1,720,981 research outputs found
Infrared spectroscopy and microscopy in cancer research and diagnosis
Full text linkSince the middle of the 20th century, infrared (IR) spectroscopy coupled to microscopy has been used as a non destructive, label free, highly sensitive and specific analytical method to reveal molecular structure. Nowadays, synchrotron based IR microspectroscopy offers a signal-to-noise spectral quality unreachable by other broadband sources, and achieves the highest optically attainable IR spatial resolution on microscopic scale samples. This is particularly relevant in Life Sciences, with a significant progression of applications in biomedical research and in particular cancer studies. In view of the validation of the IR fingerprint region as a spectral marker of cancer and anticancer therapy follow up, we have recently performed a set of key experiments on leukemic blasts at the IR beamline B22 ‘MIRIAM’. The results on identification and cross-validation of IR markers of drug actions in the spectra of K562 leukemic blasts are in the following report
InfraRed Spectroscopy and Microscopy in Cancer Research
Full text linkSince the middle of 20th century infrared (IR) spectroscopy coupled to microscopy (IR microspectroscopy) has been recognized as a non destructive, label free, highly sensitive and specific analytical method with many potential useful applications in different fields of biomedical research and in particular cancer research and diagnosis. Although many technological improvements have been made to facilitate biomedical applications of this powerful analytical technique, it has not yet properly come into the scientific background of many potential end users. Therefore, to achieve those fundamental objectives an interdisciplinary approach is needed with basic scientists, spectroscopists, biologists and clinicians who must effectively communicate and understand each other’s requirements and challenges. In this review we aim at illustrating some principles of Fourier transform (FT) Infrared (IR) vibrational spectroscopy and microscopy (microFT-IR) as a useful method to interrogate molecules in specimen by mid-IR radiation. Penetrating into basics of molecular vibrations might help us to understand whether, when and how complementary information obtained by microFT-IR could become useful in our research and/or diagnostic activities. MicroFT-IR techniques allowing to acquire information about the molecular composition and structure of a sample within a micrometric scale in a matter of seconds will be illustrated as well as some limitations will be discussed. How biochemical, structural, and dynamical information about the systems can be obtained by bench top microFTIR instrumentation will be also presented together with some methods to treat and interpret IR spectral data and applicative examples. The mid-IR absorbance spectrum is one of the most information-rich and concise way to represent the whole “...omics” of a cell and, as such, fits all the characteristics for the development of a clinically useful biomarker
Plasma selenium and glutathione peroxidase activities in individuals living in the Veneto region of Italy.
No full textIn order to assess the Se status in individuals living in the Veneto region, a series of related measurements was performed. These included plasma selenium by PIXE and glutathione-peroxidase (GSH-Px) activities in plasma, red blood cells and platelets. Individuals were either normals or people suffering from various liver diseases. Moreover, an oral supplement of sodium selenite was given to 13 patients suffering from stable chronic renal failure (CRF) in parallel to 26 normals: data on plasma GSH-Px and on serum creatinine and creatinine clearance were collected either before or after supplementation. Results were in support of a relatively low selenium status: mean +/- SD plasma Se values of normals (0.82 +/- 0.17mumol/L, n = 82) were comparable to data observed in European regions where Se deficiency was already known. Even lower values were observed in those with liver diseases. Among enzyme activities, the distribution of the data of platelet GSH-Px was in further support of low Se status in the evaluated individuals. After Se supplementation, both normals and CRF patients showed a significant increase in the creatinine clearance, reflecting an improvement of the glomerular filtration rate. We suggest that more extensive surveys of the Se status should be carried out in Italy; moreover, Se supplementation may be advisable in individuals affected with moderate impairment of renal function
Monitoring of cellular immunity by interferon gamma (IFN-g) Enzyme-Linked Immunosorbent Spot (ELISPOT) assay in kidney allograft recipients: preliminary results of a longitudinal study.
No full textSeveral efforts have been made in past years to identify markers for patients at heightened risk of acute and chronic immune-mediated allograft rejection. The ex vivo monitoring of cellular immunity by Enzyme-Linked Immunosorbent Spot (ELISPOT) assay has recently emerged as a primary tool in predicting either short and long-term outcomes in kidney allograft recipients. Therefore we started the systematic application of Interferon-gamma (IFN-g) ELISPOT assay to measure the frequency of producing IFN-g in recipient peripheral blood lymphocytes (PBLs) stimulated with donor lymphocytes before and 7, 14, 21,28 and 60 days after the transplant, respectively. Very preliminary results on 8 kidney transplant patients indicated that the number of HLA mismatches never correlated with the number of IFN-g spots. The frequencies of pre-transplant IFN-g spots were positively and significantly correlated with the number of post-transplant IFN-ã spots. Clinical outcome was better in recipients with low frequencies than in recipients with high frequencies of pre and/or post-transplant IFN-g spots. The highest pre-and post-transplant number of IFN-g spots was observed in a patient who developed early acute rejection. Significant increases of the number of IFN-g spots preceded the onset of acute rejection events and decreased after supplemental i.v. steroid administration. Considering the low number of observations, these preliminary results must be considered cautiously; nevertheless we are encouraged to extend the systematic application of serial IFN-g ELISPOT assay measurements in a more consistent cohort of patients
Immunotoxins and other conjugates: preparation and general characteristics.
