2D QSAR and similarity studies on cruzain inhibitors aimed at improving selectivity over cathepsin L

Hologram quantitative structure-activity relationships (HQSAR) were applied to a data set of 41 cruzain inhibitors. The best HQSAR model (Q(2) = 0.77; R-2 = 0.90) employing Surflex-Sim, as training and test sets generator, was obtained using atoms, bonds, and connections as fragment distinctions and 4-7 as fragment size. This model was then used to predict the potencies of 12 test set compounds, giving satisfactory predictive R-2 value of 0,88. The contribution maps obtained from the best HQSAR model are in agreement with the biological activities of the study compounds. The Trypanosoma cruzi cruzain shares high similarity with the mammalian homolog cathepsin L. The selectivity toward cruzam was checked by a database of 123 compounds, which corresponds to the 41 cruzain inhibitors used in the HQSAR model development plus 82 cathepsin L inhibitors. We screened these compounds by ROCS (Rapid Overlay of Chemical Structures), a Gaussian-shape volume overlap filter that can rapidly identify shapes that match the query molecule. Remarkably, ROCS was able to rank the first 37 hits as being only cruzain inhibitors. In addition, the area under the curve (AUC) obtained with ROCS was 0.96, indicating that the method was very efficient to distinguishing between cruzain and cathepsin L inhibitors. (c) 2007 Elsevier Ltd. All rights reserved.

Convergence of developmental mutants into a single tomato model system: 'Micro-Tom' as an effective toolkit for plant development research

Background: The tomato (Solanum lycopersicum L.) plant is both an economically important food crop and an ideal dicot model to investigate various physiological phenomena not possible in Arabidopsis thaliana. Due to the great diversity of tomato cultivars used by the research community, it is often difficult to reliably compare phenotypes. The lack of tomato developmental mutants in a single genetic background prevents the stacking of mutations to facilitate analysis of double and multiple mutants, often required for elucidating developmental pathways. Results: We took advantage of the small size and rapid life cycle of the tomato cultivar Micro-Tom (MT) to create near-isogenic lines (NILs) by introgressing a suite of hormonal and photomorphogenetic mutations (altered sensitivity or endogenous levels of auxin, ethylene, abscisic acid, gibberellin, brassinosteroid, and light response) into this genetic background. To demonstrate the usefulness of this collection, we compared developmental traits between the produced NILs. All expected mutant phenotypes were expressed in the NILs. We also created NILs harboring the wild type alleles for dwarf, self-pruning and uniform fruit, which are mutations characteristic of MT. This amplified both the applications of the mutant collection presented here and of MT as a genetic model system. Conclusions: The community resource presented here is a useful toolkit for plant research, particularly for future studies in plant development, which will require the simultaneous observation of the effect of various hormones, signaling pathways and crosstalk.

A Referential Model for Small Companies of Development Software

This paper presents the proposal for a reference model for developing software aimed at small companies. Despite the importance of that represent the small software companies in Latin America, the fact of not having its own standards, and able to meet their specific, has created serious difficulties in improving their process and also in quality certification. In this sense and as a contribution to better understanding of the subject they propose a reference model and as a means to validate the proposal, presents a report of its application in a small Brazilian company, committed to certification of the quality model MPS.BR.

Development of an animal model for allergic conjunctivitis: influence of genetic factors and allergen concentration on immune response

Purpose: Animal models of diseases are extremely important in the study of the physiopathogenesis of human diseases and for testing novel therapeutic interventions. The present study aimed to develop an animal model that simulates human allergic conjunctivitis and to study how allergic response may be influenced by the allergen dose used for immunization and by genetic factors. Methods: Sixty C57Bl/6 mice and 60 BALB/c mice were immunized with placebo, or 5 mu g or 500 mu g of allergen derived from Dermatophagoides pteronyssinus. After ocular challenge, the mice were examined in order to clinically verify the occurrence or not of conjunctivitis. Material obtained from animals was used for total and specific IgE and IgG1 dosage, for assays of Der p-specific lymphocyte proliferation and supernatant cytokine dosage, and for histopathological evaluation of conjunctiva. Results: We developed a murine model of allergic conjunctivitis induced by D. pteronyssinus. The model is similar to human disease both clinically and according to laboratory findings. In mouse, conjunctivitis was associated with a Th2 cytokine profile. However, IL-10 appeared to be involved with disease blockade. Mice of different strains have distinct immune responses, depending on the sensitization dose. Conclusions: The murine model developed is suitable for the study of immunopathogenesis and as a template for future therapies. Using BALB/c and C57BL/6 mice, we demonstrated that genetic factors play a role in determining susceptibility and resistance, as well as in establishing the allergen concentration needed to induce or to block disease development.

