Exon 3-deleted growth hormone receptor isoform is not related to worse bone mineral density or microarchitecture or to increased fracture risk in acromegaly.

PURPOSE: Acromegaly is a cause of secondary osteoporosis and is associated with increased risk of vertebral fractures (VFs). The influence of exon 3-deleted isoform of growth hormone receptor (d3-GHR) on bone microarchitecture has not been studied in acromegaly. AIM: The aim of this study was to analyze the associations between d3-GHR isoform and bone mineral density (BMD), bone microarchitecture, and VFs in acromegaly patients. METHODS: Consecutive acromegaly patients treated at a single reference center were included. BMD was analyzed using dual-energy X-ray absorptiometry (DXA) and bone microarchitecture was analyzed by high-resolution peripheral quantitative computed tomography (HR-pQCT). The presence of moderate to severe VFs was assessed by thoracic and lumbar X-ray. GHR genotyping was analyzed by PCR, and full-length isoform of GHR (fl-GHR) was represented by a 935-bp fragment and d3-GHR by a 532-bp fragment. RESULTS: Eighty-nine patients were included [56 females; median age at diagnosis: 43 years (17-78)]. Disease was uncontrolled in 63% of patients. At least one d3-GHR allele was present in 60% of patients. Frequency of active disease (p = 0.276) and hypogonadism (p = 1.000) was not different between patients with fl-GHR and those with at least one d3-GHR. There was no difference in any DXA or HR-pQCT parameters between patients with fl-GHR and those with d3-GHR. Significant VFs were observed in 14% of patients, but there was no difference in frequency between patients with fl-GHR and those with at least one d3-GHR allele (p = 0.578). CONCLUSIONS: Presence of d3-GHR was not associated with worse BMD or bone microarchitecture or with higher frequency of significant VFs.

Pixantrone anticancer drug as a DNA ligand: Depicting the mechanism of action at single molecule level.

In this work we use single molecule force spectroscopy performed with optical tweezers in order to characterize the complexes formed between the anticancer drug Pixantrone (PIX) and the DNA molecule, at two very different ionic strengths. Firstly, the changes of the mechanical properties of the DNA-PIX complexes were studied as a function of the drug concentration in the sample. Then, a quenched-disorder statistical model of ligand binding was used in order to determine the physicochemical (binding) parameters of the DNA-PIX interaction. In particular, we have found that the PIX molecular mechanism of action involves intercalation into the double helix, followed by a significant compaction of the DNA molecule due to partial neutralization of the phosphate backbone. Finally, this scenario of interaction was quantitatively compared to that found for the related drug Mitoxantrone (MTX), which binds to DNA with a considerably higher equilibrium binding constant and promotes a much stronger DNA compaction. The comparison performed between the two drugs can bring clues to the development of new (and more efficient) related compounds.

Biophysical characterization of the DNA interaction with the biogenic polyamine putrescine: A single molecule study.

We have performed a biophysical characterization, at single molecule level, of the interaction between the DNA molecule and the biogenic polyamine putrescine. By using force spectroscopy, we were able to monitor the complexes formation as putrescine is added to the sample, determining the mechanical properties of such complexes and the physicochemical (binding) parameters of the interaction for three different ionic strengths. In particular, it was shown that the behavior of the equilibrium binding constant as a function of the counterion concentration deviates from the prediction of the Record-Lohman model. The measured constants were (1.3 ± 0.2) × 105 M- 1 for [Na] = 150 mM, (2.1 ± 0.2) × 105 M- 1 for [Na] = 10 mM, and (2.2 ± 0.3) × 105 M- 1 for [Na] = 1 mM. The cooperativity degree of the binding reaction, on the other hand, increases with the ionic strength. From these analysis, the DNA-putrescine binding mechanisms are inferred, and a comparison with results reported for ordinary bivalent ions like magnesium is performed. Such study provides new insights on the general behavior of the DNA interactions with biogenic polyamines.

A cooperative transition from the semi-flexible to the flexible regime of polymer elasticity: Mitoxantrone-induced DNA condensation.

