Pretreatment with ablative fractional carbon dioxide laser improves treatment efficacy in a synergistic PDT protocol for actinic keratoses on the head

BACKGROUND

A recently proposed synergistic photodynamic therapy protocol (s-PDT) combining advantages of both conventional- and daylight-PDT proved to be an effective and almost painless treatment for patients with actinic keratoses (AKs). This study investigated the safety and efficacy of an additional ablative fractional CO2-laser (AFXL) pretreatment.

METHODS

28 patients with AKs on the head received s-PDT using 5-aminolevulinic acid. AFXL pretreatment was conducted using the following parameters: pulse energy 8 mJ, spot density 50 spots/cm², power 30 W, beam size 4-18 mm. Outcome was assessed by AK area and severity index (AKASI) and lesion count (LC) before and 3 months after treatment. Safety was monitored by blood pressure and pulse measurements. Intensity of pain was determined by use of a visual analog scale (VAS).

RESULTS

Most patients (96.4 %) showed a significant AKASI reduction (P < 0.0001) 3 months after PDT (median AKASI 1.6 [0-2.4]) compared to baseline (5.3 [4-7.75]). Median reduction rate was 75.5 % (61.3 %-100 %). Eleven patients (39.3 %) achieved AKASI 100, three (10.7 %) AKASI 75 and ten (35.7 %) AKASI 50. Blood pressure and pulse did not change significantly throughout treatment. Median VAS for pain during irradiation was 0 (0-0), 0 (0-2) and 0 (0-2) at the beginning, in the meantime and at the end, respectively. Compared to data without AFXL pretreatment, this study showed significantly higher AKASI and LC reduction rates (75.5 % vs. 63.7 % [P = 0.023] and 91.3 % vs. 80.4 % [P = 0.043]).

CONCLUSIONS

S-PDT with AFXL pretreatment represents a safe and almost painless treatment for patients with AKs on the head and improves treatment efficacy.

Pulmonary function testing in children and infants

Pulmonary function testing is performed in children and infants with the aim of documenting lung development with age and making diagnoses of lung diseases. In children and infants with an established lung disease, pulmonary function is tested to assess the disease progression and the efficacy of therapy. It is difficult to carry out the measurements in this age group without disturbances, so obtaining results of good quality and reproducibility is challenging. Young children are often uncooperative during the examinations. This is partly related to their young age but also due to the long testing duration and the unpopular equipment. We address a variety of examination techniques for lung function assessment in children and infants in this review. We describe the measuring principles, examination procedures, clinical findings and their interpretation, as well as advantages and limitations of these methods. The comparability between devices and centres as well as the availability of reference values are still considered a challenge in many of these techniques. In recent years, new technologies have emerged allowing the assessment of lung function not only on the global level but also on the regional level. This opens new possibilities for detecting regional lung function heterogeneity that might lead to a better understanding of respiratory pathophysiology in children.

Platelet factor 4 plasma levels at rest and after exercise in patients with recent myocardial infarction

Plasma levels of platelet factor 4 (PF 4) were determined in 30 patients with recent acute myocardial infarction. Comparisons were made with the levels in 26 age-matched controls. In another 15 patients, also with recent myocardial infarction, PF 4 plasma levels were determined before and immediately after a standardized exercise stress test. At rest, none of the patients had elevated PF 4 levels. Only one patient demonstrated an increase after exercise. These findings are in conflict with some recent reports. The importance of age-matched controls, the hazard of in vitro platelet activation and the possible effect of beta-blocking and calcium-antagonistic drugs on PF 4 plasma levels is discussed below.

The influence of endogenous cortisol on the peripheral conversion of thyroxine in patients with acute myocardial infarction

A study was performed to elucidate whether endogenous cortisol, as previously suggested, could be responsible for the decreased T3 levels seen in euthyroid patients with acute myocardial infarction. Levels of these hormones as well as levels of T4 and reverse-T3 were monitored in 31 consecutive patients admitted to the Coronary Care Unit with symptoms of precordial pain or with acute arrhythmias. Sixteen of the patients had proven myocardial infarction, the remaining 15 were used as a control group. The results demonstrated that a reduction of T3 levels was seen in the infarction group without evidence of a statistically significant difference between the daily mean cortisol levels. No significant difference could be observed in T4 or reverse-T3 levels in the two groups or in T3 levels in the control group. It is concluded that the decrease in T3 levels is not a consequence of the increased levels of endogenous cortisol.

