Chemical and physical properties of nanocrystalline chitosan by the method: Modified nanochitosan complex and process of obtaining modified nanochitosan.

Nanocrystalline chitosan (NCC) is a modified form of chitosan, prepared from the method for obtaining chitosan acetate (CA). Due to the greater crystallinity of chitosan nanoparticles in relation to CA, NCC is more thermally stable and thus has great potential in the development of a new generation of biomaterials potentially useful in regenerative medicine and tissue engineering. NCC is also characterized by having similar properties to its precursor chitosan, such as its biocompatibility, bioactivity, ability to be bioabsorbed and lack of toxicity. One of the major problems associated with obtaining NCC is the low productivity of the methods. While known methods of obtaining nanostructures produce small amounts (milligrams), the method of synthesis for creating NCC from its salt is often more productive and less costly, and is patented by the authors of this work (registration number: BR10201702272). Thus, the objective of this study was to characterize NCC obtained through this innovative method, and analyze its chemical and physical properties using Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and mechanical property analysis with the mean values for the elasticity module, the resistance to tensile strength and the tensile strength. The results indicate that this new process of obtaining the NCC did not modify the chemical structure of the chitosan. The structure of the film surface created was homogeneous and the mechanical properties emphasized the plastifying effect of glycerol under NCC. The thermogravimetric analysis of NCC indicated greater stability in the polysaccharide structure of the nanocrystalline, due to an increased crystalline region compared to the CA which was confirmed by DSC.

α-TCP cements prepared by syringe-foaming: Influence of Na2HPO4 and surfactant concentration.

The lack of intrinsic open porosity in calcium phosphate cements slows down the resorption rate and bone ingrowth when implanted In Vivo. In this study, macroporous structures were obtained by mixing α-TCP cement with a foamed liquid phase containing different concentrations of sodium hydrogen phosphate and a nonionic surfactant. The cement paste was prepared by hand mixing in a novel system of two syringes connected by a tube. Two different liquid to powder (L/P) ratios were used to prepare the cement paste. The cement samples showed open macropores with diameters>100µm. The specimens prepared with lower L/P ratio showed smaller porosity, macroporosity and pore size distribution. The cohesion of the cement paste in liquid solutions was assessed by adding 2wt% sodium alginate to the liquid phase. This study suggests that the final macrostructure of the foamed cements can be controlled by varying the phosphate and surfactant concentrations in the liquid phase and the L/P ratio.

In situ synthesis and characterization of hydroxyapatite/natural rubber composites for biomedical applications.

In this work, a biomimetic synthesis reaction for the production of hydroxyapatite (HA)/natural rubber (NR) composites is presented. HA was synthesized in the presence of solubilized NR in tetrahydrofuran (THF), which permits that negatively charged domains in proteins and lipids in NR work as nucleation sites for hydroxyapatite. The mechanical and physicochemical properties of composites containing 10, 20 and 30wt% HA were studied. NR influenced HA crystallite morphology, shape and size and was able to disperse the HA particles in THF. The dispersion of HA in the composites promoted the enhancement of mechanical properties and loss of solubility of composites, which is believed to be macroscopic manifestations of the physical adsorption of NR to HA particles, known as the bound rubber phenomenon. Preliminary cell studies indicated that HepG2 cells presented viabilities ranging from 71.6 to 91.3%, with cell proliferation positively influenced by HA content at shorter culture times. The good dispersion of HA in the composites is expected to improve NR bioactivity and direct its use towards bone applications.

Heyde syndrome in a 71-year-old man who underwent chest radiotherapy at young age.

We report the case of a 71-year-old man with diagnosis of aortic valve stenosis for ten years, who came to hospital because of breathlessness during the previous two months and recent low intestinal hemorrhage. On admission, laboratory tests and upper gastrointestinal endoscopy and colonoscopy revealed anemia and bleeding cecal angiodysplasia. The echocardiography study showed a severe aortic stenosis. Classical Heyde syndrome is described as the association of aortic stenosis, bleeding gastrointestinal angiodysplasia and secondary anemia. The antecedent of mediastinal radiotherapy for treatment of Hodgkin's disease during his youth, and eventual late cardiac adverse effects that may include aortic or mitral valve disturbances are highlighted. Electrocoagulation with argonium was performed on the sites of active bleeding during the colonoscopy. In sequence, surgical replacement by bioprothesis was done on the aortic valve. The patient remains asymptomatic, under long-term outpatient surveillance, with normal control evaluations. The aim of this case study is to emphasize difficulties related to diagnosis, and to highlight the role of endoscopy and imaging studies to confirm a hypothesis of this underestimated condition.

Massive pleural effusion due to metastasis of prostate cancer.

