bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a computed cleansing score to assess quality of bowel preparation in colon capsule endoscopy
Authors: Becq Aymeric , Histace Aymeric , Camus Marine , Nion-Larmurier Isabelle , Abou Ali Einas , Pietri Olivia , Romain Olivier , Chaput Ulriikka , Li Cynthia , Marteau Philippe , Florent Christian , Dray Xavier
Published: July 2018

Background and study aims Colon capsule endoscopy (CCE) does not possess an objective and reliable scoring system to assess the quality of visualization of the colon mucosa. The aim of this study was to establish a colonic computed assessment of cleansing (CAC) score able to discriminate “adequately cleansed” from “inadequately cleansed” CCE still frames.

Patients and methods Twelve normal and complete CCEs, using the Pillcam Colon 2 system (Medtronic, Minnesota, United States), were prospectively selected amongst a database. A CAC score, defined as the ratio of color intensities red over green (R/G ratio), and red over brown (R/(R + G) ratio) was calculated for each extracted colonic frame. After sorting and random selection, two sets of still frames representative of the range of these ratios were obtained. These images were analyzed twice in random order by two experienced CCE readers who were blinded to the CAC scores. A receiver operating characteristic (ROC) curve was forged for both types of ratios and a threshold established, yielding the highest diagnostic performance in terms of adequate cleansing assessment.

Results Four-hundred-and-eight frames were extracted. Regarding the R/G ratio, a threshold value of 1.55 was calculated, with a sensitivity of 86.5 % and a specificity of 77.7 %. Regarding the R/(R + G) ratio, a threshold value of 0.58 was calculated with a sensitivity of 95.5 % and a specificity of 62.9 %.

Conclusion The two proposed CAC scores based on the ratio of color intensities come with high sensitivities for discriminating between “adequately cleansed” and “inadequately cleansed” CCE still frames, but they lack specificity. Further refinement, with implementation of additional image parameters, is warranted.
Use of anticoagulants increases risk of bleeding after colorectal endoscopic submucosal dissection
Authors: Yamashita Ken , Oka Shiro , Tanaka Shinji , Boda Kazuki , Hirano Daiki , Sumimoto Kyoku , Mizumoto Takeshi , Ninomiya Yuki , Tamaru Yuzuru , Shigita Kenjiro , Hayashi Nana , Sanomura Yoji , Chayama Kazuaki
Published: July 2018

Background and study aims Japanese guidelines for gastroenterological endoscopy have recommended temporary withdrawal of anticoagulants (warfarin, direct oral anticoagulants [DOAC], or heparin) to prevent hemorrhagic complications during endoscopic submucosal dissection (ESD) for colorectal neoplasias (CRNs). However, serious thrombosis might occur during temporary withdrawal of anticoagulants. The current study aimed to evaluate outcomes with anticoagulants in patients undergoing ESD for CRNs.

Patients and methods This study was a single-institution retrospective cohort study based on clinical records. We assessed 650 consecutive patients with 698 CRNs who underwent ESD at Hiroshima University Hospital between December 2010 and June 2016. The patients were divided into three groups: the warfarin group (19 patients with 19 CRNs), DOAC group (7 patients with 9 CRNs), and no-antithrombotics group (624 patients with 670 CRNs). We replaced warfarin with heparin 3 to 5 days before endoscopy. Although DOAC was suspended on the morning of endoscopy, we did not replace heparin.

Results Bleeding after the procedure occurred in 26.3 % (5/19), 22.0 % (2/9), and 2.7 % (18/670) of patients in the warfarin, DOAC, and no-antithrombotics groups, respectively. In the warfarin group, four patients who bled after the procedure took not only warfarin but also other antiplatelets. En bloc resection rates were 94.7 % (18/19), 100 % (9/9), and 96.6 % (647/670) in the warfarin, DOAC, and no-antithrombotics groups, respectively. No patients experienced ischemic events in the perioperative period.

Conclusions Among patients undergoing ESD for CRNs, risk of bleeding was higher among patients who took anticoagulants than among those who did not. In particular, careful attention to patients who took antiplatelets in addition to warfarin before ESD for CRNs is warranted.
EUS-guided sampling with 25G biopsy needle as a rescue strategy for diagnosis of small subepithelial lesions of the upper gastrointestinal tract
Authors: Antonini Filippo , Giorgini Sara , Fuccio Lorenzo , Angelelli Lucia , Macarri Giampiero
Published: July 2018

Background and study aims This study was designed to evaluate the impact of additional tissue obtained with endoscopic ultrasound (EUS)-guided 25-gauge core biopsy needle (25G-PC) following an unsuccessful fine-needle biopsy (FNB) performed with larger-bore needles for the characterization of gastrointestinal subepithelial lesions (GI-SELs).

Patients and methods We prospectively collected and retrospectively analyzed information in our database from January 2013 to June 2017 for all patients with GI-SELs who received a EUS-guided FNB (EUS-FNB) with 25G-PC during the same procedure after failure of biopsy performed with larger-bore needle. Diagnostic yield, diagnostic accuracy and procedural complications were evaluated.

Results Sixteen patients were included in this study, 10 men and 6 women, median age 67.8 (range 43 to 76 years). Five patients were found to have a SEL localized in the distal duodenum, five in the gastric antrum, two in the gastric fundus and four in the gastric body. The mean size of the lesions was 20.5 mm (range 18 – 24 mm). EUS-FNB with 25G-PC enabled final diagnosis in nine patients (56.2 %). Regarding the subgroup of duodenal lesions, the procedure was successful in four of five (80 %). Final diagnoses with EUS-guided sampling were GIST (n = 6), leiomyoma (n = 2) and metastatic ovarian carcinoma (n = 1). No procedure-related complications were recorded.

