Using a Kirschner Wire as a Stylet for the Management of a Difficult Neonatal Airway: A Case Report.

We report the successful management of a difficult airway in an extremely low birth weight neonate (700 g) using a Kirschner wire as a substitute for an endotracheal tube stylet. Several intubation attempts were unsuccessful because of the difficulty in guiding a very small and malleable tube under the epiglottis. This study highlights that every maternity hospital should be prepared to manage airways in unexpected extremely low birth weight neonates. Appropriate size equipment and protocols should be readily available.

Evans syndrome in male lupus patient: case report / Síndrome de Evans em paciente lúpico do sexo masculino: relato de caso

ABSTRACT Evans syndrome (ES) is a rare autoimmune disease of unknown etiology. ES occurs when there is a combination of autoimmune hemolytic anemia (AIHA) with thrombocytopenia, whether or not accompanied by immune neutropenia. This syndrome fits into a special variable type of warm AHAI and may be related to rheumatic diseases, such as systemic lupus erythematosus (SLE). Its pathogenesis is still far away to be fully understood. Direct Coombs test results are positive in 98% of cases. ES treatment is required when the anemia due to hemolysis is intense, and corticotherapy is recommended initially. In refractory cases, splenectomy or rituximab therapy, as well as other immunosuppressants, such as azathioprine, may be used. In this study, we present the case of a 45-year-old patient, male, who was diagnosed with ES associated with active SLE. The patient was admitted to the emergency room presenting severe hemolytic anemia and onset of thrombocytopenia. He was treated with intravenous corticosteroid therapy, followed by azathioprine.

RESUMEN El síndrome de Evans (SE) es una enfermedad autoinmune rara de etiología desconocida; ocurre cuando hay combinación de anemia hemolítica autoinmune (AHAI) con trombocitopenia, acompañada o no de neutropenia inmune. Ese síndrome es un tipo variable especial de AHAI por anticuerpos calientes que puede se relacionar a enfermedades reumatológicas, como el lupus eritematoso sistémico (LES). Su patogénesis es aún compleja. La prueba de Coombs directa es positiva en 98% de los casos. El tratamiento del SE es necesario cuando la anemia secundaria a hemólisis es intensa, siendo indicado inicialmente el uso de corticosteroides. En casos refractarios se recomienda una esplenectomía o terapia con rituximab, además de otros inmunosupresores, como la azatioprina. En este trabajo, reportamos el caso de un paciente de 45 años, varón, que tuvo el diagnóstico de SE asociado a LES activo. Él fue admitido en la sala de urgencias con cuadro de anemia hemolítica severa y plaquetopenia. Fue tratado con corticoides por vía intravenosa, seguidos de azatioprina.

RESUMO A síndrome de Evans (SE) é uma doença autoimune rara de etiologia desconhecida; ocorre quando há combinação de anemia hemolítica autoimune (AHAI) com trombocitopenia, acompanhada ou não de neutropenia imune. Essa síndrome se enquadra em um tipo variável especial da AHAI a quente, podendo se relacionar com doenças reumatológicas, como lúpus eritematoso sistêmico (LES). Sua patogênese ainda é complexa. O Coombs direto é positivo em 98% dos casos. O tratamento da SE é necessário quando a anemia secundária à hemólise é intensa, sendo indicado inicialmente o uso de corticosteroides. Em casos refratários, pode-se optar pela esplenectomia ou terapia com rituximab, além de outros imunossupressores, como a azatioprina. Neste trabalho, relatamos o caso de um paciente de 45 anos, sexo masculino, com diagnóstico de SE associada a LES ativo. Foi admitido no pronto-socorro com quadro de anemia hemolítica severa e surgimento de plaquetopenia. O paciente foi tratado com corticoterapia intravenosa, seguida de azatioprina.

Thrombotic thrombocytopenic purpura: a case report / Púrpura trombocitopênica trombótica: relato de caso

ABSTRACT Thrombocytopenic thrombotic purpura (TTP) is a severe hemorrhagic syndrome characterized by thrombocytopenia, microangiopathic hemolytic anemia and microvascular occlusion, besides the associated symptoms that may or may not be present: fever, neurological and renal impairment. The pathophysiology involves the autoimmune or genetic deficiency of a metalloproteinases activity (ADAMTS-13), responsible for the von Willebrand Factor cleavage. The treatment is based on plasmapheresis; and in acute or recurrent cases, corticosteroids and immunosuppressants are associated. In this article, we will discuss a case report about this disease, initially treated in the Emergency Room and followed in the Intensive Care Unit of a public reference hospital in São Paulo city, Brazil. All clinical diagnostic criteria were completely filled, facilitating the therapeutic approach of the patient. The report evidences that rapid intervention when made early diagnosis evolves with a good prognosis, and this pathology must be present as a differential diagnosis in the medical routine.

RESUMO Púrpura trombocitopênica trombótica (PTT) é uma síndrome hemorrágica grave caracterizada por trombocitopenia, anemia hemolítica microangiopática e oclusão microvascular, bem como por sintomas associados que podem ou não estar presentes, como febre, comprometimento neurológico variável e comprometimento renal. A fisiopatologia implicada na doença envolve a deficiência, seja por inibição autoimune ou defeito genético, seja pela atividade de uma metaloproteinase (ADAMTS-13), responsável pela clivagem de multímeros do fator de von Willebrand (FvW). O tratamento consiste na plasmaférese e, em casos agudos graves ou recorrentes, associa-se a corticoterapia e imunossupressores. Neste artigo, abordaremos um relato de caso sobre essa doença, cuja paciente foi atendida inicialmente em pronto-socorro, sendo em seguida internada em uma unidade de terapia intensiva (UTI) de um hospital público de referência da cidade de São Paulo, Brasil. Todos os critérios clínicos diagnósticos foram completamente preenchidos, facilitando a abordagem terapêutica da paciente. O relato evidencia que a rápida intervenção, quando se faz o diagnóstico precoce, evolui com bom prognóstico, devendo esta patologia estar presente como diagnóstico diferencial no cotidiano médico.

