bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the buckling moment on rectangular hollow pipe under pure bending load
Authors: Yudo Hartono , Amiruddin Wilma , Jokosisworo Sarjito
Published: July 2018

Not only the circle hollow pipe but also the rectangular hollow pipes are used on offshore structure. In this study, the bending moment was given at both end of pipe. The strength of buckling moment can be reduced by increasing the length. The rectangular pipe models are varying from a/b = 1, 2, 4; a/t = 10, 15, 20 and L/a = 10, 15, 20. On the rectangular pipe which is have larger rectangle area (a/b), have the larger deformation. Vice versa on the rectangular pipe which is have smaller rectangle area (a/b), as though on a/b = 2 and a/b = 4 which is have smaller deformation. The conclude that is the larger one of rectangle area then the oval deformation is large too. The buckling strength will increase with decreasing a/b and deformation at mid span will be increase. The buckling strength decrease with increasing of L/a and a/t. The strength of the buckling moment in the elastic state will decrease with increasing of a/t and a/b. For a/b = 1, the strength of buckling moment will tend to be equal at L/a = 10-20. Pipe with increasing of a/t, L/a and a/b will be elastic.
System Impressed Current Anti Fouling (ICAF) Against Micro Fouling (Bacteria) on Ship’s Cooling System
Authors: Pratikno Herman , Sulistiyaning Titah Harmin , Danesto Rizky Mauludin Muhammad
Published: July 2018

Bio-fouling is the attachment and accumulation of an organism or micro-organism to a material. Bio-fouling is one of the causes of declining performance and quality in a system of structures, especially structures that have a direct relationship with the waters where the bio-fouling live and move. The research was conducting using a simple circuit that represents Impressed Current Anti Fouling (ICAF) system which is generally located on the cooling of the ship against micro-fouling or bacteria. Species of bacteria (Pseudomonas fluorescens) in the marine environment was used as an object. The bacteria were introduced into the reactor containing the cathode and anode of this simple system, with inputs of experimental time variation of 3, 5 and 7 minutes and electrical current variation of 0.1, 0.3, and 0.5 Ampere. The determination of bacteria population was conducted using standard plate count methods. The results showed that ICAF system can reduce the bacteria populations. The largest percentage of Pseudomonas fluorescens reduction was 99.9%, while the smallest percentage showed 98.5% percentage. In conclusion, the simple of ICAF system can be used to prevent appearance of micro-fouling in marine environment.
Sea level rise impact modelling on small islands: case study gili raja island of east java
Authors: Hidayah Zainul , Prayogo Luhur Mukti , Wardhani Maulinna Kusumo
Published: July 2018

Coastal regions and small islands are areas that will be adversely affected by the phenomenon of sea level rise globally. In general, Sea Level Rise (SLR) will result in coastal impacts as follows: increased frequency and intensity of floods, changes in ocean currents and widespread intrusion of sea water. This research was conducted in Gili Raja Island of Sumenep Madura. Objectives of this research were to demonstrate the ability of combining remote sensing and GIS method to determine the impact of SLR on a small island and to model its scale using different scenario. GIS based run-up model were performed to estimate and predict the impact of SLR to the island’s area. Three water level scenario (0.5 m, 1.0 m and 1.5 m) were applied. The results showed that in the first scenario 8.73% of the island was flooded by sea water, furthermore in two other scenario the flooded area was increase significantly (15.88% and 22.38%).
Analysis of Seafloor Sediment Distribution using Multibeam Backscatter Data
Authors: Pratomo Danar G , Khomsin  , Cahyadi Mokhammad N , Akbar Kamila , Aprilia Evasari
Published: July 2018

Multibeam sonars use an acoustic wave to provide a view of seafloor topography and collect its backscatter. Seafloor backscatter image can be used as a means of quantitative classification of seafloor lithology. This allows sediment expert to examine spatial distributions of seafloor sediment types and discriminate among them. This method is expected to reduce expensive bottom-sampling programs. The research examined multibeam data collected from Indonesia Exploration 2010 Project. This project employed a Kongsberg EM302 multibeam system to collect seafloor topography and backscatter data at Sangihe Talaud Sea, North Sulawesi. The average depth of the area study is approximately 2400 m. The research applied the Angular Response Curve (ARC) method to analyze the echo strength of the backscatter as a function of the grazing angle. The range of backscatter intensity in this area is from -9dB to - 67dB. Based on the backscatter data, there are five types of sediment in this area: clay, mud, gravel, sand, and boulder.
Open-pore film drainage (OFD): a new multipurpose tool for endoscopic negative pressure therapy (ENPT)
Authors: Loske Gunnar , Schorsch Tobias , Rucktaeschel Frank , Schulze Wolfgang , Riefel Burkhard , van Ackeren Vera , Mueller Christian
Published: July 2018

Background and study aims Endoscopic negative pressure therapy (ENPT) has been developed to treat gastrointestinal leakages. Up to now, ENPT has usually been performed with open-pore polyurethane foam drains (OPD). A big disadvantage of the OPDs is their large diameter. We have developed a new, small-bore open-pore film drainage (OFD). Herein we report our first experience in a case series of 16 patients.

Patients and methods OFD is constructed with a drainage tube and a very thin double-layered open-pore drainage film (Suprasorb CNP, Drainage Film, Lohmann & Rauscher International, Germany). The distal end of the tube is wrapped with only one layer of film. OFD is placed into the gastrointestinal leakage site with common endoscopic techniques. The tube is connected to an electronic vacuum device and continuous negative pressure of –125 mmHg applied.