Conclusion In patients with small GI-SELs, additional tissue obtained with 25G-PC could represents a “rescue” strategy after an unsuccessful procedure with larger-bore needles, especially when lesions are localized in the distal duodenum.
Endoscopic management of difficult benign biliary and pancreatic strictures using a wire-guided cystotome: experience with 25 cases
Authors: Puri Rajesh , Bhatia Sumit , Bansal Rinkesh , Sud Randhir
Published: July 2018

Background and study aims Endoscopic management using standard accessories is the preferred modality for treatment of benign biliary strictures. However, with difficult strictures, there is frequently failure of endoscopic therapy. We are reporting our experience regarding use of a standard diathermic dilator (cystotome) to aid in stricture dilatation and stent placement in patients with difficult strictures.

Patients and methods Data were analyzed from January 2014 to January 2017 at a single tertiary care center in North India. Total 25 patients were included.

Results The mean age was 45 years (varying from 38 – 55 years). Of the 25 patients with difficult strictures, 14 (56 %) were male and 11 (44 %) were female. Further, of these, 19 had biliary and 6 had pancreatic strictures. The average time of diathermic current application was 3.5 seconds (ranging 3 – 5 seconds). Technical and clinical success were achieved in 100 % of cases. None of the patients had any procedure-related (early or delayed) major complications.

Conclusion The cystotome is an extremely safe and useful accessory in benign biliary and pancreatic strictures, whereas conventional methods to negotiate stricture have failed.
Relationships Between Olympic Weightlifting Exercises, Peak Power of the Upper and Lower Limb, Muscle Volume and Throwing Ball Velocity in Elite Male Handball Players
Authors: Hermassi Souhail , Delank Karl Stefan , Fieseler Georg , Bartels Thomas , Chelly Mohamed Souhaiel , Khalifa Riadh , Laudner Kevin , Schulze Stephan , Schwesig René
Published: July 2018

Background This study aimed to investigate relationships between peak power (PP) as measured by upper limb (PPUL) and lower limb (PPLL) force velocity tests, maximal upper limb force assessed by clean and jerk (1RMCJ) and snatch (1RMSE) exercises, estimates of local muscle volume and throwing ball velocity.

Methods Thirty elite male handball players volunteered for the investigation (age: 20.3 ± 2.1 years; body mass: 82.5 ± 10.5 kg; height: 1.85 ± 0,07 %; body fat: 13.1 ± 2.1 %). Lower and upper limb force velocity tests were performed on appropriately modified forms of a Monark cycle ergometer with measurement of PPUL and PPLL, and the corresponding respective maximal forces (F0UL and F0LL) and velocities (V0UL and V0LL). Snatched (SN) and clean and jerk (CJ) exercises were performed to one repetition maximum (1RM). Handball throwing velocity was measured with jump shot (JS) without run-up (TW) and 3 steps shot (T3 step). Muscle volumes of the upper and lower limbs were estimated with a standard anthropometric kit.

Results The 1RM CJ proved to be the most important predictor for throwing velocity. All types of throwing showed a high correlation with this parameter (JS: r = 0.75; TW: r = 0.62; T3 step: r = 0.66). The highest relation was detected between jump shot and 1RM snatch technique (r = 0.82). The PPUL muscle volume correlated highly with PPUL absolute power (r = 0.70). In contrast, we did not find any comparable relations for the lower limb (muscle volume vs. PPUL absolute power: r = 0.07).

Conclusions Our results highlight the contribution of both lower and upper limbs to handball throwing velocity, suggesting the need for coaches to include upper and lower limb strength weightlifting exercises and power programs when improving the throwing velocity of handball players.
Demographic Characteristics and Functional Performance of the Kidneys and Hearts of Patients with Acute Tramadol Toxicity
Authors: Mohammadpour Abbas , Ashkezari Mahmood , Farahmand Behrokh , Shokrzadeh Mohammad
Published: July 2018

Background Tramadol overdose is disproportionately more common in Iran, and in recent years, it has become one of the most common causes of poisoning admissions to emergency departments in this country. Tramadol is a synthetic analogue of codeine and a weak opioid receptor (μ) agonist that can cause seizures even in commonly used doses.

Aims This study aimed to examine the relationship between seizure and plasma tramadol concentration in patients with tramadol poisoning who referred to one of the hospitals in Ghaemshahr, Iran.

Study Design This research is an analytical cross-sectional study.

Methods A total of 121 tramadol users (non-seizure group=61 and seizure group=60) were admitted to hospital. Demographic characteristics and clinical findings were collected by a questionnaire. Plasma was harvested after separation from blood cells and quantified using the HPLC method. Biochemical parameters, including urea, creatinine, troponin I, and creatine phosphokinase (CPK–MB) were determined by spectrophotometry. This study was a single blind design study.

Results The mean age of participants was 25 years. Ninety-five participants were classified as smokers. The mean serum concentrations of tramadol in subjects with seizures and those without seizures were 491.90 μg/ml and 374.42 μg/ml (p=0.211), respectively. Average concentrations of biochemical parameters in the seizure group were 53.33 (9.38) µg/ml urea, 1.71 (0.29) µg/ml Cr, 6.53 (2.89) µg/ml TPI, and 58.23 (22.20) µg/ml CPK- MB. Average concentrations of biochemical parameters were significantly higher in the seizure group than in the non-seizure group (p<0.001).

