Promoting mental health and wellbeing in schools: the impact of yoga on young people's relaxation and stress levels

This study aimed to examine students' experiences with yoga interventions in school. The findings revealed that practicing yoga made young people more aware of their need to relax and positively impacted their mental health and wellbeing. We explored the emphasis on relaxation among our study participants and how relaxation is related to other aspects, such as their experience of stress and sleep habits. This article is based on qualitative data gathered from teenagers in Norway who participated in the Norwegian part of the European research project "Hippocampus: Promoting Mental Health and Wellbeing among Young People through Yoga." The project introduced yoga to young people in schools with an emphasis on those who were disadvantaged, including those with mental health issues and other challenges related to their background. Data were collected from nine individual, semi-structured interviews and 133 logs collected in the spring of 2019. The major themes identified through the interviews and log material included becoming more relaxed and aware of the need to unwind. Thus, the focus on relaxation is based on the importance of the participants assigned to this theme. The study results suggest that yoga enhanced the students' awareness and skills and empowered them to make healthier lifestyle choices. We viewed the importance of relaxation from a salutogenic perspective, focusing on the factors that contribute to good health in contrast to a pathogenic perspective, where curing diseases is the goal.

"I Just Find It Easier to Let Go of Anger": Reflections on the Ways in Which Yoga Influences How Young People Manage Their Emotions

In this article we discuss how young people experienced a school-based yoga intervention. We pay particular attention to how yoga provides a space for young people to deal with their emotions. We base our discussion on qualitative data from young people in Norway who participated in the European research project “Hippocampus: Promoting Mental Health and Wellbeing among Young People through Yoga.” The qualitative results are based on experiences described by these young people in individual semi-structured interviews and in diaries or logs. Our data include nine interviews performed in the spring of 2019 with young people of Norwegian and refugee background in their late teens and early twenties. There were also 133 logs noted by the students exposed to the yoga intervention. In the qualitative interviews, young people talk about yoga and emotional management, improved sleep habits, and regulation. They also report improved ability to regulate and cope with stress. Yoga seemed especially beneficial for refugee trauma. In this article, we have chosen to focus on the utterances of young people about emotions, as those were quite dominant in our data, especially in the interview material. We have identified instances of emotional regulation, but also of emotional processes and changes of emotions, all of which were related to these young students practicing yoga. The impact of yoga on emotions illustrates the potential of yoga to improve the well-being and mental health of young people.

Small dense LDL cholesterol in human subjects with different chronic inflammatory diseases

BACKGROUND AND AIMS

Chronic inflammatory diseases (CID) are associated with a profound increase in cardiovascular (CV) risk resulting in reduced life expectancy. However, LDL-cholesterol is reported to be low in CID patients which is referred to as the "LDL paradoxon". The aim of the present study was to investigate whether LDL-particles in CID exhibit an increased content of the highly atherogenic small-dense LDL subfraction (sdLDL).

METHODS AND RESULTS

In this prospective, single center, observational study we enrolled 141 patients with CID (RA n = 59, inflammatory bowel disease (IBD) n = 35, ankylosing spondylitis (SpA) n = 25, Psoriasis n = 22) in 2011 through 2013 to evaluate sdLDL levels before as well as 6 and 26 weeks after initiation of different anti-cytokine therapies (anti-TNFα, anti-IL-6R antibodies). sdLDL levels were compared to 141 healthy individuals in a case control design. Compared to healthy controls, all CID patients displayed a significantly higher sdLDL content within the LDL cholesterol fraction: RA 35.0 ± 9.2% (p < 0.001), SpA 42.5 ± 10.5% (p < 0.001), IBD 37.5 ± 7.1% (p < 0.001), Psoriasis 33.6 ± 4.6% (p < 0.01). Furthermore, the sdLDL/LDL ratio was significantly higher in male compared to female RA subjects (p < 0.05). Neither anti-TNFα nor anti-IL6R medication altered sdLDL levels despite a significant improvement of disease activity.

CONCLUSION

In several different chronic inflammatory disease entities, LDL-cholesterol is shifted toward a pro-atherogenic phenotype due to an increased sdLDL content which might in part explain the LDL paradoxon. Since premature CV disease is a major burden of affected patients, specifically targeting lipid metabolism should be considered routinely in clinical patient care.

CLINICAL TRIALS

Registration at German Clinical Trial Register (DRKS): DRKS00005285.

The wingless-related integration site-5a/secreted frizzled-related protein-5 system is dysregulated in human sepsis

