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PubMed1991

Detection of porphyrin excited states in the intact bovine lens.

Previous steady state and time resolved spectroscopic studies on porphyrins have shown that the triplet lifetimes of those sensitizers that bind to lens proteins are lengthened by several orders of magnitude. Presented here is an extension of this experiment to measure these transients in an intact bovine lens. As demonstrated by steady state fluorescence spectroscopy and flash photolysis, mesotetra (p-sulfonatophenyl)porphyrin (TPPS) binds to lens proteins. In air-saturated aqueous solution, TPPS has a triplet lifetime of 2 microseconds. In an intact bovine lens the triplet state decayed via biexponential kinetics with lifetimes of 0.16 and 1.6 microseconds. In addition to a lengthening of the lifetime there was a red shift in the triplet transient spectra of 10-20 nm of the porphyrin in the intact lenses.

Animals↗
PubMed1989

Pulmonary deposition and clearance of aerosolized alpha-1-proteinase inhibitor administered to dogs and to sheep.

Augmentation of lung antiprotease levels may be an important therapeutic intervention in the prevention of pulmonary emphysema. We have administered aerosols of plasma-derived human alpha 1 proteinase inhibitor (A1PI) to the lungs of dogs and sheep to investigate (a) delivery of the protein to the distal air spaces of the lung; (b) maintenance of functional activity of the protein; and (c) flux of the protein across the components of the alveolar-capillary membrane. A1PI (26.4 mg/kg body weight) was administered as an aerosol to anesthetized animals; sheep were prepared for the chronic collection of lung lymph. Immunoperoxidase staining of lung tissue obtained 2 h after administration of A1PI demonstrated the presence of human A1PI on the surface of alveoli and distal bronchioles. Bronchoalveolar lavage fluid recovered at intervals after A1PI administration demonstrated time-dependent elevations of human A1PI levels with augmentation of lavage fluid antielastase activity in proportion to the content of human A1PI. Using radiolabeled A1PI as a tracer, we found that 32% of the aerosol was retained in the animals' lungs. Measurements of the rate of loss of A1PI from the lung and of the rate of appearance of human A1PI in plasma resulted in a calculated permeability of the alveolar-capillary membrane to A1PI of 3.49-6.39 X 10(-10) cm/s. Experiments using instrumented sheep allowed independent calculation of endothelial permeability to A1PI of 122-236 X 10(-10) cm/s and calculation of epithelial permeability of 4.70-4.81 X 10(-10) cm/s. Modeling of aerosol delivery of A1PI to humans using the results of these studies predicts that the ratio of plasma/alveolar levels of delivered A1PI will be 0.024, and that aerosolization of 175 mg A1PI/d will result in an A1PI alveolar fluid level of 1.0 mg/ml. Aerosol administration of A1PI may provide an efficient method of augmenting alveolar antiprotease levels.

Aerosols↗
PubMed1978

Development of intercellular junctions in the pulmonary epithelium of the foetal lamb.

The integrity of epithelial tight junctions in foetal mammalian lungs is essential to maintain the unique ionic composition of lung liquid, and to prevent leakage of serum proteins into peripheral air spaces. In the present study the development of intercellular junctions of the lining epithelium of foetal lamb lungs during gestation was examined by light and electron microscopy. Both thin sections and freeze-fracture replicas were examined by electron microscopy. By 39 days of gestation, epithelial tight junctions consist of a minimum of 3.1 +/- 1.6 (s.D.) and a maximum of 5.8 +/- 2.0 discontinuous rows of particles and short segments of strands on P face ridges and in complementary E face grooves, while from 58 to 76 days they are composed of a network of 4.3 +/- 1.6 to 7.7 +/- 1.9 focally interrupted P face strands. Complementary replicas show that many of the discontinuities on the P face are due to separation of junctional particles on to the E face during fracturing, and not to an absence of junctional particles. From 76 days to term, epithelial tight junctions (exclusive of upper airway epithelium which was not examined) resemble those of adult lungs, and consist of a continuous network of 4.5 +/- 2.0 to 7.5 +/- 2.5 P face strands and complementary particle-free grooves. Permeability measurements, published elsewhere, indicate that the epithelium is functionally 'tight' from 69 days onwards. Tight junctions in peripheral air-space epithelium, therefore, are structurally continuous and functionally 'tight' early in foetal lung development, and form seals at one end of long, narrow intercellular spaces; these features may be important for coupled ion and water transport. When the bounding epithelial cells become flattened, these narrow intercellular spaces remain intact as a result of complex interdigitations of adjacent cell membranes. Desmosomes were present throughout gestation near the abluminal side of the tight junctions and occasionally near the base of the intercellular space. These junctions may serve to connect cells to each other at a time when tight junctions may be mechanically weak. In addition, gap junctions are associated with tight junctions from the glandular through the canalicular stages of lung development. They disappear by 120 days when the epithelial cells are differentiated.

