[Solid-cystic supratentorial hemangioblastoma affecting the falx cerebri. Report of a case]. / Hemangioblastoma sólido-quístico supratentorial afectando la hoz del cerebro. Presentación de un caso.

INTRODUCTION: hemangioblastomas are benign neoplasias that are originated in the central nervous system and constitute between 1.5-2.5% of intracranial tumors. The majority of them are infratentorial, mainly affecting the cerebellum (76%). Supratentorial lessions are rare, being in these cases the frontal, parietal or temporal lobes the most common locations. Meningeal involvement is infrequent. Only eight cases have been reported in the literature. In 30% of the cases, these tumors are associated with von Hippel Lindau syndrome (VHL). CASE REPORT: 67 year old woman without any medical or family history. She presented with 4 month evolution neurological symptoms. The cranial MRI scan showed a solitary solid-cystic lesion on the right paramedian frontal lobe, in contact with the falx cerebri. The pathological analysis showed a cellular proliferation composed of polygonal cells with clear cytoplasm due to the presence of intracytoplasmic vacuoles and round or oval nucleus without cytologic atypia. These cells were accompanied by a rich vascular network of capillary type and blood extravasation. She was diagnosed of supratentorial hemangioblastoma. CONCLUSION: the preoperative diagnosis of these neoplasms is difficult because the clinical suspicion is low in supratentorial location. Imaging techniques are useful but definitive diagnosis is made through pathologic examination. The use of immunohistochemical techniques is helpful for the differential diagnosis with lesions that are more common in this region. The importance of a correct diagnosis of these histologically benign tumors, lies on the possible association with VHL syndrome and its complications.

Effects of preparation and experimental conditions on removal of phenol by surfactant-modified zeolites.

The removal of phenol from aqueous solutions using surfactant-modified clinoptilolite-rich tuffs (SMZ) prepared from two Mexican zeolitic tuffs (Chihuahua and Oaxaca) was investigated. Sodium homoionization of the zeolitic rocks was performed before they were modified with the surfactants: hexadecyltrimethylammonium chloride or bromide and bencylcetildimethylammonium chloride. The surfactants in the modified zeolitic materials were determined considering the total carbon in the samples. The phenol removal was determined in a batch system taking into consideration the different quantities of surfactants in the zeolitic tuffs, contact time, pH and initial phenol concentration. The phenol was determined in the aqueous solutions by UV/Vis spectroscopy. Results showed that the formation of a hemimicelle or admicelle on the zeolites depended on the initial surfactant concentration and they were responsible for the type of interactions between the phenol and the surfactant-modified zeolites. Phenol adsorption by the surfactant-modified zeolites was carried out in approximately three hours. Phenol adsorption data was best adjusted to the pseudo-second order kinetic model. Both, surface properties of the surfactant-modified zeolites and pH of solution play an important role in the removal of this pollutant from aqueous solutions and they are responsible for the type of mechanism involved.

Pulmonary blastoma evolving into carcinosarcoma. A case study.

A rare lung tumor composed of contiguous foci of classical blastoma and carcinosarcoma with transitional features is described. Based on these observations and a review of the literature, we propose that pulmonary carcinosarcomas are composed of a heterogeneous population of tumors. This case supports the concept that blastomas are a distinctive subtype of carcinosarcomas. An unusual feature in the clinical presentation was the expectoration of an endobronchial portion of tumor.

Pulmonary blastoma: report of two cases.

Pulmonary blastoma is a rare primary malignancy of the lung originating from multipotential pulmonary blastema. Two cases of this tumor are reported emphasizing lack of correlation between the microscopic appearance and the clinical course. There are no specific clinical features that differentiate this tumor from the more common lung neoplasms. Surgical resection is the preferred treatment; the merits of radiotherapy and chemotherapy have not yet been established. Prognosis after adequate resection appears no better than for other pulmonary malignancies.

Actinomycosis infections associated with intrauterine contraceptive devices.

A series of 10 instances of genital actinomycosis infection complicating the use of intrauterine contraceptive devices is recorded and its pathogenesis described. The likelihood is suggested that this complication is more frequent than is generally appreciated. A pathway of infection extending upward from the patient's anus, across the perineum, and up the vagina and cervix is suggested as the route of infection. The traumatizing effect of the device and a previously existing or intercurrent infection as additional contributing factors to the development of actinomycotic infection in the female genitalia is also postulated.

