Hydrophobic surfactant-associated polypeptides: SP-C is a lipopeptide with two palmitoylated cysteine residues, whereas SP-B lacks covalently linked fatty acyl groups

Pulmonary surfactant contains two hydrophobic polypeptides, SP-B and SP-C, with known amino acid sequences and with truncated subforms lacking the N-terminal residues. Treatment of SP-C with KOH releases fatty acids (palmitic acid to more than 85%) in molar ratios of 1.8-2.0 relative to the polypeptide. Furthermore, plasma-desorption mass spectrometry shows native SP-C of both the intact and truncated types to be monomers with masses about 500 units higher than those expected for the polypeptide chains. After treatment with KOH, trimethylamine, or dithioerythritol, the polypeptide masses are obtained. These results prove that native SP-C is a lipopeptide with two palmitoyl groups covalently linked to the polypeptide chain. The deacylation conditions, the presence of two cysteine residues in the polypeptide, and the absence of other possible attachment sites establish that the palmitoyl groups are thioester-linked to the two adjacent cysteine residues. In contrast, the major form of porcine SP-B is a dimer without fatty acid components. That SP-C is a true lipopeptide with covalently bound palmitoyl groups suggests possibilities for functional interactions. It gives a direct physical link between SP-C and surfactant phospholipid components. Long-chain acylation may constitute a means for association of proteins with membranes and could conceivably modulate the stability and biological activity of surfactant films.

Time-resolved laser-induced fluorescence spectroscopy for enhanced demarcation of human atherosclerotic plaques

We report on the enhanced demarcation between human atherosclerotic plaques and normal vessel wall obtained using time-resolved detection of laser-induced fluorescence rather than the customary time-integrated monitoring technique. A frequency-doubled mode-locked and cavity-dumped continuous wave dye laser was used for picosecond pulse generation at 320 nm, and photon-counting techniques were employed for the time-resolved signal monitoring from human aorta samples in vitro. Implications for imaging fluorescence angioscopy and spectroscopic guidance in laser ablation of plaque are indicated.

Studies on the lecithin: cholesterol acyltransferase substrate properties of HDL as determined by its subclass distribution analysed by gradient gel electrophoresis

In order to study the impact of high-density lipoproteins (HDL) subclasses on the ability of HDL to act as substrate for lecithin: cholesterol acyltransferase (LCAT), we isolated HDL from nine normolipidemic male subjects. The HDL particle size distribution was analysed by gradient gel electrophoresis and the esterification rate of the isolated homologous HDL was compared with a pool of HDL where all the nine subjects took part. It was found that the strongest determinant for HDL cholesterol esterification rate was the inhibitory action of HDL subclass 2B.

Fluorescence diagnosis and photochemical treatment of diseased tissue using lasers: Part I

Lasers are useful in many applications in medicine and biology. Historically, most laser use has involved heat generated in the interaction of the laser beam with the tissue. Today, however, the spectroscopic aspects of this laser use are playing a more dominant role in a number of applications. In this two-part series, Sune Svanberg and co-workers present illustrations of emerging clinical applications from cooperative work performed by the Lund Institute of Technology and the Lund University Hospital. Part I includes a survey of laser techniques for atomic and molecular analyses of samples of medical interest, spectroscopic analysis of the laser-induced plasma obtained when a high-power pulsed laser beam interacts with tissue, and the use of tumor-seeking agents in combination with laser radiation to provide new possibilities for malignant tumor detection and treatment. Part II, which will appear in the January 1, 1990, issue, describes the use of laser-induced fluorescence for tumor and plaque diagnostics. Different lasers have been used, and research efforts increasingly are being focused on excimer lasers and lasers in the IR region for the ablation of atherosclerotic plaques, cell layer by cell layer.

