Plasma Colloid Research Articles

Effect of hemodialysis (HD) on intraocular pressure, ocular surface, and macular change in patients with chronic renal failure

The main objective of hemodialysis (HD) is to correct the excessive accumulation and abnormal distribution of body fluid. Therefore, changes in the systemic hemodynamic parameters and in the ocular fluid volume and composition can occur during a single HD session. The aim of this study is to evaluate the short-term changes in the ophthalmologic findings after HD. Thirty eyes of 30 patients with chronic renal failure (CRF) undergoing HD were analyzed. The subjects were categorized into two groups according to the cause of CRF. Detailed ophthalmologic examinations were performed immediately before and after HD. The relationships between the systemic hemodynamic changes and the ophthalmologic changes during a single HD session were evaluated. The results show that a body fluid correction after HD involves a change in the plasma colloid osmotic pressure. The mean intraocular pressure (IOP) decreased after HD with a mean decrease of 2.4 ± 2.1 mmHg and the central corneal thickness decreased with a mean change of 6.9 ± 5.4 μm. After HD, the ocular surface changed significantly; the tear break-up time (TBUT) and basal tear secretion (Schirmer's test) decreased, whereas the keratoepitheliopathy score increased. The macular thickness measured by spectral domain optical coherence tomography (SD-OCT) decreased after HD. The mean decrease in the central subfield thickness was 7.4 ± 9.9 μm. The ocular surface changes after HD affected the visual acuity and examination quality. A significant correlation was found between the changes in the systemic hemodynamic parameters and those in the ophthalmologic findings, except for the retinal thickness. The changes in the ophthalmologic findings after HD were consistent and significant in all CRF subjects. These changes correlated with the increase in plasma colloid osmotic pressure. HD can correct the volume and composition of ocular fluid. Therefore, it can affect the ophthalmologic findings in a short period of time. In addition, for good examination quality, it is recommended that an ophthalmologic examination in CRF patients be performed on a non-dialysis day or prior to HD on a dialysis day. Furthermore, for accurate comparison of examination results, the time interval from an HD session to an ophthalmologic examination must be considered.

Plasma expander and blood storage effects on capillary perfusion in transfusion after hemorrhage

Treating hemorrhage with blood transfusions in subjects previously hemodiluted with different colloidal plasma expanders, using fresh autologous blood or blood that has been stored for 2 weeks, allows identifying the interaction between type of plasma expander and differences in blood storage. Studies used the hamster window chamber model. Fresh autologous plasma, 130-kDa starch-based plasma expander (hydroxyethyl starch [HES]), or 4% polyethylene glycol-conjugated albumin (PEG-Alb) was used for 20% of blood volume (BV) hemodilution. Hemodilution was followed by a 55% by BV 40-minute hemorrhagic shock period, treated with transfusion of fresh or blood that was stored for 2 weeks. Outcome was evaluated 1 hour after blood transfusion in terms of microvascular and systemic variables. Results were principally dependent on the type of colloidal solution used during hemodilution, 4% PEG-Alb yielding the best microvascular recovery evaluated in terms of the functional capillary density. This result was consistent whether fresh blood or stored blood was used in treating the subsequent shock period. Fresh blood results were significantly better in systemic and microvascular terms relative to stored blood. HES and fresh plasma hemodilution yielded less favorable results, a difference that was enhanced when fresh versus stored blood was compared in their efficacy of correcting the subsequent hemorrhage. The type of plasma expander used for hemodilution influences the short-term outcome of subsequent volume resuscitation using blood transfusion, 4% PEG-Alb providing the most favorable outcome by comparison to HES or fresh plasma.

Linfoadenopatia transitória secundária à síndrome nefrótica

Mediastinal lymphadenomegaly secondary to hypervolemia is an underdiagnosed tomographic finding. Herein we describe, in a patient with normal cardiac function, findings of pulmonary congestion associated to lymph node enlargement. The nephrotic syndrome causing hypoalbuminemia, low plasma colloid osmotic pressure and augmented transcapillary fluid leakage was the probable cause of the radiological findings.