Conclusion Tramadol-induced seizures were not found to be related to age, gender, or dosage. This complication can lead to cardiac and renal complications in individuals on tramadol experiencing seizures. This result indicates that stricter restrictions should be imposed on the distribution and administration of the drug tramadol.
Fluctuations in Plasma Levels of Thrombomodulin in Patients with DIC
Authors: Amano Kagehiro , Tateyama Masaki , Inaba Hiroshi , Fukutake Katsuyuki , Fujimaki Michio
Published: July 2018

Plasma thrombomodulin (TM) has attracted considerable attention as a marker of endothelial cell membrane injury. We examined fluctuations in plasma TM levels in patients receiving therapy for the disseminated intravascular coagulation syndrome (DIC) using an enzyme immunoassay. Sixty healthy controls and 18 patients with DIC were studied.

The mean ± SD of the TM values initially measured immediately after the onset of DIC was 42.00 ± 20.85 ng/ml, which was markedly increased as compared with the control value of 15.36 ±4.85 ng/ml (p <0.001).

Fluctuations in the TM levels over time were studied after dividing the patients according to the presence or absence of improvement in the underlying disease and improvement or lack thereof in the coagulation findings. Group I showed improvement in both categories, Group II showed improvement only in the latter, and Group III showed no improvement in either category.

In Group I, the mean ± SD of initial measured TM levels was 37.02 ±10.12 ng/ml and the mean of final values decreased to 58.9% of the initial value. This decrease was significant by paired Student’s t-test (p <0.01). The initial value in Group II was 45.86 ± 18.86 ng/ml and the final values increased to 117.0% of the initial values, this difference was not significant. The initial value in Group III was 44.48 ±21.53 ng/ml and the final values increased to 143.4% of the former. This increase was significant by paired Student’s t-test (p <0.05). The difference in % fluctuations between Group I and Group III was significant by Wilcoxon’s test (p <0.01).

These results suggest that the measurement of plasma TM can be useful in the management of DIC.
Comparison of the Inhibitory Effects of the TXA2 Receptor Antagonist, Vapiprost, and Other Antiplatelet Drugs on Arterial Thrombosis in Rats: Possible Role of TXA2
Authors: Takiguchi Yoshiharu , Wada Kouichirou , Nakashima Mitsuyoshi
Published: July 2018

The antithrombotic effect of the thromboxane A2 receptor antagonist, vapiprost, was compared with those of other antiplatelet drugs using an arterial thrombosis model which utilized photochemical reaction in the rat femoral artery. Vapiprost prolonged the time required to occlude the artery with thrombus and inhibited collagen-induced rat platelet aggregation in whole blood ex vivo, in a dose-dependent manner. The potency ranking of antithrombotic effect was vapiprost > ketanserin (serotonin 5-HT2 receptor antagonist) >> ticlopidine (inhibitor of ADP-induced platelet aggregation) = dipyridamole (adenosine uptake inhibitor) >aspirin (cyclooxygenase inhibitor). On the other hand, the ranking of antiplatelet effect was ticlopidine ≥vapiprost ≥aspirin. Ketanserin and dipyridamole were ineffective. Relative to their antiplatelet effect, vapiprost and ketanserin had powerful antithrombotic effects. It is possible that the potent antithrombotic effects of vapiprost and ketanserin in vivo reflect the ability of these drugs to inhibit mediator-induced vascular contractions in addition to platelet aggregation. The results of the present study also suggest that TXA2 may play an important role in thrombogenesis in rats.
A Novel Rat Model of Thrombogenicity: Its Use in Evaluation of Prothrombin Complex Concentrates and High Purity Factor IX Concentrates
Authors: McLaughlin L F , Drummond O , MacGregor I R
Published: July 2018

A non-stasis rodent model of thrombogenicity has been used for dose-ranging studies with a conventional prothrombin complex concentrate (PCC) and to evaluate high purity factor IX concentrates from different manufacturers. Fibrin monomer (soluble fibrin) and fibrinopeptide A (FPA) were monitored before and after infusion of test solution. FPA was found to be the more sensitive and reproducible indicator of thrombogenicity and exhibited a dose-related elevation after infusion of the PCC at doses of between 100–300 IU/kg. In contrast the amounts of FPA generated after 300 IU/kg of the high purity factor IX products were similar to control infusions of albumin.
Stored Platelets Release Nucleotides as Inhibitors of Platelet Function
Authors: Fijnheer Rob , Boomgaard Martine N , van den Eertwegh Alfons J M , Homburg Christa H E , Gouwerok Casparus W N , Veldman Henk A , Roos Dirk , de Korte Dirk
Published: July 2018

It is well known that the function of platelets decreases progressively during storage of platelet concentrates at room temperature. To investigate this phenomenon in more detail, we have resuspended platelets that had been stored for 24 h or 72 h in fresh plasma, and we have measured the aggregation response and the ATP secretion. Conversely, the effect of plasma in which platelet concentrates (PC) had been stored for 24 h or 72 h, was tested on fresh platelets. Both the aggregation response to collagen and ADP and the collagen-induced ATP secretion of stored platelets partially recovered after incubation with fresh plasma (p <0.05). The same parameters measured with fresh platelets incubated in stored PC-plasma were found to be significantly reduced in comparison with the response of fresh platelets in fresh plasma (p <0.05). Finally, platelets were stored in a plasma-free medium, suitable for platelet storage and the supernatant was tested. This supernatant inhibited the function of fresh platelets in a storage time-dependent fashion. Boiling of these supernatants did not change the inhibiting capacities, whereas filtration over active charcoal did. Analysis of this supernatant revealed AMP and diadenosine tetraphosphate, which both inhibit platelet function.