Sepsis and type 2 diabetes exhibit insulin resistance as a common phenotype. In type 2 diabetes we and others have recently provided evidence that alterations of the proinflammatory wingless-related integration site (wnt)-5a/anti-inflammatory secreted frizzled-related protein (sFRP)-5 system are involved in the pathogenesis of insulin resistance. The aim of the present study was to investigate whether this novel cytokine system is dysregulated in human sepsis, which may indicate a potential mechanism linking inflammation to metabolism. In this single-centre prospective observational study, critically ill adult septic patients were examined and proinflammatory wnt5a and wnt5a inhibitor sFRP5 were measured in serum samples by enzyme-linked immunosorbent assay (ELISA) at admission to the intensive care unit (ICU) and 5 days later. Sixty sepsis patients were included, and 30 healthy individuals served as controls. Wnt5a levels were found to be increased significantly in septic patients compared to healthy controls (2·21 ± 0·33 versus 0·32 ± 0·03 ng/ml, P < 0·0001). In contrast, sFRP5 was not altered significantly in septic patients (19·72 ± 3·06 versus 17·48 ± 6·38 ng/ml, P = 0·07). On admission to the ICU, wnt5a levels exhibited a significant positive correlation with the leucocyte count (rs  = 0·3797, P = 0·004). Interestingly, in patients recovering from sepsis, wnt5a levels declined significantly within 5 days (2·17 ± 0·38-1·03 ± 0·28 ng/ml, P < 0·01). In contrast, if sepsis was worsening, wnt5a levels increased in the same time-period by trend (2·34 ± 0·59-3·25 ± 1·02 ng/ml, P > 0·05). sFRP5 levels did not change significantly throughout the study period. The wnt5a/sFRP5 system is altered in human sepsis and might therefore be of interest for future studies on molecular pathophysiology of this common human disease.

Yoga for Children and Young People's Mental Health and Well-Being: Research Review and Reflections on the Mental Health Potentials of Yoga

This article discusses yoga as a potential tool for children to deal with stress and regulate themselves. Yoga provides training of mind and body to bring emotional balance. We argue that children and young people need such tools to listen inward to their bodies, feelings, and ideas. Yoga may assist them in developing in sound ways, to strengthen themselves, and be contributing social beings. First, we address how children and young people in today's world face numerous expectations and constant stimulation through the Internet and other media and communication technologies. One reason why children experience stress and mental health challenges is that globalization exposes the youth all over the world to various new demands, standards, and options. There is also increased pressure to succeed in school, partly due to increased competition but also a diverse range of options available for young people in contemporary times than in the past. Our argument also partially rests on the fact that modern society offers plenty of distractions and unwelcome attractions, especially linked to new media technologies. The dominant presence of multimedia devices and the time spent on them by children are clear indicators of the shift in lifestyles and priorities of our new generation. While these media technologies are valuable resources in children and young people's lives for communication, learning, and entertainment, they also result in constant competition for youngster's attention. A main concept in our article is that yoga may help children and young people cope with stress and thus, contribute positively to balance in life, well-being, and mental health. We present research literature suggesting that yoga improves children's physical and mental well-being. Similarly, yoga in schools helps students improve resilience, mood, and self-regulation skills pertaining to emotions and stress.

When Staff Create the Organisational Culture

Emergency units suffer from continuous overload because all types of users demand the service. The literature shows that in general, the percentage of non-urgent users varies from 20 per cent to 80 per cent, depending on the type of centre analysed, the research approach or the methodology. While some studies have analysed this phenomenon focusing on the users, the current research adopts a different perspective. In this article, we try to explain how the break-down in the emergency services affects the work that the staff do. Drawing on evidence obtained from a six-month ethnographic study in two Spanish public hospitals, we conclude that in this overloaded context, official definitions of emergencies and formal classification protocols are completely useless. Exploring the staff's perceptions about the users and the service itself we try to re-create the process by which the diverse health care workers informally re-define symbols, concepts and behaviour patterns, creating a specific internal culture that helps them cope with the complexity of the service and the excessive demand.

Bupivacaine 2.5 mg/ml versus bupivacaine 0.625 mg/ml and sufentanil l μg/ml with or without epinephrine 1 μg/ml for epidural analgesia in labour

We have compared three different methods of epidural analgesia in labour, bupivacaine 2.5 mg/ml (group B), bupivacaine 0.625 mg/ml + sufentanil 1 microg/ml (group BS) and bupivacaine 0.625 mg/ml + sufentanil 1 microg/ml + epinephrine 1 microg/ml (group BSE). One hundred and forty parturients with a singleton fetus with cephalic presentation were randomly allocated to one of the three groups. Group BSE had significantly less pain than groups B and BS. Group B had a significantly higher degree of motor blockade assessed on the Bromage scale. Significantly, more women in group B required urinary bladder catheterization than in the two other groups and they also had significantly less urge to push during active delivery. The incidence of mild pruritus was 18% in group BS and 36% in group BSE. The frequency of instrumental delivery and caesarean section was low (12% and 6.4%, respectively) with no significant differences between the groups. All women were highly satisfied with the method of analgesia and 97% would prefer the same kind of pain alleviation at the next delivery. We conclude that epidural analgesia with low-dose bupivacaine and sufentanil is as good an analgesic method as high-dose bupivacaine. Addition of low-dose epinephrine improves the analgesia.

Comparison of extracellular matrix in human osteosarcomas and melanomas growing as xenografts, multicellular spheroids, and monolayer cultures

BACKGROUND

The composition of extracellular matrix in human xenografts and spheroids were compared with the monolayer cultures from which they originated. Collagen I, fibronectin, acetylglucosamine, and acetylgalactosamine were quantitated in two osteosarcomas and one melanoma.