Tobacco smoke removal with room air cleaners

The ability of room air cleaners to remove gases and particles from air contaminated with tobacco smoke has been studied. Thirty-one air cleaners were tested. Various air-cleaning devices were used, ie, electrostatic precipitators, electret fiber filters, ionizers, activated carbon, impregnated alumina, ionizing lamps, and an electron generator. The airflow rates were in the range of 0-500 m3/h. The measurements covered particle sizes of 0.01-7.5 microns and the following gases: carbon monoxide, ammonia, formaldehyde, nitric oxide, nitrogen dioxide, hydrocarbons, and hydrogen cyanide. No formal standard procedure exists for testing room air cleaners; therefore the tests were made in the following way. Tobacco smoke was generated and mixed in a closed room. The room air cleaner was started, and the decay rates for the gases and particles were measured. The results were calculated as equivalent airflow rates, ie, the clean airflow rate causing the same decay rate for contaminant concentrations in a room. The equivalent airflow rates were 0-360 m3/h. The rate of ozone emission by electrostatic precipitators and ionizers was also measured. One general conclusion was that it is much more difficult to remove gases than particles.

Topical non-steroidal anti-inflammatory drugs inhibit non-immunologic immediate contact reactions

The effects of 3 topical applications of non-steroidal anti-inflammatory drugs (NSAIDs), diclofenac 1%, naproxene 10% and salicylic acid 5% in gel vehicles, on immediate contact reactions to 500 mM benzoic acid, 500 mM cinnamic aldehyde, 50 mM methyl nicotinate, all in pet., and 14.1 M (100%) dimethyl sulfoxide, were studied in 16 medical students. Erythema and edema reactions were observed visually, and the changes in the skin blood flow were monitored using laser-Doppler flowmetry (LDF). NSAIDs had significant inhibitory effects on erythema induced by all 4 substances tested and on edema induced by methyl nicotinate. The inhibition was probably due in part to percutaneous absorption and systemic effects of NSAIDs. There were differences between visual and LDF assessments, which stresses the importance of monitoring erythematous reactions of the skin both visually and with LDF.

Development of femoral atherosclerosis in hypercholesterolemic patients during treatment with cholestyramine and probucol/placebo: Probucol Quantitative Regression Swedish Trial (PQRST): a status report

The Probucol Quantitative Regression Swedish Trial is being performed to investigate the effects of probucol on atherosclerosis in the femoral artery. Probucol is combined with cholestyramine and dietary management in hypercholesterolemic patients, and the effects of atheroma developing in the femoral artery will be followed by a quantitative angiographic technique. A randomly selected control group is also being managed by dietary therapy and cholestyramine, but receives placebo instead of probucol. The treatment time in this double-blind trial is 3 years, and femoral angiography is performed yearly. Detailed lipoprotein and apolipoprotein analysis are performed at monthly intervals. The basic study design is described here, and some results from the open prerandomization phase of the study are presented.

Size and structure of the hydrophobic low molecular weight surfactant-associated polypeptide

The most abundant low molecular weight protein of pulmonary surfactant has unusual properties. Its primary structure has now been determined by analysis at the protein level. The highly hydrophobic polypeptide is resistant to cleavage with proteolytic enzymes, but it was possible to generate fragments by limited cleavage with concentrated HCl or with sodium in liquid ammonia. Acid hydrolysis of the peptide required exceptional conditions for release of all residues. The N-terminus is heterogeneous, and in its longest form the primary structure consists of 35 residues. This analysis establishes that the size of the major native hydrophobic surfactant polypeptide is considerably smaller than previously proposed. Biological effects of the polypeptide recombined with phospholipids are confirmed in vitro by using a pulsating bubble system and in vivo by using premature newborn rabbits. The molecule has branched-chain amino acid residues at about two-thirds of all positions and lacks nine types of residue. The middle third is composed entirely of hydrophobic residues, and fragments from this part are sparingly soluble even in organic solvents. The hydrophobic region is preceded by a more hydrophilic, N-terminal segment. Thus, the molecule has two contrasting parts, like a detergent, which may explain its essential role in the pulmonary surfactant system.

Hydrophobic 3.7 kDa surfactant polypeptide: structural characterization of the human and bovine forms

The human and bovine forms of the hydrophobic 3.7 kDa surfactant polypeptide have been structurally analyzed. The polypeptide is essentially inert to enzymatic proteolysis, and methods for analysis include peptide handling in organic solvents and fragment generation by limited acid hydrolysis. The molecule exhibits N-terminal trimming, and the relative abundance of the different starting positions varies both among species and between adult and fetal forms of the surfactant polypeptide. The bovine major form is one residue shorter than the mature 35-residue human molecule. Comparison of the porcine, human and bovine polypeptides reveals a conserved hydrophobic middle/C-terminal segment and a variable hydrophilic N-terminal part.

