395 research outputs found
Regioselective One-pot Protection and Protection-glycosylation of Carbohydrates
Deciphering the roles and structure–activity relationships of carbohydrates in biological processes requires access to sugar molecules of confirmed structure and high purity. Chemical synthesis is one of the best ways to obtain such access. However, the synthesis of carbohydrates
has long been impeded by two major challenges – the regioselective protection of the polyol moiety of each monosaccharide building block and the stereoselective glycosylation to produce oligosaccharides of desired length. Here, we review the development of the first regioselective protection-glycosylation
and a revolutionary regioselective combinatorial one-pot protection of monosaccharides that can be used to differentiate the various hydroxy groups of monosaccharides with a vast array of orthogonal protective groups in one-pot procedures
Preliminary Experience With the Use of Electromagnetic Navigation for the Diagnosis of Peripheral Pulmonary Nodules and Enlarged Mediastinal Lymph Nodes
Electromagnetic navigation is a new technique that can be
used with bronchoscopy to obtain samples of small peripheral
nodular lesions and enlarged mediastinal lymph nodes. It is
very versatile in that it enables both transbronchial biopsies
and fine-needle aspiration to be performed. We describe
2 cases in which navigation with the superDimension/
Bronchus system combined with traditional diagnostic
techniques facilitated a definitive diagnosis by bronchoscopy.
Electromagnetic navigation can obviate the need for more
invasive diagnostic procedures such as surgery, thus saving
time and money and avoiding complications
Trasplante pulmonar
A lung transplant is usually the final therapeutic
option for patients with respiratory insufficiency. In
spite of the many advances in immunology and the
management of complications, mortality and morbidity
associated with this transplant are far higher than
with others. Acute rejection is an almost universal
problem in the first year, while obliterative bronchitis
reduces long term survival. Respiratory infections
also play a significant role in the complications associated
with lung transplants due to the constant
exposure of the graft to the outside. However, the
success of this therapeutic option, which basically
depends on a suitable selection of donor and recipient,
are evident, above all with respect to quality of
life
Temporal and spatial differences of methane flux at arctic tundra in Alaska
High latitude ecosystems were thought to enhance CH_4 emission in relation to the current arctic warming. However, we have little information about this potential feedback mechanisms on climate change, thus, model parameterization is insufficient and the observational data are required. We observed CH_4 flux at several types of tundra in Alaska over the growing seasons since 1995. From these observed data, we examined current CH_4 emission and its controlling factors on Alaskan tundra. Then we discussed about spatial and temporal differences in CH_4 flux. Daily trend of half hourly CH_4 flux had little relation with soil temperature, but the seasonal trend of daily flux changed with soil or water temperature. Cumulative CH_4 fluxes during the growing seasons were 8.1gCH_4m^(-2) on wet sedge tundra at Happy Valley in 1995, 3.3gCH_4m^(-2) on non-acidic moist tundra in 1996, and 3.58-8.24gCH_4m^(-2) on wet sedge tundra at Barrow between 1999-2003. Non-acidic tundra had low CH_4 emission with low CO_2 accumulation. There was large spatial difference in CH_4 flux caused by tundra type, and the large temporal difference at the wet sedge tundra reflected yearly weather variability
An Overview of the Body Schema and Body Image: Theoretical Models, Methodological Settings and Pitfalls for Rehabilitation of Persons with Neurological Disorders
Given the widespread debate on the definition of the terms "Body Schema" and "Body Image", this article presents a broad overview of the studies that have investigated the nature of these types of body representations, especially focusing on the innovative information about these two representations that could be useful for the rehabilitation of patients with different neurological disorders with motor deficits (especially those affecting the upper limbs). In particular, we analyzed (i) the different definitions and explicative models proposed, (ii) the empirical settings used to test them and (iii) the clinical and rehabilitative implications derived from the application of interventions on specific case reports. The growing number of neurological diseases with motor impairment in the general population has required the development of new rehabilitation techniques and a new phenomenological paradigm placing body schema as fundamental and intrinsic parts for action in space. In this narrative review, the focus was placed on evidence from the application of innovative rehabilitation techniques and case reports involving the upper limbs, as body parts particularly involved in finalistic voluntary actions in everyday life, discussing body representations and their functional role
Outpatient Management of Malignant Pleural Effusion Using a Tunneled Pleural Catheter: Preliminary Experience
Inpatient management of malignant pleural effusion
includes the placement of a conventional thoracostomy tube
for drainage and talc slurry pleurodesis and/or a surgical
approach consisting of video-assisted thoracoscopic talc
insufflation. Both techniques require prolonged hospital
stays of up to 1 week. Unfortunately, life expectancy in
patients with this disease does not usually exceed 6 months,
and so the primary aim of any palliative intervention
intended to improve quality of life should be to avoid
hospital admissions and to relieve pain as far as possible.
