Positron emission tomography in the detection of occult primary head and neck carcinoma: a retrospective study

BACKGROUND: The management of cervical lymph node metastases from an unknown primary tumor remains a controversial subject. Recently, Positron Emission Tomography (PET) has proved useful in the detection of these tumors, even after an unsuccessful conventional diagnostic workup. This study was performed to assess the role of PET in the detection of occult primary head and neck carcinomas. METHODS: A retrospective analysis of a four year period at a tertiary referral oncology hospital was conducted. RESULTS: Of the 49 patients with cervical metastases of carcinoma from an unknown primary, PET detected a primary in 9 patients and gave 5 false positive and 4 false negative results. Detection rate, sensitivity, specificity and accuracy were of 18.4%, 69.2%, 86.1% and 81.6%, respectively. PET was also of substantial benefit in detecting distant metastatic disease and, thus, altered therapeutic strategies in a significant amount of patients. CONCLUSIONS: Therefore, PET is a valuable tool in the management of patients with occult primary head and neck carcinoma, not only because it provides additional information as to the location of primary tumors, but also due to the fact that it can detect unexpected distant metastase

Pharmacological potential of methylxanthines: Retrospective analysis and future expectations

Methylated xanthines (methylxanthines) are available from a significant number of different botanical species. They are ordinarily included in daily diet, in many extremely common beverages and foods. Caffeine, theophylline and theobromine are the main methylxanthines available from natural sources. The supposedly relatively low toxicity of methylxanthines, combined with the many beneficial effects that have been attributed to these compounds through time, generated a justified attention and a very prolific ground for dedicated scientific reports. Methylxanthines have been widely used as therapeutical tools, in an intriguing range of medicinal scopes. In fact, methylxanthines have been/were medically used as Central Nervous System stimulants, bronchodilators, coronary dilators, diuretics and anti-cancer adjuvant treatments. Other than these applications, methylxanthines have also been hinted to hold other beneficial health effects, namely regarding neurodegenerative diseases, cardioprotection, diabetes and fertility. However, it seems now consensual that toxicity concerns related to methylxanthine consumption and/or therapeutic use should not be dismissed. Taking all the knowledge and expectations on the potential of methylxanthines into account, we propose a systematic look at the past and future of methylxanthine pharmacologic applications, discussing all the promise and anticipating possible constraints. Anyways, methylxanthines will still substantiate considerable meaningful research and discussion for years to come.info:eu-repo/semantics/publishedVersio

Dirac fermions on wires confined to the graphene Moebius strip

We investigate the effects of the curved geometry on a massless relativistic electron constrained to a graphene strip with a Moebius strip shape. The anisotropic and parity-violating geometry of the Moebius band produces a geometric potential that inherits these features. By considering wires along the strip width and the strip length, we find exact solutions for the Dirac equation and the effects of the geometric potential on the electron were explored. In both cases, the geometric potential yields to a geometric phase on the wave function. Along the strip width, the density of states depends on the direction chosen for the wire, a consequence of the lack of axial symmetry. Moreover, the breaking of the parity symmetry enables the electronic states to be concentrated on the inner or on the outer portion of the strip. For wires along the strip length, the nontrivial topology influences the eigenfunctions by modifying their periodicity. It turns out that the ground state has a period of $4\pi$ whereas the first excited state is a $2\pi$ periodic function. Moreover, we found that the energy levels are half-integer multiples of the energy of the ground state.Comment: 27 pages, 14 captioned figures. To appear in Physical Review

Associação entre parvovírus B19 e artropatias em Belém, Pará, norte do Brasil

A total of 220 patients with arthropathy were selected in Belém, Pará between January 1994 and December 2000, and screened for the presence of human parvovirus B19 IgM and IgG antibodies by enzyme-linked immunosorbent assay (ELISA). A subgroup (n = 132) of patients with high levels of antibodies (either IgM+/IgG+ or IgM-/IgG+) were examined for the presence of DNA by polymerase chain reaction/nested PCR. Recent/active infection (detection of IgM and/or IgG-specific antibodies and presence of viral DNA) was identified in 47.7% of the 132 individuals with arthropathy. In our study, women were significantly more affected (59.7%) than men (35.4%) (P = 0.0006). The age group of 11-20 years (84.6%), among female patients, and 21-30 years (42.1%), among male, were those with the highest incidence rates. The analysis of the temporal distribution of B19-associated arthropaties showed a cyclic pattern, with peak incidence rates occuring at 3-5 year intervals. Significant diference (P = 0.01) was observed when comparing both the highest (39.0%) and the lowest (11.0%) seropositivity rates for the years of 1995 and 2000, respectively. The interfalangial joints of hands and feet were mostly affected, with 50.0% and 48.0% of cases among both women and men, respectively. In a smaller proportion, other joints such as those of knee, ankle, pulse and shoulder were affected. As for the duration, symptoms lasted 1 to 5 days in 54.0% of the individuals, whereas in 46.0% of them the disease lasted 6-10 days, if considered the subgroup (n = 63) of patients with recent/active infection by parvovirus B19. In our study, joint clinical manifestations occurred symmetrically. Our results indicate that B19 may be an important agent of arthropathies in our region, and this underscores the need for specific laboratory diagnosis when treating patients suffering from acute arthropathy, mainly pregnant women.Um total de 220 indivíduos portadores de artropatias foi selecionado em Belém, Pará, entre janeiro de 1994 e dezembro de 2000 e, posteriormente, examinado com o propósito de se detectarem anticorpos IgM e IgG para o parvovírus B19, utilizando-se a técnica imunoenzimática (ELISA). Um subgrupo (n = 132) de indivíduos com amostras de soro apresentando altos níveis de anticorpos (IgM+/IgG+ e IgM-/IgG+) foi usado para detecção de DNA do B19 através da reação em cadeia da polimerase (PCR) e do "nested" PCR. Infecção recente/ativa (detecção de IgM e/ou IgG mais a presença de DNA viral) foi diagnosticada em 47,7% dos 132 indivíduos apresentando comprometimento das articulações. O sexo feminino foi mais afetado (59,7%) que o masculino (35,4%), com diferença estatisticamente significativa (P = 0,0006). Os grupos etários mais atingidos foram os de 11-20 anos (84,6%), no sexo feminino, e 21-30 anos (42,1%), no masculino. A análise da distribuição temporal mostrou um padrão cíclico, com períodos de maior e menor atividade viral que variam de 3 a 5 anos. Diferença estatisticamente significativa (P = 0,01) foi observada quando comparadas as freqüências de positividade mais alta (39,0%) e mais baixa (11,0%) para os anos de 1995 e 2000, respectivamente. As articulações mais atingidas foram, em ordem de freqüência, as interfalangianas de mãos e pés, com 50,0% e 48,0% para o sexo feminino e masculino, respectivamente. Em menor proporção outras articulações tais como as do joelho, tornozelo, pulso e ombro foram afetadas. Quanto à duração das manifestações articulares, 54,0% evoluíram por 1-5 dias, e 46,0% ao longo de 6-10 dias, considerando o subgrupo (n = 63) de indivíduos com infecção recente/ativa para o B19 em ambos os sexos. Em nosso estudo, o comprometimento das articulações apresentou caráter simétrico. Os resultados encontrados demonstraram o freqüente acometimento articular associado às infecções recentes/ativas por parvovírus B19, ressaltando a necessidade do diagnóstico laboratorial dessa virose, principalmente entre gestantes