Mitochondrial aldehyde dehydrogenase from horse liver. Correlations of the same species variants for both the cytosolic and the mitochondrial forms of an enzyme

The primary structure of the mitochondrial form of horse liver aldehyde dehydrogenase has been determined, utilizing peptide analyses and homology with other enzyme forms. The subunit exhibits N-terminal heterogeneity in size similar to that for the corresponding human mitochondrial protein, the longest form having 500 residues. Catalase was identified as a contaminant of the preparations. All four pairs within a set of aldehyde dehydrogenases can now be compared, including the same two species variants (horse and human) for both the cytosolic and mitochondrial enzyme, revealing characteristic differences although Cys-302 and other segments of presumed functional importance are unchanged. The cytosolic and mitochondrial enzymes are clearly different (172 exchanges in the horse pair; 160 exchanges in the human pair) and the mitochondrial forms are more conserved (28 exchanges of 500 residues) than the cytosolic ones (43 exchanges). Distributions of the residue substitutions also differ between the two enzyme types. These results suggest a comparatively distant separation of the cytosolic and mitochondrial enzymes into forms with separate functional constraints that are more strict on the mitochondrial than the cytosolic enzyme. Unexpectedly, positions with residues unique to one of the four enzymes are about twice as common in both of the horse proteins than in either of the human proteins. This difference may reflect a general pattern for human/non-human proteins, showing that not only functional properties of the protein, but also other factors, such as generation time (longer in man than in horse), are important for enzyme divergence.

Low-molecular-mass surfactant protein type 1. The primary structure of a hydrophobic 8-kDa polypeptide with eight half-cystine residues

The low-molecular-mass surfactant protein fraction, soluble in chloroform/methanol, contains at least two separate polypeptide chains. The 8-kDa form (type I) was isolated, [14C]carboxymethylated after reduction, and submitted to structural analysis. Its highly hydrophobic nature complicated purification, proteolytic cleavages, and sequence analysis. Acid hydrolysis in 6 M HCl for 7 days was necessary for release of branched-chain residues in full yield. Pepsin was the only enzyme found to cleave the surfactant protein and was used to complement peptide generation by chemical cleavage with CNBr. The primary structure deduced consists of 79 residues with 8 half-cystine residues, and a total of 39% branched-chain hydrophobic residues. However, 11 residues are charged at physiological pH, and all properties of the primary structure are not entirely outstanding in relation to those of other proteins. Hydrophobic segments, coupled with a presumably tight folding from the presence of disulfide bridges, probably explain the unusual properties and the solubility in organic solvents.

Calf muscle adaptation in intermittent claudication. Side-differences in muscle metabolic characteristics in patients with unilateral arterial disease

The adaptation of enzyme activities, notably in the oxidative metabolism, and of prerequisites for tissue transport of oxygen in the claudication leg was evaluated by comparing muscle biopsies from the gastrocnemius muscle of the claudication and the symptom-free leg of seven patients with unilateral claudication. The claudication leg had higher activities of a marker enzyme for mitochondrial oxidative capacity, citrate synthase (CS), as well as of the MB and the mitochondrial isoenzyme of creatine kinase (CK), which are considered to be involved in the transfer of high energy phosphate from the mitochondria to the resynthesis of ATP in the cytoplasm. The difference between claudication and healthy leg in activities of these CK isoenzymes were well correlated with the corresponding side difference in CS activity. No significant differences between claudication and healthy leg were found in distribution of muscle fibre types or fibre dimension, capillary density or myoglobin content, nor was there any side difference in phosphofructokinase or lactate dehydrogenase. Side differences tended to be greater in those patients with the most advanced obstructive arterial disease as estimated from non-invasive pressure measurements. It is concluded that in reasonably physically-active patients, the mode of ischaemia to which the claudication leg is subjected leads to a metabolic adaptation characterized by increased activities of enzymes involved in the oxidative metabolism, but no significant adaptation of either the conditions for local oxygen transport, as estimated by myoglobin content, and capillary density, or capacity for anaerobic metabolism.