Fibrinogen as a Hemostatic Agent

Coagulation factor I (fibrinogen) plays an essential role in the hemostatic system by bridging activated platelets and being the key substrate for thrombin in establishing a consolidating fibrin network. Fibrinogen is synthesized in the liver and the plasma concentration is 1 to 5-4.0 g/L. During recent 10 years, fibrinogen has been recognized to play an important role in controlling hemorrhage. Dilutional coagulopathy induced by colloid plasma expanders is characterized by fibrinogen deficiency and dysfunctional fibrin polymerization. Trauma and use of extracorporeal circulation is also known to reduce levels of fibrinogen. A series of laboratory experiments and experimental animal studies have suggested fibrinogen as a potent hemostatic agent. These data are supported by retrospective surveys as well as a series of prospective proof of principal clinical trials. This article provides a description of the biochemistry and mechanisms of fibrinogen as well as the etiology for developing fibrinogen deficiency. Furthermore, it summarizes laboratory and experimental data on the role of fibrinogen in dilutional coagulopathy and addresses laboratory monitoring issues. Finally, it lists retrospective and prospective studies, which have been designed to assess the clinical efficacy and safety of hemostatic intervention with fibrinogen concentrate.

Single molecule tracking on supported membranes with arrays of optical nanoantennas.

Coupling of the localized surface plasmons between two closely apposed gold nanoparticles (nanoantenna) can cause strong enhancements of fluorescence or Raman signal intensity from molecules in the plasmonic “hot-spot”. Harnessing these properties for practical applications is challenging due to the need to fabricate gold particle arrays with well-defined nanometer spacing and a means of delivering functional molecules to the hot-spot. We report fabrication of billions of plasmon-coupled nanostructures on a single substrate by a combination of colloid lithography and plasma processing. Controlled spacing of the nanoantenna gaps is achieved by taking advantage of the fact that polystyrene particles melt together at their contact point during plasma processing. The resulting polymer thread shadows a gap of well-defined spacing between each pair of gold triangles in the final array. Confocal surface-enhanced Raman spectroscopy imaging confirms the array is functionally uniform. Furthermore, a fully intact supported membrane can be formed on the intervening substrate by vesicle fusion. Trajectories of freely diffusing individual proteins are traced as they sequentially pass through, and are enhanced by, multiple gaps. The nanoantenna array thus enables enhanced observation of a fluid membrane system without static entrapment of the molecules.

Nanopatterned submicron pores as a shield for nonspecific binding in surface plasmon resonance-based sensing

We present a novel approach to tackle the most common drawback of using surface plasmon resonance for analyte screening in complex biological matrices--the nonspecific binding to the sensor chip surface. By using a perforated membrane supported by a polymeric gel structure at the evanescent wave penetration depth, we have fabricated a non-fouling sieve above the sensing region. The sieve shields the evanescent wave from nonspecific interactions which interfere with SPR sensing by minimizing the fouled area of the polymeric gel and preventing the translocation of large particles, e.g. micelles or aggregates. The nanopatterned macropores were fabricated by means of colloidal lithography and plasma enhanced chemical vapor deposition of a polyethylene oxide-like film on top of a polymeric gel matrix commonly used in surface plasmon resonance analysis. The sieve was characterized using surface plasmon resonance imaging, contact angle, atomic force microscopy and scanning electron microscopy. The performance of the sieve was studied using an immunoassay for detection of antibiotic residues in full fat milk and porcine serum. The non-fouling membrane presented pores in the 92-138 nm range organized in a hexagonal crystal lattice with a clearance of about 5% of the total surface. Functionally, the membrane with the nanopatterned macropores showed significant improvements in immunoassay robustness and sensitivity in untreated complex samples. The utilization of the sensor built-in sieve for measurements in complex matrices offers reduction in pre-analytical sample preparation steps and thus shortens the total analysis time.

