were: immobilization and chronic corticosteroid therapy.

[Beta-2 microglobulinuria in children with vesico-ureteral reflux and recurrent urinary tract infections]

Recurrent urinary tract infections in children with vesico-ureteral reflux are the one of risk factors in the process of reflux nephropathy. One of markers of early kidney parenchyma damage is beta 2-microglobulin. The aim of the study was to evaluate the value of beta 2-microglobulin excretion in urine and its serum levels in children with vesico-ureteral reflux and recurrent urinary tract infections. It was found that abnormal urinary excretion of beta 2-microglobulin and its serum levels of proceeded post-inflammatory changes in kidney parenchyma observed in imaging examinations of urinary tract and impared parameters of renal function in biochemical analyses.

Thermal helix-coil transition in UV irradiated collagen from rat tail tendon

The thermal helix-coil transition in UV irradiated collagen solution, collagen film and pieces of rat tail tendon (RTT) were compared. Their thermal stability's were determined by differential scanning calorimeter (DSC) and by viscometric measurements. The denaturation temperatures of collagen solution, film and pieces of RTT were different. The helix-coil transition occur near 40 degrees C in collagen solution, near 112 degrees C in collagen film, and near 101 degrees C in pieces of RTT. After UV irradiation the thermal helix-coil transition of collagen samples were changed. These changes depend on the degree of hydratation.

Age-related muscle stiffness: predominance of non-reflex factors

This study was aimed at assessing the contribution of reflex and non-reflex factors to the muscle tone of old female Wistar rats. The hind foot of a rat was flexed or extended at the ankle joint by 25 degrees over 250 ms. The resistance of the foot to passive movements (torque, mechanomyogram), as well as the reflex electromyographic activity in the gastrocnemius and tibialis anterior muscles, were recorded simultaneously. Moreover, the impact of the blockade of the reflex activity caused by the local anesthetic lignocaine (1-2 ml of a 2% solution, injected in the vicinity of the sciatic nerve) on the muscle tone was investigated. Additionally, old rats' hind leg muscle samples were analysed using fluorescent microscopy for the expression of fibronectin, which is an early marker of connective tissue formation. It has been shown that old rats are characterized by (i) a substantially increased resistance of flexor muscle stiffness (measured during extension) and unchanged resistance of extensors (measured during flexion), (ii) the loss of a major part of the reflex electromyographic activity and (iii) the increased content of fibronectin in muscles. Moreover, it has been shown that lignocaine, which completely blocked the electromyographic reflex activity in the gastrocnemius and tibialis anterior muscles in young animals, was unable to counteract the resistance of these muscles to passive movements in old rats. The present results suggest that the muscle stiffness seen in old rats is not due to a reflex response, but depends mainly on non-reflex factors--chiefly on a large overgrowth of non-elastic connective tissue replacing degenerated active muscle fibers.

Sympathetic skin response (SSR) in multiple sclerosis

The function of the autonomic system in multiple sclerosis (MS) is often afflicted. In order to reveal the presence of autonomic disturbances examination of sympathetic skin response (SSR), as a simple non-invasive method of the evaluation of conduction in autonomic nervous system, was performed in 25 patients with clinically defined MS. The diagnosis was confirmed by MRI and evoked potentials studies. Bimodal type of stimulation was used: the median nerve was stimulated, then the auditory stimulus (burst) was presented to the patient. Responses were recorded simultaneously from the palms and soles. SSR was abnormal in 19 patients (76%). Absence of the response from lower limbs and normal response from upper limbs were found in 6 patients (24%), increase in latency and decrease in amplitude from upper and lower limbs were found in 8 patients (32%) and increase in latency, decrease in amplitude of the response from upper limbs with absence of the response from lower limbs were found in 5 patients (20%). SSR appears to be a simple and effective method of assessing sympathetic disturbances in multiple sclerosis.