Of the few outpatient alternatives to hospital management
the most frequently used is repeated thoracentesis. We
describe the outpatient management of malignant pleural
effusion by placement of a tunneled pleural catheter in a
patient with stage IIIB lung adenocarcinoma. In our
opinion, the use of this catheter offers a viable alternative to
conventional therapy and is better tolerated
Hyperleptinaemia, respiratory drive and hypercapnic response in obese patients
Leptin is a powerful stimulant of ventilation in rodents. In humans, resistance
to leptin has been consistently associated with obesity. Raised leptin levels
have been reported in subjects with sleep apnoea or obesity-hypoventilation
syndrome. The aim of the present study was to assess, by multivariate analysis,
the possible association between respiratory centre impairment and levels of
serum leptin. In total, 364 obese subjects (body mass index >or=30 kg.m(-2))
underwent the following tests: sleep studies, respiratory function tests,
baseline and hypercapnic response (mouth occlusion pressure (P(0.1)), minute
ventilation), fasting leptin levels, body composition and anthropometric
measures. Subjects with airways obstruction on spirometry were excluded. Out of
the 346 subjects undergoing testing, 245 were included in the current analysis.
Lung volumes, age, log leptin levels, end-tidal carbon dioxide tension,
percentage body fat and minimal nocturnal saturation were predictors for baseline
P(0.1). The hypercapnic response test was performed by 186 subjects; log leptin
levels were predictors for hypercapnic response in males, but not in females.
Hyperleptinaemia is associated with a reduction in respiratory drive and
hypercapnic response, irrespective of the amount of body fat. These data suggest
the extension of leptin resistance to the respiratory centre
Diagnostic yield of electromagnetic navigation bronchoscopy is highly dependent on the presence of a Bronchus sign on CT imaging: results from a prospective study
Electromagnetic navigation bronchoscopy (ENB) has been developed as a
novel ancillary tool for the bronchoscopic diagnosis of pulmonary nodules.
Despite successful navigation in 90% of patients, ENB diagnostic yield does not
generally exceed 70%. We sought to determine whether the presence of a bronchus
sign on CT imaging conditions diagnostic yield of ENB and might account for the
discrepancy between successful navigation and diagnostic yield. METHODS: We
conducted a prospective, single-center study of ENB in 51 consecutive patients
with pulmonary nodules. ENB was chosen as the least invasive diagnostic technique
in patients with a high surgical risk, suspected metastatic disease, or
advanced-stage disease, or in those who demanded a preoperative diagnosis prior
to undergoing curative resection. We studied patient and technical variables that
might condition diagnostic yield, including size, cause, location, distance to
the pleural surface, and fluorodeoxyglucose uptake of a given nodule; the
presence of a bronchus sign on CT imaging; registration point divergence; and the
minimum distance from the tip of the locatable guide to the nodule measured
during the procedure. RESULTS: The diagnostic yield of ENB was 67% (34/51). The
sensitivity and specificity of ENB for malignancy in this study were 71% and
100%, respectively. ENB was diagnostic in 79% (30/38) patients with a bronchus
sign on CT imaging but only in 4/13 (31%) with no discernible bronchus sign.