Phosphodiesterase 4 inhibition attenuates plasma volume loss and transvascular exchange in volume expanded mice

Phosphodiesterase 4 inhibition attenuates plasma volume loss and transvascular exchange in volume expanded mice

Comparison of whole blood and plasma colloid osmotic pressure in healthy dogs

To determine the difference between colloid osmotic pressure (COP) values determined from plasma versus those determined from whole blood. Prospective observational study. University veterinary teaching hospital. Fifty-three healthy dogs. None. Whole blood and plasma COP, CBC, plasma biochemistry. In all dogs, plasma COP values were significantly lower (P=0.02) than whole blood COP, with a mean of difference of 0.5 mm Hg. The mean and median whole blood COP was 21.75 and 21.4 mm Hg, respectively, with a range of 17.9-27.1 mm Hg. The mean and median plasma COP was 21.2 and 20.9 mm Hg with a range of 16.7-28.9 mm Hg. While significant difference exists between plasma and whole blood COP, the individual values are within expected reference intervals for dogs (21-25 mm Hg). Using either sample appears to provide the same information in clinically healthy dog; however, it is recommended that clinicians utilize the same sample type for comparison in an individual patient.

Design and fabrication of a superhydrophobic glass surface with micro-network of nanopillars

The wetting property of a superhydrophobic glass surface with a micro-network of nanopillars fabricated from colloidal lithography and plasma etching is investigated in this paper. The micro-network distribution of nanospheres can be modulated by diluting the nanosphere concentration and controlling the spin rate. The micro-network of nanospheres spun on the glass surface serves as a mask for nanopillars during the plasma etching process. After the fabrication, the nano-structured surface is treated with fluoroalkylsilane self-assembled monolayers to obtain superhydrophobicity. Among several spin rates, the minimum colloidal network area density from a 100nm polystyrene nanosphere solution diluted to 0.026% was found at a spin rate of 4000rpm. The sample with the lowest network area density shows a good quality of superhydrophobicity, having the highest water contact angle and the lowest sliding angle among samples with other network area densities. In particular, samples with a micro-network of pillars also showed mechanical robustness against finger rubbing. To assess the superhydrophobic behavior in-depth, a size-dependent contact angle equation is proposed for use with a high contact angle (>135°) and with a Bo (Bond number)≪1. Furmidge’s sliding angle equation is also modified; it is derived considering a static contact angle to simplify the prediction of the sliding angle. The contact and sliding angle measurements from samples with a micro-network of nanopillars show good agreement with the proposed equations.

Evaluation of the effect of hetastarch and lactated Ringer's solution on plasma colloid osmotic pressure in healthy llamas

To compare the effects of hetastarch and lactated Ringer's solution (LRS) on plasma colloid osmotic pressure (pCOP) and other hematologic variables in healthy llamas. Prospective crossover study. 6 healthy female llamas. Procedures-Llamas were administered LRS (45 mL/kg [20.5 mL/lb]) and, after a 3-day washout period, hetastarch (15 mL/kg [6.8 mL/lb]) during 60-minute IV infusions. Serum total protein, serum albumin, and hemoglobin concentrations and Hct were measured before each infusion (baseline), immediately after each infusion was completed (0 hours), and at 2, 4, 8, and 12 hours. The pCOP was measured at baseline and at 0, 2, 4, 8, 12, 24, 36, and 48 hours after each infusion was completed; additional measurements of pCOP were obtained 72 and 96 hours after hetastarch infusion. Hetastarch administration significantly increased mean ± SEM pCOP from 23.5 ± 0.3 mm Hg (baseline) to a peak of 28.4 ± 0.6 mm Hg (12 hours); significant increases in pCOP persisted at 96 hours after hetastarch administration. Administration of LRS significantly decreased albumin and total protein concentrations; in addition, mean ± SEM pCOP decreased from 24.1 ± 0.4 mm Hg (baseline) to 18.0 ± 0.3 mm Hg (0 hours). Hetastarch administration caused more pronounced decreases in Hct (0 hours) and concentrations of hemoglobin (0 hours), albumin (all time points), and total protein (all time points) than did LRS administration. Hetastarch administration increased pCOP in healthy llamas for 96 hours with no clinically important complications.