Results From 2013 to 2016, 16 patients were treated with the new OFD device. In 10 patients, transmural intestinal defects (4 esophageal, 4 rectum/colon, 1 duodenal, 1 pancreatic cyst) were closed with ENPT in median time of 12 days (range 3 – 34 days). Five of the 10 patients were treated solely with OFD devices. In five patients ENPT started with ODP and changed to OFD when the cavity was shrunken to a channel with a small opening. In four patients postoperative gastric reflux was eliminated for 5 to 16 days.

Conclusions Small-bore OFD opens up promising new treatment options within ENPT. OFD can be used in endoscopic closure management of intestinal leakages in the upper and lower gastrointestinal tract. Gastric reflux can be eliminated in an active manner. OFD can be inserted nasally. OFD may be an adequate substitute for OPD, especially when placement of the larger OPD is difficult.

Meeting presentations: The authorsʼ experience was first reported in an oral presentation at the 46th Kongress der Deutschen Gesellschaft für Endoskopie und Bildgebende Verfahren in Mannheim (DGE-BV), 17. – 19.03.2016.
Double balloon enteroscopy-assisted endoscopic retrograde cholangiopancreatography in Roux-en-Y gastric bypass anatomy: expert vs. novice experience
Authors: Kashani Amir , Abboud Gebran , Lo Simon , Jamil Laith
Published: July 2018

Background and study aims Double-balloon enteroscopy-assisted endoscopic retrograde cholangiopancreatography (DBE-ERCP) in post-Roux-en-Y gastric bypass (RYGB) patients is a technically challenging procedure. We aimed to determine the success rate of DBE-ERCP performed by a novice to the procedure in post-RYGB after training with an expert.

Patients and methods Medical records for 103 consecutive post-RYGB patients who underwent DBE-ERCP in a tertiary center were retrospectively reviewed. The procedures were performed by Operator A (18 years of high-volume ERCP practice before acquiring DBE skill in 2004), and operator B ( < 2 years’ experience in DBE and ERCP). ERCP success rate and time in patients with an intact papilla were compared between Operator A’s first and last sets of cases in equal number to the cases performed by Operator B.

Results A total of 129 DBE-ERCPs were performed (Operator A: 109; Operator B: 20) over an 80-month time span. Among patients with an intact papilla, DBE-ERCP success rates for Operator A’s first (87.5 %) and last (92.9 %) 20 cases were similar to that of Operator B (92.9 %) (P = 1.00 for both). Mean of DBE-ERCP time for the last 20 cases of Operator A was (100 minutes; 95 % confidence interval: 81,123) less than that for operator B (176 minutes; 95 % confidence interval: 138,224) (P = 0.01). Overall adverse events rates were 11 % and 5 % for Operators A and B, respectively (P = 0.69): pancreatitis (n = 10), cholangitis (n = 1), and perforation (n = 2); all were mild and treated conservatively.

Conclusions Despite the intrinsic technical difficulty, DBE-ERCP can be successfully and safely performed in post-RYGB patients by an endoscopist proficient in both conventional DBE and ERCP. Ideally, this endoscopist should observe several cases of DBE-ERCP performed by an expert to learn the techniques.
Heads or tails: confusion about “proximal” and “distal” terminology for pancreaticobiliary anatomy
Authors: Khara Harshit , Kothari Truptesh , Johal Amitpal , Kothari Shivangi , Ahuja Nina , Bhanushali Ashok , Kotru Anil , Berger Andrea , Kaul Vivek , Gross Seth , DiMaio Christopher , Hale William , Abbass Rami , Ryou Marvin , Sethi Amrita , Turner Brian , Fockens Paul , Diehl David
Published: July 2018

Background and study aims The anatomical meaning of the terms “proximal” and “distal” in relation to the pancreaticobiliary anatomy can be confusing. We aimed to investigate practice patterns of use of the terms “proximal” and “distal” for pancreaticobiliary anatomy amongst various medical specialties.

Materials and methods An online survey link to a normal pancreaticobiliary diagram was emailed to a multispecialty physician pool. Respondents were asked to label various parts of the common bile duct (CBD) and pancreatic duct (PD) using the terms “proximal,” “distal,” “not sure,” or “other.” Variability in use of these terms between specialties was assessed.

Results We received 370 completed surveys from 182 gastroenterologists (49.2 %), 97 surgeons (26.2 %), 68 radiologists (18.4 %), and 23 other physicians (6.2 %). There was overall consensus in describing the upper/sub-hepatic CBD as “proximal CBD” (73.8 %, P = 0.1499) and the lower/pre-ampullary portion as “distal CBD” (84.6 %, P = 0.1821).

However, there was marked variability when describing the PD. The PD in the head of the pancreas was labeled as “proximal PD” by 42.4 % and “distal PD” also by 42.4 % (P < 0.0001); and in the tail as “proximal PD” by 41.4 % and “distal PD” by 43.2 % (P < 0.0001). Only 13.8 % of respondents used descriptive terminology (“PD in the head” or “PD in the tail”) for the PD. Radiologists most often used descriptive terminology for both the CBD and PD. Surgeons most consistently called “proximal PD” in the head, and “distal PD” in the tail of the pancreas.