These data show that stored platelets release nucleotides that inhibit platelet function in a reversible manner. This phenomenon may contribute to the decrease of platelet function during storage and the recovery of platelet function after transfusion.
Effects of Heparin, Dermatan Sulfate and of their Association on the Inhibition of Venous Thrombosis Growth in the Rabbit
Authors: Carrie D , Caranobe C , Gabaig A M , Larroche M , Boneu B
Published: July 2018

This study compares the ability of unfractionated heparin, of dermatan sulfate, and of their simultaneous administration delivered as continuous intravenous infusion or as a single bolus injection to inhibit the growth of a standardized venous thrombosis in the rabbit.

When delivered as continuous intravenous infusion for 4 h, heparin and dermatan sulfate inhibited thrombus growth in a dose dependent manner. The maximum antithrombotic effect of heparin was achieved at the dose of 0.15 mg kg–1 h–1 (25 U kg–1 h–1) which generated a mean plasma concentration of 1.8 µg ml–1 (0.31 U ml–1) and a 1.8 fold prolongation of the activated partial thromboplastin time (APTT) in comparison to the pretreatment value. A comparable antithrombotic effect was obtained with dermatan sulfate at the dose of 2 mg kg–1 h–1. This dose generated a mean plasma concentration of 30 µg ml–1 and a 1.3 fold APTT prolongation. Increasing these doses up to 10 fold did not improve the antithrombotic effect which did not overpass 60–70% of the controls. When the compounds were delivered simultaneously, the maximum antithrombotic effect (64%) was obtained with the following association: 0.06 mg kg–1 h–1 (10 U kg–1 h–1) for heparin and 1 mg kg–1 h–1 for dermatan sulfate. Increasing these doses up to 4 to 5 fold did not improve the antithrombotic effect. Heparin, dermatan sulfate and the association of both were also delivered as single bolus injections and the resultant antithrombotic effect was determined 4 h after saline infusion. Bolus doses of 0.15 and 0.30 mg kg–1 (25 and 50 U kg–1) of heparin or of 1 and 2 mg kg–1 of dermatan sulfate were ineffective. In contrast, the association of dermatan sulfate (2 mg kg–1) to heparin (0.15 or 0.30 mg kg–1) generated antithrombotic effects of 61 and 64% respectively in the absence of detectable residual plasma anticoagulant activities, 1 h after the bolus injections. These studies indicate that: (1) under continuous intravenous regimen, dermatan sulfate is as effective as heparin to inhibit venous thrombus growth when delivered at a 13 fold higher dose on a weight basis; (2) the coadministration of the two compounds under the same regimen does moderately improve the antithrombotic effect; (3) while each of these compounds were ineffective when delivered as a single bolus, their coadministration generated a dramatic antithrombotic effect for at least 4 h; (4) simultaneous activation of antithrombin III and of heparin cofactor II may therefore represent a valuable strategy to treat an established deep vein thrombosis.
Lysing Patterns of Retracted Blood Clots with Diffusion or Bulk Flow Transport of Plasma with Urokinase into Clots – a Magnetic Resonance Imaging Study In Vitro
Authors: Blinc A , Keber D , Lahajnar G , Stegnar M , Zidanšek A , Demsar F
Published: July 2018

Fresh retracted clots are known to be poorly lysable by fibrinolytic agents. We have studied whether lysis of retracted clots could be enhanced by bulk transport in comparison to pure diffusion of plasma containing urokinase (400 IU/ml) into the clots. Cylindrical retracted blood clots were occlusively glued by a polyester into plastic tubes and put in contact with plasma through the clot bases. One group of clots (perfused clots, n = 10) was placed under a pressure difference of 6 kPa (60 cm H20) which resulted in an average plasma flow of 0.97 ± 0.34 µl/min through the clot during the first hour. Another group of clots (non-perfused clots, n = 10) was incubated in the lytic plasma without a pressure difference. Clot sizes were measured during lysis by magnetic resonance imaging (MRI). Channels representing lysed areas penetrated into perfused clots with a velocity of 5.4 ± 1.6 mm/h (n = 10), whereas the boundaries of non-perfused clots subsided with a velocity of less than 0.1 mm/h. Eight of the 10 perfused clots were recanalized after 8 h and the sizes of the perfused group were reduced to 64.0 ± 10.7% of the initial values. The relative sizes of non-perfused clots after 8 h remained significantly higher: 95.0 ± 1.3%, p <0.005. In a separate experiment good agreement was obtained between the measured clot sizes by MRI and the residual radioactivity of 125I-fibrin in the clot. The strong dependence of lysis on the transport mechanism of plasma with urokinase into retracted clots suggests that local hemodynamic conditions in vivo are likely to influence the lysis of thrombi.
Aurin Tricarboxylic Acid Inhibits Platelet Adhesion to Collagen by Binding to the 509-695 Disulphide Loop of von Willebrand Factor and Competing with Glycoprotein Ib
Authors: Girma J P , Fressinaud E , Christophe O , Rouault C , Obert B , Takahashi Y , Meyer D
Published: July 2018

