Pulmonary capillary hemangiomatosis: radiographic appearance.

Pulmonary capillary hemangiomatosis is a rare disorder that is characterized pathologically by formation of capillaries along alveolar walls that may ultimately invade the pulmonary parenchyma and pulmonary arteries. The clinic presentation overlaps that of primary pulmonary hypertension, but the natural history of pulmonary capillary hemangiomatosis is one of rapid deterioration. The typical radiographic appearance is a diffuse bilateral reticulonodular pattern associated with enlarged central pulmonary arteries.

Laser Raman characterization of conformational changes in sarcoplasmic reticulum induced by temperature, Ca2+, and Mg2+.

Laser Raman spectroscopy has been used to examine the conformations of the protein and phospholipid components of sarcoplasmic reticulum from rabbit white skeletal muscle. The phospholipid component is shown to have the conformation of fluid, liquid-crystalline lipids, even at 10 degrees C, and no breaks in the lipid conformation are observed in the range of 10-37 degrees C. Protein (predominantly the Ca2+-dependent ATPase) conformation is shown to contain very little beta-sheet structure under all conditions. Absolute content of alpha-helix and random coil or beta-turn could not be determined because of interference in the amide I and III regions. However, the Ca2+-ATPase in sarcoplasmic reticulum appears to undergo a conformational change at 15-18 degrees C which involves removal of a portion of the tryptophan residues from an aqueous environment and an increase in alpha-helical content. This conformation change coincides with a change in slope of Arrhenius plots of ATP hydrolysis activity. Increasing concentrations of Ca2+ and Mg2+ appear to slightly decrease the alpha-helical content of sarcoplasmic reticulum protein.

Laser-Raman investigation of lysozyme-phospholipid interactions.

The interaction of lysozyme with mixed 1,2-dipalmitoyl-L-phosphatidic acid/1,2-dimyristoyl-L-phosphatidylcholine liposomes was investigated by laser Raman spectroscopy. Substantial changes were observed i the spectra of both the lipid and protein in the mixed liposomes over the range 10-62 degrees C. At temperatures below 27 degrees C, interaction with lipid appears to slightly increase the amount of helical structure in lysozyme at the expense of random conformation. At temperatures above 30 degrees C, considerable beta-sheet is irreversibly formed. Onset of beta-formation appears to coincide with the formation of disordered lipid side-chains in the acidic component of the lipid. At all temperatures, the O-P-O diester stretching mode at 782 cm-1 is much more intense in the lipid/protein mixture than in lipid alone. It is observed that the dimyristoyl phosphatidylcholine chain-disorder transition is lowered by 3 degrees C, while that of the phosphatidic acid is lowered by 12 degrees C, yet the post-transition conformation contains a significantly higher proportion of trans-segments in the presence of lysozyme. These results are interpreted in terms of: (1) a polar interaction between acidic phospholipid and lysozyme at temperatures below either chain-disorder transition, in which lysozyme is essentially excluded from the hydrophobic portion of the lipid and (2) an interaction at higher temperatures which involves the lipid side-chains of dipalmitoyl phosphatidic acid in the disordered state and is manifested by a substantial conformational change.

Study of the kinetic and structural properties of a monoclonal immunoglobulin G cryoglobulin.

The precipitation of a monoclonal IgG2 crystalline cryoglobulin (WEB) is shown to occur via a nucleation mechanism. The kinetics of precipitation fits the empirical equation 1n(t2/t1) = nù(c1/c2), where t is the time to reach half-maximum turbidity for concentration c. The effect of mild reduction of interchain disulfides on the kinetics and extent of precipitation have also been determined. Cleavage of only one or two inter heavy-heavy chain disulfide bonds appears to abolish cryoprecipitation. The extent of reduction at high reductant levels suggests that there is an extra inter heavy-heavy chain disulfide in IgG-WEB. Laser Raman spectroscopy detects no structural change between reduced (noncryoprecipitable) and native (cryoprecipitable) WEB, suggesting that perturbation of a local site is responsible for loss of cryoprecipitation.

A laser Raman spectroscopic investigation of phospholipid and protein configurations in hemoglobin-free erythrocyte ghosts.

Configurations of both the protein and lipid components of human red blood cell ghosts are examined by laser Raman spectroscopy. Protein configuration is estimated from bands observed in the Amide III region at 1240-1267 cm-1 in water and the Amide I' region at 1630-1670 cm-1 observed in 2H2O. The protein fraction appears to contain 40-55 percent alpha-helix with little beta-configuration. The hydrophobic side chains of the phospholipid component, as interpreted from the 1060-1130 cm-1 C-C stretching region, are estimated to contain 55-65 percent all-trans rigid configuration. These estimated are within the limits set by other physical techniques.

Laser Raman investigation of the effect of cholesterol on conformational changes in dipalmitoyl lecithin multilayers.

Large and abrupt changes are observed at 38 degrees C in the 1100 cm(-1) region of the Raman spectrum of aqueous dipalmitoyl lecithin multilayers. They correspond to conformational changes due to the melting of the paraffin side chains. The addition of cholesterol to the multilayers broadens but does not abolish these changes. It is suggested that the addition of cholesterol decreases the interactions between adjacent paraffin side chains of lecithin, causing a change from a cooperative to a noncooperative gel-liquid crystal transition. Removal of water from dipalmitoyl lecithin also results in a noncooperative transition strikingly similar to that caused by addition of cholesterol. Raman spectroscopy thus provides a new and sensitive probe for analyzing the structures of membranes and their constituents.