Conclusions Although use of the terms “proximal” and “distal” is still very common to describe pancreaticobiliary anatomy, there is a discordance about its meaning, particularly for the PD. Use of descriptive terminology may be a more accurate alternative to prior ambiguous terminologies such as “proximal” or “distal” and can serve to improve communication and decrease the possibility of medical errors.
Endoscopic ultrasound-guided coil and glue for treatment of splenic artery pseudo-aneurysm: new kid on the block!
Authors: Rai Praveer , KC Harish , Goel Amit , Aggarwal Rakesh , Sharma Malay
Published: July 2018

Background and study aims Pseudoaneurysm most commonly involves the splenic artery and is conventionally treated with angioembolization or surgery. Herein we describe six patients with splenic artery pseudoaneurysm who were treated using a new technique of endoscopic ultrasound (EUS)-guided glue and coil injection.

Patients and methods Six patients (median age 36.7, range: 19 – 60, M: F = 5:1) with splenic artery pseudoaneurysm who had failed angiographic embolization underwent EUS-guided transgastric injection of coil and glue injection between July 2016 and September 2017.

Results The diameter of the splenic artery pseudoaneurysms varied from 2.5 cm to 6.5 cm. The size (8, 14 and 16 mm) and number (1 to 5) of coils and amount of glue (1 – 2 mL) injected all were greater in larger aneurysm. All six patients had complete occlusion of the pseudoaneurysm as determined by using computed tomography at 4 weeks and EUS at 12 weeks. No complication was encountered.

Conclusion EUS-guided coil and glue injection for obliteration of splenic artery pseudoaneurysm is a feasible, highly effective and safe technique.
Bilateral Proximal Humerus Fracture – a Rare Combination with a High Complication Rate after Surgery
Authors: Königshausen Matthias , Rausch Valentin , Mempel Eileen , von Glinski Alexander , Ull Christopher , Bernstorff Maria , Schildhauer Thomas , Seybold Dominik , Gessmann Jan
Published: July 2018

Introduction Bilateral acute proximal humerus fractures are rare. There are no data available about these bilateral injuries. The aim of the study was to analyse bilateral proximal humerus fractures retrospectively in terms of incidence, complications and revisions.

Methods All bilateral proximal humerus fractures were evaluated retrospectively using the institutionʼs database, with the focus on cause of the injury, fracture severity and the clinical course compared to published information on monolateral proximal humerus fractures. Bilateral posterior dislocation fractures were excluded, because these fractures are a separate entity.

Results Between 2005 and 2016, n = 17 patients were primarily treated within our hospital for an acute proximal humerus fracture on both sides (n = 12 female, n = 5 male, average age: 68 years; overall 34 proximal humerus fractures). The general trauma mechanism was a fall on both arms (82% [18% polytrauma]). There were 65% displaced 3-/4-part proximal humerus fractures. Angle-stable plate osteosynthesis was performed predominantly (64%), followed by fracture prosthesis (18%; tension wiring: 3%; non-operatively: 15%). Overall, n = 10 patients (59%) or n = 18 (53%) proximal humerus fractures developed a complication, primarily with loss of reduction or implant loosening (44%). In n = 14 (78%) of the complications further operations were necessary. Alcohol abuse was increasingly found in 29% of the cases within the bilateral patient cohort compared to patients with monolateral fractures.

Conclusion Bilateral proximal humerus fractures are mainly associated with comminuted displaced fractures and a higher complication rate in comparison to monolateral fractures after surgical treatment.
Coagulation Activation Following Estrogen Administration to Postmenopausal Women
Authors: Caine Yehezkel G , Bauer Kenneth A , Barzegar Samad , ten Cate Hugo , Sacks Frank M , Walsh Brian W , Schiff Isaac , Rosenberg Robert D
Published: July 2018

We investigated coagulation system activation following estrogen treatment in 29 healthy postmenopausal women. Study participants received conjugated estrogens at 0.625 and 1.25 mg per day, and placebo for 3-month periods in a randomized crossover protocol. Blood samples were obtained on two consecutive days at the end of each treatment period for immunoassays of F1+2 and fibrinopeptide A (FPA), markers of factor Xa action on prothrombin and thrombin action on fibrinogen in vivo, respectively. Treatment with estrogens at a dose of 0.625 or 1.25 mg resulted in significant increases in mean F1+2 levels of 40 and 98%, respectively, and in mean FPA levels of 37 and 71%, respectively. The measurements of F1+2 were significantly higher in women receiving 1.25 mg of estrogen than 0.625 mg. We also observed significant declines in the levels of antithrombin III and total protein S antigen. Immunologic levels of protein C increased modestly at only the 1.25 mg estrogen dose level. These data indicate that low doses of oral estrogens (≤1.25 mg per day) frequently increase the amount of thrombin generated in vivo. Our observations may help to explain the increased thrombotic risk that has been observed with higher doses of this medication (≥2.5 mg).
Reduction in Factor VII, Fibrinogen and Plasminogen Activator Inhibitor-1 Activity after Surgical Treatment of Morbid Obesity
Authors: Primrose J N , Davies J A , Prentice C R M , Hughes R , Johnston D
Published: July 2018