Acyl hydrolases from trans-AT polyketide synthases target acetyl units on acyl carrier proteins.

Acyl hydrolase (AH) domains are a common feature of trans-AT PKSs. They have been hypothesised to perform a proofreading function by removing acyl chains from stalled sites. This study determines the substrate tolerance of the AH PedC for a range of acyl-ACPs. Clear preference towards short, linear acyl-ACPs is shown, with acetyl-ACP the best substrate. These results imply a more targeted housekeeping role for PedC: namely the removal of unwanted acetyl groups from ACP domains caused by erroneous transfer of acetyl-CoA, or possibly by decarboxylation of malonyl-ACP.

Insights into the structure and assembly of the Bacillus subtilis clamp-loader complex and its interaction with the replicative helicase.

The clamp-loader complex plays a crucial role in DNA replication by loading the ß-clamp onto primed DNA to be used by the replicative polymerase. Relatively little is known about the stoichiometry, structure and assembly pathway of this complex, and how it interacts with the replicative helicase, in Gram-positive organisms. Analysis of full and partial complexes by mass spectrometry revealed that a hetero-pentameric τ3-δ-δ' Bacillus subtilis clamp-loader assembles via multiple pathways, which differ from those exhibited by the Gram-negative model Escherichia coli. Based on this information, a homology model of the B. subtilis τ3-δ-δ' complex was constructed, which revealed the spatial positioning of the full C-terminal τ domain. The structure of the δ subunit was determined by X-ray crystallography and shown to differ from that of E. coli in the nature of the amino acids comprising the τ and δ' binding regions. Most notably, the τ-δ interaction appears to be hydrophilic in nature compared with the hydrophobic interaction in E. coli. Finally, the interaction between τ3 and the replicative helicase DnaB was driven by ATP/Mg(2+) conformational changes in DnaB, and evidence is provided that hydrolysis of one ATP molecule by the DnaB hexamer is sufficient to stabilize its interaction with τ3.

Evidence for the preservation of native inter- and intra-molecular hydrogen bonds in the desolvated FK-binding protein·FK506 complex produced by electrospray ionization.

It is now well established that electrospray ionization (ESI) is capable of introducing noncovalent protein assemblies into a desolvated environment, thereby allowing their analysis by mass spectrometry. The degree to which native interactions from the solution phase are preserved in this environment is less clear. Site-directed mutagenesis of FK506-binding protein (FKBP) has been employed to probe specific intra- and inter-molecular interactions within the complex between FKBP and its ligand FK506. Collisional activation of wild-type and mutant-FKBP•FK506 ions, generated by ESI, demonstrated that removal of native protein-ligand interactions formed between residues Asp37, Tyr82, and FK506 significantly destabilized the complex. Mutation of Arg42 to Ala42, or Tyr26 to Phe26 also resulted in lower energy dissociation of the FKBP·FK506 complex. Although these residues do not form direct H-bonds to FK506, they interact with Asp37, ensuring its correct orientation to associate with the ligand. Comparison with solution-based affinity measurements of these mutants has been discussed, including the stabilization afforded by ordered water molecules. Ion mobility spectrometry (IMS) has been employed to provide gas-phase structural information on the unfolding of the complexes. The [M + 6H](6+) complexes of the wild-type and mutants have been shown to resist unfolding and retain compact conformations. However, removal of the basic Arg42 residue was found to induce significant structural weakening of the [M + 7H](7+) complex when raised to dissociation-level energies. Overall, destabilization of the FKBP·FK506 complex, resulting from targeted removal of specific H-bonds, provides evidence for the preservation of these interactions in the desolvated wild-type complex.

Structural insights into dissimilatory sulfite reductases: structure of desulforubidin from desulfomicrobium norvegicum.

Dissimilatory sulfite reductases (dSiRs) are crucial enzymes in bacterial sulfur-based energy metabolism, which are likely to have been present in some of the earliest life forms on Earth. Several classes of dSiRs have been proposed on the basis of different biochemical and spectroscopic properties, but it is not clear whether this corresponds to actual physiological or structural differences. Here, we describe the first structure of a dSiR from the desulforubidin class isolated from Desulfomicrobium norvegicum. The desulforubidin (Drub) structure is assembled as α(2)ß(2)γ(2), in which two DsrC proteins are bound to the core [DsrA](2)[DsrB](2) unit, as reported for the desulfoviridin (Dvir) structure from Desulfovibrio vulgaris. Unlike Dvir, four sirohemes and eight [4Fe-4S] clusters are present in Drub. However, the structure indicates that only two of the Drub coupled siroheme-[4Fe-4S] cofactors are catalytically active. Mass spectrometry studies of purified Drub and Dvir show that both proteins present different oligomeric complex forms that bind two, one, or no DsrC proteins, providing an explanation for conflicting spectroscopic and biochemical results in the literature, and further indicating that DsrC is not a subunit of dSiR, but rather a protein with which it interacts.