We describe the case of a 72-year old male with pleural effusion associated with prostate cancer. There was a previous history of tobacco smoking (pack/year: 47) and of total prostatectomy followed by external beam radiation therapy seven years previously for prostate cancer. Furthermore, he was submitted to orchiectomy plus non-steroidal anti-androgen blockage, in addition to docetaxel-based chemotherapy and prednisone. After the beginning of chemotherapy, a progressive elevation in prostate specific antigen (PSA) levels was observed. On admission, he presented with fever, weight loss, and respiratory symptoms due to a massive right pleural effusion. Fluid samples obtained by needle aspiration showed haemorrhagic exudates without malignant cells. Pleural metastasis were detected by thorax imaging studies, and biopsy samples revealed prostate adenocarcinoma as the origin of his pleural effusion. Pleural fluid was drained and talc pleurodesis was performed. This report aims to describe the occurrence of massive pleural effusion due to metastasis of prostate cancer and emphasizes the role of pleural biopsy with immunohistochemical studies to characterize this diagnosis.

Multinodular neurilemmoma of the tongue: a case report with differential immunohistochemical profile.

Neurilemmoma is a distinctive, encapsulated, benign tumor, derived from Schwann cells. It is the most common neurogenic tumor, eventually occurring in the mouth, particularly the tongue. It occurs most often during the second or third decades of life, with predilection in females. Clinically, neurilemmomas present as a solitary circumscribed nodule, rarely being multinodular. We report a case of a 46 year-old female who presented a multinodular neurilemmoma of the tongue. She had a sessile nodule with two months of evolution. The presumptive diagnosis was of a benign mesenchymal neoplasm and an excisional biopsy was performed. During the excision it was found that the lesion was formed by two well-delimitated firm yellowish-white nodules. Histopathologic evaluation revealed an encapsulated benign tissue, formed by spindle cells forming irregular Antoni A and Antoni B patterns, not easily recognizable. Immunostaining was strongly positive for S-100 protein and negative for neurofilament. The lesion was excised and after 12 months of follow-up there was no recurrence.

Effectiveness of computed tomography to evaluate central giant cell lesion.

Central giant cell lesion (CGCL) is a benign disease involving the mandible (70%) more than the maxilla; it tends to be more common in women. Clinically, the lesion may be associated with pain, tooth displacement, facial asymmetry, paraesthesia and ulceration of the mucosa. The radiographic aspect of CGCL is highly variable since it may appear as a unilocular or multilocular radiolucent area with expansion and perforation of the cortical bone. Few previous reports have dealt with the usefulness of CT in the evaluation of this lesion. The purpose of this study is to report the clinical and imaging features of a case, including CT, treated by a conservative method.

Chondrosarcoma involving the periodontum: clinicopathological and immunohistochemical features of a case study.

Chondrosarcoma is a rare flat bone neoplasm. Herein, we present the clinicopathological and immunohistochemical findings of a case affecting the periodontum. A 16-year-old girl presented a painless reddish mass in the lower anterior gingiva. Radiographs showed bone affected by vertical and horizontal loss and enlargement of periodontal space. The histopathological features showed atypical cartilage arranged in lobules compatible with chondrosarcoma. Immunohistochemistry showed that tumor cells were immunoreactive for the anti-vimentin and S-100 antibodies. Moreover, no tumor cells had been immunostained by anti-p53. Treatment consisted of chemotherapy, followed by radical surgery and postsurgery treatment with an association of radio and chemotherapy. After one year, no signs of recurrence have been observed.

Alpha-tricalcium phosphate cement: "in vitro" cytotoxicity.

Calcium phosphate-based bioceramics have revolutionized orthopedic and dental repair of damaged parts of the bone system. Among these materials, calcium phosphate-based cements, with hydraulic setting, stand out due to their biocompatibility and in situ hardening, which allow easy manipulation and adaptation to the shape and dimensions of bone defects. An investigation was made of the in vitro cytotoxic effect of calcium phosphate cement based on alpha-tricalcium phosphate, immersed for different lengths of time in simulated body fluid (SBF), based on the ISO-10993 "Biological Evaluation of Medical Devices" standard. The culture medium was Chinese hamster ovary (CHO) cells in contact with diluted cement extracts. The results revealed that the calcium phosphate cement used was cytotoxic and that the material's cytotoxicity decreased the longer the cement was immersed in SBF.

Maximal lactate steady state in rats submitted to swimming exercise.