The aim of this study was to determine the effects of the surgical treatment of morbid obesity on some aspects of haemostatic and fibrinolytic function. Measurement of haemostatic and fibrinolytic factors was performed before and again 6 and 12 months after operation in 19 patients suffering from morbid obesity. Surgical treatment resulted in a mean decrease in body weight of 50 kg at 6 months and 64 kg at 12 months. Weight loss was accompanied at 12 months by significant reductions in median (interquartile range) concentrations of serum cholesterol from 5.3 (4.5–6.2) mmol/1 to 3.6 (2.9–4.6) mmol/1; factor VII from 113 (92–145)% of normal to 99 (85–107)%; of fibrinogen from 3.5 (3–9.3) g/1 to 2.8 (2.4–3.8) g/1; and of plasminogen activator inhibitor-1 (PAI-1) activity from 21 (11–30) IU/ml to 6.3 (5–10) IU/ml. The decrease in PAI-1 activity probably accounted for a significant reduction in euglobulin clot lysis time. Tissue plasminogen activator activity was undetectable in most patients pre-operatively but increased slightly after 1 year to 110 (100–204) mIU/ml. There were no significant changes in plasma levels of KCCT, factor VIII, von Willebrand factor antigen, alpha-2-antiplasmin, antithrombin III, protein C antigen, beta thromboglobulin, platelet factor 4, fibrinopeptide A or platelet count. These findings provide support for the hypothesis that the surgical treatment of morbid obesity may have a long-term beneficial effect on mortality from cardiovascular and thromboembolic disease.
The Hemodynamic and Fibrinolytic Response to Low Dose Epinephrine and Phenylephrine Infusions During Total Hip Replacement Under Epidural Anesthesia
Authors: Sharrock Nigel E , Go George , Mineo Robert , Harpel Peter C
Published: July 2018

Lower rates of deep vein thrombosis have been noted following total hip replacement under epidural anesthesia in patients receiving exogenous epinephrine throughout surgery. To determine whether this is due to enhanced fibrinolysis or to circulatory effects of epinephrine, 30 patients scheduled for primary total hip replacement under epidural anesthesia were randomly assigned to receive intravenous infusions of either low dose epinephrine or phenylephrine intraoperatively. All patients received lumbar epidural anesthesia with induced hypotension and were monitored with radial artery and pulmonary artery catheters.

Patients receiving low dose epinephrine infusion had maintenance of heart rate and cardiac index whereas both heart rate and cardiac index declined significantly throughout surgery in patients receiving phenylephrine (p = 0.0001 and p = 0.0001, respectively). Tissue plasminogen activator (t-PA) activity increased significantly during surgery (p <0.0005) and declined below baseline postoperatively (p <0.005) in both groups. Low dose epinephrine was not associated with any additional augmentation of fibrinolytic activity perioperatively. There were no significant differences in changes in D-Dimer, t-PA antigen, α2-plasmin inhibitor-plasmin complexes or thrombin-antithrombin III complexes perioperatively between groups receiving low dose epinephrine or phenylephrine. The reduction in deep vein thrombosis rate with low dose epinephrine is more likely mediated by a circulatory mechanism than by augmentation of fibrinolysis.
Prolonged Bleeding Time in Patients with Lupus Anticoagulant
Authors: Orlando E , Cortelazzo S , Marchetti M , Sanfratello R , Barbui T
Published: July 2018

Platelet adhesion to collagen under flow conditions was studied in 18 patients with lupus anticoagulant, seven of which showed a prolonged bleeding time in the presence of a normal platelet count. The effect of patient plasma, IgG and purified anticardiolipin antibodies on platelet adhesion was also examined. We found a significant reduction of platelet adhesion in patients with lupus anticoagulant, which was more evident in patients with prolonged bleeding time. This platelet adhesion defect could be attributed to a plasma factor. In fact, patients' platelets regained normal adhesion when mixed with normal plasma, whereas controls' platelets showed abnormal adhesion in the presence of patient plasma. A causative role of antiphospholipid antibodies was demonstrated in experiments using purified immunoglobulins and anticardiolipin antibodies.
Plasminogen Levels in Healthy Volunteers -Influence of Age, Sex, Smoking and Oral Contraceptives
Authors: Tait R C , Walker Isobel D , Conkie J A , Islam S I A M , McCall Frances , Mitchell R , Davidson J F
Published: July 2018

There is considerable doubt as to the importance of reduced plasminogen (PLG) activity as a risk factor for venous thrombosis. In the present study we have identified a wide range of PLG activities (25–200%) in a cohort of 9,611 blood donors. Males and females not taking hormonal contraceptives show a similar distribution of PLG, however, variation related to age appears to follow a different pattern in males and females. These differences are of doubtful clinical importance as are differences related to smoking. In contrast, females taking hormonal contraceptives or hormone replacement therapy (HRT) have up to 25% higher mean PLG levels in younger females but a less marked elevation (10%) is seen in 40–50 year olds. A PLG activity <65% was recorded in 61 donors, none of whom appeared to have a history of thrombosis. These findings do not support the notion that reduced PLG is an important thrombophilic risk factor, however, further investigation of the donors with low PLG is required.
Congenital Deficiency of All Vitamin K-Dependent Blood Coagulation Factors Due to a Defective Vitamin K-Dependent Carboxylase in Devon Rex Cats
Authors: Soute Berry A M , Ulrich Magda M W , Watson A David J , Maddison Jill E , Ebberink Rob H M , Vermeer Cees
Published: July 2018