METHODS

Using fluorescence microscopy, extracellular matrix constituents in the cellular and extracellular compartment were measured, whereas flow cytometry measured the extracellular matrix constituents bound to the cell surface as well as the total cellular amount including intracellular and surface bound constituents.

RESULTS

The fluorescence microscopy measurements, demonstrated that the xenografts contained more or equal quantities of the extracellular matrix constituents compared with the spheroids. Flow cytometric measurements of total cellular amounts, showed that cells from xenografts usually contained more or equal amounts as the spheroid cells, which contained less or equal amounts as the monolayer cells. The surface expression of the extracellular matrix constituents increased or there were no significant differences, comparing cells grown as monolayers, spheroids, and xenografts.

CONCLUSIONS

The data shows that multicellular spheroids being an in vitro system of intermediate complexity between monolayer cultures and tumours, contain an extracellular matrix corresponding to some degree to this intermediate position.

Determination of polycyclic aromatic hydrocarbons in urine from coke-oven workers with a radioimmunoassay

Considerable amounts of polycyclic aromatic hydrocarbons (PAH) are present in the workplace. In order to obtain a better understanding of the occupational hazards connected with PAH exposure various biomonitoring methods need to be applied. The level of PAH in urine collected from coke-oven workers has been measured by a recently developed radioimmunoassay. A significant correlation between estimated exposure levels for PAH and urinary levels of PAH was observed. During the winter period the control group was found to have an average concentration of 0.44 ng PAH/mmol creatinine, whereas the low, medium and high exposure groups contained 0.44, 0.71 and 0.85 ng PAH/mmol creatinine respectively. The urinary PAH level in the samples collected during the summer period was higher, i.e. 0.81, 0.94 and 1.10 ng PAH/mmol creatinine, for the low, medium and high exposure groups. Furthermore, a correlation was also observed between smoking and levels of urinary PAH. We conclude that this radioimmunoassay may be suitable as a simple and sensitive routine assay for monitoring individuals exposed to PAH.

A monoclonal antibody against PDGF B-chain inhibits PDGF-induced DNA synthesis in C3H fibroblasts and prevents binding of PDGF to its receptor

A monoclonal antibody (MAb 6D11) against platelet-derived growth factor (PDGF) was studied. We found that the MAb 6D11 in concentrations equimolar to PDGF blocked the [3H]thymidine incorporation in C3H/10T1/2 C18 fibroblasts stimulated by PDGF B-B and PDGF A-B. This inhibition was overcome by high doses of PDGF. The [3H]thymidine incorporation stimulated by other growth factors (aFGF, bFGF and bombesin) was not inhibited by the antibody. The MAb 6D11 blocked receptor binding of PDGF B-B, but not PDGF A-A. These findings suggest that the MAb 6D11 abolishes PDGF-induced DNA synthesis by blocking PDGF receptor binding. In this communication we demonstrate an isoform-specific monoclonal antibody against PDGF.

Mutagenicity testing of human milk from smokers and non-smokers in the Salmonella/microsome test

Human milk was tested in the Ames plate incorporation test using strain TA98. Pools from smokers and non-smokers respectively, as well as individual samples from 14 smokers and 15 controls were tested. No difference was found between milk from smokers and non-smokers in the concentrations and volumes used. Preliminary to this a cigarette smoke condensate (CSC) was tested. The CSC was then incubated with human milk which was fractionated, concentrated and the different fractions tested for mutagenic activity. 98% of the mutagenic effect added (measured as number of revertants caused by an equivalent volume of CSC) was recovered 52% of the revertant colonies were recovered from the fat fractions, 40% from the skimmed milk and 8% from a precipitate. Breast milk was also incubated with C14-benzo(a)pyrene and then fractionated by density gradient ultracentrifugation. 97% of the radioactivity was found in the lipid fraction.

Electroimmunochemical characterization of endothelial cell proteins: antigenic relationship with platelet and erythrocyte membrane proteins

Human endothelial cells isolated from umbilical cords and cultured in primary cultures were solubilized in Triton X-100 and examined by crossed immunoelectrophoresis using rabbit antiserum against endothelial cells. Endogeneous labelling of the endothelial cell proteins with 35S-methionine or 14C-mannose followed by crossed immunoelectrophoresis and autoradiography revealed about 30 or 8 immunoprecipitates, respectively. Antigenic relationship between endothelial cell proteins and proteins in human platelets or erythrocyte membranes was demonstrated by use of the corresponding antisera and by antigen addition experiments. One of the endothelial cell proteins cross-reacted with antiserum against erythrocyte membranes and showed a partial antigenic identity reaction with the band 3 protein complex of erythrocyte membranes. The same protein showed antigenic relationship also with a platelet protein. In addition, endothelial cells contain at least 7 proteins antigenically related to platelet proteins, of which at least 5 were labelled with 14C-mannose and thus were glycoproteins. Three of these glycoproteins were antigenically related to proteins from isolated platelet membranes and three were related to the release products obtained after thrombin treatment of platelets. The present study demonstrated numerous platelet and endothelial cell proteins that were antigenically related, more than previously anticipated.