Effect of hydroxyethyl starch on intracranial pressure and plasma colloid osmotic pressure in rats with cerebral ischemia/reperfusion injury

To investigate the regulatory effect of hydroxyethyl starch on colloidal osmotic pressure (COP), and its effect on intracranial pressure (ICP) in rats with cerebral ischemia/reperfusion (I/R) injury. Twenty four male Sprague Dawley (SD) rats were randomly divided into sham operation group, model group and the hydroxyethyl starch group, each n =8. Cerebral I/R model was reproduced by middle cerebral artery occlusion (MCAO), followed by reperfusion after ischemia for 2 hours. Rats in hydroxyethyl starch group received hydroxyethyl starch 130/0.4206 ml × kg(-1)× d(-1) ia tail vein at the beginning of reperfusion. ICP and COP were evaluated at 0, 2, 6, 12, 18, 24 hours after the surgery. The rats were sacrificed by decapitation. The water content of the right hemisphere was measured at 24 hours after the surgery, and the ratio of apoptosis of neurons was observed by immunohistochemical method. Two hours after surgery the ICP (mm Hg, 1 mm Hg=0.133 kPa) of model group and hydroxyethyl starch group was significantly increased compared with sham operation group (11.50 ± 1.43, 12.48 ± 0.75 vs. 7.95 ± 0.92, both P <0.05). With prolongation of time, the ICP gradually increased and reached the peak at 24 hours (22.76 ± 0.72, 23.32 ± 0.98 vs. 8.15 ± 1.09, both P <0.05). But there was no significant difference in ICP in the hydroxyethyl starch group compared with that of the model group at all time points. The COP (mm Hg) of hydroxyethyl starch group was significantly higher than the model group and sham operation group at each time point, and peaked at 6 hours after surgery (13.49 ± 0.50 vs. 12.04 ± 0.47, 12.00 ± 0.39, both P <0.01). There was no significant difference in COP between the model group and the sham operation group at all time points. The brain water content, neuronal apoptosis of hydroxyethyl starch group and model group was significantly higher than sham operation group [brain water content: (80.16 ± 0.44)%, (80.59 ± 0.67)% vs. (78.72 ± 0.52)%; neuronal apoptosis:(44.27 ± 7.86)%,(42.82 ± 7.82)%vs. (3.26 ± 0.00)%, P <0.05 or P <0.01], but there was no significant difference between the hydroxyethyl starch group and model group (both P >0.05). Intravenous injection of hydroxyethyl starch 130/0.4 can increase the plasma COP, but it can not significantly reduce ICP and brain water content, and it also can not improve the neuronal apoptosis.

From Superamphiphobic to Amphiphilic Polymeric Surfaces with Ordered Hierarchical Roughness Fabricated with Colloidal Lithography and Plasma Nanotexturing

Ordered, hierarchical (triple-scale), superhydrophobic, oleophobic, superoleophobic, and amphiphilic surfaces on poly(methyl methacrylate) PMMA polymer substrates are fabricated using polystyrene (PS) microparticle colloidal lithography, followed by oxygen plasma etching-nanotexturing (for amphiphilic surfaces) and optional subsequent fluorocarbon plasma deposition (for amphiphobic surfaces). The PS colloidal microparticles were assembled by spin-coating. After etching/nanotexturing, the PMMA plates are amphiphilic and exhibit hierarchical (triple-scale) roughness with microscale ordered columns, and dual-scale (hundred nano/ten nano meter) nanoscale texture on the particles (top of the column) and on the etched PMMA surface. The spacing, diameter, height, and reentrant profile of the microcolumns are controlled with the etching process. Following the design requirements for superamphiphobic surfaces, we demonstrate enhancement of both hydrophobicity and oleophobicity as a result of hierarchical (triple-scale) and re-entrant topography. After fluorocarbon film deposition, we demonstrate superhydrophobic surfaces (contact angle for water 168°, compared to 110° for a flat surface), as well as superoleophobic surfaces (153° for diiodomethane, compared to 80° for a flat surface).

