RESUMO
Metastasis to the pituitary gland is a very rare occurrence. The most common primary cancer that metastasizes to the pituitary are breast cancer and lung cancer. Most of the pituitary metastases are asymptomatic. The most commonly reported symptoms include anterior pituitary dysfunction, visual field defects, headaches, and diabetes insipidus. Metastasis from renal cell carcinoma (RCC) is very rare. Here, we present the case of a 59-year-old male who presented with vision changes, fatigue, low libido, a low appetite, and excessive thirst. The hormonal evaluation was consistent with panhypopituitarism, and he was started on hydrocortisone, levothyroxine, testosterone, and desmopressin. Brain MRI showed a suprasellar enhancing mass that progressively increased in size. He underwent endoscopic endonasal transplanum and transtuberculum approach for tumor removal. Biopsy of the tumor was reported as metastatic RCC. He was later scheduled for a gamma knife. Metastatic RCC to pituitary is rare, with most being asymptomatic, leading to a delay in diagnosis. Treatment of pituitary metastases is not standardized and should be tailored to patients' clinical conditions, histology, and the presence of extrapituitary metastases. More prospective studies are needed to formulate guidelines for the management of pituitary metastases.
RESUMO
Langerhans cell histiocytosis (LCH) is a rare disorder involving an abnormal clonal proliferation of precursor cells of the mononuclear phagocytic system. The hypothalamic-pituitary axis is commonly affected by central nervous system (CNS) involvement, with central diabetes insipidus being the most common endocrine abnormality observed. We report the case of a 55-year-old female presenting with vision changes and found to have a hypothalamic mass that was responsive to high-dose steroids. After an initial diagnostic dilemma, the surgical pathology eventually confirmed the diagnosis of LCH. She is being treated with hormone supplementation for panhypopituitarism and intensity-modulated radiation therapy (IMRT) for the LCH. Our case highlights that LCH can present as isolated hypothalamic-pituitary involvement. Early diagnosis is critical to prevent extensive progression of the disease, ultimately leading to permanent physical and endocrine abnormalities. More studies are required to develop specific guidelines and approaches for patients with isolated hypothalamic-pituitary involvement due to LCH.
RESUMO
Humoral hypercalcemia of malignancy (HHM) comprises the majority of cases with malignancy-related hypercalcemia and is mediated by elevated parathyroid hormone-related peptide (PTHrP). HHM is rare in cholangiocarcinoma and has been reported only in a few case reports and series. We report a case of a 63-year-old male with a history of locally advanced fibroblast growth factor receptor (FGFR) fusion-positive intrahepatic cholangiocarcinoma who presented with recurrent HHM. The first episode of his hypercalcemia occurred 15 months after the initial diagnosis of cholangiocarcinoma and coincided with disease progression. The hypercalcemia was treated with zoledronic acid, and an FGFR inhibitor was started for the treatment of his malignancy. The second hypercalcemia episode occurred nine months later, with evidence of further disease progression. HHM is associated with poor clinical outcomes; a high index of suspicion should be present to identify and treat this complication in cases of cholangiocarcinoma promptly. With an increased understanding of the molecular alterations underlying cholangiocarcinoma, it will also be necessary to further evaluate its co-occurrence with HHM as the specific molecular alterations in this setting could lay the groundwork for targeted therapies and improve risk stratification for these patients.
RESUMO
Viral quasispecies are distinct but closely related mutants formed by the disparity in viral genomes due to recombination, mutations, competition, and selection pressure. Theoretical derivation for the origin of a quasispecies is owed to the error-prone replication by polymerase and mutants of RNA replicators. Here, we briefly addressed the theoretical and mathematical origin of quasispecies and their dynamics. The impact of quasispecies for major salient human pathogens is reviewed. In the current global scenario, rapid changes in geographical landscapes favor the origin and selection of mutants. It comes as no surprise that a cauldron of mutants poses a significant risk to public health, capable of causing pandemics. Mutation rates in RNA viruses are magnitudes higher than in DNA organisms, explaining their enhanced virulence and evolvability. RNA viruses cause the most devastating pandemics; for example, members of the Orthomyxoviridae family caused the great influenza pandemic (1918 flu or Spanish flu), the SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome) outbreak, and the human immunodeficiency viruses (HIV), lentiviruses of the Retroviridae family, caused worldwide devastation. Rapidly evolving RNA virus populations are a daunting challenge for the designing of effective control measures like vaccines. Developing awareness of the evolutionary dispositions of RNA viral mutant spectra and what influences their adaptation and virulence will help curtail outbreaks of past and future pathogens.
RESUMO
A 22-year-old female presented with unexplained, non-specific, constitutional symptoms of fever, chills, rigors, and headaches of more than two-week duration. An extensive workup was done that included labs, imaging, and a liver biopsy. On examination, lymphadenopathy was found, with worsening transaminitis on labs. She was ultimately found to be hepatitis E positive. The disease was self-limited with subsidence of all symptoms with only symptomatic treatment. Hepatitis E virus infection can be a missed diagnosis as it is not common in the United States. An indicated differential diagnosis can save an extensive workup and prevent delayed diagnosis for a patient.
RESUMO
Non-alcoholic steatohepatitis (NASH) is a chronic and progressive form of non-alcoholic fatty liver disease. Its global incidence is increasing and makes NASH an epidemic and a public health threat. Non-alcoholic fatty liver disease is associated with major morbidity and mortality, with a heavy burden on quality of life and liver transplant requirements. Due to repeated insults to the liver, patients are at risk for developing hepatocellular carcinoma. The progression of NASH was initially defined according to a two-hit model involving an initial development of steatosis, followed by a process of lipid peroxidation and inflammation. In contrast, current evidence proposes a "multi-hit" or "multi-parallel hit" model that includes multiple pathways promoting progressive fibrosis and oncogenesis. This model includes multiple cellular, genetic, immunological, metabolic, and endocrine pathways leading to hepatocellular carcinoma development, underscoring the complexity of this disease.