Mutagenicity of polycyclic aromatic compounds (PAC) identified in source emissions and ambient air

Several polycyclic aromatic compounds (PAC) including nitrated and oxygenated derivatives of polycyclic aromatic hydrocarbons (PAH) were tested for mutagenic activity in the Salmonella/microsome assay. Among the compounds tested the isomer mix of nitro-1-hydroxypyrenes showed the highest direct mutagenic response in both the Salmonella strain TA98 and TA100 (1251 revertants/micrograms and 463 revertants/micrograms, respectively). The direct-acting mutagenicity of the nitro-1-hydroxypyrene isomer mix was dependent upon reduction of the nitro function as evidenced by the decrease in activity observed with the nitroreductase-deficient and arylhydroxylamine esterifying-deficient tester strains. The oxygenated derivatives of PAH containing aldehyde or keto groups showed weak or no mutagenic responses. In most cases addition of S9 was essential for any mutagenic activity and the strain TA100 was more sensitive than the strain TA98. Within this group, 7H-dibenzo[c,g]fluoren-7-one showed the highest mutagenic effect; 7 and 22 revertants/micrograms using the strains TA98 and TA100, respectively.

No effect of vitamin B-6 against premenstrual tension. A controlled clinical study

Vitamin B-6 100 mg given daily throughout the menstrual cycle was compared with placebo in a randomized, double-blind crossover trial in 34 women who suffered from premenstrual tension. Vitamin B-6 was no better than placebo. There was a substantial period effect, as the women evidenced a considerable preference for the second drug they received, irrespective of whether this was vitamin B-6 or placebo. Blood magnesium was measured; no significant difference was found between the 34 women with premenstrual tension and 10 healthy women without such complaints. Vitamin B-6 caused a small but statistically significant rise in blood magnesium level. In the individual patients, no correlation was found between changes in blood magnesium and premenstrual symptoms.

Demonstration of 125I-labelled thrombin binding platelet proteins by use of crossed immunoelectrophoresis and autoradiography

A possible receptor for thrombin on the platelet membrane has been identified. Whole platelets were treated with 125I-labelled thrombin followed by washing of the platelets, solubilization in Triton X-100, crossed immunoelectrophoresis and autoradiography. A heavily labelled antigen which migrated slightly more slowly than albumin was observed. No corresponding arc was seen on the same immunoplate when stained with Coomassie brilliant blue, indicating that the antigen possessed weak antigenic properties and/or was present in very small amounts. When 125I-labelled thrombin that had been inactivated by phenylmethylsulphonyl fluoride was used, no such labelled arc was seen. The radiolabelled immunoprecipitate does not represent any of the antigens identified hitherto in the immunoelectrophoretic patterns obtained with platelets or platelet material. The electrophoretic mobility of the antigen was influenced neither by neuraminidase treatment of the platelets prior to the 125I-labelled thrombin exposure nor by inclusion of concanavalin A, wheat-germ lectin or lentil lectin in the gel during the first-dimension electrophoresis. This suggests that the antigen does not represent a glycoprotein. Upon subcellular fractionation the radioactively labelled arc was observed in the cytosol fraction following crossed immunoelectrophoresis and autoradiography. Analysis of the secreted proteins after induction of the release reaction with 125I-labelled thrombin revealed labelling of immunoprecipitates representing thrombospondin, albumin and the 'line' form of platelet factor 4. This confirms that stable complexes of 125I-labelled thrombin and platelet proteins can exist in the presence of Triton X-100 and during electrophoresis.

Demonstration of a new glycoprotein Ib-related component in platelet extracts prepared in the presence of leupeptin

The water-soluble protein glycocalicin is generated during platelet lysis by a proteolytic attack on the integral membrane glycoprotein GP Ib. However, only small amounts of glycocalicin are formed when platelets are solubilized by 1% Triton X-100. Crossed immunoelectrophoresis of such extracts using an antiserum to glycocalicin, shows a continuous immunoprecipitate consisting of two peaks, one representing glycocalicin and the other GP Ib. When leupeptin was present during solubilization, subsequent immunoelectrophoresis revealed yet another GP Ib-related component represented by a third, slow-migrating peak of the immunoprecipitate. During incubation of platelets with dibucaine followed by solubilization in the presence of leupeptin, a gradual transformation of this new form of GP Ib into the previously defined one took place prior to the formation of glycocalicin. An increase followed by a decrease in the agglutination response of the platelets to bovine von Willebrand factor occurred concomitant with these transformations. SDS-polyacrylamide gel electrophoresis of Triton X-100 extracts of platelets did not reveal any difference in the size of GP Ib whether or not leupeptin had been present during the solubilization.

Further studies on the interaction between thrombin and GP Ib using crossed immunoelectrophoresis. Effect of thrombin inhibitors

The platelet surface protein GP Ib (glycocalicin-related protein) has been shown to be retarded by thrombin-Sepharose 4B in a crossed immunoelectrophoresis system. The interaction between GP Ib and thrombin was abolished when thrombin was blocked either at the active serine site with tosyl-lysine-chloromethyl-ketone (TLCK) or phenylmethylsulfonylfluoride (PMSF) or at the fibrinogen binding site (macromolecular binding site) with N-bromosuccinimide (NBS) or heparin, indicating that both sites have to be freely accessible for the retention of the glycocalicin-related protein by thrombin.