Aurin tricarboxylic acid (ATA) is known to inhibit ristocetin-induced platelet agglutination but not arachidonic acid-, epinephrine- or ADP-induced aggregation. Its capacity to abolish human von Willebrand factor (vWF)-platelet interactions was further investigated by measurement of platelet adhesion to collagen, platelet agglutination tests and binding studies. In flowing blood using parallel-plate perfusion chambers and human collagen, ATA inhibited platelet adhesion to completion in a dose-dependent manner only at the highest shear rate tested (2,600 s–1). It was without effect at 100 and 650 s–1. ATA completely abolished vWF-dependent platelet agglutination induced by ristocetin, botrocetin and asialo-vWF, respectively. 125I-vWF binding to ristocetin- and botrocetin-treated platelets, to heparin and to sulfatides as well as 125I-botrocetin binding to vWF was competitively inhibited by ATA. By contrast, binding of 125I-vWF to collagen was not affected. To further localize the domain of vWF interacting with ATA, experiments of inhibition of binding of selected 125I-monoclonal antibodies (MoAbs) to immobilized vWF by ATA were performed. Our data led to the conclusion that: 1) the interaction of ATA with vWF involves sequences of the A1 disulphide loop of vWF (residues 509–695) and close epitopes which interact with GPIb and 2) the inhibition of platelet adhesion by ATA occurs only at a high shear rate where vWF is known to play a key role. Thus ATA, which blocks the vWF/GPIb pathway by interfering with vWF and not with platelets, is a potential tool in preventing the early stages of thrombosis.
Arachidonate Transfer Between Platelets and Lipoproteins
Authors: Surya Ingrid I , Gorter Gertie , Akkerman Jan Willem N
Published: July 2018

Although platelets have specific bindingsites for LDL and HDL, it is doubtful whether lipoproteins modulate platelet functions via receptor-mediated processes. We investigated platelet-lipoprotein interaction during prolonged incubation with concentrations of LDL and HDL that saturate the bindingsites within a few minutes. When [3H]arachidonate-labeled human platelets were incubated for 4 h with lipoproteins, part of the 3H-radioactivity transferred to LDL and to a lesser extent to HDL. The transfer was temperature-sensitive, unaffected by modification of lysine in LDL or indomethacin treatment of the platelets, and almost irreversible. [3H]arachidonate transfer to lipoproteins could be mimicked by incubating platelets with a high concentration of fatty acid free albumin. This showed, that the loss of 3H-radioactivity reflected a decrease in endogenous arachidonate, leading to impaired aggregation, secretion and thromboxane B2 formation in platelets after stimulation with thrombin but not with arachidonate. Thus, the decrease in platelet functions seen after long incubation with HDL is caused by depletion of platelet arachidonate. Despite an even stronger arachidonate depletion by LDL, this lipoprotein initiated arachidonate metabolism and secretion independent of specific binding sites for LDL on the platelet. Surprisingly, the major part of the secretion was preserved when the formation of prostaglandin endoperoxides/ thromboxane A2 was inhibited with indomethacin. These findings argue against a role for LDL and HDL receptors in the modulation of platelet functions and are more in favor of lipid exchange processes between platelets and lipoproteins.
Pentamidine: A Non-Peptide GPIIb/IIIa Antagonist – In Vitro Studies on Platelets from Humans and Other Species
Authors: Cox Dermot , Motoyama Yukio , Seki Jiro , Aoki Toshiaki , Dohi Miwako , Yoshida Keizo
Published: July 2018

In this paper we show that the non-peptide anti-parasite agent pentamidine is a broad spectrum anti-platelet agent with an IC50 of 1.1 µM in ADP-induced platelet aggregation in human platelet rich plasma (PRP). It had similar activity when collagen, arachidonic acid, platelet activating factor, thrombin and epinephrine were used. It had no effect on platelet intracellular cAMP levels. It inhibited 125I-fibrinogen, 125I-fibronectin and 125I-von Willebrand factor binding to ADP-activated fixed platelets with IC50 values of 160, 160 and 60 nM respectively. Pentamidine showed a high degree of species selectivity with slightly less activity in monkey and dog PRP and little activity in guinea pig, rabbit, rat and mouse PRP compared with human. This was similar to the other RGD analogues tested. This species specificity was shown to be dependent on the species of platelets and independent of the species of fibrinogen. Thus, pentamidine is a potent non-peptide inhibitor of fibrinogen binding to GPIIb/IIIa.
Thrombin Production, Inactivation and Expression during Open Heart Surgery Measured by Assays for Activation Fragments Including a New ELISA for Prothrombin Fragment F1+2
Authors: Boisclair Michael D , Lane David A , Philippou Helen , Sheikh Sajila , Hunt Beverley
Published: July 2018

Activation of coagulation was studied during the peri-operative period in patients undergoing cardiopulmonary bypass (CPB) surgery using activation markers which have recently become available: prothrombin fragment F1 + 2 (F1 + 2), which is a measure of total thrombin generation, and thrombin-antithrombin complex, which is a measure of inactivation of free thrombin by antithrombin. Levels of the specific marker of fibrin breakdown, D-dimer, were also determined. F1 + 2 levels were assessed using a newly developed ELISA described herein which employs a neoantigen-specific capture antibody raised using a synthetic peptide; the latter antibody has been pre-adsorbed against prothrombin to ensure high specificity for F1 + 2.

