Variable Interfacial Water Nanosized Arrangements Measured by Atomic Force Microscopy.

While there seems to be broad agreement that cluster formation does exist near solid surfaces, its presence at the liquid/vapor interface is controversial. We report experimental studies we have carried out on interfacial water attached on hydrophobic and hydrophilic surfaces. Nanosized steps in the measured force vs distance to the surface curves characterize water cluster profiles. An expansion of the interfacial structure with time is observed; the initial profile extent is typically ∼1 nm, and for longer times expanded structures of ∼70 nm are observed. Our previous results showed that the interfacial water structure has a relative permittivity of ε ≈ 3 at the air/water interface homogeneously increasing to ε ≈ 80 at 300 nm inside the bulk, but here we have shown that the interfacial dielectric permittivity may have an oscillating profile describing the spatial steps in the force vs distance curves. This low dielectric permittivity arrangements of clusters extend the region with ε ≈ 3 inside bulk water and exhibit a behavior similar to that of water networks that expand in time.

Revalidação do painel sorológico destinado a avaliação de kits para o diagnóstico sorológico do HIV / Revalidation of the positive serological panel intended for the quality control of kits for HIV serological diagnosis

Introdução:Os kits empregados no diagnóstico do vírus da imunodeficiência humana (HIV) devem cumprir requisitos da RDC n° 36, de 26 de agosto de 2015, para registro junto à Agência Nacional de Vigilância Sanitária e da Lei n° 6.360, de 23 de setembro de 1976, para comercialização no país. Uma das etapas do registro é a análise prévia laboratorial dos produtos de maior classe de risco (classe IV), realizada pelo Laboratório de Sangue e Hemoderivados (LSH). Na análise dos produtos são utilizados painéis sorológicos constituídos de amostras verdadeiro positivas como principal ferramenta na avaliação de sensibilidade. Objetivo: Revalidar painel sorológico verdadeiro positivo para HIV, destinado à avaliação de kits de diagnóstico in vitro do HIV. Método: Foram realizadas a avaliação retrospectiva e a seleção dos resultados do painel frente aos kits recebidos para análise prévia de janeiro de 2010 a dezembro de 2011 que obtiveram resultado satisfatório. Foi utilizado como critério de revalidação a reatividade das amostras do painel em três ensaios imunoenzimáticos (ELISA), em três ensaios de quimiluminescência (CLIA), em três ensaios imunocromatográfcos (testes rápidos) e em três western blot; e reatividade em um ensaio enzimático fluorescente ligado à enzima (ELFA), além do volume igual ou superior a 1 mL. Resultados: No período foram recebidos para análise no LSH 73 kits para diagnóstico in vitro da infecção pelo HIV, sendo 47 (64,4%) satisfatórios, assim distribuídos: 43,0% (20/47) ELISA, 34,0% (16/47) ensaios imunocromatográfcos, 13,0% (06/47) western blot, 2,0% (01/47) ELFA e 8,0% (04/47) ensaios de quimiluminescência. Após a avaliação, 77,0% (34/44) das unidades foram revalidadas, sendo excluídas do painel 23,0% (10/44), pois não alcançaram os critérios estabelecidos. Conclusões: O painel revalidado atualmente é composto por 34 unidades de amostras verdadeiro positivas, com resultados consistentes, aumentando, assim, a confiabilidade e a segurança das análises realizadas e dos testes comercializados no país.