TMP revisited: the importance of plasma colloid osmotic pressure in high-flux dialysers

With high-flux dialysers and volume-controlled machines, transmembrane pressure (TMP) is no longer used to prescribe and control the adjustment of patient volume but still used to monitor filter function and membrane integrity. A drop in TMP at given operation characteristics indicates a leak or even a rupture in the membrane, while an increase in TMP indicates a loss in hydraulic permeability, most likely because of gradual clogging of the filter by formation of secondary membranes or obstruction of individual capillary fibers. Monitoring dialyser function is of special interest in different forms of haemofiltration and haemodiafiltration, where ultrafiltration rates are allowed to reach very high values exposing all components of

Fibrinogen concentrate for management of bleeding

Fibrinogen concentrate for management of bleeding

Hematocrit level correlates with lungs resistivity in elderly patients with cardiogenic pulmonary edema

Regular monitoring of pulmonary congestion in car-diogenic pulmonary edema (CPE) patients is neces-sary for its adequate management via pharmaceuti-cal treatment. It is well known that the development of CPE is accompanied with an increase in hema-tocrit, plasma protein concentration and colloid os-motic pressure due to the decrease in the plasma volume. In the present study the mean left and right lung resistivity values taken pre- and post treatment with diuretics using a hybrid bio-impedance electri-cal impedance tomography system were correlate to the measured changes in hematocrit level. A marginal significant correlation was found between the abso-lute mean lung resistivity and hematocrit levels (Pearson’s correlation coefficient of R = 0.4, p-value = 0.057). When the change in the mean lung resistivity of a patient was plotted vs. the change in hematocrit readout, a significant linear correlation was found (R = 0.7, p-value = 0.02). These results support the validity of the resistivity measurements using bio-impedance system in monitoring changes of pulmonary edema in CPE patients.

Nanoscale Protein Patterning on Si Substrates using Colloidal Lithography and Plasma Processing

Selective immobilization of proteins in well-defined patterns on substrates has recently attracted considerable attention as an enabling technology for applications ranging from basic research to biosensors and bioMEMS. In this work we demonstrate a low-cost and high throughput process for nanoscale, selective immobilization of proteins on patterned Si substrates, based on colloidal lithography and plasma processing in order to define the spots (< 300nm) where proteins are adsorbed. A close- packed monolayer of PS microparticles is deposited on oxidized Si substrates and is used as etching mask to define SiO2 spots (on Si), which after plasma-induced chemical modification are appropriate for selective protein immobilization. The immobilized proteins are detected by means of confocal microscopy and evaluated by means of atomic force microscopy. Such nanoscale immobilized proteins can be successfully integrated into BioMEMS and microanalytical systems.

The role of fibrinogen: a new paradigm in the treatment of coagulopathic bleeding

Fibrinogen is involved in both primary and secondary hemostasis, playing an important role in platelet aggregation and the establishment of a fibrin network. Recent evidence suggests that very high levels of fibrinogen act as antithrombin and can reduce endogenous thrombin potential and compromise clot stability, particularly following a low tissue factor stimulus. Several laboratory methods for measuring plasma fibrinogen concentrations are available, but results vary depending on the type of method and the use of artificial colloid plasma expanders. Adopting only the Clauss method can provide erroneously high levels when used in patients who have received colloid plasma expanders. This may contribute to a hazardous delay or complete lack of treatment. Multiple in vitro experiments, animal studies, and proof-of-principle randomized, clinical studies have recently suggested that hemostatic intervention with a fibrinogen concentrate may be efficient and safe in controling perioperative bleeding. In particular, fibrinogen concentrate has a key role in improving clotting function and reducing blood loss in settings such as trauma and cardiothoracic surgery. However, prospective studies are needed to determine the clinical efficacy and safety of fibrinogen concentrate when used as a hemostatic intervention for patients with massive bleeding due to trauma or surgery.