Dissociation of the glycoprotein IIb-IIIa complex in isolated human platelet membranes. Dependence of pH divalent cations

The platelet membrane glycoproteins IIb and IIIa normally exist as a complex which forms a predominant immunoprecipitate after crossed immunoelectrophoresis of Triton-X-100-solubilized platelets. Dissociation of the complex occurs by solubilization in the presence of EDTA or EGTA at pH 8.7 and is readily verified by crossed immunoelectrophoresis. Incubations of isolated membranes with EDTA or EGTA at various pH levels were performed. Removal of the chelators and solubilization showed no dissociation of the glycoprotein IIb-IIIa complex in membranes incubated at pH below 8.0. At pH above 8.0 a dissociation which increased with increasing pH was seen. Under these conditions, dissociation appears to take place already in the intact membranes. The tendency of the glycoprotein IIb-IIIa complex to become dissociated with EDTA or EGTA at increasing pH seems to be due to increased chelating capacity of the chelators concomitant with a decreased chelating capacity of glycoprotein IIb and IIIa. The divalent cations Ca2+ and Mg2+, but not Cu2+, Zn2+, Mn2+ or Sr2+, in molar concentrations below that of EGTA were able to prevent the dissociation of the glycoprotein IIb-IIIa complex by the chelator at pH 9.0, indicating that Ca2+ as well as Mg2+ can be used to keep the complex together. In some experiments it was possible to reverse the dissociation in the membranes after removal of EDTA. At pH 7.5 reassociation occurred within 15 min whether divalent cations were added or not. At pH 9.0. reassociation occurred within 2 h provided Ca2+ was present. The tendency of glycoprotein IIb and IIIa to form a complex thus appeared to be most pronounced over the physiological pH range and to be a rapid process in platelet membranes under such conditions.

Demonstration of variable forms of the platelet factor 4 immunoprecipitate using crossed immunoelectrophoresis

Proteins with different electrophoretic properties were precipitated by a monospecific antiserum to platelet factor 4 either as a "line" or as a "peak" precipitate. The "line" form seen on crossed immunoelectrophoresis of whole platelets was retained when immobilized thrombin was included in the intermediate gel. The retention was partially abolished when thrombin had been blocked at the active serine site or at the fibrinogen binding site. The "peak" form seen on analysis of material secreted from platelets passed unaffected through thrombin-Sepharose. It is suggested that platelet factor 4 exists in the platelets in a state different from that observed extracellularly after platelet secretion.

Evidence for release of soluble, but not of membrane-integrated, proteins from human platelet alpha-granules

Proteins released from stimulated platelets were compared to those of a well-defined preparation of alpha-granules and the soluble cytoplasm by crossed immunoelectrophoresis. Nearly all releasable proteins were detected in the alpha-granule, whereas the true proteins of the soluble cytoplasm were not released. The released glycoproteins interacted with lectins similarly to their alpha-granula-located counterparts. The alpha-granules were divided into soluble contents and membranes by ultrasonication followed by ultracentrifugation. The proteins of the soluble content corresponded to those released from the stimulated platelets. This observation was also supported by SDS-polyacrylamide gel electrophoresis. The results indicate that the bulk of the proteins released from stimulated platelets originate from the soluble content of the alpha-granules. Two major alpha-granule antigens as well as the myosin heavy chain were not released and recovered in the alpha-granule membrane. These results support the hypothetical exocytosis mechanism for the release of alpha-granule proteins from platelets.

Characterization of the proteins of isolated human platelet alpha-granules. Evidence for a separate alpha-granule-pool of the glycoproteins IIb and IIIa

The protein composition of a well-defined alpha-granule preparation isolated from human platelets has been studied. Crossed immunoelectrophoresis against polyspecific platelet antibodies revealed more than 20 immunoprecipitates. The glycoprotein IIb-IIIa complex represented a major antigen in the Triton X-100-solubilized alpha-granule preparation and cross-reacted with the corresponding platelet membrane antigen. Furthermore, after lactoperoxidase-catalyzed 125I-iodination of whole platelets it was not labelled, in contrast to its membrane-located counterpart. This indicates an intracellular location of glycoproteins IIb and IIIa, probably as constituents of the alpha-granules. Fibrinogen, platelet factor 4, albumin, factor VIII-related antigen and the main granule glycoprotein (thrombinsensitive protein, thrombospondin) were identified in the alpha-granule preparation by the crossed immunoelectrophoresis technique. Crossed affinity immunoelectrophoresis using lectins revealed the presence of at least seven glycoproteins, and six sialoglycoproteins were identified by their altered electrophoretic mobility after neuraminidase treatment. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of reduced samples of the alpha-granules revealed at least 15 Coomassie Brilliant Blue-staining polypeptide bands, one of which comigrated with myosin heavy chain. No prominent band was observed in the actin region. Five glycopolypeptide bands were observed after periodic acid-Schiff staining. The dominant three represented the main granule glycoprotein, glycoprotein IIb and glycoprotein IIIa, respectively. More glycoproteins seem to be present in the alpha-granules than was previously recognized.

