ABSTRACT
Osmolytes are naturally occurring organic compounds that protect cellular proteins and other macromolecules against various forms of stress including temperature extremes. While biological studies have correlated the accumulation of certain classes of osmolytes with specific forms of stress, including thermal stress, it remains unclear whether or not these observations reflect an intrinsic chemical class hierarchy amongst the osmolytes with respect to effects on protein stability. In addition, very little is known in regards to the molecular elements of the osmolytes themselves that are essential for their functions. In this study, we use differential scanning fluorimetry to quantify the thermal stabilizing effects of members from each of the three main classes of protecting osmolytes on two model protein systems, C-reactive protein and tumor necrosis factor alpha. Our data reveals the absence of a strict chemical class hierarchy amongst the osmolytes with respect to protein thermal stabilization, and indicates differential responses of these proteins to certain osmolytes. In the second part of this investigation we dissected the molecular elements of amino acid osmolytes required for thermal stabilization of myoglobin and C-reactive protein. We show that the complete amino acid zwitterion is required for thermal stabilization of myoglobin, whereas removal of the osmolyte amino group does not diminish stabilizing effects on C-reactive protein. These disparate responses of proteins to osmolytes and other small molecules are consistent with previous observations that osmolyte effects on protein stability are protein-specific. Moreover, the data reported in this study support the view that osmolyte effects cannot be fully explained by considering only the solvent accessibility of the polypeptide backbone in the native and denatured states, and corroborate the need for more complex models that take into account the entire protein fabric.
Subject(s)
Organic Chemicals/chemistry , Proteins/chemistry , Amino Acids/chemistry , C-Reactive Protein/chemistry , Fluorometry/methods , Humans , Myoglobin/chemistry , Osmolar Concentration , Protein Denaturation , Protein Stability , Temperature , Tumor Necrosis Factor-alpha/chemistryABSTRACT
OBJECTIVE: This study compares 2 imaging protocols, planar pinhole technique (PPHT) and SPECT, for evaluating ocular masses with 99mTc-MIBI. METHODS: Sixteen patients with ocular lesions were studied. Planar images were acquired 10 min after the injection of 740 MBq 99mTc-MIBI with an LFOV camera fitted with a pinhole collimator (5.0 mm). A SPECT study was performed immediately after the planar study, using a 360 degrees orbit, 64 steps, 20 s/stop, a 128 x 128 matrix, and a low-energy high-resolution (LEHR) collimator. Twelve lesions (9.5-18.0 mm) proved to be malignant: 8 primary tumors (ocular melanoma); 3 local relapses of different tumors of the conjunctiva; and 1 ocular metastasis from breast cancer. The remaining 4 lesions (10.0-16.0 mm) were benign: 1 inflammatory lesion; 1 benign intraocular calcification; and 2 naevi. RESULTS: SPECT images showed 11 of 12 malignant lesions (91.6%), whereas the planar technique demonstrated only 4 of the 12 lesions (33.3%). One false-positive result, the inflammatory lesion, was visualized by both techniques. The remaining benign lesions were not detected with either method. CONCLUSION: Technetium-99m-MIBI SPECT is a sensitive technique for detecting malignant ocular tumors. SPECT imaging is a better alternative to planar imaging for ocular tumors.
Subject(s)
Eye Neoplasms/diagnostic imaging , Gamma Cameras , Radiopharmaceuticals , Technetium Tc 99m Sestamibi , Tomography, Emission-Computed, Single-Photon , Adolescent , Adult , Aged , Aged, 80 and over , Breast Neoplasms/pathology , Calcinosis/diagnostic imaging , Conjunctival Neoplasms/diagnostic imaging , Equipment Design , Eye Diseases/diagnostic imaging , Eye Neoplasms/secondary , False Positive Reactions , Female , Humans , Image Processing, Computer-Assisted/instrumentation , Image Processing, Computer-Assisted/methods , Male , Melanoma/diagnostic imaging , Middle Aged , Neoplasm Recurrence, Local/diagnostic imaging , Nevus/diagnostic imaging , Sensitivity and Specificity , Tomography, Emission-Computed/instrumentation , Tomography, Emission-Computed/methods , Tomography, Emission-Computed, Single-Photon/methods , Uveitis/diagnostic imagingABSTRACT
Hemodialized pediatric patients are a risk population for the hepatitis B and C virus infection. The aim of this paper was to study the serum prevalence of HBV and HCV infection in hemodialized children. We study 61 pediatric patients at hemodialisis, 12 on renal transplant, range between 2 and 20 years old (mean: 12.9 years), 23 male and 38 female. The specific anti-HCV IgC were measured by enzyme immunoassay (ELISA Abbott) and confirmed by LIA-TEK (Organon). The anti-HBV were measured by ELISA Abbott and transaminases by cinetic method (ASAT: 29 UI/L and ALT: 33 UI/L). The 19.7% of studied children were HCV (+) and 29.5% were HBV (+), 38.9% of them were HbsAg (+) and 50% anti-HBs (+). The HCV and HBV infection was more elevated in relation to the transfusion number and the hemodilisis time. The elevation of ALT/ASAT activity isn't a right infection index for HCV and HBV in this children.