Animals↗
PubMed2000

[Allergy to house dust mites].

The prevalence of atopic disease in Switzerland is 15-20%. About 30% of these patients have perennial symptoms and a substantial proportion are allergic to house-dust mite proteins. If absolute air humidity is lower than 7.0 g water per kg air, house-dust mites will not proliferate. This is why the occurrence of house-dust mites varies between different regions. About half of the patients with allergy to house-dust mites complain of rhinitis, a quarter of asthma and a quarter of asthma and rhinitis. The diagnosis is usually by history, skin prick tests and if necessary provocation. Therapy includes allergen avoidance (reduction of air humidity in dwellings by ventilation, encasing of mattresses and bedding), medication (mainly topical corticosteroids) and specific immunotherapy.

Animals↗
PubMed2004

Changes in the mitochondrial proteome during the anoxia to air transition in rice focus around cytochrome-containing respiratory complexes.

The ability of rice seedlings to grow from dry seed under anoxia provides a rare opportunity in a multicellular eukaryote to study the stages of mitochondrial biogenesis triggered by oxygen availability. The function and proteome of rice mitochondria synthesized under 6 days of anoxia following 1 day of air adaptation have been compared with mitochondria isolated from 7-day aerobically grown rice seedlings. Rice coleoptiles grown under anoxia, and the mitochondria isolated from them respired very slowly compared with air-adapted and air-grown seedlings. Immunodetection of key mitochondrial protein markers, isoelectric focusing electrophoresis followed by SDS-PAGE to make soluble mitochondria proteome maps, and shotgun sequencing of mitochondrial proteins by liquid chromatography-tandem mass spectrometry all revealed similar patterns of the major function categories of mitochondrial proteins from both anoxic and air-adapted samples. Activity analysis showed respiratory oxidases markedly increased in activity during the air adaptation of seedlings. Blue-native electrophoresis followed by SDS-PAGE of mitochondrial membrane proteins clearly showed the very low abundance of assembled b/c complex and cytochrome c(1) oxidase complex in the mitochondrial membrane in anoxic samples and the dramatic increase in the abundance of these complexes on air adaptation. Total heme content, cytochrome absorbance spectra, and the electron carrier, cytochrome c, also increased markedly on air adaptation. These results likely reflect limited heme synthesis for cytochrome assembly in the absence of oxygen and represent a discrete and reversible blockage of full mitochondrial biogenesis in this anoxia-tolerant species.

Air↗
PubMed1989

Heterogeneous lobular distribution of hepatocytes expressing acute-phase genes during the acute inflammatory reaction.

Functional heterogeneity in the lobule with regard to plasma protein synthesis is still debated. Therefore, we have localized in liver sections from normal rats and from rats with turpentine-induced AIR the mRNA and protein products of three genes with different alterations in their hepatic expression during an AIR: alpha 2M and alpha 1PI, two positively reacting acute-phase genes, and alpha 1I3, a negative acute-phase reactant. In normal liver, all hepatocytes expressed alpha 2M and alpha 1I3 mRNA, but a preferential expression of alpha 2M and alpha 1I3 mRNA and protein in the PP and ML zones was observed. During an AIR, the level of alpha 2M mRNA increased fourfold in the cytoplasm of PP and ML hepatocytes, while the level of cytoplasmic alpha 1I3 mRNA was decreased about fourfold in the same zones, with parallel variations in the expression of the corresponding proteins. In contrast, no significant modulation of the RNA and protein concentrations of both genes was detected in PV areas. alpha 1PI mRNA was expressed at the same levels in the three lobular zones in normal liver, but staining for the alpha 1PI protein was more intense in the PV zones. During the acute-phase response alpha 1PI mRNA levels were increased twofold in all three lobular zones, and alpha 1PI staining became homogeneous within the lobule. These results demonstrate that the location of a hepatocyte with the liver lobule can influence the expression of the three genes under study both at pre- and post-translational levels, in basal conditions, as well as during modulation of their expression during the inflammatory reaction.

Acute Disease↗
PubMed2005

Flow injection analysis with diode array absorbance detection and dynamic surface tension detection for studying denaturation and surface activity of globular proteins.