Two Devon Rex cats from the same litter, which had no evidence of liver disease, malabsorption of vitamin K or chronic ingestion of coumarin derivatives, were found to have plasma deficiencies of factors II, VII, IX and X. Oral treatment with vitamin K1 resulted in the normalization of these coagulation factors. After taking liver biopsies it was demonstrated that the coagulation abnormality was accompanied by a defective γ-glutamyl-carboxylase, which had a decreased affinity for both vitamin K hydroquinone and propeptide. This observation prompted us to study in a well-defined in vitro system the possible allosteric interaction between the propeptide binding site and the vitamin K hydroquinone binding site on carboxylase. It was shown that by the binding of a propeptide-containing substrate to γ-glutamylcarboxylase the apparent K
M for vitamin K hydroquinone is decreased about 20-fold. On the basis of these in vitro data the observed defect in the Devon Rex cats can be fully explained.
Influence of Heparin and a Low Molecular Weight Heparinoid on Specific Endogenous and Exogenous Fibrinolytic Factors during Rest and Exercise
Authors: de Boer A , Kluft C , Dooijewaard G , Kasper F J , Kroon J M , Breimer D D , Stiekema J C J , Cohen A F
Published: July 2018

The effects of heparin (5,000 IU i.v.) and the low molecular weight heparinoid Org 10172 (Orgaran®) (3,250 anti-Xa units i. v.) on components of the fibrinolytic system were studied in two double-blind, randomised, placebo-controlled, cross-over trials using healthy subjects. In study A (n = 6) the effects were studied during rest and standardized exercise and in study B (n = 6) during a low dose infusion of recombinant tissue-type plasminogen activator (rt-PA; 80 µg over 16 min). At rest, heparin and Org 10172 did not influence the plasma concentrations of endogenous t-PA antigen, and activity, urokinase-type PA (u-PA) antigen, plasmin activatable pro-urokinase (scu-PA), active urokinase (tcu-PA) and plasminogen activator inhibitor-1 (PAI-1) antigen. Recombinant t-PA antigen and activity during rt-PA infusion were also not affected. During exercise, neither heparin nor Org 10172 influenced the area under the curve (AUC) of t-PA and u-PA antigen and t-PA activity when compared with placebo. Unexpectedly, after heparin the AUC of t-PA activity was 49% larger (range +19 to +245%) than after Org 10172 (p <0.05). The last difference was considered spurious. scu-PA, tcu-PA and PAI-1 antigen levels at 2 min after termination of exercise were unaffected by both compounds (p >0.05). Sulphated polysaccharides do not increase fibrinolytic activity of the plasma by changing the concentrations of the components of the fibrinolytic system.
Influence of Selected Heparins on Human Neutrophil Functions In Vitro
Authors: Labrouche S , Freyburger G , Belloc F , Boisseau M R
Published: July 2018

The effects of four heparin derivatives [unfractionated heparin (UFH) at 5–50 IU/ml, low molecular weight heparin (LMWH) at 2–20 IU/ml, pentasaccharide (Penta) at 5 IU/ml and a synthetic heparinoid (PPS) at 10–6–10–5 M] on various polymorphonuclear (PMN) leukocyte end-functions (aggregation, chemotaxis, phagocytosis and burst) were examined. CR3 expression, actin polymerization and membrane surface charge were also studied to gain more insight on the mechanisms of the action of heparins on PMN. The different heparins were found to have rather different actions. PMN were found to be hyperreactive to PPS. Pentasaccharide hat no effect on PMN functions, while UFH and LMWH had intermediate reactivity, modulating responses in an adenosine-like manner. Interactions of heparins with PMN were attributed to biophysical properties of the molecules rather than to the presence of a specific sequence such as a pentasaccharide.

Our results show that certain heparin derivatives, apart their well-known anticoagulant action, modulate polymorphonuclear leukocyte functions that may be involved in vascular injury.
Neutrophil Elastase Potentiates Cathepsin G-lnduced Platelet Activation
Authors: Selak Mary A
Published: July 2018

We have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.
Decreased Platelet Membrane Fluidity Due to Glycation or Acetylation of Membrane Proteins
Authors: Winocour Peter D , Watala Cezary , Perry Dennis W , Kinlough-Rathbone Raelene L
Published: July 2018

Platelets from diabetic subjects and animals are hypersensitive to agonists in vitro. Membrane fluidity modulates cell function and previously we observed reduced membrane fluidity in platelets from diabetic patients associated with hypersensitivity to thrombin. We previously reported that decreased fluidity of isolated platelet membranes from diabetic patients is associated with increased glycation of platelet membrane proteins, but not with any change in the cholesterol to phospholipid molar ratio. We have now examined in vitro whether incubation of platelet membranes in a high glucose medium causes sufficient glycation to reduce membrane fluidity. Incubation of platelet membranes from control subjects in a high glucose (16.1 mM) medium for 10 days at 37° C led to an increase in the extent of glycation of membrane proteins and a decrease in membrane fluidity (indicated by an increase in steady state fluorescence polarization); most of the changes occurred within the first 3 days of incubation. Incubation of platelet membranes with 5.4 mM glucose had less effect. In contrast, incubation of platelet membranes with the same concentrations of 1–0-methylglucose did not cause a change in either the extent of glycation of proteins or membrane fluidity. We also determined if acetylation by aspirin or acetyl chloride of the sites available for glycation on platelet membrane proteins leads to a similar reduction in membrane fluidity. Pretreatment of platelet membranes with aspirin or acetyl chloride diminished the extent of glycation that occurred when platelet membranes were subsequently incubated with glucose, but membrane fluidity was reduced even in the absence of glucose; subsequent incubation with glucose caused no further reduction in membrane fluidity. Similar results were obtained when red blood cells were incubated with high concentrations of glucose or methyl glucose either with or without pretreatment with aspirin or acetyl chloride. Further experiments using platelet membranes showed that the reduction in membrane fluidity due to aspirin was independent of its acetylating effect on platelet cyclo-oxygenase. Ingestion of aspirin also caused a reduction in membrane fluidity of platelets. Therefore, glycation of platelet membrane proteins reduces membrane fluidity, but the effect results from occupation of the sites available for glycation and not the presence of glucose moieties per se at these sites. Acetylation of platelet membrane proteins either in vitro or in vivo also reduces membrane fluidity; this effect is not associated with platelet hypersensitivity to thrombin.
Quantitation of Platelet Glycoprotein IV (CD36) in Healthy Subjects and in Patients with Essential Thrombocythemia Using an Immunocapture Assay
Authors: Thibert Valérie , Bellucci Sylvia , Edelman Lena , Tandon Narendra N , Legrand Chantal
Published: July 2018