Assuntos
Carcinoma Hepatocelular/epidemiologia , Cirrose Hepática/epidemiologia , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Animais , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/virologia , Modelos Animais de Doenças , Progressão da Doença , Humanos , Inflamação/epidemiologia , Inflamação/patologia , Inflamação/virologia , Peroxidação de Lipídeos/fisiologia , Fígado/patologia , Fígado/virologia , Cirrose Hepática/patologia , Cirrose Hepática/virologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/virologia , Hepatopatia Gordurosa não Alcoólica/patologia , Hepatopatia Gordurosa não Alcoólica/virologiaRESUMO
This study reports the facile synthesis of highly photoactive TiO2@C core@shell nanocomposites through a single alkoxide precursor. TiO2 and carbon-based hybrid nanomaterials are popular photocatalysts owing to their abundance, low toxicity, and high stability, making them strong candidates for practical solar water-treatment applications. However, synthesis of such nanomaterials is often a multi-step process and requires careful control of the external carbon source for producing the desired morphology. In this regard, this study reports the synthesis of well-dispersed TiO2@C nanocomposites without the need of an external carbon source. The resulting photocatalyst was employed for treatment of various water-borne pollutants including several dyes, pharmaceuticals, and pathogens. Rapid mineralization of pollutants could be achieved even with low amounts of catalyst, with the performance well exceeding that of pristine TiO2 and P25 Degussa. Results indicate that incorporation of C increases visible-light absorption and greatly improves the separation of photogenerated charge carriers. Given the facile synthesis and the wide scope of operation, the proposed catalyst could be a significant step towards practical photocatalytic solar water-treatment.
RESUMO
This article aims to propose a cantilever based cooling device employing non-axis symmetric placement of bulk ferroelectric patches. Ambient mechanical vibrations produce large stresses in cantilevers resulting in elastocaloric effect associated with ferroelectrics. Further, design allows cascading of several cantilevers to achieve large cooling response. A finite element analysis of the system was performed using material properties of bulk 0.50Ba(Zr0.2Ti0.8)O3-0.50(Ba0.7Ca0.3)TiO3. An individual element could produce a peak elastocaloric effect of 0.02 K (324 K); whereas the proposed system could achieve a temperature drop of 0.2 K within 50 seconds (10 elements, 1.5 Hz). Furthermore, net cooling can be further improved about ~2 K (using 10 cantilevers) for a starting temperature of 358 K. This study shows that elastocaloric effect in ferroelectric materials is capable of converting waste mechanical vibration into refrigeration effect which is not reported so far.
RESUMO
Ag3PO4 photocatalyst has attracted interest of the scientific community in recent times due to its reported high efficiency for water oxidation and dye degradation. However, Ag3PO4 photo-corrodes if electron accepter such as AgNO3 is not used as scavenger. Synthesis of efficient Ag3PO4 followed by a simple protocol for regeneration of the photocatalyst is therefore a prerequisite for practical application. Herein, we present a facile method for the synthesis of a highly efficient Ag3PO4, whose photocatalytic efficiency was demonstrated using 3 different organic dyes: Methylene Blue (MB), Methyl orange (MO) and Rhodamine B (RhB) organic dyes for degradation tests. Approximately, 19 % of Ag3PO4 is converted to Ag0 after 4.30 hours of continuous UV-Vis irradiation in presence of MB organic dye. We have shown that the Ag/Ag3PO4 composite can be rejuvenated by a simple chemical oxidation step after several cycles of photocatalysis tests. At an optimal pH of 6.5, a mixture of cubic, rhombic dodecahedron, nanosphere and nanocrystals morphologies of the photocatalyst was formed. H2O2 served as the chemical oxidant to re-insert the surface metallic Ag into the Ag3PO4 photocatalyst but also as the agent that can control morphology of the regenerated as-prepared photocatalyst without the need for any other morphology controlling Agent (MCA). Surprisingly, the as- regenerated Ag3PO4 was found to have higher photocatalytic reactivity than the freshly made material and superior at least 17 times in comparison with the conventional Degussa TiO2, and some of TiO2 composites tested in this work.
RESUMO
With an ever increasing dependence on electrical energy for powering modern equipment and electronics, research is focused on the development of efficient methods for the generation, storage and distribution of electrical power. In this regard, the development of suitable dielectric based solid-state capacitors will play a key role in revolutionizing modern day electronic and electrical devices. Among the popular dielectric materials, anti-ferroelectrics (AFE) display evidence of being a strong contender for future ceramic capacitors. AFE materials possess low dielectric loss, low coercive field, low remnant polarization, high energy density, high material efficiency, and fast discharge rates; all of these characteristics makes AFE materials a lucrative research direction. However, despite the evident advantages, there have only been limited attempts to develop this area. This article attempts to provide a focus to this area by presenting a timely review on the topic, on the relevant scientific advancements that have been made with respect to utilization and development of anti-ferroelectric materials for electric energy storage applications. The article begins with a general introduction discussing the need for high energy density capacitors, the present solutions being used to address this problem, and a brief discussion of various advantages of anti-ferroelectric materials for high energy storage applications. This is followed by a general description of anti-ferroelectricity and important anti-ferroelectric materials. The remainder of the paper is divided into two subsections, the first of which presents various physical routes for enhancing the energy storage density while the latter section describes chemical routes for enhanced storage density. This is followed by conclusions and future prospects and challenges which need to be addressed in this particular field.