Sonographic patterns of lung consolidation in mechanically ventilated patients with and without ventilator-associated pneumonia: A prospective cohort study.

PURPOSE Thoracic ultrasound (TUS) has been successfully used in the diagnosis of community-acquired pneumonia. Little is known about its diagnostic potential in ventilator-associated pneumonia (VAP). The purpose of this study was to systematically describe the morphology and temporal changes of sonographic patterns in mechanically ventilated patients and to evaluate the diagnostic performance characteristics of TUS-based VAP diagnoses. MATERIALS AND METHODS Patients who were placed on invasive ventilation for reasons other than pneumonia and who were considered at risk for the development of VAP received daily TUS examinations while being closely monitored for the development of pneumonia. RESULTS Fifty-seven patients were studied. The incidence of VAP was 21.1%. Sonographic patterns of reduced or absent lung aeration were found in 64.2% of examinations. The sonographic pattern of lung consolidation with either dynamic or static air bronchograms was 100% sensitive and 60% specific for VAP in those patients who developed clinical signs and symptoms compatible with pneumonia. The pretest and posttest probabilities were 0.38 and 0.6, respectively. CONCLUSIONS Sonographic patterns of abnormal aeration are frequently observed in mechanically ventilated patients. If sonographic lung consolidation with either static or dynamic air bronchograms is absent, VAP is highly unlikely. The presence of these sonographic patterns in patients with signs and symptoms suggestive of pneumonia significantly increases the probability of VAP.

A Logical Descriptor for Regular Languages via Stone Duality

In this paper we introduce a class of descriptors for regular languages arising from an application of the Stone duality between finite Boolean algebras and finite sets. These descriptors, called classical fortresses, are object specified in classical propositional logic and capable to accept exactly regular languages. To prove this, we show that the languages accepted by classical fortresses and deterministic finite automata coincide. Classical fortresses, besides being propositional descriptors for regular languages, also turn out to be an efficient tool for providing alternative and intuitive proofs for the closure properties of regular languages.

The Vacuolar H+-ATPase B1 Subunit Polymorphism p.E161K Associates with Impaired Urinary Acidification in Recurrent Stone Formers

Mutations in the vacuolar–type H+-ATPase B1 subunit gene ATP6V1B1 cause autosomal–recessive distal renal tubular acidosis (dRTA). We previously identified a single-nucleotide polymorphism (SNP) in the human B1 subunit (c.481G.A; p.E161K) that causes greatly diminished pump function in vitro. To investigate the effect of this SNP on urinary acidification, we conducted a genotype-phenotype analysis of recurrent stone formers in theDallas and Bern kidney stone registries. Of 555 patients examined, 32 (5.8%) were heterozygous for the p.E161K SNP, and the remaining 523 (94.2%) carried two wild–type alleles. After adjustment for sex, age, body mass index, and dietary acid and alkali intake, p.E161K SNP carriers had a nonsignificant tendency to higher urinary pH on a random diet (6.31 versus 6.09; P=0.09). Under an instructed low–Ca and low–Na diet, urinary pH was higher in p.E161K SNP carriers (6.56 versus 6.01; P,0.01). Kidney stones of p.E161K carriers were more likely to contain calcium phosphate than stones of wild-type patients. In acute NH4Cl loading, p.E161K carriers displayed a higher trough urinary pH (5.34 versus 4.89; P=0.01) than wild-type patients. Overall, 14.6% of wild-type patients and 52.4% of p.E161K carriers were unable to acidify their urine below pH 5.3 and thus, can be considered to have incomplete dRTA. In summary, our data indicate that recurrent stone formers with the vacuolar H+-ATPase B1 subunit p.E161K SNP exhibit a urinary acidification deficit with an increased prevalence of calcium phosphate– containing kidney stones. The burden of E161K heterozygosity may be a forme fruste of dRTA.

Normal values for pancreatic stone protein in different age groups.

BACKGROUND Pancreatic stone protein (PSP) has been identified as a promising sepsis marker in adults, children and neonates. However, data on population-based reference values are lacking. This study aimed to establish age-specific reference values for PSP. METHODS PSP was determined using a specific ELISA. PSP serum concentrations were determined in 372 healthy subjects including 217 neonates, 94 infants and children up to 16 years, and 61 adults. The adjacent categories method was used to determine which age categories had significantly different PSP concentrations. RESULTS PSP circulating levels were not gender-dependent and ranged from 1.0 to 99.4 ng/ml with a median of 9.2 ng/ml. PSP increased significantly between the age categories, from a median of 2.6 ng/ml in very preterm newborns, to 6.3 ng/ml in term newborns, to 16.1 ng/ml in older children (p < 0.001). PSP levels were higher on postnatal day three compared to levels measured immediately post delivery (p < 0.001). Paired umbilical artery and umbilical vein samples were strongly correlated (p < 0.001). Simultaneously obtained capillary heel-prick versus venous samples showed a good level of agreement for PSP (Rho 0.89, bias 19 %). CONCLUSIONS This study provides age-specific normal values that may be used to define cut-offs for future trials on PSP. We demonstrate an age-dependent increase of PSP from birth to childhood.