Increased generation of thrombin during surgery was clearly demonstrated despite maintenance of a high concentration of heparin during the period of extracorporeal blood circulation. There was a close association (r = 0.882) between the generation of thrombin (F1 + 2 levels) and its inhibition (TAT levels). Differences were noted, however, between the information provided by F1 + 2 and TAT, which are interpreted with regard to the different in vivo fates of F1 + 2 and thrombin. The enhanced activation and inhibition of coagulation observed during CPB was suppressed once physiological blood circulation was restored, with F1 + 2 returning to pre-surgical levels within 24 h after surgery. During the post-operative period D-dimer levels, which rose in concert with F1 + 2 and TAT levels, remained highly elevated, suggesting that not all of the generated thrombin was inactivated by antithrombin. It is concluded that heparin is only partially effective as an anticoagulant during CPB surgery. F1 + 2 is an unambiguous marker of thrombin generation and its measurement may be a useful means of evaluating more effective coagulation inhibitors in CPB.
Pharmacokinetics of Monoclonally-Purified and Recombinant Factor VIII in Patients with Severe von Willebrand Disease
Authors: Morfini M , Mannucci P M , Tenconi P M , Longo G , Mazzucconi M G , Rodeghiero F , Ciavarella N , De Rosa V , Arter A
Published: July 2018

A monoclonally-purified factor VIII (FVIII) concentrate, containing little von Willebrand factor (vWF), was infused to 11 patients with severe von Willebrand disease and unmeasurable levels of plasma vWF. In comparison with the historical data obtained infusing hemophiliacs in the same conditions, monoclonally-purified FVIII had a significantly shorter half-life and faster clearance from plasma but similar in vivo recovery and volume of distribution. Two additional patients with severe von Willebrand disease were also infused with recombinant FVIII totally devoid of vWF. Half-life was very short and in vivo recovery low, with a larger volume of distribution than for monoclonally-purified FVIII. We conclude that in patients with severe von Willebrand disease the small amounts of vWF contained in the monoclonally-purified FVIII concentrate are not sufficient to stabilize infused FVIII, nor to support the normal circulation of endogenous FVIII that these patients produce at a normal rate.
Standards for Assay of von Willebrand Factor Concentrates: A Collaborative Study
Authors: Fricke W A , Lamb M A , Rastogi S C
Published: July 2018

A multilaboratory collaborative study was undertaken to assess the feasibility of using a plasma standard for expressing the results of assays for the von Willebrand factor content of von Willebrand factor concentrates and of factor VIII concentrates. Thirteen laboratories tested six concentrates for von Willebrand factor antigen, ristocetin cofactor activity, and multimer content using the World Health Organization plasma standard for factor VIII/von Willebrand factor, 87/718, as a standard. Only a few assays were invalid because of nonparallelism or nonlinearity. Significant interlaboratory and interassay differences were found for both von Willebrand factor antigen and ristocetin cofactor activity. There was generally good agreement between the laboratories with respect to the multimer content in the preparations. With respect to assay validity, a plasma standard could be suitable for assaying concentrated preparations of von Willebrand factor.
Respective Roles of Antithrombin III and Alpha 2 Macroglobulin in Thrombin Inactivation
Authors: Fischer A M , Tapon-Bretaudiere J , Bros A , Josso F
Published: July 2018

In order to investigate the mechanism of thrombin inactivation in the presence of both antithrombin III (AT III) and α 2-macroglobulin (α 2 M), thrombin and the inhibitors have been purified from human material and thrombin inactivation studied using purified reagents either alone or added to defibrinated plasma. Comparison of clotting and amidolytic activities of residual thrombin allowed to measure the amount of thrombin bound to α 2 M. In a purified reagent system as well as in plasma, part of exogenous thrombin is bound to α 2 M. The amount of bound thrombin is related to α 2 M concentration. Conversely, previous plasma α 2 M depletion by immunoabsorption increases the consumption of heparin-cofactor activity by exogenous thrombin. Thus AT III and α 2 M compete for thrombin inactivation. This finding could be of practical interest in clinical situations associating high plasma α 2 M levels and a decrease of AT III concentration.
125I-Fibrinogen Leg Scanning: Reassessment of Its Role for the Diagnosis of Venous Thrombosis in Post-Operative Patients
Authors: Lensing Anthonie W A , Hirsh Jack
Published: July 2018

Objective: To determine the reasons why 125I-fibrinogen leg scanning, a screening test which was reported to be very sensitive for the detection of post-operative thrombosis, has shown poor sensitivity in contemporary studies.

Study Identification: English-language reports were identified through a Medline computer search (1965-1991), Current Contents, and an extensive manual search of the bibliographies in identified articles.

Study Selection: Studies in orthopaedic or general surgical patients were reviewed that compared 125I-fibrinogen leg scanning with venography in all patients (accuracy studies) or in patients in whom 125I-fibrinogen leg scanning became positive (positive predictive value studies).

Data Extraction: A systematic appraisal of study design and specific descriptive information concerning the selection of patients.

Results of Data Synthesis: Six of the 15 studies which compared 125I-fibrinogen leg scanning with venography were level 1 studies (potential for bias minimized) and nine were classified as level 2 studies (potential for bias not minimized). In orthopaedic surgical patients, the pooled sensitivity of leg scanning for isolated calf vein thrombosis, for all venous thrombosis, and the pooled specificity were 55%, 45%, and 92% for the level 1 studies, respectively. These indices were 88%, 82%, and 79%, respectively for the level 2 studies (P <0.001). Only two (level 2) studies were found that evaluated the accuracy of leg scanning for venous thrombosis in general surgical patients.

Conclusion: We conclude that leg scanning is an insensitive method for the screening of post-operative venous thrombosis in orthopaedic patients. Our findings call into question the validity of the many studies (including meta-analyses) evaluating prophylactic agents for venous thrombosis which used leg scanning as the only test for the assessment of efficacy.
Platelet Aggregation Induced in Vitro by Therapeutic Ultrasound
Authors: Chater B. V , Williams A. R
Published: July 2018

Platelets were found to aggregate spontaneously when exposed to ultrasound generated by a commercial therapeutic device. At a given frequency, aggregation was found to be a dose-related phenomenon, increasing intensities of ultrasound inducing more extensive and more rapid aggregation. At any single intensity, the extent aggregation was increased as the frequency of the applied ultrasound was decreased (from 3.0 to 0.75 MHz).

