Comparative assessment of biodegradable-antireflux heparine coated ureteral stent: animal model study.

BACKGROUND: Double J ureteral stents are widely used on urological patients to provide drainage of the upper urinary tract. Unfourtunately, ureteral stents are not free from complications, as bacterial colonization and require a second procedure for removal. The purpose of the current comparative experimental study is to evaluate a new heparin-coated biodegradable antireflux ureteral stent (BraidStent®-H) to prevent urinary bacterial colonization. METHODS: A total of 24 female pigs were underwent determination of bacteriuria and nephrosonographic, endoscopic and contrast fluoroscopy assessment of the urinary tract. Afterward, were randomly assigned animals to Group-I, in which a 5Fr double-pigtail ureteral stent was placed for 6 weeks, or Group-II, in which a BraidStent®-H was placed. Follow-up assessments were performed at 1, 3, 6, 8, 12 weeks. The final follow-up includes the above methods and an exhaustive pathological study of the urinary tract was accomplished after 20 weeks. RESULTS: Bacteriuria findings in the first 48 h were significant between groups at 6 h and 12 h. Asymptomatic bacteriuria does not reach 100% of the animals in Group-II until 48 h versus Group-I where it appears at 6 h. The weekly bacteriuria mean rate was 27.7% and 44.4% in Group I and II respectively, without statistical significance. In Group II there were no animals with vesicoureteral reflux, with statistical significance at 3 and 6 weeks with Group-I. The 91.2% of stents in Group-II were degraded between 3 and 6 weeks, without obstructive fragments. Distal ureteral peristalsis was maintained in 66.6-75% in Group-II at 1-6 weeks. CONCLUSIONS: The heparin coating of BraidStent® allows an early decrease of bacterial colonization, but its effectiveness is low at the long term. Heparin coating did not affect scheduled degradation rate or size of stents fragments. BraidStent®-H avoids the side effects associated with current ureteral stents, thus should cause less discomfort to patients.

A facile chemiluminescence sensing for ultrasensitive detection of heparin using charge effect of positively-charged AuNPs.

Heparin is a glycosaminoglycan with the highest negative charge density of any known biological molecule. Herein, this highly negative charge structure of heparin and the charge effect from positively-charged AuNPs for luminol chemiluminescence (CL) reaction were combined to build a facile and sensitive CL strategy for detection of heparin. The highly negative charge structure of heparin molecules (four negatively-charged side groups per repeat unit) and the effective signal amplification of charge effect from positively-charged AuNPs make this analysis to display high sensitivity for heparin detection, and the detection limit is as low as 0.06 ng/mL. It is about two orders of magnitude lower than the previously reported colorimetric assay and far lower than the current analysis methods. The established CL strategy is to use the electrostatic interaction between heparin and signal probe (positively-charged AuNPs). Since polyanionic heparin has the highest negative charge in biological system, this CL sensing shows high selectivity for the detection of heparin, and hyaluronic acid (HA), an analogue of heparin, cannot cause interference. This CL sensing succeeded in detecting heparin in human serum samples. Besides, polycationic protamine, heparin antidote, can respond to the system's CL signals through its strong interactions with heparin, thus indirectly detecting protamine. For protamine in serum samples, the detection result was basically consistent with Coomassie brilliant blue assay.

An assessment of polydispersed species in unfractionated and low molecular weight heparins by diffusion ordered nuclear magnetic resonance spectroscopy method.

The primary goal of this project is to extend a (1)H NMR based method, which combines elements of separation on the basis of molecular size with the information specific to (1)H-1D NMR, to the assessment of the heparin contaminant oversulfated chondroitin sulfate (OSCS) and process related impurity dermatan sulfate (DS), and their polydisperse degradation products in samples of unfractionated heparins (UFHs) and low molecular weight heparins (LMWHs) used as the active pharmaceutical ingredients (APIs) in finished pharmaceutical products. The method has been briefly introduced by us in a recent contribution (vide infra). We propose a labelling of the N-acetyl peaks in the (1)H NMR spectra of the UFHs and LMWHs with the parameter D(i), the translational diffusion coefficient available from DOSY NMR. It is shown how DOSY can be applied for screening lots of unfractionated and depolymerised heparins for obtaining molecular size information for heparins and any impurities when using (1)H NMR. The evidence has been presented that title method can be applied as a routine means for assessment of the OSCS and DS contaminants and the polydisperse chemical entities present in the UFHs and LMWHs used as the APIs in heparin pharmaceuticals.