Univariate analysis identified the bronchus sign (P = .005) and nodule size (P =
.04) as statistically significant variables conditioning yield, but on
multivariate analysis, only the bronchus sign remained significant (OR, 7.6; 95%
CI, 1.8-31.7). No procedure-related complications were observed. CONCLUSIONS: ENB
diagnostic yield is highly dependent on the presence of a bronchus sign on CT
imaging
Análisis multiescala de las comunidades de coral hermatÃpico del PacÃfico Central Mexicano
The Mexican Central Pacific is located in a zone of oceanographic transition between two biogeographic provinces with particular conditions that affect the associated fauna. The objective of this study was to evaluate the variation of hermatypic coral assemblages in this region and to determine their relationship with the heterogeneity of the benthonic habitat and spatial variables. A total of 156 transects were carried out at 41 sites in the years 2010 and 2011. The sampling effort returned 96.7% of the coral richness expected for the area, with a total of 15 species recorded. The results showed that richness, diversity and cover of corals varied only at the site and state scales. However, the composition and coverage of all coral species, as well as the benthonic habitat structure, differed significantly across the study scales (i.e. sites, zones and states). Canonical redundancy analysis showed that variation in the richness, diversity and assemblages of corals was explained by the cover of live corals, articulated calcareous algae, sandy substrate, sponges and fleshy macroalgae. This study suggests that local scale (i.e. site) variation in the coral assemblages of the Mexican Central Pacific is the result of the heterogeneity of the benthonic habitat, while geomorphological and oceanographic characteristics play a greater role at regional scale.El PacÃfico Central Mexicano se localiza en una zona de transición oceanográfica entre dos provincias biogeográficas con condiciones ambientales particulares que afectan la fauna asociada. El objetivo del estudio fue evaluar la variación de las comunidades de coral hermatÃpico de esta región y determinar su relación con la heterogeneidad del hábitat bentónico y variables espaciales. Se realizaron 156 transectos en 41 sitios en los años 2010 y 2011. El esfuerzo de muestreo representó el 96.7% de la riqueza de coral esperada para el área, con un total de 15 especies registradas. Los resultados mostraron que la riqueza, diversidad y cobertura de corales variaron sólo en las escalas de sitio y de estado. En cambio, la composición y cobertura de todas las especies de coral, asà como la estructura del hábitat bentónico, fueron significativamente diferentes en todas las escalas estudiadas (i.e. sitio, zona y estado). Los análisis de redundancia canónica mostraron que la variación de la riqueza, diversidad y de las comunidades de corales eran explicadas por la cobertura de coral vivo, algas calcáreas articuladas, sustrato arenoso, esponjas y macroalgas carnosas. Este trabajo sugiere que la variación de las comunidades de coral en el PacÃfico Central Mexicano a escala local (i.e. sitio) se debe a la heterogeneidad del hábitat bentónico, mientras que a escala regional, las caracterÃsticas geomorfológicas y oceanográficas desempeñan un papel más importante
Emphysema presence, severity, and distribution has little impact on the clinical presentation of a cohort of patients with mild to moderate COPD
Phenotypic characterization of patients with COPD may have potential
prognostic and therapeutic implications. Available information on the
relationship between emphysema and the clinical presentation in patients with
COPD is limited to advanced stages of the disease. The objective of this study
was to describe emphysema presence, severity, and distribution and its impact on
clinical presentation of patients with mild to moderate COPD. METHODS: One
hundred fifteen patients with COPD underwent clinical and chest CT scan
evaluation for the presence, severity, and distribution of emphysema. Patients
with and without emphysema and with different forms of emphysema distribution
(upper/lower/core/peel) were compared. The impact of emphysema severity and
distribution on clinical presentation was determined. RESULTS: Fifty percent of
the patients had mild homogeneously distributed emphysema (1.84; 0.76%-4.77%).
Upper and core zones had the more severe degree of emphysema. Patients with
emphysema were older, more frequently men, and had lower FEV(1)%, higher total
lung capacity percentage, and lower diffusing capacity of the lung for carbon
monoxide. No differences were found between the clinical or physiologic
parameters of the different emphysema distributions. CONCLUSIONS: In patients
with mild to moderate COPD, although the presence of emphysema has an impact on
physiologic presentation, its severity and distribution seem to have little
impact on clinical presentation
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