In this article, a multidimensional dynamic surface tension detector (DSTD), in a parallel configuration with a UV-visible diode array absorbance detector, is presented in a novel flow injection analysis (FIA) application to study the effects of chemical denaturants urea, guanidinium hydrochloride (GdmHCl), and guanidinium thyocyanate (GdmSCN) on the surface activity of globular proteins at the liquid-air interface. The DSTD signal is obtained by measuring the changing pressure across the liquid-air interface of 4-mul drops repeatedly forming at the end of a capillary using FIA. The sensitivity and selectivity of the DSTD signal is related to the surface-active protein concentration in aqueous solution combined with the thermodynamics and kinetics of protein interaction at a liquid-air drop interface. Rapid on-line calibration and measurement of dynamic surface tension is applied, with the surface tension converted into surface pressure results. Continuous surface tension measurement throughout the entire drop growth is achieved, providing insight into kinetic behavior of protein interactive processes at the liquid-air drop interface. Specifically, chemical denaturation of 12 commercial globular proteins-chicken egg albumin, bovine serum albumin, human serum albumin, alpha-lactalbumin (alpha-Lac), myoglobin, cytochrome c, hemoglobin, carbonic anhydrase, alpha-chymotrypsinogen A, beta-lactoglobulin (beta-LG), lysozyme, and glyceraldehyde-3-phosphate-dehydrogenase-is studied in terms of surface pressure (i.e., surface activity) after treatment with increasing concentrations of urea, GdmHCl, and GdmSCN in the 0-8, 0-6, and 0-5 M ranges, respectively. For several of these proteins, the spectroscopic absorbance changes are monitored simultaneously to provide additional information prior to drop formation. Results show that surface pressure of proteins generally increases as the denaturant concentration increases and that effectiveness is GdmSCN > GdmHCl > urea. Protein unfolding curves obtained by plotting surface pressure as a function of denaturant concentration are presented and compared with respect to unfolding curves obtained by using UV absorbance and literature data. Kinetic information relative to the protein adsorption to the air-liquid interface of two proteins, alpha-Lac and beta-LG (chosen as representative proteins for comparison), denatured by the three denaturants is also studied and discussed.

Animals↗
PubMedDate not supplied

Metal storage and transport proteins increase after exposure of the rat lung to an air pollution particle.

With the single exception of mercury, all metals in the atmosphere are associated with particles. The lungs are subsequently exposed to metals present in air pollution particles on a continuous basis. Because metal exposure can be associated with an oxidative stress, a mechanism that isolates the metal in a chemically less reactive form would be of benefit. We tested the hypothesis that the concentrations of both lactoferrin and ferritin in the rat lung increase after exposure to a metal-rich emission source air pollution particle. Using immunohistochemistry, we characterized changes in the concentrations of ferritin and lactoferrin after exposure of rats to an emission source air pollution particle. Lavage metal concentrations, measured by inductively coupled plasma emission spectroscopy, increased 4 hr after exposure to an oil fly ash. After exposure to this metal-rich emission source air pollution particle, ferritin concentrations in the lower respiratory tract increased. Comparable to the iron-storage protein, concentrations of both lactoferrin and transferrin were elevated after exposure. The greatest concentrations of ferritin, lactoferrin, and transferrin occurred at approximately 24 hr after exposure to the air pollution particle. Levels then decreased, and by 96 hr after instillation of the oil fly ash, ferritin, lactoferrin, and transferrin were not elevated relative to those animals exposed to saline. We conclude that, in response to an emission source air pollution particle with high concentrations of metals, there is an increase in ferritin, lactoferrin, and transferrin concentrations in the lungs of the host. The function of these increases in iron-binding proteins may be to control the oxidative stress associated with the exposure to metals.

Air Pollution↗
PubMed1998

Spray-drying of air-liquid interface sensitive recombinant human growth hormone.

Spray-drying is an attractive method for preparing fine recombinant human growth hormone (rhGH) powders if the detrimental effect of protein degradation at the air-liquid interface on the protein can be minimized. In this study, we demonstrated that rhGH degradation (insoluble and soluble aggregate formation), as the consequence of air-liquid interfacial degradation, could be prevented using the appropriate formulation. Adding polysorbate-20 surfactant into the liquid feed (with no presence of sugar protectant) significantly reduced the formation of insoluble protein aggregates, while adding the divalent metal zinc ion effectively suppressed the formation of soluble protein aggregates. The combination of the two yielded a spray-dried rhGH powder having insignificant protein degradation. Our data suggest that the two components might protect the protein through different mechanisms. Polysorbate molecules occupy the air-liquid interface of spray droplets, thereby reducing the chance for rhGH to form insoluble aggregates by surface denaturation. Two zinc ions associate with two rhGH molecules to form a dimer complex that can resist the formation of soluble protein aggregates. Characterization of spray-dried powders by scanning electron microscopy suggests that both formulation and drying conditions have a strong influence on particle morphology and shape. Overall, spherical rhGH powders of smooth surface and good biochemical quality can be prepared by spray-drying using this formulation with no addition of sugar protectant.