[Contaminated heparins]. / Les héparines contaminées.

In January 2008, following the detection of severe allergic reaction, several batches of heparins were removed from the United-States market. Although less dramatic, comparable side effects were also reported in Germany but not in France despite the fact that low-weight heparins, obtained from contaminated batches of unfractionated heparins, were used to limit shortage. So far, tainted injectable heparin has been linked to over 80 deaths in the USA. Analyses demonstrated that such tainted heparins were contaminated by high levels of chondroïtin persulfate (5-20%), a cheaper hemi-synthetic product. All batches were furnished by several Chinese chemical industries, China representing 50% of all heparins produced worldwide. Thus, contamination of the heparin supply is a worldwide problem. Following this event, the efficiency of the quality insurance, particularly analytical controls before proceeding, remains questionable. The strict respect of the pharmaceutical chain is urgently required to avoid any kind of quality problem in the future.

An international survey of current practice in the laboratory assessment of anticoagulant therapy with heparin.

AIMS: We conducted a survey of laboratory practice for assessment of heparin anticoagulant therapy by participants of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP). METHODS: A questionnaire was sent to 646 laboratories enrolled in the Haematology component of the QAP, requesting details of tests used for monitoring heparin therapy. RESULTS: Seventy laboratories (10.8%) returned results that indicated that they performed laboratory monitoring of heparin therapy. Most laboratories (69/70 = 98.6%) use the activated partial thromboplastin time (APTT) to monitor unfractionated heparin, with eight (11.4%) also using the APTT for monitoring low molecular weight (LMW) heparin. Five (7.1%) laboratories use the thrombin time (TT) test to help monitor heparin therapy and 37 (52.9%) laboratories use an anti-Xa assay to monitor heparin (either LMW or unfractionated). Normal reference ranges (NRR) for APTT differed considerably between laboratories, even those using the same reagent. Therapeutic ranges (TR) also differed considerably between laboratories, for both APTT and the anti-Xa assay. Laboratory differences in NRR and TR using the same reagents could only be partly explained by the use of different instrumentation. CONCLUSIONS: There is a large variation in current laboratory practice relating to monitoring of heparin anticoagulant therapy. This finding is similar to that of a similar survey conducted by the RCPA QAP almost a decade ago. This study suggests that better standardisation is still required for laboratory monitoring of heparin therapy.

The role of proteomics in the assessment of premature rupture of fetal membranes.

The presence and integrity of amniotic fluid is fundamental for the normal development of the human fetus during pregnancy. Its production rate changes throughout pregnancy and is mainly related to the functions of the different fetal, placental and amniotic compartments. Premature rupture of the membranes (PROM) occurs in about 5% of deliveries, with complications such as infection and preterm birth. The management of patients with PROM, regardless of gestational age, remains controversial, and it is therefore important to develop new biological tests in order to achieve accurate diagnoses by identifying the presence of specific amniotic fluid markers in vaginal environment. We recently showed the usefulness of amniotic fluid proteomics in identifying a series of peptides that were absent from the corresponding maternal plasma. Several peptides corresponded to fragments of plasma proteins. Two peptides, absent from plasma samples of pregnant women, were identified in amniotic fluid. They corresponded to the COOH-terminal parts of perlecan (SwissProt: P98160) and of agrin (SwissProt: O00468) protein cores, two major heparan sulfate proteoglycans of basement membranes. In this review we will discuss modern proteomic strategies that may improve the laboratory assessment of PROM, and will focus on some of the biochemical characteristics of agrin and perlecan fragments identified in amniotic fluid.

An institution-specific heparin titration nomogram: development, validation, and assessment of compliance.