Lymphosarcoma of the breast.

Four patients with lymphosarcoma of the breast are reported. Three had involvement of some nodes at the time of diagnosis. Violaceous skin discoloration was observed in two patients. A review of the literature indicates that although many of these patients present with disease initially localized to the breast, dissemination eventually occurs.

Effect of dialysis treatment on the aggregation state of montmorillonite clay.

In this work dialysis was used as a technique to modify the aggregation state of montmorillonite clay. Na-montmorillonite clay suspension was treated by a dialysis process and the effect of dialysis time on the surface area of the treated clay was studied. In a clay suspension, a decrease in cation content increases the interparticle repulsion forces exponentially, leading to separation of clay into the elementary clusters of layers by osmotic swelling. During dialysis treatment, the classical delamination process and mechanism were not observed. According to N(2) adsorption isotherms, the increase of surface area concerns to the development of mesoporosity. Nevertheless, the surface area increase cannot be explained by the delamination or exfoliation of some layers, since an increase in the expected number of layers that would yield the surface area does not explain the mesoporosity observed after dialysis. Based on these results, a new mechanism of evolution of the clay aggregation state after dialysis and drying is proposed.

Ion exchange resins as catalyst for the isomerization of alpha-pinene to camphene.

Camphene is an industrial intermediate compound for commercial chemicals such as isoborneol, isobornyl acetate and camphor. Industrially, the conventional process for camphene production consists of the isomerization of alpha-pinene using acidic TiO2 as catalyst. The use of this catalyst presents problems such as considerable time for preparation, reproducibility and recovery of catalyst from products after the alpha-pinene isomerization. For the first time, a commercial exchange resin was used as catalyst for this reaction. Based on the concentration of product as a function of the reaction time, the path of the alpha-pinene transformation to camphene and byproducts is proposed. Temperature and alpha-pinene/catalyst ratio were studied in order to optimize the yield to camphene production. The obtained results were comparable with those reported for acidic TiO2.

Resection of a vipoma of the pancreas in a 15-year-old girl.

A 15-year-old girl had massive watery and protein-losing diarrhea. She was found to have a pancreatic islet cell tumor secreting high levels of vasoactive intestinal polypeptide. Eighty-five percent pancreatic resection was needed to remove the tumor. She has normal serum VIP levels and no tumor recurrence 6 years later.

Incontinentia pigmenti with unusual features.

A case is presented of incontinentia pigmenti with severe neurological handicaps and unusual features such as single umbilical artery, pigmented lesion at birth, and biochemical changes including elevated alkaline phosphatase and immunoglobulin M.

Al(2)O(3(w))-Al(2)O(3(n))-ZrO(2) (TZ-3Y)(n) multi-scale nanocomposite: an alternative for different dental applications?

The influence of the addition of Al(2)O(3) whiskers (2.5wt.% up to 30wt.%) on Vickers hardness and fracture toughness in an Al(2)O(3(n))+ZrO(2) (TZ-3Y)(n) (90, 80 and 70wt.%) composite was investigated. Green compacts were obtained by uniaxial pressing at 50MPa and pressureless sintering at 1500 degrees C in air for 2h. After sintering, relative densities ranging from 75% to 97% were reached. The whiskers resisted particle rearrangement owing to the extensive sliding distances along the whisker boundaries during sintering and the high length/diameter ratios. Sintering becomes more difficult with increasing whisker content, because whiskers come into contact with each other, forming a rigid network which hinders densification. The 2.5wt.% Al(2)O(3) whiskers+27.5wt.% Al(2)O(3) nanoparticles+70wt.% TZ-3Y composite showed a hardness>13GPa and a maximum fracture toughness of 6.9MPam(-1/2), with an average grain size of 0.4+/-0.17microm. The observed crack deflection was an important mechanism in the improved fracture toughness of the composite. In addition, the grain size and residual porosity also seem to be factors in obtaining a wide range of hardness as well as fracture toughness by varying the Al(2)O(3) whiskers and ZrO(2) (TZ-3Y) content. The use of alumina-whisker-reinforced composites in dental applications could be promising for increasing hardness and fracture toughness compared with other materials. The reported values for these composites can compete with those of commercially available materials in different dental applications.

