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PubMed1990

Clinicopathologic impact of colloid in colorectal carcinoma.

The overall incidence of colloid (mucinous) carcinoma in patients with colorectal cancer is 17 percent, and its influence on patterns of failure and survival in patients with colorectal cancer varies throughout the literature. The presence of colloid carcinoma may have a real but small impact on the patterns of failure or survival in colorectal cancer. The data are conflicting and, furthermore, by proportional hazards analysis, colloid carcinoma is not an independent prognostic factor for survival. Therefore, despite it being common clinical practice, a change in treatment recommendations based solely on the presence or absence of colloid cancer is not recommended. Treatment recommendations should be based primarily on the tumor stage and site. However, given the trend toward increased failure and decreased survival compared with adenocarcinoma, colloid carcinoma should be reported separate from other histological patterns to better understand its natural history.

Adenocarcinoma, Mucinous↗
PubMed2005

Colloid cysts in children, a clinical and radiological study.

INTRODUCTION: Colloid cysts are uncommon in children. They occur more frequently in young adults. METHODOLOGY: This is a retrospective study on all pediatric patients (<or=18 years) with colloid cysts treated surgically in our institute between 1977 and 2005. RESULTS: A total of 43 patients with colloid cyst were treated surgically. Seven pediatric patients (16% of the total number of patients) were identified. Patients' ages ranged from 6 to 18 years (mean of 14.1+/-4.67). They all presented clinically with symptoms and signs of increased intracranial pressure. Radiologically, the cyst size ranged from 10 to 25 mm (mean of 16.1+/-5.2). All patients had either diagnostic computed tomography (CT) or magnetic resonance imaging (MRI), or both. The colloid cysts appeared hyperdense on CT in five patients (83%) and isodense in one (six available studies). On MRI, all (five available studies) lesions were hyperintense on T2-weighted images. All seven patients had complete cyst resection. Either transcortical (five patients) or transcallosal approaches (two patients) was used in the surgical resection. There was no mortality. One patient developed a delayed cerebrospinal fluid leak related to hydrocephalus, and another patient developed a delayed postoperative seizure. The radiological findings supported the aggressive clinical scenario of these lesions in the pediatric group of patients. CONCLUSION: In conclusion, colloid cysts can occur in children. They are associated with more aggressive clinical and radiological patterns. Early surgical intervention is highly recommended.

Adolescent↗
PubMed1991

Histological maturity of healed duodenal ulcers and ulcer recurrence after treatment with colloidal bismuth subcitrate or cimetidine.

The relationship between histological maturity of healed duodenal ulcers and ulcer recurrence after 6 weeks of treatment with colloidal bismuth subcitrate or cimetidine was investigated. There was no significant difference in healing rates between colloidal bismuth subcitrate- and cimetidine-treated patients (85.7% and 71.8%, respectively; P greater than 0.05). Histologically, the regenerating mucosa of healed ulcers was divided into three categories--good, fair, and poor--according to pattern. Sixty percent of healed colloidal bismuth subcitrate-treated and 30.9% of healed cimetidine-treated ulcers had a good pattern; the difference was statistically significant (P = 0.027). The difference in recurrence rates between healed colloidal bismuth subcitrate-treated and healed cimetidine-treated patients was statistically significant at 3 months (3.45% and 20%, respectively; P = 0.044). All recurrent ulcers in both groups had fair or poor patterns of regenerating mucosa. It was concluded that the greater histological maturity of the regenerating mucosa may contribute to the lower recurrence rate in colloidal bismuth subcitrate-treated patients than in cimetidine-treated patients.

Adolescent↗
PubMed1992

Establishment of a multi-dose study of chondroitin sulfate iron colloid for evaluation of the reticuloendothelial system function.