Subject(s)
Hepatitis B Antibodies/isolation & purification , Hepatitis B/epidemiology , Hepatitis C Antibodies/isolation & purification , Hepatitis C/epidemiology , Renal Dialysis , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Male , Prevalence , Seroepidemiologic StudiesABSTRACT
Diffusely reduced 99Tc(m)-pertechnetate uptake is a relatively infrequent but annoying finding that impairs evaluation of the thyroid gland. We studied 32 female patients aged 19-85 years with markedly reduced pertechnetate uptake. The following causes of reduced pertechnetate uptake were recognized: treatment with iodinated pharmaceuticals (n = 15), suppression therapy with T4 (n = 11), subacute thyroiditis (n = 5) and massive tumour replacement (n = 1). 99Tc(m)-MIBI thyroid scintigraphy was performed within 24 h of the pertechnetate study. The results were correlated with neck ultrasound, serum TSH (n = 25) and surgical findings in patients who had been operated on. The technique identified the following conditions: normally sized thyroids (n = 4), diffuse goitres (n = 8), multinodular goitres (n = 17) and solitary thyroid nodules (n = 3). Moreover, substernal goitres were identified in nine patients. This condition was confirmed at surgery in seven patients. Ultrasonography was concordant in 29 of 32 patients in terms of thyroid size and structure, but failed to demonstrate substernal thyroid tissue. Our results suggest that 99Tc(m)-MIBI scintigraphy may contribute to the diagnosis of thyroid pathology and treatment planning in patients with diffusely decreased 99Tc(m)-pertechnetate uptake.
Subject(s)
Goiter/diagnostic imaging , Radiopharmaceuticals/pharmacokinetics , Sodium Pertechnetate Tc 99m/pharmacokinetics , Technetium Tc 99m Sestamibi , Thyroid Diseases/diagnosis , Thyroid Gland/diagnostic imaging , Thyroid Nodule/diagnostic imaging , Adult , Aged , Aged, 80 and over , Female , Goiter/surgery , Humans , Middle Aged , Radionuclide Imaging , Technetium Tc 99m Sestamibi/pharmacokinetics , Thyroid Diseases/diagnostic imaging , Thyroid Nodule/surgery , Thyrotropin/blood , Thyroxine/adverse effects , UltrasonographyABSTRACT
Los pacientes Hd constituyen una población de riesgo para la infección por los virus de las hepatitis B y C. El objetivo de este trabajo fue evaluar la prevalencia de la infección por HCV y HBV en un corte de una población de niños hemodializados. Se estudiaron 61 pacientes pediátricos en hemodiálisis, 12 de los cuales eran Tx, con edades comprendidas entre 2 y 20 años (media: 12,9), 23 varones y 38 mujeres. Se determinaron los anticuerps anti-HCV IgG por enzimoinmunoensayo (EIE) (Abbott 2 generación) y como método confirmatorio se utilizó inmunoblotting de péptidos sintéticos linearizados (LIA-TEK) (Organon). La detección de los marcadores para HBV fue por EIE y el nivel de actividad de las transaminasas se determinó por método cintético. El 19,7 por ciento de los niños estudiados fueron HCV positivos y el 29,5 por ciento fueron HBV positivos, de los cuales el 38,9 por ciento fueron HBsAg positivos el 50 por ciento Anti-HBs positivos. La infección por HCV y HBV se vió incrementada en relación al número de transfusiones y al tiempo de inclusión en Hd. La elevación de nivel de actividad de las transaminasas no fue un buen índice de infección para HBV y HCV en estos pacientes.
Subject(s)
Humans , Male , Female , Child, Preschool , Child , Adolescent , Adult , Hepatitis B , Hepatitis B Antibodies/isolation & purification , Hepatitis C , Hepatitis C Antibodies/isolation & purification , Renal Dialysis , PrevalenceABSTRACT
Los pacientes Hd constituyen una población de riesgo para la infección por los virus de las hepatitis B y C. El objetivo de este trabajo fue evaluar la prevalencia de la infección por HCV y HBV en un corte de una población de niños hemodializados. Se estudiaron 61 pacientes pediátricos en hemodiálisis, 12 de los cuales eran Tx, con edades comprendidas entre 2 y 20 años (media: 12,9), 23 varones y 38 mujeres. Se determinaron los anticuerps anti-HCV IgG por enzimoinmunoensayo (EIE) (Abbott 2 generación) y como método confirmatorio se utilizó inmunoblotting de péptidos sintéticos linearizados (LIA-TEK) (Organon). La detección de los marcadores para HBV fue por EIE y el nivel de actividad de las transaminasas se determinó por método cintético. El 19,7 por ciento de los niños estudiados fueron HCV positivos y el 29,5 por ciento fueron HBV positivos, de los cuales el 38,9 por ciento fueron HBsAg positivos el 50 por ciento Anti-HBs positivos. La infección por HCV y HBV se vió incrementada en relación al número de transfusiones y al tiempo de inclusión en Hd. La elevación de nivel de actividad de las transaminasas no fue un buen índice de infección para HBV y HCV en estos pacientes. (AU)