Glycoprotein IV (GPIIIb, CD36) is a major platelet membrane glycoprotein which is thought to participate in a number of adhesive reactions and to mediate signal transduction. In order to measure the total content of GPIV in human platelets, we have developed a simple and sensitive solid-phase radioimmunoassay based on the immunocapture of GPIV from Triton X-100-solubilized platelets. FA6-152, a monoclonal antibody to GPIV was coated on microtiter plates and bound antigen was quantified with a radiolabeled polyclonal antibody to GPIV Using purified GPIV as a standard, the coefficients of variation of the assay were found to be less than 10% at concentrations of GPIV ranging from 0.15 to 0.75 µg/ml. The assay was validated by the parallelism obtained between purified GPIV dose-response curves and those obtained with platelet lysates, indicating a similar antigenic activity for GPIV in both samples. The level of GPIV in platelets from healthy donors was 0.23 ± 0.05 (mean ± SD, n = 15) µg per 100 µg of platelet proteins and a mean value of 27,440 ± 6,200 (SD) molecules per platelet was calculated. The radioimmunoassay could be used to discriminate between the high level of platelet GPIV in patients with essential thrombocythemia (mean ± SD = 81,850 ± 27,780 molecules/platelet; n = 8) and the normal GPIV level in patients with secondary thrombocytosis (mean ± SD = 26,810 ± 4,030 molecules/platelet; n = 5), thereby demonstrating the clinical usefulness of the assay. The specific increase in platelet GPIV in patients with essential thrombocythemia was confirmed by immunoblot analysis whereas no increase in platelet GPIb or GPIIb-IIIa was observed by this technique.
Recombinant Variants of Tissue-Type Plasminogen Activator Containing Amino Acid Substitutions in the Finger Domain
Authors: Yahara Hitoshi , Matsumoto Keiji , Maruyama Hiroyuki , Nagaoka Tetsuya , Ikenaka Yasuhiro , Yajima Kazuyoshi , Fukao Hideharu , Ueshima Shigeru , Matsuo Osamu
Published: July 2018

Tissue-type plasminogen activator (t-PA) is a fibrin-specific agent which has been used to treat acute myocardial infarction. In an attempt to clarify the determinants for its rapid clearance in vivo and high affinity for fibrin clots, we produced five variants containing amino acid substitutions in the finger domain, at amino acid residues 7–9, 10–14, 15–19, 28–33, and 37–42. All the variants had a prolonged half-life and a decreased affinity for fibrin of various degrees. The 37–42 variant demonstrated about a 6-fold longer half-life with a lower affinity for fibrin. Human plasma clot lysis assay estimated the fibrinolytic activity of the 37–42 variant to be 1.4-fold less effective than that of the wild-type rt-PA. In a rabbit jugular vein clot lysis model, doses of 1.0 and 0.15 mg/kg were required for about 70% lysis in the wild-type and 37–42 variant, respectively. Fibrinogen was degraded only when the wild-type rt-PA was administered at a dose of 1.0 mg/kg. These findings suggest that the 37–42 variant can be employed at a lower dosage and that it is a more fibrin-specific thrombolytic agent than the wild-type rt-PA.
The Residues AGDV of Recombinant γ Chains of Human Fibrinogen Must Be Carboxy-Terminal to Support Human Platelet Aggregation
Authors: Hettasch Joann M , Bolyard Mark G , Lord Susan T
Published: July 2018

The carboxy-terminus of the γ chain of fibrinogen contains a sequence which is believed to be one of the domains that interacts with glycoprotein (GP) IIb/IIIa to support platelet aggregation. A normal variant of fibrinogen exists in which the four carboxy-terminal amino acids are replaced by 20 amino acids. This variant, known as γ’, has been reported to bind less effectively to platelets. The purpose of the present study was to engineer novel proteins to determine what differences in amino acid sequence between the γ and γ’ chains influence the interaction of the carboxyterminus with GPIIb/IIIa. In this regard, the γ chain cDNA in a bacterial plasmid expression vector was modified by oligonucleotide-directed mutagenesis to produce recombinant γ chains with amino acid changes in the carboxy-terminus which reflect the differences between γ and γ’. The recombinant γ chain with an unmodified carboxy-terminus supported adenosine diphosphate (ADP)-induced platelet aggregation to the same extent as intact fibrinogen. In contrast, the ability of γ’ 427 (the recombinant γ’ variant) and γ 427 (where the 16 amino acid γ’ extension [412–427] was added to the carboxy-terminus of γ) to support platelet aggregation was markedly reduced. In addition, the extent of ADP-induced platelet aggregation was decreased in the presence of γ’ 411 (where amino acids 408–411 in γ were replaced with amino acids 408–411 in γ’), while γ 407 (where the four carboxy-terminal amino acids were deleted) was not capable of supporting aggregation. These findings demonstrate that the four residues AGDV are not only required but must be carboxy-terminal to support platelet aggregation.
Vitamin E Binds to Specific Binding Sites and Enhances Prostacyclin Production by Cultured Aortic Endothelial Cells
Authors: Kunisaki Makoto , Umeda Fumio , Inoguchi Toyoshi , Nawata Hajime
Published: July 2018