Introduction: Kits used in the diagnosis of the human immunodefciency virus (HIV) must meet the requirements of RDC No. 36, of August 26, 2015 for registration with the National Health Surveillance Agency and Law No. 6.360, of September 23 1976 for commercialization in the country. One of the registration steps corresponds to the previous laboratory analysis of the products with the highest risk class (class IV), carried out by the Laboratory of Blood and Blood Products (LSH). In the analysis of the products, serological panels consisting of true positive samples are used as the main tool in the sensitivity assessment. Objective: To revalidate a true HIV positive serological panel for the evaluation of in vitro HIV diagnostic kits. Method: A retrospective evaluation and selection of the panel results was performed against the kits that obtained satisfactory results and were received for prior analysis from January 2010 to December 2011. The reactivity of the panel samples in three immunoenzymatic assays (ELISA), in three chemiluminescence assays (CLIA), in three immunochromatographic assays (rapid tests) and in three western blots was used as revalidation criterion; and reactivity in an enzyme-linked fluorescent enzyme assay (ELFA), in addition to a volume equal to or greater than 1 mL. Results: During the period, 73 kits for in vitro diagnosis of HIV infection were received for analysis at the LSH, 47 (64.4%) of which were satisfactory, distributed as follows: 43.0% (20/47) ELISA, 34.0% (16/47) immunochromatographic assays, 13.0% (06/47) western blot, 2.0% (01/47) ELFA, 8.0% (04/47) chemiluminescence assays. After the evaluation, 77.0% (34/44) of the units were revalidated, and 23.0% (10/44) were excluded from the panel, as they did not meet the established criteria. Conclusions: The revalidated panel currently consists of 34 units of true positive samples, with consistent results, thus increasing the reliability and safety of the analyses carried out and of the tests marketed in the country.

Hydrated excess protons and their local hydrogen bond transport network as measured by translational, librational, and vibrational frequencies.

A clear molecular description of excess hydrated protons and their local hydrogen bond transport network remains elusive. Here, the hydrogen bond network of excess hydrated protons in water bridges was probed by measuring their Raman spectra and comparing them to the spectra of protons in ice and water. The proton vibrational spectrum and the hydrogen bond network translational and librational spectra were recorded. The spectra of the water bridge and water exhibit clear differences, indicating the presence of a structure in water bridges when subjected to an electric field of ∼106 V/m that has not been previously reported. The intermolecular Raman spectrum of the floating water bridge exhibits a hydrogen bond stretching band at 150-250 cm-1, librational bands within the 300-1000 cm-1 spectral range, and a large band at 1500-3000 cm-1, which corresponds to the vibrational signature of excess hydrated protons in the water bridge structure. The excess protons are shown to move predominantly at the air/water interface, and the effect of this distribution is a measurable change in the air/water interfacial tension from ∼80 to ∼32 N/m. Therefore, hydrated protons must have a unique water arrangement that enables them to propagate without sinking into bulk water. This local polarized hydrogen bond network in the interfacial water region is characterized by a translational spectrum similar to that of ice V.

Pregnancy favors the expansion of circulating functional follicular helper T Cells.

Pregnancy favors antibody production, and some evidence has suggested a direct effect of estrogen on B cells. The impact of pregnancy on circulating follicular helper T (TFH) cells, typically identified by the expression of CD45RO and CXCR5, has not been previously investigated. Here, the percentage of TFH cells, co-expressing or not PD-1, ICOS, or CXCR3 markers was significantly higher in pregnant women (PW) as compared with non-pregnant ones (nPW). Furthermore, the percentage of CXCR3+ TFH cells able to produce IL-6, IL-21, and IL-10 was significantly higher in PW than nPW. Interestingly, anti-CMV and anti-HBs antibody titers were significantly higher in the plasma of PW and were directly correlated with IL-21-producing CXCR3+ TFH cells. Finally, peripheral estrogen levels, but not progesterone, were positively related to either PD-1+ CXCR3+ TFH cells or plasma anti-CMV and anti-HBs IgG antibodies. In summary, our data suggests a positive effect of pregnancy on the proportion of CD4+ T cell subset specialized in helping B cells. This phenomenon, which could be related to the high estrogen levels produced during pregnancy, may help to explain why pregnancy favor humoral immunity.

The proportion of different interleukin-17-producing T-cell subsets is associated with liver fibrosis in chronic hepatitis C.