Ultrasound-induced platelet aggregation was found to be related to overall platelet sensitivity to adenosine diphosphate. More sensitive platelets were found to aggregate spontaneously at lower intensities of sound, and also the maximum extent of aggregation was found to be greater. Examination of ultrasound-induced platelet aggregates by electron microscopy demonstrated that the platelets had undergone the release reaction.

The observation that haemoglobin was released from erythrocytes in whole blood irradiated under identical physical conditions suggests that the platelets are being distrupted by ultrasonic cavitation (violent gas/bubble oscillation).

It is postulated that overall platelet aggregation is the result of two distinct effects. Firstly, the direct action of ultrasonic cavitation disrupts a small proportion of the platelet population, resulting in the liberation of active substances. These substances produce aggregation, both directly and indirectly by inducing the physiological release reaction in adjacent undamaged platelets.
The Relationship of Plasma Fibrinogen, Erythrocyte Flexibility and Blood Viscosity
Authors: Dupont P. A , Sirs J. A
Published: July 2018

Measurements have been made of plasma fibrinogen concentration, erythrocyte flexibility and blood viscosity at shear rates from 5.75 to 230 sec−1 during and following surgery. In the post-operative period the plasma fibrinogen level in the patient rose to over 1,000 mg/dl and because there were subsequent complications, only returned to normal after 4 weeks. There was an associated change of erythrocyte flexibility, with a correlation coefficient of 0.98. The blood viscosity also varied with the plasma fibrinogen level, the effect being more pronounced at low shear rates. The internal viscosity of the red blood cell, calculated from the plasma viscosity and whole blood viscosity at 230 sec−1, decreases with increasing plasma fibrinogen concentration, in agreement with the direct measurements made of erythrocyte flexibility. It is proposed that at high shear rates an increase in plasma viscosity due to an elevation of fibrinogen concentration, is offset by a decrease in the rigidity of the erythrocytes, and these 2 effects counter-balance.
Participation of Hageman Factor Dependent Pathways in Human Disease States
Authors: Colman Robert W. , Wong Patrick Y.
Published: July 2018

Abnormalities of Hageman factor dependent pathways have been described in a wide variety of human disease states. Congenital deficiencies of factor XII (Hageman trait) prekallikrein (Fletcher trait) and high molecular weight kininogen (Williams, Fitzgerald and Flaujeac traits) although resulting in profound in vitro changes, do not cause in vivo difficulties. In contrast, deficiency of Cl esterase inhibitor (hereditary angioedema) results in significant morbidity and mortality. Acquired diseases may exhibit decreased synthesis of these three proteins in cirrhosis and dengue fever. In vivo activation of factor XII initiated pathways occur in septic shock, disseminated or localized intravascular coagulation, typhoid fever, polycythemia vera, hyperbetalipoproteinemia, coronary artery disease, nephrotic syndrome, transfusion reactions, hemodialysis and extracorporeal bypass. Activation of both the intrinsic system and tissue mediators contribute to the vasomotor phenomena in carcinoid syndrome and postgastrectomy dumping. Roles for factor XII, prekallikrein and kininogen have been suggested in gouty arthritis, allergic disorders and cystic fibrosis but the evidence is not yet convincing in these disorders.
Reduction of Coagulation Factor XIII Concentration in Patients with Myocardial Infarction, Cerebral infarction, and other Thromboembolic Disorders
Authors: Alkjaersig Norma , Fletcher Anthony P. , Lewis Martin , Ittyerah Roy
Published: July 2018

Coagulation factor XIII and plasma fibrinogen chromatographic assays have been performed serially in patients suffering from acute myocardial and cerebral infarction, and in others with disseminated intravascular coagulation. The findings were compared with 2 groups of “controls”; normal clinically-well subjects and hospitalized patients with cerebral infarction who exhibited minimal, stable, or improving neurological deficits. Substantial depression of factor XIII concentrations developed in the 3 patient groups, together with concomitant significant increases in the proportion and concentration of plasma high molecular weight fibrin(ogen) complexes (HMWFC). An inverse correlation (p<0.05) between coagulation factor XIII concentration and percentage of HMWFC was demonstrated in the early stages of the illness. These findings suggest that depression of coagulation factor XIII concentration in these states, is secondary to extra vascular or intravascular coagulation and may reflect its degree.
Platelet Membrane Glycoproteins and the Interaction between Bovine Factor VIII Related Protein and Human Platelets
Authors: Solum Nils Olav , Hagen Inger , Gjemdal Torbjørn
Published: July 2018

The “GP I fraction” seen on polyacrylamide gel electrophoresis of reduced samples of whole normal platelets contains three glycopolypeptides corresponding to the integral membrane protein GP I (GP Ia), the easily solubilized membrane protein GPS (GP Ib, glycocalicin) and a granule-located glycoprotein.

Freezing and thawing of platelets in tris-buffered saline leads to a lysis of platelets and platelet granules with the result that both GPS and the granule glycoprotein is found in the soluble fraction. The two glycoproteins can be separated by SDS polyacrylamide gel electrophoresis both in reduced and unreduced samples when urea and EDTA is incorporated into the gels. This permitted electrophoretic studies of GPS using the granule glycoprotein as a control and marker substance.