Expression of a Functional Proteinase Inhibitor Capable of Accepting Xylose: Bikunin

Bikunin is a Kunitz-type proteinase inhibitor, which is cross-linked to heavy chains via a chondroitin sulfate chain, forming inter-alpha-inhibitor and related molecules. Rat bikunin was produced by baculovirus-infected insect cells. The protein could be purified with a total yield of 20 mg/liter medium. Unlike naturally occuring bikunin the recombinant protein had no galactosaminoglycan chain. Endoglycosidase digestion also suggested that the recombinant form lacked N-linked oligosaccharides. Bikunin is translated as a part of a precursor, alpha1-microglobulin/bikunin, but the functional significance of the cotranslation is unknown. Our results indicate that the proteinase inhibitory function of bikunin is not regulated by the alpha1-microglobulin-part of the alpha1-microglobulin/bikunin precursor since recombinant bikunin had the same trypsin inhibitory activity as the recombinant precursor. Both free bikunin and the precursor were also functional as a substrate in an in vitro xylosylation system. This demonstrates that the alpha1-microglobulin-part is not necessary for the first step of galactosaminoglycan assembly.

Increase of bikunin and alpha1-microglobulin concentrations in urine of rats during pregnancy is due to decreased tubular reabsorption

Bikunin and alpha1-microglobulin are two plasma proteins of about 25 kDa which are made in the liver from a common precursor. The concentration of bikunin in human urine has been shown to increase several fold during various conditions of stress. The mechanism behind this increase is unknown. We have studied pregnant rats and found that the bikunin and alpha1-microglobulin levels in their urine increased 3-fold towards the end of the pregnancy, whereas those of albumin and orosomucoid did not. There were no significant changes in either the bikunin/alpha1-microglobulin mRNA level or the concentrations of the two proteins in serum. These findings imply that the synthesis and the clearance rates of bikunin and alpha1-microglobulin are normal during pregnancy but that the tubular reabsorption of these proteins is decreased.

Alpha1-microglobulin and bikunin in rats with collagen II-induced arthritis: plasma levels and liver mRNA content

The plasma proteins alpha1-microglobulin (alpha1-m) and bikunin are synthesized in the liver as a common precursor which is cleaved just before secretion. Half of plasma alpha1-m is covalently linked to fibronectin and alpha1-inhibitor-3, and more than 95% of bikunin is part of pre-alpha-inhibitor, inter-alpha-inhibitor and related large molecules. Both alpha1-m and bikunin have been shown to be involved in inflammation, but the regulation of their synthesis is not clear. The authors have measured the plasma and urinary concentrations of alpha1-m and bikunin as well as their hepatic mRNA levels in rats during the development of collagen-induced arthritis. Also, the plasma concentrations of acknowledged acute-phase proteins were measured. The results suggested a biphasic inflammatory reaction: an early response after 1 week, represented by an elevated fibronectin level; and a late response after 3 weeks, represented by elevated alpha1-acid glycoprotein and decreased albumin and alpha1-inhibitor-3 levels. The alpha1-m-bikunin mRNA content in liver was slightly reduced after 1 week and elevated after 3 weeks, but the total concentrations of free and bound alpha1-m and bikunin in plasma were unchanged. The free bikunin fraction as well as the fibronectin/alpha1-m complex in plasma, however, were elevated after 1 week. Urinary bikunin levels were also elevated after 1 week, whereas urinary alpha1-m levels remained unchanged. The results thus suggest that free bikunin in plasma is increased and excreted in the urine at an early stage during the development of collagen-induced arthritis. Later, when the synthesis rate of alpha1-m-bikunin is elevated, both proteins are most likely directed to other locations in the body.