Temperature-biofeedback treatment of migraine headache. Specific effects and the effects of "generalization training"

Digital skin temperature biofeedback was used in the treatment of migraine headache. The value of a "generalization-training" procedure as well as the relationship between temperature control and clinical effects were studied. In all, 24 migraine sufferers were randomly assigned to either "standard" or a "generalization-training" biofeedback procedure and were given eight treatment sessions. Headache activity was measured before, during, and after treatment; and digital skin temperature was continuously measured during training sessions. From the results the following tentative conclusions were drawn: (1) Those who acquire temperature control show greater decrease in headache, (2) pretreatment baseline finger temperatures might predict if temperature control will be achieved, and (3) "generalization-training" methods do not seem to result in a greater degree of temperature control.

Lipid bilayer polypeptide interactions studied by molecular dynamics simulation

A model membrane with a polypeptide alpha-helix inserted has been simulated by molecular dynamics at a temperature well above the gel/liquid crystalline phase transition temperature. Order parameters of the lipids and other equilibrium and dynamic quantities have been calculated. Three systems, polyglycine constrained into an alpha-helical configuration, glycophorin with similarly conformationally constrained backbone and finally glycophorin free to change its backbone conformation, have been studied. In all cases there was an ordering of the chains close to the helix. This effect was, however, much smaller for glycophorin with its rather bulky side chains than for polyglycine. The dynamics of the lipids were affected by the neighbouring helix, not drastically however. Lateral diffusion and reorientational time correlations of lipids close to the helix were slower than for the bulk ones, but not more than two or three times. Thus, we did not find any evidence of bound or frozen boundary lipids.

Results of surgical treatment for iliofemoral venous thrombosis

The long-term results after venous thrombectomy combined with a temporary arteriovenous fistula were evaluated in 19 patients. Clinical status, isotope phlebography, venous occlusion plethysmography and foot volumetry were performed after a mean follow-up time of 38 months (range 13-75). The primary operation was successful in 17 of the 19 patients; the 2 remaining had chronic occlusions of their iliac veins. At the time of closure of the arteriovenous fistula, i.e. 3 months after thrombectomy, 14 patients had a patent iliac vein. At follow-up eight patients were considered to have a patent iliac vein, eight had a partial restitution and three had an occluded iliac vein. The group as a whole had no impaired venous emptying of the leg, but the small group of patients with occlusion at follow-up according to isotope phlebography seemed to have an impaired venous emptying. Foot volumetry showed only minor signs of valvular insufficiency, mainly in limbs with distal extension of the initial thrombus or only partial restitution of venous patency. A good long-term result can be expected after venous thrombectomy with a temporary arteriovenous fistula particularly in younger patients where the thrombosis is limited to the iliofemoral segment. This emphasizes the importance of early operation before distal extension of the thrombus occurs.

Long-Term Results of Thrombectomy with Temporary Arteriovenous Fistula for Ileofemoral Venous Thrombosis

Nineteen patients with acute ileofemoral venous thrombosis were subjected to thrombectomy with the addition of a temporary a-v fistula and anticoagulant treatment. At follow-up 3 years after surgery isotope phlebography disclosed more-or-less patent ileofemoral segments in 16 patients. The venous outflow capacity as estimated from venous emptying curves was normal in all but three totally occluded limbs, indicating an adequate collateral compensation. Foot volumetry demonstrated signs of venous valvular insufficiency, mainly in legs with a distal extension of the initial thrombosis; these patients complained of symptoms of post-thrombotic syndrome, which emphasizes the importance of early operation.

Superoxide dismutase in human testis preparations

A protein fraction from human testis was structurally investigated. The main component of the fraction reported to contain inhibin-like activity was purified and analyzed by tryptic digestion. The peptides obtained identified the protein as an enzyme, superoxide dismutase, previously known to be present in seminal plasma. The results show that superoxide dismutase is a major enzyme, also of testicular material. They further demonstrate the importance of using pure fractions, and controls such as checks with structural analysis or synthetic peptides, in the work of elucidating the nature of inhibin and other hormonal peptides.