STUDY OBJECTIVE: To develop, validate, and assess compliance with a heparin titration nomogram. DESIGN: Prospective, open-label trial. SETTING: University teaching hospital. SUBJECTS: Patients admitted with heart failure who required therapy with intravenous unfractionated heparin. Intervention. An in vitro concentration-response was determined by measuring activated partial thromboplastin times (aPTTs) on normal pooled plasma containing known concentrations of heparin. The therapeutic aPTT range was determined from the concentration-response by using the therapeutic heparin concentration range of 0.2-0.4 U/ml (protamine neutralization). Patients were consecutively enrolled, and therapy was managed by using the heparin titration nomogram. Paired aPTT-heparin concentrations were obtained, and nomogram validation was performed by comparing the in vitro and the ex vivo concentration-responses with use of linear regression. Nomogram compliance also was assessed. MEASUREMENTS AND MAIN RESULTS: The therapeutic aPTT ranges based on in vitro and ex vivo data were determined to be 45-72 seconds and 47-61 seconds, respectively. The ranges were significantly different (p<0.001). Overall compliance with the nomogram was 88%. CONCLUSION: These results confirm that, even in a relatively homogeneous disease-state patient population, in vitro data do not accurately predict ex vivo data. If in vitro data are used to develop an institution-specific nomogram, a validation procedure should be used to ensure accuracy. Although 100% compliance to a nomogram may not be attainable, it should be expected. Therefore, a compliance rate of 88% is concerning and suggests a need for increased nursing and physician education.

Quality assessment of intraoperative blood salvage and autotransfusion.

Intraoperative blood salvage and autotransfusion are commonly used to minimize exposure to banked blood. Although this technique has been used widely for years, data vary regarding the quality of autotransfused blood. Salvaged blood may contain plasma, residual heparin, and free hemoglobin released from damaged cells. All of these factors may contribute to the adverse sequelae sometimes seen with autotransfusion. For these reasons, we have monitored autotransfused blood to assess its quality. Intraoperative blood salvage was used during most cardiac procedures and at the discretion of the surgeon in other specialties. Blood was collected through a double lumen catheter that was anticoagulated with heparin, filtered, centrifuged, and washed with saline. A sample of the blood was removed for analysis, which included hematocrit, heparin assay, fibrinogen, and free hemoglobin levels. Over a 6-year period, 1593 patients had intraoperative blood salvage with quality assessment. The majority of patients underwent cardiac operations (941 patients, 59%), whereas 243 had orthopedic (15%) and 208 had vascular (13%) procedures. Additionally, there were 127 pediatric patients (8%) and 74 miscellaneous procedures (5%). The highest average yield of salvaged blood was during vascular procedures (1073 +/- 76 mL), whereas orthopedic cases had the lowest yield (378 +/- 19 mL) and hematocrit (39%). There was minimal residual heparin activity, even in patients requiring systemic anticoagulation (0.3 to 0.5 units/mL). Patients undergoing pediatric procedures had the lowest concentration of free hemoglobin (476 mg/L), whereas all adult patients had higher free hemoglobin levels, especially vascular operations (990 mg/L). Intraoperative salvaged blood has minimal heparin activity, even in procedures requiring systemic anticoagulation. Fibrinogen, a marker of residual plasma, was undetectable in the majority of cases. These data indicate that intraoperative blood salvage generally results in a high-quality product (good hematocrit, low heparin, minimal plasma), although there are significant differences in free hemoglobin levels depending on the operative procedure.

The preparation of a sensitive partial thromboplastin reagent from bovine brain.

Commercial partial thromboplastin reagents markedly differ in their sensitivity to factor deficiency, heparin, or the lupus anticoagulant. These differences may be partly due to the variable phospholipid content of different commercially available reagents. For over 15 years, we have routinely used a partial thromboplastin prepared from human brain. In the past four years, we have been using a similarly prepared bovine partial thromboplastin reagent. This report describes the preparation of our partial thromboplastin reagent, as well as an analysis of the phospholipid composition of both the human and bovine thromboplastin reagents. Four separate brain preparations produced consistent percentages of the anionic phospholipids, phosphatidylserine, and phosphatidylinositol. The bovine reagent was also compared with commercial partial thromboplastin reagents in the detection of coagulation factor deficiency, heparin, and the lupus anticoagulant.