Prothrombin, albumin and immunoglobulin A form covalent complexes with alpha1-microglobulin in human plasma

Molecules containing the 33-kDa plasma protein alpha1-microglobulin were isolated from human plasma by anti-(alpha1-microglobulin) affinity chromatography. Five major bands could be seen after electrophoretic separation of the alpha1-microglobulin-containing proteins under native conditions. Immunoblotting demonstrated alpha1-microglobulin in all five bands. Two of these have been described previously: free alpha1-microglobulin and alpha1-microglobulin complexed with IgA (IgA x alpha1-microglobulin). The other three bands were identified as prothrombin alpha1-microglobulin, albumin x alpha1-microglobulin and dimeric alpha1-microglobulin. Prothrombin x alpha1-microglobulin were 1:2 and 1:1 complexes which carried approximately 1% of total alpha1-microglobulin, had molecular masses of about 145 kDa and 110 kDa upon SDS/PAGE and dissociated completely to free alpha1-microglobulin and prothrombin (72 kDa) when reducing agents were added, suggesting that the complexes were stabilized by disulfide bonds. The alpha1-microglobulin molecules did not inhibit cleavage of prothrombin by factor Xa and were bound to the peptides which were released upon activation of prothrombin. Albumin x alpha1-microglobulin, corresponding to 7% of total plasma alpha1-microglobulin, was a mixture between 1:1 and 1:2 complexes, with masses upon SDS/PAGE of approximately 100 kDa and 135 kDa, respectively. Both these complexes dissociated only partially to free alpha1-microglobulin and albumin when reducing agents were added. The albumin x alpha1-microglobulin complexes carried a yellow-brown chromophore similar to free alpha1-microglobulin. The complex-binding to alpha1-microglobulin did not block the fatty-acid-binding ability of albumin. The plasma concentrations of albumin x alpha1-microglobulin and prothrombin x alpha1-microglobulin were estimated to 5.2 mg/l and 1.1 mg/l, respectively.

alpha 1-Microglobulin destroys the proteinase inhibitory activity of alpha 1-inhibitor-3 by complex formation

The immunoregulatory plasma protein alpha 1-microglobulin (alpha 1-m) and the proteinase inhibitor alpha 1-inhibitor-3 (alpha 1I3) form a complex in rat plasma. In the present work, it was demonstrated that the alpha 1I3.alpha 1-m complex has no inhibitory activity, the bait region was not cleaved by low amounts of proteinases, and it was unable to covalently incorporate proteinases. The results also indicated that the thiolester bond of the alpha 1I3.alpha 1-m complex was broken. The alpha 1I3.alpha 1-m complex was cleared from the circulation much faster than native alpha 1I3, with a half-life of approximately 7 min. Structurally, however, the alpha 1I3.alpha 1-m complex was similar to native alpha 1I3 rather than alpha 1I3 cleaved by proteinases. It is speculated that the role of alpha 1-m is to destroy the function of alpha 1I3 by blocking the bait region and breaking the thiolester and causing its physical elimination by rapid clearing from the blood circulation. It is also possible that the formation of complexes between alpha 1-m and alpha 1I3 may serve as a mean to regulate the function of alpha 1-m since its complex with alpha 1I3 is taken up rapidly by cellular receptors for alpha-macroglobulins.

Isolation and characterization of fibronectin-alpha 1-microglobulin complex in rat plasma

Molecules containing the 28 kDa immunoregulatory protein alpha 1-microglobulin (alpha 1-m), also known as protein HC, were isolated from rat plasma or serum by immunoaffinity chromatography. Three molecular species were distinguished on the basis of nondenaturing PAGE. Two of these have been described previously: uncomplexed alpha 1-m, and the complex of alpha 1-m with alpha 1-inhibitor-3. The third species was analysed by denaturing PAGE, immunoblotting, proteinase digestion and N-terminal-sequence analyses, and shown to consist of a complex between alpha 1-m and fibronectin. This complex, with a mass of about 560 kDa, was resistant to dissociation in the presence of denaturants, but not in the presence of reducing agents in combination with denaturants, and we conclude that the two components are linked by disulphide bonds. About 60% of the total detectable plasma alpha 1-m exists as high-molecular-mass complexes distributed approximately evenly between fibronectin and alpha 1-inhibitor-3. Immunochemical analyses were used to determine the proportion of the total plasma pools of fibronectin and alpha 1-inhibitor-3 that circulate in complex with alpha 1-m. About 3-7% of the total plasma fibronectin from three different rat strains contained alpha 1-m, whereas 0.3-0.8% of the total plasma alpha 1-inhibitor-3 contained alpha 1-m. Complexes were found at similar levels in plasma and serum, indicating that coagulation is not responsible for complex formation. Moreover, immunochemical analyses of human plasma revealed small amounts of alpha 1-m in complex with fibronectin and alpha 2-macroglobulin (an alpha 1-inhibitor-3 homologue). The existence of a complex between alpha 1-m and fibronectin in rats and humans suggests a mechanism for the incorporation of the immunoregulatory molecule alpha 1-m into the extracellular matrix.