Peptides of postulated inhibin activity. Lack of in vitro inhibin activity of a 94-residue peptide isolated from human seminal plasma, and of a synthetic replicate of its C-terminal 28-residue segment

A 94-residue polypeptide isolated from human seminal plasma and its chemically synthesized C-terminal 28-residue segment were studied in an in vitro inhibin bioassay utilizing rat pituitary cell cultures. Both peptides have previously been claimed to have inhibin activities, and the effects on the secretion and cellular content of gonadotrophins (FSH and LH) were now assessed in the in vitro assay. No inhibition was found. After 72 h of culture, both the cellular content and the spontaneous as well as the LHRH-stimulated release of bioactive or immunoactive FSH and LH remained unaffected. Similarly, no effects were found on the storage and/or release of prolactin, growth hormone, or thyrotropin. We conclude that both the native 94-residue peptide and the synthetic replicate of its C-terminal 28-residue segment, do not influence the pituitary FSH secretion when assessed in this in vitro system.

Concentration and chemical composition of plasma lipoprotein subfractions in patients with peripheral vascular disease. Evidence for normal apolipoprotein B but low cholesteryl ester content in small VLDL

Subfractionation of the 3 major plasma lipoprotein classes was performed in 20 male patients with symptomatic peripheral vascular disease (PVD) and 18 male healthy controls of similar age and serum lipid levels as the patients in order to investigate if, at comparable levels of total serum lipids, any difference in the distribution or the chemical composition of the lipoprotein subfractions existed between patients and controls. Concentrations of free and esterified cholesterol, triglycerides, phospholipids, apolipoprotein B (apo B) and soluble apolipoproteins did not differ significantly in any lipoprotein subfraction of PVD patients compared to controls. Calculated molecular weights and numbers of lipoprotein particles/ml plasma were also similar in the 2 groups except that there were more heavy LDL particles in the patient group. Plotting concentrations of apo B against cholesteryl ester in the VLDL-D subfraction (Sf 20-100) yielded a linear regression in both groups. The PVD regression line was significantly steeper than that of controls. Calculation of the molecular mass of the various constituents of the VLDL-D fraction in the subjects with the highest content of esterified cholesterol in VLDL-D, where this difference was most pronounced, suggests that this difference was due entirely to a decreased number of cholesteryl ester molecules per lipoprotein particle in PVD. The findings suggest that a disordered metabolism of plasma cholesteryl esters may be present in certain PVD patients.

The tRNA cycle and its relation to the rate of protein synthesis

With the aid of a kinetic model, we have investigated how the adaptation between the various components of the tRNA cycle and the codon frequencies affects the rate of protein synthesis. Depending on the relative amounts of total tRNA, synthetase and ribosomes, the optimal correlations vary between a situation where all tRNA species are either present in equal amounts or are present in amounts proportional to the square-root of the corresponding codon frequencies, and a situation where the amounts of the different tRNA species present are linearly proportional to the codon frequencies.

Error propagation in E. coli protein synthesis

A new approach to the error catastrophe theory, proposed by Leslie Orgel, is presented here. Our model is a development of previous models, but differs in several respects: the overall activity is assumed to be dependent on the error level, the effect of errors in the translating system, giving rise to additional errors in the succeeding generation of products, is explicitly included as a special term in our model, and scavenging enzymes are assumed to break down and eliminate products with a loose structure. Their efficiency is dependent on the error level. The model also takes into account the dilution of incorrect ribosomes and enzymes, and is described by a time-dependence in terms of ribosome/enzyme generations. The model and the contribution to the time development are discussed in the light of experiments on E. coli treated with streptomycin.

Analysis of an inhibin preparation reveals apparent identity between a peptide with inhibin-like activity and a sperm-coating antigen

The amino acid sequence of a large form of inhibin-like peptide in human seminal plasma was determined, and compared with structures reported for similar inhibin preparations and a seminal plasma globulin. The data confirm and correlate previous reports on this form of inhibin-like peptide. The structural comparisons further suggest that the peptide is closely similar to or possibly identical to a sperm-coating antigen reported to be synthesized from prostatic epithelium. This may correlate with non-gonadal origins of inhibin-like material and will help to elucidate the biological roles of inhibin(s).