“Mesh-assisted” colloidal lithography and plasma etching: A route to large-area, uniform, ordered nano-pillar and nanopost fabrication on versatile substrates

We propose a variation of colloidal (microparticle) lithography, which we term “mesh-assisted” colloidal lithography, to improve uniformity and quality of monolayer microparticle assembly over large areas: a square mesh with 200–1000μm open squares (total open-area larger than 75%) and of appropriate height is created/placed on a substrate surface, and acts as template facilitating uniform, monolayer assembly of polystyrene (PS) microparticles with spin-coating. We also study the pattern transfer, the pillar/post formation and their dimensional control on several substrates, namely polymers, silicon and silicon dioxide. Highly ordered nanopillar or nanopost arrays are produced on: (a) PMMA plates by one anisotropic etching step, (b) silicon, and (c) silicon dioxide. The silicon nanopillars and silicon dioxide nanoposts are fabricated by a two step plasma etching: an isotropic oxygen plasma step which shrinks the PS microspheres followed by an anisotropic step to transfer the pattern. The obtained pillars have nanotexture on top of the PS sphere due to plasma roughening, and thus present dual-scale topography, useful for applications such as superhydrophobic surfaces. Our method is thus a combination of photolithography, colloidal lithography, and plasma etching for low-cost, large area nanopost formation.

Fibrinogen estimates are influenced by methods of measurement and hemodilution with colloid plasma expanders

Measurement of plasma fibrinogen is often required in critically ill patients or massively bleeding patients being resuscitated with colloid plasma expander. This study aimed at evaluating different assays of plasma fibrinogen after in vitro dilution with commonly used plasma expanders and challenged the hypothesis that levels of fibrinogen are estimated significantly higher in plasma diluted with colloid plasma expander compared with isotonic saline. Fibrinogen measurements were established in plasma samples each diluted in vitro to 30 or 50% with isotonic saline, hydroxyethyl starch (HES) 130/0.4, and human albumin. Fibrinogen levels were assessed using an antigen determination, three photo-optical Clauss methods, one mechanical Clauss method, a prothrombin-derived method, and viscoelastic measurement through thromboelastometry. Measurement of fibrinogen levels was significantly different when performed on alternate analytical platforms. By 30 and 50% dilution with HES 130/0.4 coagulation analyzers using the photo-optical Clauss methods significantly overestimated levels of fibrinogen. Dilution with human albumin did not affect fibrinogen levels except from one analyzer by 50% dilution level. Viscoelastic measurement of fibrin polymerization was reduced at both dilution levels and appeared to reflect the impairment of fibrin polymerization induced by HES 130/0.4 and to a lesser extent human albumin. This study demonstrated that different automated coagulation analyzers revealed significantly different levels of fibrinogen. The presence of colloid plasma expander gave rise to erroneous high levels of fibrinogen returned from some coagulation analyzers employing the method of Clauss.

High‐Resolution Surface Chemical Analysis of a Trifunctional Pattern Made by Sequential Colloidal Shadowing

We present a new method for creating surface chemical patterns where three chemistries can be periodically arranged at alternate positions on a single substrate without the use of top-down approaches. High-resolution chemical imaging by time-of-flight secondary ion mass spectrometry (ToF-SIMS), with nanometer spatial resolution, is used to prove the success of the patterning and subsequent chemical modification steps. We use a combination of colloidal self-assembly, plasma etching, self-assembled monolayers (SAMs) and physical vapour deposition (PVD). The method utilizes a double colloid assembly process in which a first layer of close-packed colloids is created, followed by plasma etching, coating with gold and deposition of a first SAM layer. A second particle layer is deposited on top of the first layer masking the interstitial spaces containing the first SAM. A second gold layer is deposited followed by a second SAM. After particle removal the surface consists of the pattern containing two different SAMs and a SiO(2) layer that can be readily functionalized with silanes. The possibility in the replacement of the two different thiols is investigated by X-ray photoelectron spectroscopy (XPS) and it was found that no replacement is taking place. ToF-SIMS imaging is used to show the periodicity of the chemical patterns by tracking unique fragment ions from the different surface regions. The patterning method is adaptable to create smaller or larger chemical patterns by appropriate choice of particle sizes. The patterns are useful for immobilizing biomolecules for cell studies or as multiplexed biosensors.