Calorimetry, Differential Scanning↗
PubMed1989

Interactions between plasma proteins and pulmonary surfactant: pulsating bubble studies.

The influence of human albumin, alpha-globulin, and fibrinogen on the actions of porcine pulmonary surfactant in a pulsating bubble surfactometer has been investigated. All three proteins detracted from the ability of the surfactant to adsorb to the air-water interface. The proteins also reduced the ability of surfactant to lower the opening pressures of bubbles cycling between different sizes in suspensions of surfactant. This was equivalent to restricting the ability of the surfactant to achieve low surface tension during compression of the surface. Of the three proteins, globulin competed most effectively with surfactant during the adsorption process, and albumin competed the least effectively. The proteins also may have interfered with the processes of surface refinement, which usually yields a monolayer enriched enough in dipalmitoyl phosphatidylcholine to achieve very low surface tension (very low opening pressures in the bubbles). Of the three proteins tested, albumin was least deleterious to surface refining whereas globulin and fibrinogen appeared to be about equally detrimental to the process.

Alpha-Globulins↗
PubMed1995

Interaction of alkylresorcinols with proteins.

Alkylresorcinol homologs form stable monomolecular layers at air-water interface. Their interaction with proteins present in the subphase results in an increase of alkylresorcinol molecular packing in the extent dependent upon the protein studied. Strongest effects were observed for proteins with large hydrophobic regions, e.g. glycophorin or serum albumin. Interaction of proteins with alkylresorcinol monolayers is stronger than with phospholipids. A decrease and a shift of intrinsic protein fluorescence upon interaction with the compounds studied support their involvement in alteration of hydrophobic regions. For trypsin, 50% quenching was observed at the alkylresorcinol/trypsin ratio of 0.75. Concomitantly, an apparent inhibition of the enzymatic activity was noted. These results indicate that direct interaction of alkylresorcinols and modulation of enzymatic activities should be recognised as a significant part of the biological effect of these cereal bran components.

Alkylation↗
PubMed1994

Nutrition and air-fluidized beds: a literature review.

This is a review of the literature on air-fluidized beds and nutrition with an emphasis on patients with pressure ulcers. Studies suggest that the warm, dry environment of the air-fluidized bed may affect nutritional status. Patients maintained on air-fluidized beds have increased fluid losses and decreased urinary nitrogen losses. While the evidence suggests that air-fluidized beds may reduce protein catabolism, further and lengthier metabolic studies are needed. Clinicians should continue to provide high levels of energy and protein for patients with pressure ulcers on air-fluidized beds.

Air↗
PubMed1993

Effects of air embolism on sheep lung fluid volumes.

Changes in lung fluid volumes and hyaluronan clearance were measured in six awake sheep during increased microvascular permeability induced by pulmonary air embolism (AE). After a 1- to 2-h baseline, filtered room air was infused through a proximal port of a Swan-Ganz catheter for 2 h at a rate sufficient to double pulmonary vascular resistance. The air infusion was discontinued, and the sheep were monitored for an additional 2 h (recovery). Lung lymph flow and protein flux increased during air infusion and continued to increase during recovery. During AE, lymph-to-plasma ratio for albumin decreased while lymph-to-plasma ratio for large protein remained the same. This would suggest that both microvascular pressure and microvascular permeability increase during AE. Protein clearance increased similarly for all protein sizes during AE and recovery. After 2 h of recovery, interstitial and extravascular volumes were elevated with no change in cellular volume. The volume of the interstitium available to albumin was more than twice control. The fraction of the interstitium that excludes albumin was calculated to be 0.32 +/- 0.04, with a 51% reduction in absolute excluded volume 2 h after AE. Clearance of hyaluronan by the lymphatics (normalized to baseline) increased 6- to 10-fold during and after AE. It was estimated that < 2% of the total hyaluronan in the lung would be cleared in 24 h under baseline conditions. This amount increased to approximately 11% under AE conditions and approximately 15% under recovery conditions. Changes in lung fluid volumes and protein clearance indicate increased microvascular permeability 2 h after AE.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Imaging the proteins pseudoazurin and apo-pseudoazurin on gold by STM in air: effect of the bias voltage.

