ICAR: endoscopic skull‐base surgery

n/

Pressure sores among malnourished necropsied adults - preliminary data Escaras de decúbito em adultos necropsiados com subnutrição - dados preliminares

Pressure sores are common among bedridden, elderly, or malnourished patients, and may occur in terminal ill patients because of impaired mobility, fecal or urinary incontinence, and decreased healing capacity. The aim of this study was to compare frequency of pressure sores between malnourished and non-malnourished necropsied adults. METHOD: All (n = 201) adults (age <FONT FACE="Symbol">³</font> 18 years) autopsied between 1986 and 1996 at the Teaching Hospital of Triangulo Mineiro Medical School (Uberaba) were eligible for the study. Gender, race, weight, height and main diagnoses were recorded. Ninety-six cases were excluded because of probable body water retention (congestive heart failure, hepatic insufficiency, nephrotic syndrome) or pressure sores secondary to peripheral vascular ischemia. Body mass index (BMI) was used to define malnourished (BMI < 18.5 kg/m²) and non-malnourished (BMI > 18.5kg/m²) groups. RESULTS: Except for weight (42.5kg; range: 28-57 vs. 60; 36-134.5kg) and BMI (16.9; range: 12.4-18.5 vs. 22.7; range: 18.5-54.6kg/m²), respectively, there were no statistical differences among 43 malnourished and 62 non-malnourished cases in relation to age (54.9 ± 20.4 vs. 52.9 ± 17.9 years), percentage of white persons (74.4 vs. 64.5%), male gender (76.7 vs. 69.3%) and main diagnoses. Five malnourished (11.6%) and 7 (11.5%) non-malnourished cases had pressure sores (p=0.89). CONCLUSION: Pressure sores were equally common findings in necropsied persons with protein-energy malnutrition, as assessed by body mass index.<br>Escaras de decúbito são comuns em pacientes acamados, idosos e subnutridos e podem ocorrer em pacientes terminais devido à imobilidade, incontinência fecal e urinária e imunodepressão. Além disso, a contaminação das Escaras de decúbito aumentam o risco de sepsis e podem piorar o estado nutricional. O objetivo deste estudo foi comparar a freqüência de Escaras de decúbito entre adultos necropsiados com ou sem subnutrição. MÉTODO: Adultos (n=201) necropsiados no Hospital Escola da FMTM-Uberaba entre 1986 e 1996 foram inicialmente incluídos, sendo registrados os dados demográficos e diagnósticos principais, além de peso e altura corporais. Foram excluídos os casos (n=96) com edema (insuficiência cardíaca ou hepática, síndrome nefrótica) e com úlceras de origem vascular. O indice de massa corporal (IMC = kg/m²) foi utilizado para alocação dos casos em subnutridos (IMC < 18,5kg/m²) e não-subnutridos (IMC <FONT FACE="Symbol">³</font> 18,5kg/m²). RESULTADOS: Exceto pelo peso corporal (42,5; variação: 28-57 vs 60; 36-134,5kg) e IMC (16,9; variação: 12,4-18,5 vs 22,7; variação: 18,5-54,kg/m²), respectivamente, não houve diferença estatística entre subnutridos (n=43) e não-subnutridos (n=62) em relação à idade (54,9 ± 20,4 vs 52,9 ± 17,9 anos), percentagem de pessoas brancas (74,4 vs 64,5%), do sexo masculino (76,7 vs 69,3%) e diagnósticos principais. Escaras de decúbito ocorreram em freqüência similar entre subnutridos (11,6%) e não-subnutridos (11,5%). CONCLUSÃO: Escaras de decúbito foram igualmente comuns em adultos necropsiados com ou sem subnutrição energética crônica, conforme estimada pelo índice de massa corporal

Ion mobility-mass spectrometry of a rotary ATPase reveals ATP-induced reduction in conformational flexibility.

Rotary ATPases play fundamental roles in energy conversion as their catalytic rotation is associated with interdomain fluctuations and heterogeneity of conformational states. Using ion mobility mass spectrometry we compared the conformational dynamics of the intact ATPase from Thermus thermophilus with those of its membrane and soluble subcomplexes. Our results define regions with enhanced flexibility assigned to distinct subunits within the overall assembly. To provide a structural context for our experimental data we performed molecular dynamics simulations and observed conformational changes of the peripheral stalks that reflect their intrinsic flexibility. By isolating complexes at different phases of cell growth and manipulating nucleotides, metal ions and pH during isolation, we reveal differences that can be related to conformational changes in the Vo complex triggered by ATP binding. Together these results implicate nucleotides in modulating flexibility of the stator components and uncover mechanistic detail that underlies operation and regulation in the context of the holoenzyme

Structure of the vacuolar-type ATPase from Saccharomyces cerevisiae at 11-Å resolution

Vacuolar-type ATPases (V-type ATPases) in eukaryotic cells are large membrane protein complexes that acidify various intracellular compartments. The enzymes are regulated by dissociation of the V(1) and V(O) regions of the complex. Here we present the structure of the Saccharomyces cerevisiae V-type ATPase at 11-Å resolution by cryo-EM of protein particles in ice. The structure explains many cross-linking and protein interaction studies. Docking of crystal structures suggests that inhibition of ATPase activity by the dissociated V(1) region involves rearrangement of the N- and C-terminal domains of subunit H and also suggests how this inhibition is triggered upon dissociation. We provide support for this model by demonstrating that mutation of subunit H to increase the rigidity of the linker between its two domains decreases its ability to inhibit ATPase activity.We thank V. Kanelis for advice on rigidifying the subunit H linker region and V. Kanelis, P. Rosenthal, E. Kunji and R. Henderson for discussions and a critical reading of this manuscript. Computations were done on the general-purpose cluster supercomputer at the SciNet High Performance Computing Consortium. J.L.R. was supported by a New Investigator Award from the Canadian Institutes of Health Research (CIHR) and an Early Researcher Award from the Ontario Ministry of Research and Innovation. This research was funded by operating grant MOP 81294 to J.L.R. from the CIHR