Being Deaf in Mainstream Schools: The Effect of a Hearing Loss in Children’s Playground Behaviors

Naturalistic playground observations are a rich source of information when studying the social interactions of preschool children. On the playground, children can interact with their peers, explore different places and activities, and engage in different types of play. For deaf and hard of hearing (DHH) children, interactions at a playground can be more difficult because of the large number of auditory stimuli surrounding them. Constraints in the access to the social world on the playground might hamper DHH children's interactions with their typically hearing (TH) peers, activities, and play. This pilot study aimed to examine the playground behaviors of preschool DHH children across three aspects: social levels, type of activities, and play choices. For this purpose, 12 preschool DHH children were observed during recess time, and their behaviors were coded and compared to their 85 TH peers. The preliminary findings indicate that DHH children spend less time in social interactions compared to their TH peers and that they still face difficulties when socially engaging with their TH peers. These findings suggest that interventions should focus on three aspects: the physical environment awareness of TH peers about communicating with DHH children, and the use of exercise play to facilitate social interactions between DHH children and their TH peers.info:eu-repo/semantics/publishedVersio

Efeito da temperatura na germinação de sementes de mororó (Bauhinia cheilantha (Bong.) Steud - Leguminosae).

O presente trabalho, desenvolvido no Laboratório de Sementes da Embrapa Semi-Árido, em Petrolina ? Pernambuco, teve por objetivo verificar a influência da temperatura na germinação de sementes de espécies forrageiras nativas de valor econômico para o semi-árido brasileiro

Efeito da temperatura na germinação de sementes de mulungu (Erythrina vellutina Wild - Leguminosae).

Com o objetivo de estudar a influência da temperatura na germinação de sementes de espécies arbóreas/arbustivas que ocorrem na caatinga, foi avaliado no Laboratório de Sementes da Embrapa Semi-Arido, lotes de sementes de mulungu (Erythrina vellutina Wild), colhido em junho de 2002, na região de Manoel Vitorino, Bahia. Foram avaliadas a porcentagem de germinação (G) e o índice de velocidade de germinação (IVG) das sementes, submetidas às temperaturas constantes de 20, 25 e 40ºC

Impact of atomic layer deposited TiO2 on the photocatalytic efficiency of TiO2/w-VA-CNT nanocomposite materials

Titanium oxide (TiO2) has been widely investigated as a photocatalytic material, and the fact that its performance depends on its crystalline structure motivates further research on the relationship between preparation methods and material properties. In this work, TiO2 thin films were grown on non- functionalized wave-like patterned vertically aligned carbon nanotubes (w-VA-CNTs) via the atomic layer deposition (ALD) technique. Grazing incidence X-ray diffraction (GIXRD) analysis revealed that the structure of the TiO2/VA-CNT nanocomposites varied from amorphous to a crystalline phase with increasing deposition temperature, suggesting a “critical deposition temperature” for the anatase crystalline phase formation. On the other hand, scanning transmission electron microscopy (STEM) studies revealed that the non-functionalized carbon nanotubes were conformally and homogeneously coated with TiO2, forming a nanocomposite while preserving the morphology of the nanotubes. X-ray photoelectron spectroscopy (XPS) provided information about the surface chemistry and stoichiometry of TiO2. The photodegradation experiments under ultraviolet (UV) light on a model pollutant (Rhodamine B, RhB) revealed that the nanocomposite comprised of anatase crystalline TiO2 grown at 200 ?C (11.2 nm thickness) presented the highest degradation efficiency viz 55% with an illumination time of 240 min. Furthermore, its recyclability was also demonstrated for multiple cycles, showing good recovery and potential for practical applications.publishe

Influência da temperatura na germinação de pau ferro (Caesalpinea ferrea Mart. Ex. Tul - Leguminosae).

O objetivo da pesquisa foi estudar a influência da temperatura na germinação de sementes de pau ferro (Caesalpinea ferrea Mart. Ex. Tul - LEGUMINOSAE), espécie do semi-árido do ambiente caatinga