Localization of the binding site for streptococcal protein G on human serum albumin. Identification of a 5.5-kilodalton protein G binding albumin fragment

Protein G is a streptococcal cell wall protein with separate and repetitively arranged binding domains for immunoglobulin G (IgG) and human serum albumin (HSA). In this work, the binding of protein G to HSA was studied. The results suggest that a single binding site is present on HSA: the apparent size of the HSA-protein G complex (230 kDa) corresponded to two or three HSA molecules bound to one protein G molecule, and Ouchterlony immunodiffusion did not yield any precipitate between protein G and HSA. HSA was cleaved by pepsin and CNBr into several fragments which were identified by SDS-PAGE and N-terminal amino acid sequencing, and the binding of protein G to the fragments was studied in Western blot experiments. The results indicated that the binding area was located in disulfide loops 6-8, involving both the second (loop 6) and the third (loops 7 and 8) domain of HSA. One of the protein G binding pepsin fragments, with an apparent molecular mass of 5.5 kDa, located in loops 7 and 8, was isolated and found to completely inhibit the binding between protein G and the intact HSA, again suggesting a single protein G binding site on serum albumin. Reducing the disulfide bonds of HSA, and subsequent alkylation of the half-cystine residues, significantly decreased the affinity for protein G. Protein G bound to albumin from baboon, cat, guinea pig, hamster, hen, horse, man, mouse, and rat, but not to albumin from cow, dog, goat, pig, rabbit, sheep, snake, or turkey.

Pulmonary reactions caused by welding-induced decomposed trichloroethylene

This is the report of a welder who performed argon-shielded electric arc welding in an atmosphere containing trichloroethylene. He developed immediate respiratory symptoms, pulmonary edema 12 hours after exposure, and recurring dyspnea ten days after exposure. These pulmonary reactions might be explained by inhalation of decomposition products of trichloroethylene such as dichloroacetyl chloride and phosgene.

Isolation of rat serum alpha 1-microglobulin. Identification of a complex with alpha 1-inhibitor-3, a rat alpha 2-macroglobulin homologue

Alpha 1-Microglobulin (alpha 1-m), or protein HC, a low molecular weight plasma protein with immunoregulatory properties, was isolated from rat serum by affinity chromatography using Sepharose-coupled monoclonal anti-alpha 1-m antibodies. High molecular weight forms of alpha 1-m were then separated from the low molecular weight alpha 1-m by gel chromatography of the eluted proteins. The apparent Mr (28,000), the charge heterogeneity, the N-linked carbohydrate, and yellow-brown chromophore suggest that the low molecular weight alpha 1-m is the serum counterpart to urinary alpha 1-m, which was purified previously. A high molecular weight complex of alpha 1-m was also isolated by the gel chromatography. It was homogeneous as judged by nondenaturing polyacrylamide gel electrophoresis. The molecule was bound by antibodies against human alpha 2-macroglobulin, and experiments with antisera against the three alpha-macroglobulin variants in rat serum, alpha 1-macroglobulin, alpha 2-macroglobulin, and alpha 1-inhibitor-3 (alpha 1I3) suggested that alpha 1I3 was the complex-partner of alpha 1-m. An antiserum raised against high molecular weight alpha 1-m was then used to isolate the complex-partner of alpha 1-m from rat serum with affinity chromatography, and this molecule was positively identified as alpha 1I3 by its physicochemical properties. Gel chromatography of the alpha 1I3.alpha 1-m complex suggested a molecule with an Mr of 266,000. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, however, it migrated as three major molecular species with apparent molecular weights of 224,000, 205,000, and 194,000 and several minor species of both higher and lower molecular weights, suggesting a complex subunit structure. alpha 1-m and alpha 1I3 could be detected in all three major species by Western blotting, and NH2-terminal amino acid sequencing suggested a molar ratio of 1:1 of alpha 1-m and alpha 1I3 in all three species. alpha 1I3.alpha 1-m was colorless, did not show light absorbance beyond 300 nm which is typical of low molecular weight alpha 1-m and was electrophoretically homogeneous, suggesting that it lacks the chromophore. Finally, the serum concentrations of the alpha 1I3.alpha 1-m complex and free alpha 1-m were determined as 0.16 and 0.010 g/liter, respectively. Thus, alpha 1I3.alpha 1-m constitutes 1-3% of the total alpha 1I3 in rat serum (w/w) and approximately 60% of the total alpha 1-m.