The assay system of chondroitin sulfate iron colloid (CSFe) was established to evaluate the reticuloendothelial system (RES) function in individual rabbits. In the multi-dose study of CSFe, CSFe was repeatedly administered to each individual rabbit with increasing doses (0.6, 1.2, 2.4, 6.0 mg/kg) at set intervals. Blood samples were serially collected after injection of CSFe and the concentration of CSFe in serum was directly measured as an iron concentration by modifying the previously described assay method [1] to minimize the sample volume. The clearance rate of CSFe at each injected dose was computed by the least-squares method and the double-reciprocal plotting of the doses against the phagocytic velocities by the Lineweaver-Burk method was obtained in each rabbit. The maximum phagocytic velocity (Vmax) and the CSFe concentration producing 1/2 Vmax (Kp) obtained in ten rabbits were 0.129 +/- 0.025 mg/kg per min and 0.417 +/- 0.121 mg/kg (mean +/- S.D.), respectively. The results obtained from this multi-dose study were comparable to our previous results obtained from the mean values of five groups given different doses [1]. The clearance rates of CSFe (0.6, 1.2, 6 mg/kg) decreased after the co-injection of 80 mg/kg of carbon colloid. The calculated Vmax and Kp in 29 rabbits were 0.125 mg/kg per min and 1.167 mg/kg. The Kp was apparently greater than that of the control (Vmax = 0.128 mg/kg per min, Kp = 0.421 mg/kg). Carbon colloid (80 mg/kg) was injected to six rabbits after the completion of the first multi-dose study of CSFe and then the second multi-dose study of CSFe was repeated after 24 h. No differences were found in Vmax and Kp between the two studies as were in the control group (10 rabbits) where saline was injected instead of carbon colloid. These results indicated that carbon colloid (80 mg/kg) gives a competitive and reversible inhibition on the RES. This multi-dose study of CSFe may be applicable for a bed-side analysis of the RES function in a patient.

Animals↗
PubMed1990

Acute plasmapheresis during cardiac surgery: volume replacement by crystalloids versus colloids.

Acute plasmapheresis (APP) is an additional tool for blood conservation during cardiac surgery. In a randomized study of 60 aortocoronary bypass patients undergoing APP, the influence of replacement of the withdrawn autologous plasma (10 mL/kg) by either colloids (low molecular weight hydroxyethyl starch solution [6% HES 200/0.5]) or crystalloids (Ringer's solution) was investigated. APP was performed by means of a centrifugation technique producing platelet-poor plasma. During and after cardiopulmonary bypass (CPB), either a cell saver (CS) or a hemofiltration (HF) device was also used for blood concentration. Almost three times as much crystalloid as HES solution was necessary for replacement of autologous plasma. Fluid balance during CPB was significantly more positive in the crystalloid patients, particularly when a CS was used. Blood loss was highest in the crystalloid patients in whom a CS was used in addition to APP, and these were the only patients who needed packed red cells. The platelet count, AT-III and fibrinogen plasma concentrations, colloid osmotic pressure, albumin, and total protein were significantly less compromised in the patients with colloid volume replacement. These parameters were closest to control values in patients receiving colloid replacement and HF. It is concluded that colloid is preferred for replacement of autologous plasma withdrawn by APP, and HF is superior to the CS when the combined technique for blood conservation is used.

Coronary Artery Bypass↗
PubMed2004

Investigation of the effects of Au-colloid modification on cobalt hexacyanoferrate film growth and mass transport by electrochemical quartz crystal microbalance.

The growth of cobalt hexacyanoferrate (CoHCF) films on bare and Au-colloid-modified electrodes in nitrate or sulfate solutions was monitored by electrochemical quartz crystal microbalance. The average efficiency of CoHCF film growth for Au colloid modified electrodes is 23 and 12 ng cm(-2) s(-1) in KNO3 and K2SO4 solutions, respectively, while those values for the bare gold electrode are 15 and 9 ng cm(-2) s(-1), respectively. In K2SO4 solution, the apparent molar masses for the Au-colloid-modified electrode at lower and higher potential is 58.4 and 37.3 g mol(-1), respectively, which is larger than those for the bare gold electrode (51.7 and 26.3 g mol(-1), respectively). The respective results were also obtained in KNO3 solution. Furthermore, the difference of the apparent molar masses at lower and higher potential for Au-colloid-modified electrodes is smaller than that for bare gold electrodes in the same electrolyte. Additionally, the mechanism of charge propagation is dependent on different anions in electrolyte solutions at higher potentials where the second redox reaction of CoHCF occurs. Therefore, the existence of Au colloids can accelerate CoHCF film growth and weaken the effect of anions on mass transport.

Journal Article↗
PubMed2005

Attractive interactions between like-charged colloidal particles at the air/water interface.