The higher concentration during exercise at which lactate entry in blood equals its removal is known as 'maximal lactate steady state' (MLSS) and is considered an important indicator of endurance exercise capacity. The aim of the present study was to determine MLSS in rats during swimming exercise. Adult male Wistar rats, which were adapted to water for 3 weeks, were used. After this, the animals were separated at random into groups and submitted once a week to swimming sessions of 20 min, supporting loads of 5, 6, 7, 8, 9 or 10% of body wt. for 6 consecutive weeks. Blood lactate was determined every 5 min to find the MLSS. Sedentary animals presented MLSS with overloads of 5 and 6% at 5.5 mmol/l blood lactate. There was a significant (P<0.05) increase in blood lactate with the other loads. In another set of experiments, rats of the same strain, sex and age were submitted daily to 60 min of swimming with an 8% body wt. overload, 5 days/week, for 9 weeks. The rats were then submitted to a swimming session of 20 min with an 8% body wt. overload and blood lactate was determined before the beginning of the session and after 10 and 20 min of exercise. Sedentary rats submitted to the same acute exercise protocol were used as a control. Physical training did not alter the MLSS value (P<0.05) but shifted it to a higher exercise intensity (8% body wt. overload). Taken together these results indicate that MLSS measured in rats in the conditions of the present study was reproducible and seemed to be independent of the physical condition of the animals.

Parasitic thyroid nodule in a patient with Hashimoto's chronic thyroiditis.

A case of parasitic thyroid nodule is presented. The patient was a non symptomatic 53-year-old white woman, on irregular course of L-thyroxine to treat hypothyroidism due to Hashimoto's thyroiditis. Without a history of thyroid trauma or surgery, she presented a 1.6 x 0.7 x 0.5cm right pre-laryngeal lymph node-like mass which, on ultrasonography, appeared distinct from the gland. TSH, thyroid peroxidase antibody and thyroglobulin antibody serum levels were elevated and T4-free level was normal. Thyroid and total body 99mTc isonitrile scintiscan showed a topic thyroid without radionuclide uptake in the nodule. Fine-needle aspiration of the nodule showed epithelial cells with nuclear atypia and oncocytic changes plus intense lymphoid infiltration and germinative center formation, simulating lymph node metastasis of papillary thyroid carcinoma. Conventional biopsy revealed a parasitic thyroid nodule with Hashimoto's chronic thyroiditis. Parasitic thyroid nodule must always be remembered so that unnecessary surgical assessment and undesirable sequels may be avoided.

Fiber reinforced calcium phosphate cement.

The term calcium phosphate cement was introduced by Gruninger et al. (1). This type of cement can be prepared by reacting a calcium phosphate salt with an aqueous solution, which causes it to set by the crossing of the precipitated crystals. These cements offer a series of advantages that allow their use as grafts and substitutes of damaged parts of the bone system. However, these cements have low mechanical strength compared to human bones. This work studied the influence of the use of polyamide fibers in the mechanical properties of a calcium phosphate cement based on alpha-tricalcium phosphate as well as the mechanisms involved in the increase of mechanical strength. The results demonstrate the feasibility of the use of polymeric fibers to increase mechanical strength and the need for coupling agents for the effective performance of the fibers as reinforcement in these materials.

Influence of polymeric additives on the mechanical properties of alpha-tricalcium phosphate cement.

Recently, great attention has been paid to calcium phosphate cements, because of their advantages in comparison with conventional calcium phosphate bioceramics employed for bone repairing, regarding in situ handling, and shaping abilities. Nevertheless, the calcium phosphate cements exhibit relatively low mechanical strength. The aim of this work was the improvement of the compressive strength of alpha-tricalcium phosphate-based cement. The hydraulic setting reaction of this system produces a calcium-deficient hydroxyapatite phase suitable for bone repairing: alpha-Ca3(PO4)2 + H2O --> Ca9(HPO4)(PO4)5OH. Mechanical strength can be improved using technological solutions developed for other applications, such as Portland cement and dual-setting glass-ionomers, by using polymeric additives. The additives used in this work were sodium alginate, sodium polyacrylate, and an in situ polymerization system resulting in a polyacrylamide crosslinked hydrogel. Parameters evaluated were setting time, compressive strength before and after immersion in simulated body fluid, density, porosity, crystalline phases, and microstructure. Sodium alginate and sodium polyacrylate were deleterious to both setting time and mechanical strength. When the in situ polymerization system was added, two setting reactions progressed in parallel: the conventional hydraulic reaction and the copolymerization of acrylamide and crosslinking water-soluble monomers. The initial and final setting times of the "dual-setting" cement were 9 and 35 min, respectively, and they can be regulated varying the initiator, catalyst, and monomers concentrations. The initial compressive strength of the dual-setting cement (6.8 MPa at 0 h, and 15.2 MPa at 24 h) is higher than that of unmodified cement. The major crystalline phase after setting is hydroxyapatite. The dual-setting cement seems to be suitable for clinical applications in bone repairing and remodeling.

Headache in chagasic women.