Development of an animal model for endometrial ablation using trichloroacetic acid

Objective: To develop an animal model of endometrial ablation, and to evaluate the histologic effects of trichloroacetic acid (TCA) in the uterine cavity. Design: Experimental prospective. Setting: Department of gynecology. Patient(s): Thirty female adult rats. Intervention(s): Animals were submitted to injection of TCA in one uterine horn and saline solution in the other. Group 1 was sacrificed the day after the procedure. Group 2 was sacrificed in phase of diestrus. Superficial epithelia of the endometrium, stromal thickness, endometrial glands, and myometrium thickness were compared among the uterine horns of the same rats of group 1. The same evaluation was performed in group 2. Endometrial regeneration was evaluated. Main Outcome Measure(s): Histologic effects. Result(s): In group 1, histologic parameters showed endometrial destruction on TCA injected uterine horn. In group 2, four rats died after the procedure, and six rats had no viable material. In the rest of the group, TCA-injected uterine horns showed endometrial destruction. Superficial epithelia of the endometrium and stromal thickness were similar between TCA uterine horn from groups. However, the number of endometrial glands was higher in group 1. Conclusion(s): The study developed an experimental model for endometrial ablation. TCA acid is a potent agent for endometrial ablation in rat model. No endometrial regeneration was observed after recovery of cycle. (Fertil Steril (R) 2011; 95: 2418-21. (C) 2011 by American Society for Reproductive Medicine.)

The development of a rat model of erectile dysfunction after radical prostatectomy: preliminary findings

To develop a rat model of erectile dysfunction (ED) after cavernous nerve injury. Given the great similarity between the anatomical structure of the cavernous nerve in rats and humans, 24 rats underwent dissections and the cavernous nerves were identified with the aid of an operating microscope. Then the rats were randomized into two groups: sham-operated controls and a bilateral cavernous nerve section group. At 3 months after surgery, the rats were evaluated for their response to an apomorphine challenge. The erectile response after an apomorphine challenge was normal in all the control rats, while there were no erections in the bilateral injured group. The rat major autonomic ganglion and its cavernous nerve can be identified with the aid of a microscope. Rats are inexpensive and easy to handle, thus a good animal for developing an ED model of cavernous nerve injury. In the present study, the rats with cavernous nerve injury lost erectile capacity in a reliable and reproducible fashion. Because of the great similarity between the cavernous nerve of rats and humans, one may consider this technique as a reliable experimental model for studying ED after radical prostatectomy.

Endoscopic Anatomy of the Pterygopalatine Fossa and the Transpterygoid Approach: Development of a Surgical Instruction Model

Introduction: The pterygopalatine fossa (PPF) is a narrow space located between the posterior wall of the antrum and the pterygoid plates. Surgical access to the PPF is difficult because of its protected position and its complex neurovascular anatomy. Endonasal approaches using rod lens endoscopes, however, provide better visualization of this area and are associated with less morbidity than external approaches. Our aim was to develop a simple anatomical model using cadaveric specimens injected with intravascular colored silicone to demonstrate the endoscopic anatomy of the PPF. This model could be used for surgical instruction of the transpterygoid approach. Methods: We dissected six PPF in three cadaveric specimens prepared with intravascular injection of colored material using two different injection techniques. An endoscopic endonasal approach, including a wide nasoantral window and removal of the posterior antrum wall, provided access to the PPF. Results: We produced our best anatomical model injecting colored silicone via the common carotid artery. We found that, using an endoscopic approach, a retrograde dissection of the sphenopalatine artery helped to identify the internal maxillary artery (IMA) and its branches. Neural structures were identified deeper to the vascular elements. Notable anatomical landmarks for the endoscopic surgeon are the vidian nerve and its canal that leads to the petrous portion of the internal carotid artery (ICA), and the foramen rotundum, and V2 that leads to Meckel`s cave in the middle cranial fossa. These two nerves, vidian and V2, are separated by a pyramidal shaped bone and its apex marks the ICA. Conclusion: Our anatomical model provides the means to learn the endoscopic anatomy of the PPF and may be used for the simulation of surgical techniques. An endoscopic endonasal approach provides adequate exposure to all anatomical structures within the PPF. These structures may be used as landmarks to identify and control deeper neurovascular structures. The significance is that an anatomical model facilitates learning the surgical anatomy and the acquisition of surgical skills. A dissection superficial to the vascular structures preserves the neural elements. These nerves and their bony foramina, such as the vidian nerve and V2, are critical anatomical landmarks to identify and control the ICA at the skull base.