In the past few years, measurements of the pair interaction potential have shown evidence of micrometer-range attractive interactions between colloidal particles trapped between glass plates. In these experiments it is believed that the glass walls play an important role in the observed attractions. Colloidal particles trapped at the air/water interface show the formation of different 2-D colloidal patterns such as foams, clusters, and chains, whose formation has been taken as evidence of micrometer-range attractive interaction. Here, we present measurements of the pair interaction potential between 0.5-microm colloidal particles at the air/water interface. Indeed, the pair potential shows an attractive secondary minimum at about 1.9sigma, where sigma is the particle's diameter. Surprisingly, the position and depth of the secondary well are similar to those found in colloidal systems trapped between glass plates. However, we do not have a clear explanation on the origin of the attractive component of the interaction potential.

Air↗
PubMed2006

Effect of the ionic surfactant concentration on the stabilization/destabilization of polystyrene colloidal particles.

One of the most interesting properties of the surfactants is that they are able to alter the stability of colloidal dispersions. Despite its great industrial relevance, only a few works analyze the colloidal stability of these systems at high surfactant concentrations (well above the critical micelle concentration (CMC)). In the present work, the colloidal stability of polystyrene particles is studied under a wide range of ionic surfactant concentrations. The effects of the surface charge of the latex particles (evaluating both sign and value), and surfactant type (cationic or anionic) have been examined. Colloidal stability data have been gathered by monitoring aggregation using a nephelometric technique. As will be shown, it is possible to reach different stability regimes using the same colloidal system just by changing the surfactant concentration. Independently of the sign of both the surfactant and the surface, the destabilization of the system consistently takes place above certain surfactant concentration due to a depletion effect from non-adsorbed micelles. This destabilization can be predicted by adding to the DLVO interaction energy a new contribution addressing the force between two spherical particles in the presence of non-adsorbing spherical macromolecules.

Journal Article↗
PubMed2006

Direct-write fabrication of colloidal photonic crystal microarrays by ink-jet printing.

An array of the colloidal photonic crystals was directly fabricated using an ink-jet printing. The colloidal ink droplets containing the monodispersed polystyrene latex particles were selectively deposited on a hydrophobic surface. Solvent evaporation from each ink droplet leads to a formation of microdome-shaped colloidal assembles of close-packed structures. Microspectroscopic analysis has confirmed that the individual assembly serves as a photonic crystal and its optical properties can be correlated with the microstructural features. Unlike other techniques of patterned growth of colloidal photonic crystal, the substrate does not need to be patterned first and no template is needed in the direct writing by the ink-jet printing. Using our strategy, we have rapidly produced the colloidal photonic crystal microarrays composed of different-sized spheres addressably patterned on the same substrate.

Journal Article↗
PubMed1986

Presence of met-enkephalin in bovine pituitary intraglandular colloid of intermediate lobe origin.

Met-enkephalin, and opioid peptide present in the intermediate lobe of the pituitary gland, is herein demonstrated, for the first time, in bovine pituitary intraglandular colloid. Colloid samples were taken from the glands of freshly slaughtered cattle, pooled, lyophilized, extracted on octadecylsilyl-silica and assessed by radioimmunoassay. Met-enkephalin was indeed present in this colloid extract at levels varying from 0.40 to 0.85 nanograms per milligram dry weight. Locating an intermediate lobe peptide in intraglandular colloid is a significant finding since this implies that colloid, housed in the intraglandular lumen, may serve as a transport medium. Intermediate lobe peptides which, because the intermediate lobe is avascular, are otherwise denied the vascular transport routes available to the anterior and posterior lobe hormones.

Amino Acid Sequence↗
PubMed1988

Colloid (hyaline) inclusion bodies in the central nervous system: their presence in the substantia nigra is diagnostic of Parkinson's disease.

Intracytoplasmic "colloid" inclusions have been described within neurons of several discrete central nervous system nuclei in a variety of entities. Although they lack specificity for any particular disease, they are believed to represent one of the morphologic changes of neuronal aging. Because premature aging of the substantia nigra has been one of the claimed mechanisms occurring in Parkinson's disease, the prevalence of colloid inclusions was studied within the substantia nigra in 15 patients with Parkinson's disease, 15 age-matched controls, 50 "normal" individuals, 10 patients with dementia of Alzheimer's type, and two patients with amyotrophic lateral sclerosis. Colloid bodies were found in the substantia nigra of all patients with Parkinson's disease and were virtually absent in the other populations. Histochemical and ultrastructural analyses showed that colloid bodies differ from early and mature Lewy bodies. They may represent the "pale" inclusions rarely mentioned in the literature and often mistaken for early Lewy bodies. "Colloid" bodies in the substantia nigra are diagnostic of Parkinson's disease. These findings support the theory of "premature" aging of the substantia nigra in this disease.