We report a high cooperative transition from the semi-flexible to the flexible regime of polymer elasticity during the interaction of the DNA molecule with the chemotherapeutic drug Mitoxantrone (MTX). By using single molecule force spectroscopy, we show that the force-extension curves of the DNA-MTX complexes deviate from the typical worm-like chain behavior as the MTX concentration in the sample increases, becoming straight lines for sufficiently high drug concentrations. The behavior of the radius of gyration of the complexes as a function of the bound MTX concentration was used to quantitatively investigate the cooperativity of the condensation process. The present methodology can be promptly applied to other ligands that condense the DNA molecule upon binding, opening new possibilities in the investigation of this type of process and, more generally, in the investigation of phase transitions in polymer physics.

Doxorubicin hinders DNA condensation promoted by the protein bovine serum albumin (BSA).

In this work, we have studied the interaction between the anticancer drug doxorubicin (doxo) and condensed DNA, using optical tweezers. To perform this task, we use the protein bovine serum albumin (BSA) in the working buffer to mimic two key conditions present in the real intracellular environment: the condensed state of the DNA and the abundant presence of charged macromolecules in the surrounding medium. In particular, we have found that, when doxo is previously intercalated in disperse DNA, the drug hinders the DNA condensation process upon the addition of BSA in the buffer. On the other hand, when bare DNA is firstly condensed by BSA, doxo is capable to intercalate and to unfold the DNA condensates at relatively high concentrations. In addition, a specific interaction between BSA and doxo was verified, which significantly changes the chemical equilibrium of the DNA-doxo interaction. Finally, the presence of BSA in the buffer stabilizes the double-helix structure of the DNA-doxo complexes, preventing partial DNA denaturation induced by the stretching forces.

Frequency of familial pituitary adenoma syndromes among patients with functioning pituitary adenomas in a reference outpatient clinic.

INTRODUCTION: Pituitary adenomas (PA) occur mainly as sporadic disease, but familial syndromes are found in approximately 5% of cases. Identification of these syndromes is important in order to diagnose individuals at risk at an earlier stage. AIMS: To evaluate the frequency of familial PA in a reference outpatient clinic devoted to PA treatment and to identify family members suspected to have pituitary disease. METHODS: Patients with PA were interviewed with respect to the presence of family members with diagnosis of PA or with signs or symptoms suggestive of them. The family members who had a clinical picture suggestive of pituitary disease were further evaluated in an attempt to identify new PA cases. In families with familial disease, the AIP gene was sequenced. RESULTS: 262 patients were evaluated and familial syndrome was found in 13 (5%). Ten (3.8%) patients had familial isolated PA (FIPA) and three (1.2%) had multiple endocrine neoplasia type 1. After evaluation of family members' symptomatology, 110 were considered suspected of having pituitary disease, but only 24 participated in the study. Of these 24, 1 was diagnosed with a corticotropinoma. AIP mutations were found in 20% of FIPA families. CONCLUSION: We found a frequency of familial PA similar to that previously described, as well as a similar frequency of AIP mutations among FIPA families. An active search of the affected family members was able to identify one case of Cushing´s disease. Patients should be aware of pituitary disease's clinical picture to identify possibly affected family members.

Unfolding DNA condensates produced by DNA-like charged depletants: A force spectroscopy study.

In this work, we have measured, by means of optical tweezers, forces acting on depletion-induced DNA condensates due to the presence of the DNA-like charged protein bovine serum albumin (BSA). The stretching and unfolding measurements performed on the semi-flexible DNA chain reveal (1) the softening of the uncondensed DNA contour length and (2) a mechanical behavior strikingly different from those previously observed: the force-extension curves of BSA-induced DNA condensates lack the "saw-tooth" pattern and applied external forces as high as ≈80 pN are unable to fully unfold the condensed DNA contour length. This last mechanical experimental finding is in agreement with force-induced "unpacking" detailed Langevin dynamics simulations recently performed by Cortini et al. on model rod-like shaped condensates. Furthermore, a simple thermodynamics analysis of the unfolding process has enabled us to estimate the free energy involved in the DNA condensation: the estimated depletion-induced interactions vary linearly with both the condensed DNA contour length and the BSA concentration, in agreement with the analytical and numerical analysis performed on model DNA condensates. We hope that future additional experiments can decide whether the rod-like morphology is the actual one we are dealing with (e.g. pulling experiments coupled with super-resolution fluorescence microscopy).