Experimental and theoretical determination of the low-loss electron energy loss spectroscopy of LiMn2O4.

The dielectric properties of cubic spinel-type LiMn(2)O(4), used as cathode material in lithium ion secondary batteries, are studied by analyzing the low-loss region of the electron energy loss spectroscopy (EELS) spectrum in a transmission electron microscope. A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2k code) within the generalized gradient approximation (GGA) is presented. The origins of interband transitions are identified in the electronic band structure, by calculating the partial imaginary part of the dielectric function and the partial density of states of Li, Mn and O. Good agreement with experimental spectra is observed which allowed interpreting main features of the EELS spectrum.

In situ study of the metal-insulator transition in VO2 by EELS and ab initio calculations.

Changes in the dielectric properties during the thermochromic transition of commercial VO(2) powders were determined in situ, by analyzing the low-loss region of the electron energy-loss spectroscopy (EELS) spectra in a transmission electron microscope at room temperature (insulator phase) and 100 degrees C (metallic phase). A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2k code) within the generalized gradient approximation (GGA) is presented. A characteristic peak around 5.6 eV appears in the energy-loss function in metallic phase, which is absent in insulator phase. The origin of the characteristic peak is analyzed by means of energy-band structure calculations.

Phenol sorption on surfactant-modified Mexican zeolitic-rich tuff in batch and continuous systems.

Surfactant modified clinoptilolite-rich tuff was used for the removal of phenol from aqueous solutions. The zeolitic rock from Oaxaca (Mexico) was treated with sodium chloride and then modified with hexadecyltrimethylammonium chloride or bencylcetildimethylammonium chloride in different experimental conditions. Phenol sorption isotherms and column experiments were performed; in both cases, phenol was determined in the aqueous solutions by UV-vis spectroscopy. The results showed that the sorption of phenol depends on the quantities of surfactant in the zeolitic rocks, the kind of surfactant, modification conditions and pH of the solutions. When the initial concentration of phenol increased, the adsorption of phenol in the surfactant-modified zeolite increased and the experimental data was best adjusted to the Langmuir model. The saturation of the columns rapidly reached high percentages.

Evidence of multi-walled carbon nanotube fragmentation induced by sonication during nanotube encapsulation via bulk-suspension polymerization.

The synthesis of multi-walled carbon nanotube/polystyrene composites, with nanotube concentrations of 0.04, 0.08 and 0.16 wt%, was carried out by in situ bulk-suspension polymerization with the assistance of sonication. By using this method both encapsulation and exfoliation of the nanotubes into the polymer host were achieved. Evidence of significant nanotube fragmentation was found by scanning electron microscopy; the cause of such fragmentation was attributed to the induction of strong cavitation due to the application of ultrasound during the synthesis. Infrared spectroscopy showed no evidence of the formation of covalent bonds between the nanotubes and the polystyrene during the process of synthesis. The thermal stability was not improved by the inclusion of the nanotubes, it was attributed to the low nanotube concentrations; however, composites glass transition temperature showed improvements.

[Neuro-Behçet: clinicopathological findings in an autopsy case]. / Neurobehçet: hallazgos clinicopatológicos de un caso de autopsia.

INTRODUCTION: Behçet's disease (BD) was first described by Hulusi Behçet in 1937 as a triad of oral aphthae, genital ulcers and uveitis. It affects most of tissues and organs without exception and has a prevalence of neurologic involvement between 5 and 30%. Histopathological research of autopsy cases is limited, even though the cause of death is confirmed in this study. CASE REPORT: A 30-years-old man without prior medical history of interest debuting with a BD with progressive neurological manifestations and fatal evolution. The autopsy showed, in gross examination, oral and scrotal ulcers. Moreover, the brain revealed a marked cerebral edema, opaque leptomeninges and hemorrhagic infarction of the left frontal lobule extended to the homolateral ventricular cavity. In the brain stem, multiples hemorrhagic infarctions and hemorrhage in the fourth ventricle. The microscopic examination showed a generalized perivascular lymphocytic and neutrophilic inflammation in small and medium vessels with intense diapedesis bleeding. This phenomenon was predominant in brain stem. CONCLUSIONS: The necropsy studies of patients with neuro-Behcet's disease are scarce. We report the clinicopathological findings in a patient with BD and neurological involvement, in which stands out a cerebral vascular affectation predominant in brain stem.