Adult↗
PubMed2003

Third ventricle colloid cyst associated with subarachnoid haemorrhage.

Colloid cyst of the third ventricle is a rare, benign pathology of endothelial origin. Excellent prognosis is achieved when the cyst is diagnosed early and excised. Hydrocephalus can occur as an acute, fatal complication or can cause chronic symptoms such as headaches. A case of a patient with a third ventricle colloid cyst in association with prepontine subarachnoid haemorrhage is presented. This was a 29-year-old healthy male who was admitted because of a depressed consciousness. Neuro-radiological imaging revealed a mass in the third ventricle, a biventricular hydrocephalus and a prepontine subarachnoid haemorrhage without any evidence of a cerebral aneurysm. Perimesencephalic nonaneurysmal subarachnoid haemorrhage is well known but its cause is still a matter of debate. A description is given of the association of this type of subarachnoid haemorrhage with an acute hydrocephalus caused by a third ventricle colloid cyst. Because of the potential morbidity and mortality of third ventricle colloid cysts, this association is described and should be considered as a rare presentation of third ventricle colloid cyst.

Adult↗
PubMed2003

Preparation of conducting polyaniline colloids under ultrasonication.

The effects of ultrasonication on the chemical polymerization of aniline leading to the formation of conducting polyaniline colloids were examined. The formation rate of the colloids was significantly increased under ultrasonication. Furthermore, it was also observed that the morphological structure of the colloids thus prepared was greatly affected by the sonication. The polyaniline colloids were further characterized by a range of techniques including electric resistance meter, gel permeation chromatography, FT-IR and cyclic voltammetry. It is noteworthy that the application of ultrasound to the polymerization resulted in a marked increase in the doping level, which reflected to the high electroconductivity of polyaniline colloids.

Journal Article↗
PubMed2002

Increased sensitivity of surface plasmon resonance of gold nanoshells compared to that of gold solid colloids in response to environmental changes.

Gold nanoshells have been synthesized by reacting aqueous HAuCl4 solutions with solid templates such as silver nanoparticles. The morphology, void space, and wall thickness of these hollow nanostructures were all determined by the templates, which were completely converted into soluble species during the replacement reaction. The surface plasmon peaks of these gold nanoshells were considerably red-shifted as compared to gold solid colloids having approximately the same dimensions. In addition, the surface plasmon resonance of gold nanoshells exhibited a much more sensitive response toward environmental changes even when compared with solid colloids with a mean size much smaller than that of gold nanoshells. For example, the sensitivity factor (i.e., the shift in peak position per unit change in the refractive index of the surrounding medium) was 408.8, 60.0, and 70.9 nm per refractive index unit for gold nanoshells with a mean diameter of 50 nm and wall thickness of 4.5 nm, gold solid colloids of 50 nm in diameter, and gold solid colloids of 30 nm in diameter, respectively. The formation of alkanethiolate self-assembled monolayers on their surfaces caused the plasmon peaks to red-shift by 3.0 nm per methylene unit for gold nanoshells and 0.2 nm per methylene unit for solid colloids with a mean size of 50 nm. Such enhanced sensitivities should make gold nanoshells particularly useful as optical probes for chemical or biological binding events at solid-liquid interfaces.

Journal Article↗
PubMed2006

Nanofluidic injection and heterogeneous kinetics of organomercaptan surface displacement reactions on colloidal gold in a microfluidic stream.

Colloidal gold is developed as a molecular capture reagent in hybrid nanofluidic-microfluidic devices for mass-limited sample analysis. Two fluorescent organomercaptans are injected through a nanocapillary array membrane and subsequently captured at the surface of 19-nm-diameter colloidal Au nanoparticles. The surface displacement kinetics are monitored via quenching of the organomercaptan fluorescence by the metallic particles coupled to a distance-time conversion based on fluid velocity in the microfluidic channel using the point of mixing as the zero of time. The adsorbate concentration, colloid concentration, and fluid velocity are varied to determine the surface displacement rate constants for these heterogeneous reactions in the microfluidic device. Surface displacement rate constants are approximately 10(4) M(-1) s(-1) for a small organic molecule and for an octapeptide. These values are similar to values determined in macroscale measurements made with a traditional fluorometer and are 1 order of magnitude larger than values reported for adsorption of organomercaptans on planar Au, indicating faster kinetics in the colloid-adsorbate system. These results highlight the utility of colloidal Au nanoparticles as molecular carriers for the sequestration of analytes, allowing the manipulation of mass-limited samples and ultimately the capture and delivery of selected analytes from a microfabricated device to an off-line detector.