Neoskin development in the fetus with the use of a three-layer graft: an animal model for in utero closure of large skin defects

Objective: To assess the ability of a three-layer graft in the closuse of large fetal skin defects. Methods: Ovine fetuses underwent a large (4 x 3 cm) full-thickness skin defect over the lumbar region at 105 days` gestation (term = 140 days). A bilaminar artificial skin was placed over a cellulose interface to cover the defect (3-layer graft). The skin was partially reapproximated with a continuous nylon suture. Pregnancy was allowed to continue and the surgical site was submitted to histopathological analysis at different post-operative intervals. Results: Seven fetuses underwent surgery. One maternal/fetal death occurred, and the remaining 6 fetuses were analyzed. Artificial skin adherence to the wound edges was observed in cases that remained in utero for at least 15 days. Neoskin was present beneath the silicone layer of the bilaminar artificial skin. Conclusions: Our study shows that neoskin can develop in the fetus using a 3-layer graft, including epidermal growth beneath the silicone layer of the bilaminar skin graft. These findings suggest that the fetus is able to reepithelialise even large skin defects. Further experience is necessary to assess the quality of this repair.

Changes in postnatal skeletal muscle development induced by alternative immobilization model in female rat

The objective of this study was to adapt a model of hind limb immobilization to newly weaned female rats and to determine the morphology of shortened soleus and plantaris muscles. Female Wistar rats were divided into three groups: control zero (n = 3) and control and free (n = 8), animals aged 21 and 31 days, respectively, submitted to no intervention, and immobilized (n = 25), animals aged 21 days submitted to immobilization for 10 days and sacrificed at 31 days of age. The device used for immobilization had advantages such as easy connection, good fit, and low cost. The immobilized rats showed a reduction in muscle fiber area and in connective tissue. The adaptation of this immobilization model originally used for adult rats was an excellent alternative for newly weaned rats and was also efficient in inducing significant hind limb disuse.

A modified rat model of neonatal anoxia: Development and evaluation by pulseoximetry, arterial gasometry and Fos immunoreactivity

Neonatal anoxia is a worldwide clinical problem that has serious and lasting consequences. The diversity of models does not allow complete reproducibility, so a standardized model is needed. In this study, we developed a rat model of neonatal anoxia that utilizes a semi-hermetic system suitable for oxygen deprivation. The validity of this model was confirmed using pulse oximetry, arterial gasometry, observation of skin color and behavior and analysis of Fos immunoreactivity in brain regions that function in respiratory control. For these experiments, 87 male albino neonate rats (Rattus norvegicus, lineage Wistar) aged approximate 30 postnatal hours were divided into anoxia and control groups. The pups were kept in an euthanasia polycarbonate chamber at 36 +/- 1 degrees C, with continuous 100% nitrogen gas flow at 3 L/min and 101.7 kPa for 25 min. The peripheral arterial oxygen saturation of the anoxia group decreased 75% from its initial value. Decreased pH and partial pressure of oxygen and increased partial pressure of carbon dioxide were observed in this group, indicating metabolic acidosis, hypoxia and hypercapnia. respectively. Analysis of neuronal activation showed Fos immunoreactivity in the solitary tract nucleus, the lateral reticular nucleus and the area postrema, confirming that those conditions activated areas related to respiratory control in the nervous system. Therefore, the proposed model of neonatal anoxia allows standardization and precise control of the anoxic condition, which should be of great value in indentifying both the mechanisms underlying neonatal anoxia and novel therapeutic strategies to combat or prevent this widespread public health problem. (C) 2011 Elsevier B.V. All rights reserved.

Validation of an experimental polyurethane model for biomechanical studies on implant supported prosthesis - tension tests

OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, frequently hinder the development of clinical trials. The purpose of this in vitro study was to determine the modulus of elasticity of a polyurethane isotropic experimental model via tension tests, comparing the results to those reported in the literature for mandibular bone, in order to validate the use of such a model in lieu of mandibular bone in biomechanical studies. MATERIAL AND METHODS: Forty-five polyurethane test specimens were divided into 3 groups of 15 specimens each, according to the ratio (A/B) of polyurethane reagents (PU-1: 1/0.5, PU-2: 1/1, PU-3: 1/1.5). RESULTS: Tension tests were performed in each experimental group and the modulus of elasticity values found were 192.98 MPa (SD=57.20) for PU-1, 347.90 MPa (SD=109.54) for PU-2 and 304.64 MPa (SD=25.48) for PU-3. CONCLUSION: The concentration of choice for building the experimental model was 1/1.