Crossed immunoelectrophoresis using immobilized thrombin in intermediate gel. A method for demonstration of thrombin-binding platelet proteins

A method is described in which the interaction between thrombin and platelet proteins can be studied directly. Solubilized platelet proteins were examined by crossed immunoelectrophoresis against polyspecific antiplatelet antibodies, and the interaction with thrombin observed by insertion of an intermediate gel containing thrombin coupled to Sepharose 4-B. Four immunoprecipitates were absent or showed an altered position compared to that of the control containing regular Sepharose 4-B in the intermediate gel. These were No. 1 (representing platelet factor 4), No. 13 (glycocalicin-related protein, probably GP lb), No. 19 (factor XIII), and No. 2a which has not yet been identified. Immunoprecipitates No. 16, representing a complex of GP IIb and GP IIIa, and No. 6 (albumin) as well as the other immunoprecipitates seen in the control pattern were unaffected by the presence of immobilized thrombin in the intermediate gel. The interaction of glycocalicin-related protein as well as purified glycocalicin with thrombin was confirmed by use of a monospecific antiserum. It is concluded that crossed immunoelectrophoresis using immobilized thrombin in an intermediate gel represents a new and useful approach to the investigation of the interaction between thrombin and platelet proteins. This procedure may also be extended to many other interactions between agents and cell proteins.

Platelet glycocalicin. Its membrane association and solubilization in aqueous media

Glycocalicin has been extracted from human platelets by 3 M KCl and purified using affinity chromatography on columns of Sepharose-coupled wheat germ agglutinin as the most efficient step. Rabbit antiserum to the purified protein agglutinated human platelets and inhibited the agglutination induced by bovine Factor VIII-related protein. Crossed immunoelectrophoresis of Triton X-100 extracts of platelets in Triton X-100-containing agarose revealed the presence of two glycocalicin-related components of different electrophoretic mobilities giving a continuous double-peak immunoprecipitate with this antiserum. The fast-moving component, which represented the minor peak of the immunoprecipitate, corresponded to purified soluble glycocalicin. Crossed hydrophobic interaction immunoelectrophoresis did not demonstrate binding of the purified glycocalicin or the fast-moving component to phenyl-Sepharose CL-4B as hydrophobic matrix. The slow-moving component, which represented the major peak of the immunoprecipitate, showed a strong binding to the hydrophobic matrix. Immunoelectrophoretic quantitation of glycocalicin present in the aqueous media demonstrated that the presence of EDTA, N-ethylmaleimide and iodoacetamide during lysis of platelets significantly reduced the solubilization of glycocalicin. At the same concentrations these inhibitors strongly inhibited the calcium-activated protease of platelet sonicates. Sialic acid determination after acid hydrolysis of aliquots from the soluble fractions showed that their content of sialic acid was considerably higher when lysis was performed in the absence, rather than in the presence, of EDTA and that glycocalicin contributes significantly to the total platelet sialic acid.

Immunochemical evidence for protein abnormalities in platelets from patients with Glanzmann's thrombasthenia and Bernard-Soulier syndrome

Crossed immunoelectrophoresis of Triton X-100 solubilized proteins from normal and abnormal platelets was performed with rabbit antibodies raised against normal platelets. In Bernard-Soulier platelets protein 13 was not detected, and neither the amphiphilic (probably GP Ib) nor the hydrophilic (glycocalicin) glycocalicin-related proteins were seen when monospecific antiglycocalicin antiserum was used. The most prominent precipitate, 16, and platelet fibrinogen, 24 were not detected in platelets of two patients with type I thrombasthenia, whereas in one patient with type II thrombasthenia fibrinogen was clearly detected, but the amount of protein 16 remained severely reduced. Protein 16 was heavily labeled after lactoperoxidase-catalyzed (125)I iodination of normal platelets, and was precipitated by IgG-L, an alloantibody from a polytransfused thrombasthenic patient. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or protein 16 cut out from immunoplates showed two (125)I-labeled glycoprotein bands, which migrate as GP IIb and GP IIIa. SDS-PAGE of (125)I-labeled type I thrombasthenic platelets showed no periodic acid-Schiff bands or peaks of radioactivity in the GP IIb and GP IIIa regions, whereas in the GP I region both the periodic acid-Schiff band intensity and the radiolabeling were within the normal range. Autoradiography after crossed immunoelectrophoresis of iodinated thrombasthenic platelets showed that the bulk of radioactivity was bound to protein 17. This glycoprotein, which was also present in normal and Bernard-Soulier platelets, migrates in the GP I region on SDS-PAGE. Thus, the bulk of radioactivity observed in the GP I region after SDS-PAGE is associated with protein 17 and not with glycocalicin.