Force-dependent persistence length of DNA-intercalator complexes measured in single molecule stretching experiments.

By using optical tweezers with an adjustable trap stiffness, we have performed systematic single molecule stretching experiments with two types of DNA-intercalator complexes, in order to investigate the effects of the maximum applied forces on the mechanical response of such complexes. We have explicitly shown that even in the low-force entropic regime the persistence length of the DNA-intercalator complexes is strongly force-dependent, although such behavior is not exhibited by bare DNA molecules. We discuss the possible physicochemical effects that can lead to such results. In particular, we propose that the stretching force can promote partial denaturation on the highly distorted double-helix of the DNA-intercalator complexes, which interfere strongly in the measured values of the persistence length.

Efficiency and economic feasibility of pest control systems in watermelon cropping.

The aim of this work was to determine the efficiency and feasibility of two different watermelon pest control systems on pest infestations, natural enemies, and on the productivity and sustainability of watermelon cropping. Two independent experiments were carried out during the dry season of 2011. Both experiments were carried out using a randomized block experimental design, with three treatments; weekly application of pesticide (WAP), integrated pest management (IPM), and nonpesticide application (control); and four replicates. Arthropods sampling was performed every 2 d by direct counting at five randomly selected points in each plot. Samples were taken by beating the leaves from the apical portion of the plant against a white plastic tray. Arthropods that moved along the soil surface were sampled weekly using pitfall traps. Both WAP and IPM treatments negatively affected the arthropod population. We conclude that IPM is an attractive strategy for watermelon cropping both economically and environmentally because it provides the grower with an option to lower production cost, achieves the same production, and there is less need for pesticide application when compared with the prophylactic control treatment when pesticides are applied on a weekly basis. This has not been reported for watermelon before.

Synthesis and antimycobacterial evaluation of N'-(E)-heteroaromaticpyrazine-2-carbohydrazide derivatives.

A series of nine N'-(E)-heteroaromatic-pyrazine-2-carbohydrazide derivatives (5a-f and 6a-c) have been synthesized and evaluated against M. tuberculosis ATCC 27294 using the micro plate Alamar Blue assay (MABA), being the activities expressed as the minimum inhibitory concentration (MIC) in µg/ml. Compounds 5a and 5f exhibited potent activities (3.12 and 50µg/mL, respectively) when compared to the first line drug pyrazinamide (MIC>100 µg/mL). Afterwards, these compounds were evaluated for their cell viabilities in non-infected and infected macrophages with Mycobaterium bovis Bacillus Calmette-Guerin (BCG) and 5f was not cytotoxic to host cells in the effective concentration to inhibit the growth of M. tuberculosis.

Utilizaçäo do AMP (2-amino-2-metil-1-propanol) em substituiçäo à DEA (Dietanolamina) na dosagem de fosfato inorgânico no soro e urina pelo método direto de NCL / The use of amp (2-amino-2-methyl-1-propanol) as a substitute of DEA (Diethanolamine) in the determination of inorganic phosphate ins erum and urine, by the MCL direct method

O emprego do AMP (2-amino-2-metil-1-propanol) é proposto como substituto da DEA (Dietanolamina) na determinaçäo de fosfato inorgânico no soro na urina, pelo método direto MCL (Mendes eta al., 1988) Este reagente é mais estável em condiçöes de armazenamento e possui alto poder de solubilizaçäo do precipitado de fosfomolibdato. A análise dos resultados demonstrou uma excelente correlaçäo linear, concluindo que o AMP preenche todos os requisitos necessários para seu emprego na determinacäo de fosfato inorgânico