Helical sidedness and the distribution of polar residues in trans-membrane helices

Trans-membrane helices have often been claimed to show "sidedness" in the distribution of polar and hydrophobic residues. However, an analysis of the statistical distribution of polar residues in randomly generated helices shows that the degree of bias commonly observed in real helices is far from statistically significant. It is concluded that "patchy" distributions of residues in such helices should be interpreted with great care.

Ethylene mass flow measurements with an automatic CO(2) laser long-path absorption system

A computer controlled CO(2) laser long-path absorption system has been used in a field experiment to measure the total emission of ethylene from a petrochemical factory. The ethylene concentration was measured along eight measurement paths at different elevations. Simultaneously meteorological data were collected. From these data we have calculated the mass flow from the factory. The result of the calculations agree well with the value estimated at the factory using conventional methods.

Self-control procedures in biofeedback: a review of temperature biofeedback in the treatment of migraine

It is argued that in order to optimize the achievement of self-control and to evaluate the clinical effects of biofeedback three skills should be included in training and assessment, namely: (1) the ability of voluntary control with external feedback, (2) the ability of voluntary control without external feedback, and (3) the ability to apply the self-control skill in critical situations in everyday life. A review of the literature concerning temperature-biofeedback in the treatment of migraine headaches shows that the research from this point of view is in a rather poor state of affairs and that no definite conclusion can in fact be drawn about the degree of self-control which has been achieved and hence of the ultimate clinical value of biofeedback.

Applied relaxation in treatment of "cardiac neurosis": a systematic case study

The treatment of a case of “cardiac neurosis” is described. Using an applied relaxation treatment program the client was taught relaxation as a coping skill to be used when she felt changes in cardiac activity. The therapy was conducted with minimal contact, the client did most of the training on her own with the help of taped instructions. The results showed a definite decrease in severity of the problem during the treatment period, and by the time of the follow-ups at 6 and 21 mo. after treatment, the client was almost completely relieved from these problems.

Temperature and pressure dependence of NH(3) and C(2)H(4) absorption cross sections at CO(2) laser wavelengths

Absorption cross sections at CO(2) laser wavelengths have been measured for ethylene and ammonia. The dependence of the cross sections on pressure and temperature have been investigated for pressures and temperatures normally occurring in the atmosphere. The changes in cross section are, e.g., 5% for ethylene at the P(14) 00 degrees 1-10 degrees 0 line and 10% for ammonia at the R(8) 00 degrees 1-10 degrees 0 line for a temperature change of 30 K. A comparison with theoretical calculations is made for ammonia.

Fracture of the capitulum humeri in children: a rare injury, often misdiagnosed

Fracture of the capitulum humeri is very uncommon in children. Two typical cases in adolescent girls illustrate the importance of distinguishing capitulum from lateral humeral condyle fractures, and of the feasibility of treatment of the former by excisional surgery.

[Determination of the amino acid spectrum as an aid in the up-dating of skeletal findings]

Estimation of the age of skeletal remains is usually based on subjective evaluation of the morphological grade of decomposition. This assumes, that the investigator is provided with pertinent experience. Experimentally elaborated physical and chemical methods proposed for objectification of the statements did not yet assest until today due to lacking temporal correlation. Our investigations were stimulated by observations on fossil bones indicating that the collagenbound amino acids diminish very slowly dependent on geological age. Samples of 53 skeletons of five to 2500 years were pulverized and subjected to acid hydrolysis. The amino acids released from bone collagen were separated by means of thin-layer chromatography and detected by isatin and ninhydrin reagents. The dye complexes of alanine, hydroxyproline, proline, tyrosine, and valine were measured densitometrically and quantified through calibration curves. We established, that the concentrations of the amino acids exhibited a time dependent reduction as equivalent of a loss collagen. The temporal correlation is very narrow (r less than -- 0,8) and sufficient for datings within plus/minus ten years of the more recent bones. Environmental conditions during post-mortem decay seem to have little influence on this process.