Characterization of human platelet proteins solubilized with Triton X-100 and examined by crossed immunoelectrophoresis. Reference patterns of extracts from whole platelets and isolated membranes

Whole human platelets and platelet membranes have been solubilized in 1% Triton X-100, and the solubilized proteins examined by crossed immunoelectrophoresis using rabbit antibodies raised against either whole platelets or isolated membranes. 90% of the platelet proteins were solubilized by this extraction. About twenty immunoprecipitates were observed using the extracts obtained from whole platelets, whereas normally eight immunoprecipitates were seen with extracts from isolated membranes. Albumin, factor VIII and fibrinogen were identified with monospecific antibodies. Correlation of the patterns obtained for platelets or membranes was obtained by addition experiments, by crossed-line immunoelectrophoresis and by crossed immunoelectrophoresis of a mixture of extracts from unlabeled whole platelets and membranes isolated from platelets labeled by lactoperoxidase-catalyzed 125I iodination. Four sialoglycoproteins were identified by their reduced electrophoretic migration after neuraminidase treatment, and six proteins interacted with various lectins, indicating them to be glycosylated. Seven amphiphilic proteins were identified by charge-shift crossed immunoelectrophoresis, and nine by crossed hydrophobic interaction immunoelectrophoresis with phenyl-Sepharose. The topographical arrangement of the membrane proteins was examined with lactoperoxidase-catalyzed 125I-labeled platelets as antigens, and by antibodies absorbed with a suspension of whole platelets. Four and six radioactively labeled precipitates could be identified using the platelet and membrane extracts, respectively, indicating them to be exposed at the outer platelet surface. This was confirmed by the use of antibodies absorbed with intact platelets.

Protein Distribution in Human Endothelial Cells in Primary Culture Studied by Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophores

The surface structure and protein composition of cultured human endothelial cells were examined by lactoperoxidase catalyzed iodonation followed by SDS-PAGE of the cells. Five major protein bands (MW 224.000, 187.000, 70.000, 52.000 and 42.000) and several minor bands were seen. No differences in the protein pattern were observed between samples from confluent and nonconfluent cultures. In contrast, PAS staining of the gels revealed no glycoprotein bands unless the cells had grown to confluency. Then PAS staining revealed three bands of MW 240.000, 208.000 and 145.000. The fire one may represent fibronectin. The radioavtive iodine was associated with proteins in the 230.000, 145.000, 70.000, 55.000 and 45.000 MW regions. The first two regions showed iodination only in samples from confluent cultures. 33% of the acid-hydrolyzable sialic acid was liberated after neuraminidase treatment of the cells. No difference in the protein or glycoprotein pattern was seen after SDS-PAGE of neuraminidase-treated cells. In conclusion, four of the protein bands were susceptible to iodination, indicating an external localization in the plasma membrane. Two of these were iodinated only when cells had grown to confluency.

A New Approach to the Study of Platelet Proteins: Crossed Immuni-electrophoresis in the Presence of Detergent

Crossed immunoelectrophoresis o f human platelet proteins solubilized in 1% Triton X-100 against rabbit whole platelet antibodies revealed more than 20 immun precipi tates. Identification o f albumin (No.6), factor VIII, (No.9) and fibrin ogen(No.24) was done with the respective monospecific antibodies The topographical arrangement of the membr an eproteins was examined with extracts from lactoperoxidase(125I)-iodinated platelets as antigens, and with antibodies absorbed with a suspension of whole platelets. Four radioactive precipitates (No.16, l7, 20, 23) were observed, indicating a surface exposure of the corresp o nding proteins in the membrane. This was confirmed by the use of absorbed antibodies. Six glycoproteins(No.S, 8,9,16,l7,23) (were identified by crossed affino-immunoelectrophoresis using four different lectins, and four sialoglycoprote in s(No.9,15,16, 20) by their reduced electrophoretic migration after neuraminidase-treatment. Charge shift crossed immunoelectrophores is and crossed hydrophobic intera ction immunoelectrophoresis revealed that all the membrane prote ins were amiphilic. The present methods represent a new approach to the study of the stru cture and function of platelet proteins.

On the Membrane Association of Platelet Glycocalicin

More observations indicate that the hydrophilic protein glycocalicin found in soluble fractions after homogenization of platelets in the presence of calcium ions, exists in a different molecular form on the intact platelet. Thus, SDS-PAGE of SDS-dissolved whole platelets show glycocalicin to be derived from a more complex protein than the solubilized protein itself. Crossed immunoelectrophoresis of Triton x-100 extracts of platelets revealed anti-glycocalicin-reactive material existing as two components with different eloctrophoretic mobilities and with the fast-moving one corresponding to highly purified water-soluble glycocalicin. Crossed hydrophobic interaction immunoelectrophoresis confirmed the hydrophilic nature of this component, whereas the slow-moving component showed the characteristic retardation of an amphiphilic membrane protein. Glycocalicin is solubilized during freezing and thawing of platelets in buffer, immunoquantitation (Laurell) of solubilized glycocalicin showed that EDTA(3,6mM), NEM (4.0mM) and IAA(4.0mM)reduced solubilization by 87%, 65% and 57%, respectively, and also inhibited calcium-dependent protease of platelet homogenatos indicating that the solubilization may be enzyme-mediated.