We evaluated the effect of d-α-tocopherol (vitamin E) on the production of prostacyclin (PGI2) by cultured bovine aortic endothelial cells. Vitamin E at physiological doses significantly enhanced the production of PGI2 by aortic endothelial cells when added to the culture simultaneously with histamine, the Ca2+ ionophore A23187 (A23187), plasma-derived serum (PDS), or arachidonic acid. This effect was found to occur in a time- and dose-dependent manner, and the maximal enhancement was produced by 9.28 µM of vitamin E for 1 h incubations. Significantly lower amounts of lipid peroxides were measured in endothelial cells stimulated by 10% PDS with 9.28 µM of vitamin E than in those stimulated without vitamin E for over 24 h, although the stimulation during the initial 1 to 12 h period did not have a significant effect on lipid peroxide formation in cultured aortic endothelial cells.

We also demonstrated that bovine aortic endothelial cells have specific binding sites for [3H]vitamin E that exhibited time- and temperature-dependent saturability. At 4° C, the nonspecific binding was 8–12% of the total binding, and the specific binding reached equilibrium by 2 h. Specific binding increased with the concentration of [3H]vitamin E and became saturated at concentrations between 1.5 µM and 2.0 µM per 2.0 × 105 cells. Raising the unlabeled vitamin E concentration from 97.7 nM to 1,000 µM reduced the specific binding of 2.0 µM [3H]vitamin E. The Scatchard plot of [3H]vitamin E binding to the endothelial cells shows two classes of binding sites: one with a high affinity {K
a1 2.48 ± 0.32 × 107 NT-1, n = 6} and a low capacity {n
1 1.20 ± 0.34 × 107 sites/cell} and the other with a low affinity {K
a2 1.18 ± 0.32 × 105 M–1} and a high capacity {n
2 3.39 ± 0.53 × 109 sites/cell}.

Our results suggest that the endothelial cells binding sites for vitamin E may play some roles in vascular homeostasis in vivo, and that vitamin E may prevent the development of atherosclerotic changes due in part to the enhancement of PGI2 production by the vascular wall and its action as an antioxidant in vascular endothelial cell.
The Formation of the Haemostatic Plug – A Special Case of Platelet Aggregation
Authors: Lüscher Ernst F , Weber Susanne
Published: July 2018

The formation of the haemostatic plug is an extremely fast process. This excludes, at least in its first phase, the involvement of soluble activating agents released from or produced by the platelets. An experiment with ADP-activated, formaldehyde-fixed platelets shows that platelets with activated fibrinogen receptors will bind inactive platelets in the presence of fibrinogen and Ca2+-ions. A survey of the literature shows that platelet activation is accompanied by the clustering of the fibrinogen receptors. The surface of an activated platelet, which makes part of the growing haemostatic plug therefore is covered with patches of tightly packed fibrinogen. This allows the multisite combination with the statistically distributed low affinity receptors of the newly arriving platelets. Tightly packed fibrinogen, as present on clusters of the activated GP IIb/IIIa receptors as well as when absorbed to artificial surfaces acts as an activator of platelets. Thus, the propagation of the activation process is possible without a requirement for other, external activators. Such agents, which are released from platelets and, finally, thrombin formation, are nonetheless of vital importance, not for the formation but for the consolidation of the haemostatic plug.
Treatment with Tranexamic Acid during Pregnancy, and the Risk of Thrombo-Embolic Complications
Authors: Lindoff Claes , Rybo Göran , Åstedt Birger
Published: July 2018

Tranexamic acid (AMCA) is an inhibitor of fibrinolysis used to treat fibrinolytic bleeding (e.g., menorrhagia and gastro-intestinal haemorrhage), and to prevent bleeding at surgery, in cases of abruptio placentae and general haemorrhage. As AMCA stabilises preformed clots and prolongs their dissolution, it has been debated whether treatment with AMCA might predispose to thrombosis by depressing the fibrinolytic system. Pregnant women constitute a group with low fibrinolytic capacity and an increased frequency of thrombosis further increased after Caesarean section, and are thus more likely to be susceptible to antifibrinolytic therapy. We therefore carried out a retrospective analysis of the case records of 2,102 patients with various bleeding disorders during pregnancy. Of the 256 patients treated with AMCA (mean duration of treatment, 46 days), 169 were delivered by Caesarean section. Of the remaining 1,846 patients (i.e., controls), 443 were delivered by Caesarean section. The relationship between the use of AMCA and the occurrence of thrombo-embolism was calculated with 95% confidence limits.