The aim of this study was to compare the frequency of headache between Chagasic and Non-chagasic women. The cross-sectional study comprised 647 female > or = 40 years old, Chagasic (n = 362) and Controls (n = 285) at a Brazilian University Hospital. Chagasic were classified as Cardiac (n = 179), Megas (n = 58) or Indeterminate (n = 125) clinical forms. Headache was ascertained according to Headache International Society diagnostic criteria. The age (57.0 +/- 11.3 versus 57.3 +/- 10.4 years), and the percentage of white women (75.8% versus 77.1%) were similar between Chagasic and Controls, respectively. Headache was more prevalent among Chagasic (32.9%) than Controls (16.1%), mainly in Cardiac form (odds ratio, 2.41; 95% confidence interval, 1.38-4.23), phenomenon possibly related to parasympathetic denervation and cerebral vessels changes.

[Frequency of diabetes mellitus and hyperglycemia in chagasic and non-chagasic women]. / Freqüência de diabetes mellitus e hiperglicemia em mulheres chagásicas e não-chagásicas.

Medical records of > or = 40 years old female seen at University Hospital from June/93 to July/95 were submitted to a cross-sectional study. According to Chagas' disease tests, patients were divided into chagasic (n = 362) and controls (n = 285). Diabetes mellitus was defined on the basis of two fasting blood glucose levels > or = 140 mg/dl and hyperglycemia as fasting blood glucose > 110 mg/dl. Chagasic patients were divided into groups with the cardiac form of the disease (n = 179), with megas (n = 58), and asymptomatic (n = 125). Groups were compared by the chi 2 test, analysis of variance, Student's "t" test, and Kruskal-Wallis and Mann-Whitney tests. A significant difference was assumed when p < 0.05. Chagasic and control groups were matched for age, white color and body mass index. Diabetes mellitus was more prevalent in patients with the cardiac form of Chagas' disease than in controls, or patients with the megas or the asymptomatic form (15.1%, 7.4%, 7.4%, and 5.6%, respectively); the same was observed for hyperglycemia (37.4%, 26.7%, 25.9%, 27.2%), in agreement with the hypothesis that the reduced parasympathetic activity caused by Trypanosoma cruzi leads to relative sympathetic hyperactivity.

[Pancreatic anatomopathologic changes in chronic chagasic women. Preliminary data]. / Alterações anatomo-patológicasdo pâncreas em chagásicas crônicas. Dados preliminares.

The aim of this study was to compare the frequency of pancreas morphologic and morphometric changes in chagasic women (n = 6) aged > or = 40 years, with non-chagasic controls (n = 4), paired concerning to age (59.8 +/- 11.5 versus 59.0 +/- 6.3 years), white color (33.3% versus 50.0%) and body mass index (22.3 +/- 7.0 versus 18.8 +/- 2.1 kg/m2). There were no pancreatic morphometric differences between necropsied chagasic and control groups. However, there was a smaller intrapancreatic neuronal population and a higher frequency of leukocyte perineural infiltrate in the pancreas of chagasic women. This possible intrapancreatic denervation could be associated with changes in carbohydrate metabolism, including hyperglycemia and diabetes mellitus, in some chronic chagasic women.

[Guillain-Barré syndrome associated with acute pancreatitis. Case report]. / Síndrome de Guillain-Barré associada a pancreatite aguda. Relato de caso.

We report a clinical case of Guillain-Barré syndrome associated with acute pancreatitis, and perform a review in literature about clinical complications related to Guillain-Barré syndrome. We suggest the possibility of being the events immunologically related.

[Frequency of precordialgia in chagasic and non-chagasic women]. / Freqüência de precordialgia em mulheres chagásicas e não-chagásicas.

The aim of this study was to compare the frequency of precordialgia between chagasic and non-chagasic women. A cross-sectional study comprised 647 female aged > or = 40, chagasic (n = 362) and controls (n = 285) was done at a Brazilian university hospital. Chagasic were classified as cardiac (n = 179), megas (n = 58) or indeterminate (n = 125) clinical forms. Chest pain was ascertained by typical or atypical retrosternal pain. Age (57.0 +/- 11.3 vs 57.3 +/- 10.4 years), and percentage of white women (75.8% vs 77.1%) were similar between chagasic and controls, respectively. Chest pain was more prevalent (p < 0.01) among chagasic (14.6%) than controls (5.6%), mainly in the cardiac form (relative risk = 2.41; range: 1.38-4.23), a phenomenon possibly related to cardiac parasympathetic denervation and myocardial microvascular changes.

[Cryptococcus infection limited to the prostate in an AIDS patient with disseminated mycobacteriosis. A necropsy report]. / Infecção por Cryptococcus limitada à próstata em paciente aidético com micobacteriose disseminada. Relato de necropsia.

This is a case report of asymptomatic and restrained cryptococcal prostatic infection in a 32-year-old black male with the acquired immunodeficiency syndrome, whose death was caused by systemic mycobacteriosis probably pertaining to MAI complex. The importance of autopsy studies to evaluate the real prevalence of fungus infections in AIDS patients, specially in cases of persistent silent focuses, is emphasized.