The Pluto system: Initial results from its exploration by New Horizons.

The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.

Wilson's disease.

The following case involves a young man initially diagnosed as having a mental disorder. Confirmation of Kayser-Fleischer rings on the cornea greatly assisted in the final diagnosis of Wilson's disease (hepatolenticular degeneration).

The bronchial leak squeak: a new sign for the physical diagnosis of bronchopleurocutaneous fistula.

We describe a unique physical diagnostic sign that we have observed in seven patients with bronchopleurocutaneous fistulas. Such patients have a highpitched squeak over the affected chest area during sustained Valsalva maneuver. We postulate that turbulence across the bronchial fistula due to high transbronchial pressure gradient during the Valsalva maneuver produces the squeaking sound. The pitch of the leak squeak sign is higher in smaller fistulas than in larger fistulas; decreases in intensity and increases in pitch occurred in two patients in whom the bronchial fistula slowly closed. The absence of the leak squeak sound in patients with spontaneous pneumothorax suggests that this sign can be used to differentiate central airways from alveolar air leaks.

Use of an acoustic helium analyzer for measuring lung volumes.

We have evaluated the use of an acoustic gas analyzer (AGA) for the measurement of total lung capacity (TLC) by single-breath helium dilution. The AGA has a rapid response time (0-90% response = 160 ms for 10% He), is linear for helium concentration of 0.1-10%, is stable over a wide range of ambient temperatures, and is small and portable. We plotted the output of the AGA vs. expired lung volume after a vital capacity breath of 10% He. However, since the AGA is sensitive to changes in speed of sound relative to air, the AGA output signal also reports an artifact due to alveolar gases. We corrected for this artifact by replotting a single-breath expiration after a vital capacity breath of room air. Mean alveolar helium concentration (HeA) was then measured by planimetry, using this alveolar gas curve as the base line. TLC was calculated using the HeA from the corrected AGA output and compared with TLC calculated from HeA simultaneously measured using a mass spectrometer (MS). In 12 normal subjects and 9 patients with chronic obstructive pulmonary disease (COPD) TLC-AGA and TLC-MS were compared by linear regression analysis; correlation coefficient (r) was 0.973 for normals and 0.968 for COPD patients (P less than 0.001). This single-breath; estimation of TLC using the corrected signal of the AGA vs. Expired volume seems ideally suited for the measurement of subdivisions of lung volume in field studies.

Age-dependent resistance of human alveolar macrophages to herpes simplex virus.

Studies in mice demonstrate an age-dependent susceptibility to disseminated herpesvirus infection which is mediated. at least in part, by a defect in macrophage antiviral function. We examined the growth of herpes simplex virus within human alveolar macrophages obtained by bronchopulmonary lavage from neonates, adults with a variety of immunosuppressive disorders, and healthy adult volunteers. At 24 h postinfection, mean viral titers in neonatal macrophages increased 19-fold over adsorbed virus levels, a highly significant increase when compared to either immunosuppressed or normal adult macrophages (P less than 0.0005). These findings indicate that human macrophages, like those of mice, exhibit age-dependent permissiveness for the replication of herpes simplex virus. This permissiveness may at least partially account for the clinical observation that human newborns are highly susceptible to disseminated herpes simplex virus infections, whereas adults are not.

Growth of herpes simplex and cytomegalovirus in cultured human alveolar macrophages.

In laboratory animals, macrophages play a central role in controlling certain viral infections. Because the adult human lung is more susceptible to infection with cytomegalovirus than herpes simplex virus, we compared the replication of these two viruses in vitro in human alveolar macrophages. The growth of herpes simplex virus in alveolar macrophages was extremely limited, peak titers being only 1.8-fold greater than adsorbed virus titers. Cytomegalovirus, on the other hand, replicated in normal adult alveolar macrophages to the same extent as in permissive tissue culture cell. These data suggest that the human alveolar macrophage may play a central role in the control of lung infection with herpes simplex virus.

Radiographic aspects of occult pulmonary haemorrhage.

Patients with leukaemia, on anticoagulant therapy, or with disseminated intravascular coagulation may develop occult pulmonary haemorrhage; it will mimic pulmonary oedema, pulmonary hemosiderosis or opportunistic infections. It can be diagnosed by bronchopulmonary lavage. The radiographic changes are described and the differential diagnosis discussed in a series of 12 such patients.