Of the AMCA treated group (n = 256), two patients – one of whom belonged to the Caesarean section subgroup (n = 168) – had pulmonary embolism. Of the controls (n = 1,846), three patients had deep vein thrombosis and one had pulmonary embolism, all four cases belonging to the Caesarean section subgroup (n = 443). Thus, the findings in this high risk group of women with complicated pregnancies, frequently entailing delivery by Caesarean section, provided no evidence of any thrombogenic effect of AMCA.
Effect of Three Fibrate Derivatives and of Two HMG-CoA Reductase Inhibitors on Plasma Fibrinogen Level in Patients with Primary Hypercholesterolemia
Authors: Branchi Adriana , Rovellini Angelo , Sommariva Domenico , Gugliandolo Angelo G , Fasoli Angelo
Published: July 2018

In order to evaluate the effects of hypocholesterolemic drugs on plasma fibrinogen concentration, six groups of subjects with primary hypercholesterolemia have been put on treatment with diet alone or diet plus fenofibrate (100 mg t.i.d.), slow release bezafibrate (400 mg once a day), gemfibrozil (600 mg b.i.d.), simvastatin (20 mg once a day) or pravastatin (20 mg once a day) respectively. After 1 month of therapy, plasma fibrinogen significantly decreased by 9% and 15% in fenofibrate and bezafibrate groups respectively and increased by 19% in gemfibrozil treated patients. After 4 months of therapy the changes were −16% with fenofibrate, −10% with bezafibrate and +20% with gemfibrozil. No significant changes were observed in patients treated with diet alone, simvastatin or pravastatin. The fibrinogen lowering effect of fenofibrate and bezafibrate does not seem to be related to the hypolipidemic activity of the drugs.
A Variant of t-PA (T103N, KHRR 296-299 AAAA) that, by Bolus, Has Increased Potency and Decreased Systemic Activation of Plasminogen
Authors: Refino Canio J , Paoni Nicholas F , Keyt Bruce A , Pater Cheryl S , Badillo Julie M , Wurm Florian M , Ogez John , Bennett William F
Published: July 2018

In the accompanying paper, we reported that the properties of decreased plasma clearance rate, increased fibrin specificity, and resistance to inactivation by PAI-1 could be effectively combined in the t-PA variant T103N, KHRR 296-299 AAAA. In the current study we evaluated the in vivo efficacy of this variant as well as variants containing the individual mutations T103N and KHRR 296-299 AAAA. Plasma clearance and in vivo lysis of whole blood and platelet-rich clots were determined in a rabbit arterio-venous shunt model. The T103N containing variants were administered as an intravenous (i.v.) bolus. KHRR 296-299 AAAA and t-PA were infused i.v. over 90 min. The clearance rate of the KHRR 296-299 AAAA variant was similar to t-PA. However, the clearance of the T103N and T103N, KHRR 296-299 AAAA variants were 8 and 6-fold reduced, respectively. Potency of the variants relative to t-PA on whole blood clots ranged from 0.9 (T103N, KHRR 296-299 AAAA) to 1.7 (T103N). Relative potency on platelet-rich clots ranged from 2.4 (T103N) to 4.2 (T103N, KHRR 296-299 AAAA). Fibrinogen concentrations in rabbits 120 min after dosing with a 2.5 mg/kg bolus were: 24, 16, 82, and 77% of initial for t-PA; T103N; KHRR 296-299 AAAA; and T103N, KHRR 296-299 AAAA treatment groups, respectively. These results suggest that the T103N, KHRR 296-299 AAAA variant of t-PA, given as a bolus, could result in greater efficacy, particularly on refractory platelet-rich clots, without inducing the severe systemic lytic state produced by a bolus of a less fibrin specific variant.
Anticardiolipin Antibodies Block the Inhibition by β2-Glycoprotein I of the Factor Xa Generating Activity of Platelets
Authors: Shi Wei , Chong Beng H , Hogg Philip J , Chesterman Colin N
Published: July 2018

Antiphospholipid antibodies, defined either by lupus anticoagulant (LA) activity or positive anticardiolipin immunoabsorbent assay (ACA) are associated with a predisposition to thromboses, recurrent fetal loss or thrombocytopenia. The mechanisms for these predispositions remain undefined. We have enriched immunoglobulin fractions from two patient plasmas to obtain antibodies with LA activity but no ACA, or conversely, with ACA positivity but no LA, in order to investigate in vitro characteristics which might explain a thrombotic propensity. β2-glycoprotein I (β2-GPI), the plasma cofactor required for ACA binding to negatively charged phospholipid, has previously been shown to inhibit prothrombinase generation in the presence of activated platelets (8). We now report that β2-GPI, at physiological concentrations, inhibits the generation of factor Xa in the presence of activated gel-filtered platelets. Further, ACA interferes with this inhibition, resulting in protracted, unopposed factor Xa generation. This interference with β2-GPI, a natural anticoagulant component of plasma, is potentially prothrombotic. LA immunoglobulins behave differently and inhibit factor Xa generation in a manner similar to β2-GPI. These findings provide the basis for a previously unsuspected mechanism for thrombosis in patients with aPL.
Von Willebrand Factor Release and P-Selectin Expression Is Stimulated by Thrombin and Trypsin but not IL-1 in Cultured Human Endothelial Cells
Authors: Collins Peter W , Macey Marion G , Cahill Mary R , Newland Adrian C
Published: July 2018

The stimulated release of von Willebrand factor (vWF) from endothelial cells by secretagogues such as thrombin is associated with the translocation of Weibel-Palade bodies to the cell membrane and the surface expression of P-selectin (also known as GMP 140, PADGEM and CD 62). P-selectin, which is stored in Weibel-Palade bodies, is a neutrophil and monocyte adhesion molecule important in the initiation of inflammation.

We have developed a simple assay for the detection of P-selectin on endothelial cells using indirect immunofluorescence and flow cytometry and have confirmed that this is temporally related to vWF release. The assay has been used to demonstrate that IL-1 does not cause Weibel-Palade body degranulation but that trypsin does. This has implications for the use of passaged endothelial cells in the study of vWF release and the assay has numerous possible applications in study of mechanisms of stimulated vWF release.