Membrane Glycocalicin and Platelet Agglutination by Bovine Factor VIII Related Protein

Membrane glycocalicin was extracted from human platelets in 3 M KCl and purified using affinity chromatography on WGA-Sepharose as the most efficient step. Antibodies to the purified material were raised in rabbits. Monospecific antiserum was obtained either directly or after adsorption with soluble fraction from platelets which had been frozen and thawn in ED TA-buff er and therefore contained very little glycocalicin. Such anti serum agglutinated human platelets, and in low amounts it inhibited agglutination by bovine factor VIII. This inhibition could be reversed by adsorption with platelet “ghosts” dependent on their glycocalicin content. Immunoelectrophoretic quantitation (Laurell) gave values of 47-67{U 9 of glycocalicin per 10 platelets corresponding to around 3% of tota plateLet prote in and accounting for most of the neuraminidase-sensitive plateletsialic acid. Whereas glycocalicin was quantitatively removed from whole platelets by 3M KCl, this procedure could remove only 39% of glycocalicin from glycocalicin-containing platelet ghosts prepared in the presence of EDTA. Such KCl treated ghosts could still agglutinate by bovine factor VIII whereas the KCl-treated whoie platelets were not agglutinated.

A syndrome of factor VII deficiency and abnormal platelet release reaction

A 15-year-old girl with severe factor VII deficiency and chronic arthropathy showed an excessively prolonged bleeding time. Further studies demonstrated low platelet adhesiveness and abnormal platelet aggregation with ADP, collagen and epinephrine. Release of 14C-serotonin was deficient after aggregation with ADP and epinephrine, but was normal with thrombin. Transfusion of plasma or prothrombin complex concentrate resulted in a partial or complete correction of the bleeding time, respectively, but had no effect on in vitro platelet function tests. Both parents and the only sister had factor VII activities of 42%-72% and factor VII antigen levels of 45%-66% of normal and may thus be heterozygotes with respect to factor VII deficiency. All three had normal bleeding times in spite of abnormal in vitro platelet functions. The observations are interpreted to mean that in this family with factor VII deficiency and abnormal platelet release reaction the platelet abnormality as such was not sufficiently severe to prolong the bleeding time unless the factor VII activity was also very low.

Studies on subcellular fractions of human platelets by the lactoperoxidase-iodination technique

Lactoperoxidase-catalyzed 125I iodination and sodium dodecyl sulphate-polyacrylamide gel electrophoresis have been performed on whole, washed platelets as well as on isolated platelet membranes and granules. Electrophoresis of the whole platelets demonstrated two major radioactive peaks, corresponding to glycopolypeptides of estimated molecular weights of 120 000 and 100 000. A small, but consistent amount of radioactivity was also associated with a 147 000 dalton glycopolypeptide. The membranes showed the same pattern of radioactivity as the whole platelets, whereas only negligible amounts of labeled material was found in the soluble and granule fractions. Practically all the polypeptides were labeled in membranes iodinated after their isolation. A glycopolypeptide of 147 000 molecular weight was observed also in the soluble and the granule fractions, but no radioactivity was associated with these substances. In unreduced form, the granule glycopolypeptide penetrated only slightly into the polyacrylamide gel. Thrombin induced the relase of this granule-located substance from whole platelets, as observed by gel electrophoresis of the supernatant after release reaction (secretion). The granule glycoproteins were only partly exposed on the granule membrane since about 50% of the acid-hydrolyzable sialic acid could be liberated by neuraminidase treatment of isolated granules. In whole, iodinated granules the bulk of the radioactivity was associated with a polypeptide of estimated molecular weight 46 000 (possibly actin). This polypeptide was not seen in the supernatant after removal of the thrombin-degranulated platelets by centrifugation, which indicates that the granule membrane is retained with the platelets during the secretion process.

Effects of thrombin on washed, human platelets: changes in the subcellular fractions

Pressure homogenization and subcellular fractionation has been performed on washed, human platelets and platelets treated with thrombin to undergo the so-called release reaction. Electron microscopy revealed that the particulate zones obtained from the control sample corresponded to membrane vesicles (B), small storage granules (D) as well as mitochondria and larger storage granules (E). Only a few storage granules could be observed in the particulate zones isolated from thrombin-treated platelets. Visual comparison of the sucrose gradient patterns revealed that one granule fraction (D) had disappeared from the thrombin-treated sample. Sodium dodecysulfate-polyacrylamide gel electrophoresis showed a major protein band (mol. wt 145 500 plus or minus 1000) in the extracellular phase (supernatant after removal of the platelets) of the thrombin-treated sample and in the granule fractions (D and E) of the control (mol. wt 147 000 plus or minus 1000). Incubation of whole, washed platelets with thrombin for 5 min at 37 degrees C followed by sodium dodecylsulfate-polyacrylamide gel electrophoresis of the isolated membrane fraction revealed no reproducible differences in the protein band pattern compared to membranes isolated from control platelets. However, after treatment with thrombin for 30 min, a protein band (mol. wt 183 000 plus or minus 3500) had disappeared. The distribution of protein and beta-N-acetylglucosaminidase activity among the subcellular fractions were measured. Both were mainly recovered in the soluble fraction (greater than 77%). The granule fractions, D and E of the control contained 3.0% plus or minus 0.8% and 6.4% plus or minus 1.3% of the total amount of beta-N-acetylglucosaminidase in the gradient. Fraction E of the thrombin-treated cells contained 3.3% plus or minus 1.0% of total while fraction D was lacking.