Diagnostic lavage and occult pulmonary hemorrhage in thrombocytopenic immunocompromised patients.

Twenty consecutive thrombocytopenic immunocompromised patients with pulmonary infiltrates underwent diagnostic bronchopulmonary lavage. Nine patients were found to have occult pulmonary hemorrhage as evidenced by increased stainable hemosiderin within alveolar macrophages. Other diagnoses established included Pneumocystis carinii pneumonia in 2 patients and metastatic carcinoma in 1. No hemorrhage was precipitated by the procedure, even in 7 patients whose platelet counts were less than or equal to 20,000 per mm3. We concluded that bronchopulmonary lavage is a safe and effective diagnostic procedure in thrombocytopenic immunocompromised patients and that occult pulmonary hemorrhage is a common cause of diffuse pulmonary infiltrates in such patients.

Prevention of tracheal injuries in prolonged ventilation. Laboratory and clinical observations on the use of self-inflating cuffs on ventilating tubes.

We have previously described the design for a new self-inflating cuff for use on endotracheal and tracheostomy tubes. The pressure characteristics of this new cuff have been reported. The present report presents our experience with this self-inflating cuff in over 200 laboratory observations demonstrating its effectiveness in preventing tracheal damage. Tracheostomy tubes mounted with self-inflating cuffs were kept in the dogs for six weeks without causing tracheal ulceration. Our clinical experience in 52 patients is also described. Endotracheal, nasotracheal, and tracheostomy tubes were used intraoperatively and for long periods of ventilation. No tracheal damage could be shown at postmortem examination in two patients dying of their disease, 10 and 25 days after continuous ventilation.

Defective lung macrophages in pulmonary alveolar proteinosis.

Lung macrophages obtained by segmental lavage from three patients with pulmonary alveolar proteinosis were studied in vitro. The macrophages exhibited morphologic abnormalities including excessive lipid accumulation and giant secondary lysosome formation. These cells survived poorly in tissue culture, showed impaired chemotactic activity, and had decreased adhesiveness to glass. They phagocytized normally but had substantially decreased capacity to kill ingested Candida pseudotropicalis. Evidence was obtained that the macrophage defect was acquired and probably related to ingestion of the proteinaceous alveolar fluid. Peripheral blood monocyte function was normal in one patient and morphologic abnormalities were produced in normal monocyte-derived macrophages cultured with proteinaceous lavage material. These studies suggest that the lung macrophage in alveolar proteinosis is a defective cell as a consequence of an abnormal pulmonary environment.

Occult pulmonary hemorrhage in anticoagulated patients.

Evidence for severe intrapulmonary bleeding was obtained in 3 anticoagulated patients who presented with pulmonary infiltrates. The diagnosis of pulmonary hemorrhage was based on findings of markedly elevated quantities of stainable hemosiderin and hemoglobin in alveolar macrophages retrieved by bronchopulmonary lavage. In 2 of the patients, roentgenographic abnormalities regressed after anticoagulation was reversed. The third patient died and massive bilateral pulmonary hemorrhage was found at autopsy. The syndrome of occult pulmonary hemorrhage was characterized clinically by dyspnea, unexplained acute anemia, and infiltrates with an alveolar pattern on chest roentgenogram. Hemoptysis was conspicuously absent. Bronchopulmonary lavage and quantification of alveolar macrophage hemosiderin content may be useful in identifying intrapulmonary bleeding occurring in an otherwise occult manner. Recognition of pulmonary hemorrage in anticoagulated patients is important because reversal of anticoagulation can be life saving.

Occult pulmonary haemorrhage in leukaemia.

Through gleeding into the lung parenchyma is responsible for morbidity and mortality in patients with leukaemia pulmonary haemorrhage is seldom diagnosed during life. We diagnosed occult pulmonary haemorrhage in five leukaemic patients with unexplained infiltrates on chest roetgenograms by examining alveolar macrophages retrieved by bronchopulmonary lavage. Macrophage haemosiderin content was greatly increased in the patients with pulmonary haemorrhage as compared to normal and thrombocytopenic control subjects. Haemoglobin and intact erythrocytes in alveolar macrophages were taken as evidence of recent haemorrhage. Intrapulmonary bleeding may occur often in patients with leukaemia, and bronchopulmonary lavage offers a safe approach to diagnosis and allows for concomitant identification of pulmonary infection.