Development of a flow through photo-reactor to study degradation of organic compounds by Sequential Injection Analysis (SIA)

This work describes a photo-reactor to perform in line degradation of organic compounds by photo-Fenton reaction using Sequential Injection Analysis (SIA) system. A copper phthalocyanine-3,4',4²,4²¢-tetrasulfonic acid tetrasodium salt dye solution was used as a model compound for the phthalocyanine family, whose pigments have a large use in automotive coatings industry. Based on preliminary tests, 97% of color removal was obtained from a solution containing 20 µmol L-1 of this dye.

The Rg1 allele as a valuable tool for genetic transformation of the tomato 'Micro-Tom' model system

Background: The cultivar Micro-Tom (MT) is regarded as a model system for tomato genetics due to its short life cycle and miniature size. However, efforts to improve tomato genetic transformation have led to protocols dependent on the costly hormone zeatin, combined with an excessive number of steps. Results: Here we report the development of a MT near-isogenic genotype harboring the allele Rg1 (MT-Rg1), which greatly improves tomato in vitro regeneration. Regeneration was further improved in MT by including a two-day incubation of cotyledonary explants onto medium containing 0.4 mu M 1-naphthaleneacetic acid (NAA) before cytokinin treatment. Both strategies allowed the use of 5 mu M 6-benzylaminopurine (BAP), a cytokinin 100 times less expensive than zeatin. The use of MT-Rg1 and NAA pre-incubation, followed by BAP regeneration, resulted in high transformation frequencies (near 40%), in a shorter protocol with fewer steps, spanning approximately 40 days from Agrobacterium infection to transgenic plant acclimatization. Conclusions: The genetic resource and the protocol presented here represent invaluable tools for routine gene expression manipulation and high throughput functional genomics by insertional mutagenesis in tomato.

EVALUATING VIBRATIONS ON A SMALL-SCALE MODEL OF A TIMBER FOOTBRIDGE

In Brazil, the study of pedestrian-induced vibration on footbridges has been undertaken since the early 1990s, for concrete and steel footbridges. However, there are no recorded studies of this kind for timber footbridges. Brazilian code ABNT NBR 7190 (1997) gives design requirements only for static loads in the case of timber footbridges, without considering the serviceability limit state from pedestrian-induced vibrations. The aim of this work is to perform a theoretical dynamic, numerical and experimental analysis on simply-supported timber footbridges, by using a small-scale model developed from a 24 m span and 2 m width timber footbridge, with two main timber beams. Span and width were scaled down (1:4) to 6 m e 0.5 in, respectively. Among the conclusions reached herein, it is emphasized that the Euler-Bernoulli beam theory is suitable for calculating the vertical and lateral first natural frequencies in simply-supported timber footbridges; however, special attention should be given to the evaluation of lateral bending stiffness, as it leads to conservative values.

Relatedness and HLA-DRB1 typing may discriminate the magnitude of the genetic susceptibility to tuberculosis using a household contact model

Background Tuberculosis clusters in families may be due to increased household exposure, shared genetic factors, or both. Household contact studies are useful to control exposure because socioeconomic and environmental conditions are similar to all subjects, allowing the evaluation of the contribution of relatedness to disease development. Methods In this study, the familial aggregation of tuberculosis using relatedness and a specific inherited marker (HLA-DRB1) was evaluated. Fifty families, which had at least two cases of tuberculosis diagnosed within the past 5 years, were selected from a cohort of tuberculosis carried out in Recife, Brazil. The first case diagnosed was considered to be a primary case. The secondary attack rate of tuberculosis in household contacts was estimated according to the degree of relatedness. The relative risk of having tuberculosis based on the degree of relatedness household and the population attributable fraction to relatedness were also estimated. HLA-DRB1 typing and attributable etiologic/preventive fractions were calculated among sick and healthy household contacts. Results Compared to unrelated contacts, the relative risk for tuberculosis adjusted for age was 1.38 (95% CI 0.86 to 2.21). Relatedness contributed 23% to the development of tuberculosis at the population levels. The HLA-DRB1*04 allele group (OR = 2.44; p =0.0324; etiologic fraction =0.15) was overrepresented and the DRB1*15 allele group (OR=0.48; p=0.0488; protective fraction=0.19) was underrepresented among household contacts exhibiting tuberculosis. The presence of DRB1 shared alleles between primary cases and their contacts was a risk factor for tuberculosis (p=0.0281). Conclusion This household contact model together with the utilisation of two genetic variables permitted the evaluation of genetic factors contributing towards tuberculosis development.