Studies have suggested the pivotal role of T helper type 1 (Th1) -related cytokines on the outcome of hepatitis C virus (HCV) infection. Nevertheless, the role of different interleukin-17 (IL-17) -secreting T cells on chronic hepatitis C (CHC) is less clear. Here, the in vivo IL-1ß, IL-6, and IL-17 levels were positively correlated with both alanine transaminase (ALT) levels and hepatic lesions. When compared with the control group, CHC patients showed a lower proportion of IL-17-secreting (CD4+ and CD8+ ) T cells capable of simultaneously producing IL-21. Moreover, the percentage of IL-10-secreting Th17 cells was also lower in CHC patients. Notably, advanced liver lesions were observed among those patients with lower percentage levels of IL-17-producing T cells positive for IL-21, interferon-γ (IFN-γ) and IL-10. In contrast, the severity of hepatic damage was associated with peripheral single IL-17+ T cells. The percentage of IL-17+ IL-21- IFN-γ+ (CD4+ and CD8+ ) T-cell phenotypes was positively associated with plasma CD14 levels. Finally, elevated levels of circulating CD14 were detected among CHC patients with extensive liver damage. In summary, although preliminary, our results suggest that a balance between different IL-17-producing T cells, associated with peripheral levels of CD14, may be a progress marker for liver disease in chronically HCV-infected patients.

Insuficiência renal aguda secundária a acidentes ofídicos botrópico e crotálico: análise de 63 casos / Acute renal insuficiency secondary to ophidian bothropic and crotalic accidents

Sessenta e três pacientes com insuficiência renal aguda secundária a acidente ofídico foram tratados no CTI do Hospital das Clínicas da UFMG. Em 32 pacientes (51%) o acidente foi produzido por serpentes do gênero Bothrops (grupo botrópico) e em 32 pacientes (49%) pela cascavel sul-americana (grupo crotálico). As principais complicaçöes apresentadas pelos pacientes foram a uremia (100%) dos casos), hiperpotassemia (89% dos casos), anemia (78% dos casos), infecçäo urinária (37% dos casos), hiper-hidrataçäo (17% dos casos), parada cardíaca (14% dos casos) e edema agudo dos pulmöes (11% dos casos). Cinco pacientes do grupo crotálico (16%) tiveram insuficiência respiratória aguda atribuída à açäo neurotóxica do veneno,quatro dos quais se recuperaram completamente. Sete pacientes do grupo botrópico (22%) tiveram necrose cortical renal diagnosticada em cinco através da biópsia renal e em dois na necrópsia. Quarenta e cinco pacientes (71%) foram tratados com diálise peritoneal e a hemodiálise foi necessária em dois pacientes, um dos quais havia sido submetido a diálise peritoneal. Em 17 pacientes (27%) o tratamento foi conservador. Cinqüenta e cinco pacientes receberam alta hospitalar, quatro dos quais com insuficiência renal crônica secundária a necrose cortical renal e oito (13%) faleceram. Os óbitos foram atribuídos a edema pulmonar agudo em quatro pacientes, a estado de choque em dois pacientes e a coma e infecçäo respiratória após parada cardíaca em dois pacientes

Insuficiência renal aguda associada à rabdomiólise de etiologia näo traumática: relato de um caso / Acute renal failure associated with non-traumatic rhabdomyolysis: a case report

Relata-se o caso de um paciente com insuficiência renal aguda (IRA) associada à rabdomiólise de etiologia näo traumática. O diagnóstico de rabdomiólise baseou-se na intensa mialgia e edema muscular apresentados pelo paciente, na reaçäo de ortotoluidina positiva na urina constataçäo de níveis séricos elevados de CPK, TGO, TGP e LDH, sendo confirmado através de biópsia muscular. O diagnóstico de IRA baseou-se na instalaçäo de oligúria acompanhada de elevaçäo progressiva dos níveis plasmáticos de uréia e creatinina. A IRA foi atribuída à rabdomiólise associada à hipovolemia e acidose metabólica. Além de complicaçöes como a anemia e acidose metabólica, o paciente apresentou, na fase oligúrica, hiperpotassemia grave e hipocalcemia relacionadas à extensäo da necrose muscular. O paciente foi tratado com diálise peritoneal, tendo apresentado recuperaçäo da funçäo renal. Os fatores etiológicos de rabdomiólise identificados foram o alcoolismo crônico e o traço falciforme. Nove meses após o episódio agudo, o paciente apresentava evidências clínico-laboratoriais compatíveis com persistência de lesäo muscular