We have applied scanning tunnelling microscopy (STM) to the study of two proteins: pseudoazurin and apo-pseudoazurin. Both proteins adsorbed onto a Au (1 1 1) surface are visible to STM individually, forming into layers and multilayers, with currents from about 55 to 600 pA. The images reproduce well the expected dimensions laterally but not in the z direction. The apparent height of the proteins varies with the voltage polarity, being higher at negative sample voltages. The bias also affects their shape. Negative sample voltages of more than 1.5 V orient the proteins present on a gold terrace in parallel rows. The layer of water adsorbed on surfaces in ambient conditions can be related to our results to explain the reduced z dimensions, the asymmetry with the voltage polarity and the alignment of proteins at voltages more negative than -1.5 V.

Air↗
PubMed2005

Cooperative activation of transcription by autoimmune regulator AIRE and CBP.

Autoimmune regulator (AIRE) is a transcriptional regulator that is believed to control the expression of tissue-specific genes in the thymus. Mutated AIRE is responsible for onset of the hereditary autoimmune disease APECED. AIRE is able to form nuclear bodies (NBs) and interacts with the ubiquitous transcriptional coactivator CBP. In this paper, we show that CBP and AIRE synergistically activate transcription on different promoter reporters whereas AIRE gene mutation R257X, found in APECED patients, interferes with this coactivation effect. Furthermore, the overexpression of AIRE and CBP collaboratively enhance endogenous IFNbeta mRNA expression. The immunohistochemical studies suggest that CBP, depending on the balance of nuclear proteins, is a component of AIRE NBs. We also show that AIRE NBs are devoid of active chromatin and, therefore, not sites of transcription. In addition, we demonstrate by 3D analyses that AIRE and CBP, when colocalizing, are located spatially differently within AIRE NBs. In conclusion, our data suggest that AIRE activates transcription of the target genes, i.e., autoantigens in collaboration with CBP and that this activation occurs outside of AIRE NBs.

Animals↗
PubMed1990

On the hydrodynamic instability of hemoglobin solutions.

The formation of heterogeneous fibers well observable under a magnifying glass in stirred "stroma-free" hemolysates of outdated banked erythrocytes was found to be predominantly due to random surface denaturation of both hemoglobin and non-heme proteins at the air-liquid interface. Electrophoretic analysis revealed that the precipitated and washed fibers contain residual membrane proteins as well as a certain amount of hemoglobin. The latter, however, largely remains in solution.

Blood Substitutes↗
PubMed2003

In situ measurement of conformational changes in proteins at liquid interfaces by circular dichroism spectroscopy.

A new circular dichroism (CD) spectroscopy technique for studying conformational changes in proteins in situ at the air-water interface is described. By using this technique, conformations of four proteins, viz., beta-casein, bovine serum albumin (BSA), lysozyme, and fibrinogen in the adsorbed state at the air-water interface have been studied. beta-Casein, which is predominantly in a disordered state in solution, assumes a beta-sheet conformation at the air-water interface. On the other hand, lysozyme and fibrinogen, which are alpha+beta-type proteins in solution, become beta-type proteins by completely transforming their alpha-helix structure into beta-sheets. Bovine serum albumin, which is an alpha-type protein in solution, loses its alpha-helix and becomes a disordered protein at the air-water interface. The results indicated that during unfolding and film formation at the interface, structural changes in proteins, regardless of their initial native state, follow the course of increasing beta-sheet and disordered structure and decreasing alpha-helix content. Although this seems to be the general trend, the exceptional case of BSA suggests, however, that this is not universal.

Animals↗
PubMed1980

Cerebral air embolism and the blood-brain barrier in the rat.

Cerebral air embolism can have hemodynamic effects such as increases in blood pressure and cerebral blood flow. It has been suggested that these factors play a role for the induction of the blood-brain barrier (BBB) dysfunction. In the present study, 5 microliters air was injected into the right internal carotid artery from a catheter in the external carotid artery after ligation of the extracerebral branches. No consistent change in blood pressure was observed with this small amount of air. Hypercapnia, which increases protein leakage in the brain under conditions of high intraluminal pressure, significantly reduced the extravasation in air embolism. Lidocaine and SITS (4 acetamido-4-isothiocyano-stilbene-2,2-disulfonic acid disodium), two drugs that effectively reduce the albumin leakage in acute hypertension, had no prophylactic effect in cerebral air embolism. Spontaneously hypertensive rats are less vulnerable than normotensive rats to pressure-induced BBB dysfunction but did not significantly differ from controls regarding albumin leakage in the present study. It is concluded that the increased cerebrovascular permeability in air embolism is not related to hemodynamic factors.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