Journal Article↗
PubMed2001

Template-assisted self-assembly: a practical route to complex aggregates of monodispersed colloids with well-defined sizes, shapes, and structures.

This paper describes a strategy that combines physical templating and capillary forces to assemble monodispersed spherical colloids into uniform aggregates with well-controlled sizes, shapes, and structures. When an aqueous dispersion of colloidal particles was allowed to dewet from a solid surface that had been patterned with appropriate relief structures, the particles were trapped by the recessed regions and assembled into aggregates whose structures were determined by the geometric confinement provided by the templates. We have demonstrated the capability and feasibility of this approach by assembling polystyrene beads and silica colloids (> or =150 nm in diameter) into complex aggregates that include polygonal or polyhedral clusters, linear or zigzag chains, and circular rings. We have also been able to generate hybrid aggregates in the shape of HF or H2O molecules that are composed of polymer beads having different diameters, polymer beads labeled with different organic dyes, and a combination of polymeric and inorganic beads. These colloidal aggregates can serve as a useful model system to investigate the hydrodynamic and optical scattering properties of colloidal particles having nonspherical morphologies. They should also find use as the building blocks to generate hierarchically self-assembled systems that may exhibit interesting properties highly valuable to areas ranging from photonics to condensed matter physics.

Journal Article↗
PubMed2002

A high-throughput optical screening method for the optimization of colloidal water oxidation catalysts.

A high-throughput method has been developed for screening and optimization of colloidal water oxidation catalysts. The catalysts are irradiated in parallel by visible light from an overhead projector in solutions containing tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) and persulfate. The array of reaction solutions is held in a 96-well plate, and absorbance readings are taken intermittently using a bioassay plate reader. The absorbance at 430 nm is indicative of the amount of Ru(bpy)(3)(2+) remaining in solution. The best catalysts give the most persistent absorbance, because the oxygen evolution reaction is kinetically competitive with decomposition of Ru(bpy)(3)(3+). Reagent concentrations were varied using a factorial design-of-experiment approach in order to optimize reaction conditions for a IrO(2).xH(2)O colloidal catalyst. A higher colloid concentration, a lower Ru(bpy)(3)(2+) concentration, and a higher pH buffer doubled the number of turnovers relative to the original conditions. Metal oxide colloids consisting of IrO(2).xH(2)O doped with varying amounts of Pt, Ru, and Os were made using a parallel microwave synthesis technique and were tested both by the parallel screening method and by direct measurement of oxygen evolution. The correlation between the two methods was good, with Ir-Pt-Os oxide compositions showing the highest activity. The effect of adding small amounts of Pt and Os to IrO(2).xH(2)O appears to be predominantly to reduce the particle size of the colloids.

Journal Article↗
PubMed2003

Photothermal patterning of microgel/gold nanoparticle composite colloidal crystals.

We present a new method for laser direct writing in self-assembled hydrogel microparticle colloidal crystals via photothermal excitation of co-assembled colloidal Au particles. Close-packed colloidal crystals are assembled from approximately 224 nm diameter, thermoresponsive, poly-N-isopropylacrylamide hydrogel microparticles (microgels); these crystals display sharp Bragg diffraction peaks in the mid-visible region of the spectrum due to the periodic dielectric function of the assembly. Raising the temperature of the crystal above the characteristic volume phase transition temperature of the microgel particles results in a reversible melting of the crystalline material due to the particle-based deswelling event. This transition can be used either to anneal defects from the crystalline material or to controllably and reversibly convert the assembly from the colored, crystalline state to a nondiffracting glassy material. Crystal-to-glass transitions are similarly accomplished via photothermal excitation when 16 nm diameter colloidal Au particles are co-assembled with the responsive microgels. Excitation of the colloidal Au plasmon absorption with a frequency doubled Nd:YAG laser (lambda = 532 nm) results in optically directed conversion of either glasses to crystals or crystals to glasses, depending on the initial state of the assembly and the illumination time. These results represent a fundamentally new method for the patterning of self-assembled photonic materials.

Journal Article↗