Our single-item, GSRH questions demonstrated good reproducibility, reliability, and strong concurrent and discriminant scale performance with an established health status measure.

The quantitation of substances in the epithelial lining fluid (ELF) of the lower respiratory tract, as obtained by bronchoalveolar lavage (BAL), is not precise because of the variable dilution of the ELF by the instilled lavage fluid. It has been reported that the absolute concentration of proteins in ELF can be determined by using the ratio of urea concentration in BAL fluid to that in serum as a method to calculate the volume of ELF recovered by BAL. Furthermore, it has been suggested that the error caused by diffusion of urea into the instilled lavage fluid can be minimized by instilling only 100 ml (5 X 20 ml) of saline rather than 300 ml (6 X 50 ml). We tested the validity of this method by collecting and individually analyzing aliquots from 2 different BAL protocols--a 100-ml (5 X 20 ml) BAL and a 300-ml (6 X 50 ml) BAL--performed in 6 healthy, nonsmoking subjects. Total protein, albumin, and urea were measured in each aliquot and in pooled fluid from each BAL procedure, and urea was measured in serum. In the 300-ml BAL, total protein and albumin concentrations tended to decrease progressively from the second to the sixth aliquots. In contrast, the urea concentration increased progressively from the first to the sixth aliquots. The concentration of albumin in ELF, calculated from the concentration of urea and albumin in each BAL aliquot, tended to decrease in each successive aliquot, becoming significant by the fourth aliquot.(ABSTRACT TRUNCATED AT 250 WORDS)

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This work attempts to explain the types of computation that neural networks can perform by relating them to automata. We first define what it means for a real-time network with bounded precision to accept a language. A measure of network memory follows from this definition. We then characterize the classes of languages acceptable by various recurrent networks, attention, and convolutional networks. We find that LSTMs function like counter machines and relate convolutional networks to the subregular hierarchy. Overall, this work attempts to increase our understanding and ability to interpret neural networks through the lens of theory. These theoretical insights help explain neural computation, as well as the relationship between neural networks and natural language grammar.

A B S T R A C T Alveolar macrophages are the initial phagocytic cells that encounter foreign material and particulates deposited in the terminal airways. We have examined a mechanism by which these cells, after phagocytic challenge, may control or amplify the inflammatory response in lung parenchyma. Normal human alveolar macrophages (AM) were studied from eight subjects. With in vitro culture, AM produced and released two substances into culture media which have potent chemoattractant activity for blood polymorphonuclear granulocytes(PMN) and negligible activity for mononuclear cells. Release of these factors is maximally stimulated by aggregated human immunoglobulin (Ig)G or zymosan particles; however, simple adhesion of the macrophages to plastic surfaces is also sufficient to stimulate release of these chemotactic substances.The larger substance (10,000 daltons) is immunologically distinct from C5a and interacts with a different PMN membrane receptor than that known to exist for formyl-methionyl-leucyl-phenylalanine. Its chemotactic activity is sensitive to the enzymatic effect of trypsin. Although producing a single elution peak on gelfiltration chromatography, electrofocusing in polyacrylamide gels yielded five peaks of radioactivity. Chemotactic activity was localized to a fraction with a pI = 5.0. The smaller molecular weight substance has been less well characterized. Thus, the human AM can produce at least two factors which attract PMN and this capability may augment the local inflammatory response in the lung.

A hyperdynamic circulatory state frequently is ob-Portal hypertension accompanied by anatomic or served in portal hypertension with liver failure or exten-functional portal-systemic shunting very often is assosive portal-systemic shunting. Tumor necrosis factor a ciated with a hyperdynamic circulatory state. The so-(TNF) causes marked hypotension in mammals by in-called hyperdynamic circulatory syndrome (HCS) is ducing nitric oxide synthesis and has been shown to play characterized by generalized vasodilatation with a dea role in the development of the hemodynamic changes crease in mean arterial pressure and systemic vascular observed in portal hypertension. Thalidomide selec-resistance and an increase in cardiac output and retively inhibits TNF production by enhancing messenger gional blood flows. Although the cause of this syndrome RNA degradation. We investigated the systemic and poris still a matter of controversy, it seems that vasodilatatal hemodynamic effects of thalidomide in a prehepatic model of portal hypertension and evaluated whether tion, induced by increased activity of endothelial-indesuppressing TNF synthesis decreases NO production. pendent and endothelial-dependent vasodilators, initiPortal hypertension was induced by partial ligation of ates the hyperdynamic state. 1 the portal vein (PVL). Animals received thalidomide (T)Various substances have been proposed as mediators (50 mg/kg/d) / water or water alone (W), orally, daily for of the HCS. Recently, a role for endogenous nitric oxide 2 days before and 13 days after PVL operation, at which in the regulation of blood flow and vascular tone of the time hemodynamic studies were performed and TNF systemic and splanchnic circulations in portal hypertenplasma levels were obtained. Sham-operated animals sion has been suggested by several in vivo and in vitro were studied identically. In an additional group of PVL animals, 24-hour urinary excretion of NO 0 2 and NO 0 3 was studies, implying that excessive synthesis of NO could measured during treatment. PVL animals receiving T be responsible for these circulatory abnormalities. 2,3 presented with a significantly higher mean arterial presTumor necrosis factor a (TNF), a 17-kd, mononusure and systemic vascular resistance and significantly clear-derived cytotoxic protein, causes marked hypolower portal pressure, TNF plasma levels, and 24-hour tension in mammals. 4 inhibiting TNF synthesis and decreasing NO synthesis,

Previous in vitro studies have suggested that bacterial adherence to buccal squamous epithelial cells may be a mechanism involved in postoperative colonization of the oropharynx. However, the relationship between bacterial binding to oral epithelial and ciliated respiratory cells is unknown. To investigate bacterial binding to other cells in the human respiratory tract, we measured adherence of Pseudomonas seruginosa to ciliated cells (from nose and trachea) and compared this to squamous cells (from buccal mucosa), Cell samples were collected from 16 noncolonized individuals undergoing either elective surgery or volunteer bronchoscopy. Adherence (mean +/- SEM) to tracheal cells (4.6 +/- 0.8 bacteria per cell) and to nasal cells (4.7 +/- 0.6 bacteria per cell) was similar. These values significantly (p less than 0.001) exceeded buccal cell adherence (0.9 +/- 0.2 bacteria per cell). Because cells from ciliated surfaces bind more bacteria than cells from squamous surfaces, bacterial adherence at these respiratory sites may involve different mechanisms. The enhanced bacterial attachment to ciliated cells may assume pathogenic importance when mucociliary function is impaired.