No full textTargeted toxins represent an invaluable tool offering a wide range of potential applications, both in experimental models and in the clinics. Here we will review several aspects related to the preparation and properties of carrier molecule-toxin heteroconjugates and fusion toxins
The identification of cystic fibrosis (CF) cells and their pharmacological correction by mid-infrared microspectroscopy and unsupervised data analysis methods
No full textWe aimed at demonstrating that non-cystic fibrosis (CF) cells and isogenic, CF bronchial epithelial cell lines can be correctly classified by Fourier transform (FT) mid-infrared (IR) absorbance spectra and unsupervised methods for multivariate data analysis such as principal component analysis (PCA) and hierarchical cluster analysis (HCA). CF cells were exposed “ex vivo” to VRT-325, a chemical corrector of defective anion transporter Cystic Fibrosis Transmembrane conductance Regulator (CFTR) caused by the F508del mutation. Unstained epithelial cells from CF patients and a healthy control were deposited on ZnSe window and analyzed with an IR interferometer connected to a FTIR microscope (microFTIR). In order to explain spectral variability reflecting biochemical differences between CF and non-CF cells, we applied PCA to dataset of untreated cells and cells treated for 24 hours with 1x10-5 M VRT-325. The information achieved with IR analysis was cross validated by the findings on CFTR expression and by the results of functional CFTR bioassays carried out in replicate samples. We conclude suggesting the possibility to utilize IR spectra analysis to recognize CF cells and the effect of pharmacological treatment aimed to correct the basic defect of C
Glutathione-peroxidase activity in normal and pathologic liver and its inhibition by bromosulphalein
No full textPlasma fibronectin in liver cirrhosis and its diagnostic value
No full textPlasma fibronectin (FN) has been measured by immunonephelometric method in 100 cirrhotic patients and compared with that of 77 normal subjects and with that of 57 patients suffering from liver disorders different from cirrhosis. Both, compensated and decompensated cirrhotics had lower plasma FN than controls (31.14 +/- 11.42 and 20.88 +/- 10.43 respectively vs 40.13 +/- 8.58 mg/dl; rho less than 0.02 and rho less than 0.001). FN in ascitic patients was lower than in non-ascitic (rho less than 0.001). These differences were not due to different weight or age of patients. It appears, therefore, that FN parallels in cirrhosis the grade of liver function impairment. No significant difference has been noted between plasma FN of patients with liver diseases different from cirrhosis and control subjects. In cirrhosis, a positive relation has been observed among FN and other parameters of liver function such as serum albumin, cholinesterase activity, fibrinogen and prothrombin time. Plasma FN has a low sensitivity but a high specificity and a good positive predictive value in distinguishing normals and patients with liver disorders different from cirrhosis. This diagnostic value is similar to that of serum albumin
Selenium enhances glutathione peroxidase activity and prostacyclin release in ultured human endothelial cells. Concurrent effects on mRNA levels
No full textSelenium (Se) is an essential component of glutathione peroxidase (GSH-Px), an enzyme that protects cells by reducing intracellular peroxides. Impaired Se status and GSH-Px activity seem associated with increased risk of atherosclerotic vascular diseases. This study reports the effects of Se supplementation on GSH-Px activity, on prostacyclin (PGI2) production, on 12-hydroxy-eicosatetraenoic acid (12-HETE) levels, and on GSH-Px mRNA expression in cultured human umbilical vein endothelial cells (HUVEC). Se-enriched HUVEC showed significant increase of both GSH-Px activity and thrombin-stimulated production of PGI2 in the presence of stable concentrations of 12-HETE. On the other hand, an inverse correlation between Se concentrations in culture media and GSH-Px mRNA levels in Northern blot analysis was shown; this suggests that a major degree of regulation for GSH-Px expression by Se is most likely exerted at the posttranscriptional level. These observations may help to explain the increased incidence of atherosclerosis described in Se-deficient individuals
Inhibition of erythrocyte glutathione-peroxidase by bromsulphalein.
No full text42 different samples of human erythrocytes were tested for glutathione-peroxidase activity ) in an attempt to study the inhibitory effect of Bromsulphalein (BSP). The mean activity of the enzyme was 11.90 +/- 3.61 U/g Hb, with no significant difference between males and females. BSP was used at different concentrations from 1 to 45 mM and inhibited GSH-Px activity; the inhibition curve showed a sinusoidal pattern. The major effect was obtained at 30 mM BSP when almost 65% of the initial activity was inhibited. The inhibition of GSH-Px by BSP has also been confirmed using partially purified GSH-Px obtained from human erythrocytes, as well as purified bovine GSH-Px. Some difference was noted between males and females: females may be divided into two subgroups, one with a lower and a second with a higher level of GSH-Px. 1 mM BSP increased the activity in the first group, whereas it reduced the activity in the second group. The inhibition by BSP was positively correlated with the basal value of GSH-Px and this effect was particularly evident in females (r = 0.865; p less than 0.001). The possibility that GSH-Px may be inhibited by BSP would be of some importance considering the strategic role of GSH-Px in protecting the cell from oxidative attack
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