A working hypothesis stating that the presence of GPS on the platelet surface is a prerequisite to the agglutination of human platelets with bovine factor VIII related protein, has been investigated. The hypothesis was supported by the observation that storage of platelets in tris-buffered saline at 4° C led to the elution of GPS and loss of agglutination, as was also the case when platelets were frozen and thawed in tris-buffered saline, or preincubated in 3 M KCl and resuspended in either tris-buffered saline or the EDTA-containing medium A. GPS was not, or only slightly, solubilized when platelets were frozen and thawed in the EDTA-containing medium and the resulting platelet ghosts still agglutinated.

Platelets from 1 patient of the Bernard-Soulier type did not agglutinate with the bovine factor VIII-related protein, nor did the platelets contain GPS. An improved technique for the isolation of such platelets is described.
Insights into the Mechanism of Platelet Action through Studies at pH 5.3.
Authors: Mürer E. H , Stewart G. J
Published: July 2018

Incubation of washed human platelets at pH 5.3 at 37° C induces a slow secretion of stored compounds. The secretion is 60% inhibited by metabolic inhibitors and blocked at 0° C.
The major changes in the metabolic adenine nucleotide levels in the platelets precede the secretion, which is accompanied by a drop in ADP and an increase in inosine and hypoxanthine. The incubation does not lead to significantly increased loss in cytoplasmic compounds from the platelets.

Ultrastructural changes which accompany pH 5.3-induced secretion include a coalescence of cytoplasmic material in the center and a decrease in densely stained material in the periphery of the platelet. These changes are only seen by prolonged incubation (60 min). In the presence of 2 mM fluoride similar changes are seen after 3 min incubation. Other changes induced by fluoride, i. e. the formation of swollen areas in the periphery of the platelet are not induced by incubation at pH 5.3 alone.

The metabolic changes seen by incubation at pH 5.3 are to a great degree reversible, even when secretion has been induced. Although secretion cannot be induced by incubation of platelets at pH 7.6 alone, pH 5.3-induced secretion continues at the higher pH. Whereas incubation at pH 5.3 in the cold does not induce secretion, incubation with 2 mM fluoride under these conditions will result in at least 50% secretion of stored compounds when pH and temperature are increased, indicating that fluoride has been taken up by the platelet by passive diffusion. This concentration of fluoride is below the threshold for induction of secretion at pH 7.6.

In contrast to secretion induced by thrombin, and in agreement with the findings with fluoride, the calcium ionophore A 23187 is equally effective as inducer of secretion at pH 5.3 and at pH 7.6. This also agrees with the findings that when secretion has been “initiated” in the cold with thrombin at pH 7.4, the extrusion which takes place at higher temperature has a shift in pH optimum towards the acid pH and is only partially inhibited at pH 5.5, while the action of agents which effect platelet secretion from the outside, including added Ca++, is blocked below pH 6, and the induction effect of thrombin below pH 6.5.

We propose that the agents which cause secretion at low pH have a direct intracellular effect, probably on the level of cytoplasmic Ca++, while the agents which are inhibited by the low pH act indirectly via external membrane sites.
Laboratory Evaluation and Clinical Characteristics of 2,132 Consecutive Unselected Patients with Venous Thromboembolism – Results of the Spanish Multicentric Study on Thrombophilia (EMET*-Study)
Authors: Mateo José , Oliver Artur , Borrell Montserrat , Sala Núria , Fontcuberta Jordi ,   EMET Group
Published: July 2018

Previous studies on the prevalence of biological abnormalities causing venous thrombosis and the clinical characteristics of thrombotic patients are conflicting. We conducted a prospective study on 2,132 consecutive evaluable patients with venous thromboembolism to determine the prevalence of biological causes. Antithrombin, protein C, protein S, plasminogen and heparin cofactor-II deficiencies, dysfibrinoge-nemia, lupus anticoagulant and antiphospholipid antibodies were investigated. The risk of any of these alterations in patients with familial, recurrent, spontaneous or juvenile venous thrombosis was assessed. The overall prevalence of protein deficiencies was 12.85% (274/2,132) and antiphospholipid antibodies were found in 4.08% (87/2,132). Ten patients (0.47%) had antithrombin deficiency, 68 (3.19%) protein C deficiency, 155 (7.27%) protein S deficiency, 16 (0.75%) plasminogen deficiency, 8 (0.38%) heparin cofactor-II deficiency and 1 had dysfib-rinogenemia. Combined deficiencies were found in 16 cases (0.75%). A protein deficiency was found in 69 of 303 (22.8%) patients with a family history of thrombosis and in 205/1,829 (11.2%) without a history (crude odds ratio 2.34, 95% Cl 1.72-3.17); in 119/665 (17.9%) patients with thrombosis before the age of 45 and in 153/1,425 (10.7%) after the age of 45 (crude odds ratio 1.81, 95% Cl 1.40-2.35); in 103/616 (16.7%) with spontaneous thrombosis and in 171/1,516 (11.3%) with secondary thrombosis (crude odds ratio 1.58, 95% Cl 1.21-2.06); in 68/358 (19.0%) with recurrent thrombosis and in 206/1,774 (11.6%) with a single episode (crude odds ratio 1.78,95% Cl 1.32-2.41). Patients with combined clinical factors had a higher risk of carrying some deficiency. Biological causes of venous thrombosis can be identified in 16.93% of unselected patients. Family history of thrombosis, juvenile, spontaneous and recurrent thrombosis are the main clinical factors which enhance the risk of a deficiency. Laboratory evaluation of thrombotic patients is advisable, especially if some of these clinical factors are present.