Isolation and characterization of a 14-kDa albumin-binding fragment of streptococcal protein G

Protein G, a streptococcal cell wall protein, has separate binding sites for human albumin and IgG. Streptococci expressing protein G were treated with the bacteriolytic agent mutanolysin. Several IgG- and human serum albumin (HSA)-binding peptides were identified in the material thus solubilized and one of these, a 14-kDa peptide, was found to bind HSA but not IgG in Western blot experiments. This molecule was purified by affinity chromatography on Sepharose coupled with HSA followed by gel filtration on Sepharose 6B and a final affinity chromatography on IgG-Sepharose, by which low Mr W(15 to 20 kDa)IgG-binding peptides were removed. In different binding experiments the purified 14-kDa peptide bound exclusively HSA and the equilibrium constant between the peptide and HSA was determined to be 3.4 X 10(8) M-1. The relation between the 14-kDa molecule and protein G was studied by analyzing the N-terminal amino acid sequence of the peptide and comparing it with the previously determined protein G sequence. The 40 N-terminal amino acids were found to be identical with an amino acid sequence starting at position 62 in the protein G molecule. These and previous data enabled us to locate the albumin binding to the repetitively arranged domains in the N-terminal half of the protein G molecule.

Isolation and characterization of a 14-kDa albumin-binding fragment of streptococcal protein G

Protein G, a streptococcal cell wall protein, has separate binding sites for human albumin and IgG. Streptococci expressing protein G were treated with the bacteriolytic agent mutanolysin. Several IgG- and human serum albumin (HSA)-binding peptides were identified in the material thus solubilized and one of these, a 14-kDa peptide, was found to bind HSA but not IgG in Western blot experiments. This molecule was purified by affinity chromatography on Sepharose coupled with HSA followed by gel filtration on Sepharose 6B and a final affinity chromatography on IgG-Sepharose, by which low Mr W(15 to 20 kDa)IgG-binding peptides were removed. In different binding experiments the purified 14-kDa peptide bound exclusively HSA and the equilibrium constant between the peptide and HSA was determined to be 3.4 X 10(8) M-1. The relation between the 14-kDa molecule and protein G was studied by analyzing the N-terminal amino acid sequence of the peptide and comparing it with the previously determined protein G sequence. The 40 N-terminal amino acids were found to be identical with an amino acid sequence starting at position 62 in the protein G molecule. These and previous data enabled us to locate the albumin binding to the repetitively arranged domains in the N-terminal half of the protein G molecule.

Purification of streptococcal protein G expressed by Escherichia coli by high performance liquid affinity chromatography using immobilized immunoglobulin G and albumin

A one-step HPLC method was developed for the purification of protein G, a cell wall molecule from group C and G streptococci with immunoglobulin G- and albumin-binding properties. Lysed Escherichia coli bacteria infected with lambda-phages containing the protein G gene from group G streptococci were used as a starting material for the preparations. The lysate was applied to a column with immobilized human immunoglobulin G or human serum albumin. Protein G was selectively bound and eluted at pH 2.0. A 750-fold purification was achieved. Sodium dodecylsulfate + polyacrylamide gel electrophoresis showed that the highly purified protein G consisted of three sets of doublets with the apparent molecular weight of 64 and 67, 56 and 58, and 45 and 47 kilodaltons, respectively. A specific method for quantitation of small amounts of protein G was developed and used for specific tracing of the protein after the affinity chromatography. Goat polyclonal antibodies were bound to an antigen coated to the plastic walls of microtiter plates, causing the Fc-region of the immunoglobulins to be directed outwards. Unknown samples of protein G were then allowed to compete with radio-iodinated protein G (solid phase radioassay) or protein G coupled to alkaline phosphatase (enzyme linked sorbent assay) for the Fc-regions.