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PubMed2006

Noninvasive quantitative measurement of colloid transport in mesoscale porous media using time lapse fluorescence imaging.

We demonstrate noninvasive quantitative imaging of colloid and solute transport at millimeter to decimeter (meso-) scale. Ultraviolet (UV) excited fluorescent solute and colloid tracers were independently measured simultaneously during co-advection through saturated quartz sand. Pulse-input experiments were conducted at constant flow rates and ionic strengths 10(-3), 10(-2) and 10(-1) M NaCl. Tracers were 1.9 microm carboxylate latex microspheres and disodium fluorescein. Spatial moments analysis was used to quantify relative changes in mass distribution of the colloid and solute tracers over time. The solute advected through the sand at a constant velocity proportional to flow rate and was described well by a conservative transport model (CXTFIT). In unfavorable deposition conditions increasing ionic strength produced significant reduction in colloid center of mass transport velocity over time. Velocity trends correlated with the increasing fraction of colloid mass retained along the flowpath. Attachment efficiencies (defined by colloid filtration theory) calculated from nondestructive retained mass data were 0.013 +/- 0.03, 0.09 +/- 0.02, and 0.22 +/- 0.05 at 10(-3), 10(-2), and 10(-1) M ionic strength, respectively, which compared well with previously published data from breakthrough curves and destructive sampling. Mesoscale imaging of colloid mass dynamics can quantify key deposition and transport parameters based on noninvasive, nondestructive, spatially high-resolution data.

Colloids↗
PubMed2006

Colloid mobilization during soil iron redox oscillations.

In redox-dynamic soils, iron reduction-oxidation events may initiate wide shifts in the concentration of colloidal and dissolved material because of either Fe mineral dissolution or pH shifts associated with Fe oxidation state changes. This can have profound effects on the mobilization of organic and metal constituents. We conducted laboratory studies of colloid dynamics in a Hawaiian soil subjected to four consecutive 14-day reduction-oxidation cycles across the "soil-Fe" (Fe(OH)3)/(Fe2+(aq)) equilibrium. Size fractionated samples were isolated by differential centrifugation and characterized based on analysis of the framework and trace elements (Si, C, Fe, Ti, Al, Zr, Nb, La, and U). Intracycle oscillations in all colloidal (3 kDa to 160 nm) elements peaked during the reduction half-cycles, mobilizing 10% of total soil Ti and from 1-5% of total soil Zr, Nb, La, and U at peak dispersion. Colloid dynamics were dependent on pH shifts accompanying the redox oscillations rather than the fluctuating solubility of Fe oxides. TEM/EDS and mass-balance calculations suggest a carbon-based colloid matrix with zones of metal enrichment. The cumulative effects of four redox cycles included an apparent increase in colloid stability. Proton production/consumption associated with Fe-redox cycling has important implications for mobilization colloid-borne trace elements and sorbed contaminants.

Colloids↗
PubMed2001

Interfacial phase transition of an environmentally responsive elastin biopolymer adsorbed on functionalized gold nanoparticles studied by colloidal surface plasmon resonance.

The change in optical properties of colloidal gold upon aggregation has been used to develop an experimentally convenient colorimetric method to study the interfacial phase transition of an elastin-like polypeptide (ELP), a thermally responsive biopolymer. Gold nanoparticles, functionalized with a self-assembled monolayer (SAM) of mercaptoundecanoic acid onto which an ELP was adsorbed, exhibit a characteristic red color due to the surface plasmon resonance (SPR) of individual colloids. Raising the solution temperature from 10 degrees C to 40 degrees C thermally triggered the hydrophilic-to-hydrophobic phase transition of the adsorbed ELP resulting in formation of large aggregates due to interparticle hydrophobic interaction. Formation of large aggregates caused a change in color of the colloidal suspension from red to violet due to coupling of surface plasmons in aggregated colloids. The surface phase transition of the ELP was reversible, as seen from the reversible change in color upon cooling the suspension to 10 degrees C. The formation of colloidal aggregates due to the interfacial phase transition of adsorbed ELP was independently verified by dynamic light scattering of ELP-modified gold colloids as a function of temperature. Colloidal SPR provides a simple and convenient colorimetric method to study the influence of the solution environment, interfacial properties, and grafting method on the transition properties of ELPs and other environmentally responsive polymers at the solid-water interface.

Adsorption↗
PubMed2005

Inward-growing self-assembly of colloidal crystal films on horizontal substrates.

Colloidal crystal films have been fabricated on solid substrates with a horizontal deposition method. Scanning electron microscope images showed that the colloidal crystal films exhibit ordered face-centered cubic structures in large domains. Optical measurements demonstrated the presence of photonic band gap along the crystallographic [111] direction. The fabrication method described in this paper allows one to rapidly fabricate colloidal crystal films of different thicknesses, which can be controlled by varying colloidal suspension concentration or volume. In addition, the method also works well for growing colloidal crystal films on a hydrophilic solid substrate with a rough surface. Furthermore, the fabrication of colloidal crystal heterostructures has been demonstrated. An inward-growing mechanism responsible for self-assembly of colloidal spheres on horizontal substrates has been proposed to interpret the observed experimental results.

Colloids↗
PubMed2004

Theoretical consideration on preparing silver particle films by adsorbing nanoparticles from bulk colloids to an air-water interface.

In our previous paper, a method for preparing enormous surface-enhanced Raman scattering (SERS) active substrates through the aggregation of silver particles trapped at an air-water interface was reported. Here, further efforts were devoted to investigate the origin of assembling silver particle films by adsorbing nanoparticles from bulk colloids to the air-water interface. It was revealed that it is thermodynamically favorable for a colloidal particle in bulk colloids to adsorb to the air-water interface; however, a finite sorption barrier between it and the nearby particles usually restrains the adsorption process. When an electrolyte such as KCl, which is commonly used as an activating agent for additional SERS enhancement, was added into silver colloids, it largely reduced the sorption barrier. Thus, silver nanoparticles can break through the sorption barrier, pop up, and be trapped at the air-water interface. The trapped silver particles are more inclined to aggregate at the interface than those in bulk colloids due to the increase of van der Waals forces and the reduction of electrostatic forces. The morphology of the as-prepared silver particle films was characterized by scanning electron microscope, and their SERS activity was tested using NaSCN as a probe molecule. The surface enhancement of the silver particle films is about 1-2 orders of magnitude higher compared with that of silver colloids, because most of the silver particles in the films are in the aggregation form that provides enormous SERS enhancement. Furthermore, the stability of such type of films is much better that of colloid solutions.

Adsorption↗
PubMed2005

Fabrication of spherical colloidal crystals using electrospray.

We demonstrated the use of electrohydrodynamic atomization to prepare uniform-sized emulsion droplets in which equal spheres of silica or polystyrene were dispersed. The size of the emulsion droplets was easily controlled by the electric field strength and the flow rate, independently of the diameter of the nozzles. During the evaporation of solvent in the droplets, spherical colloidal crystals were formed by self-assembly of the monodisperse colloidal spheres. The diameter of the spherical colloidal crystals was in the range of 10-40 microm. Depending on the stability of colloidal particles, the morphology of the self-assembled structure was varied. In particular, silica spheres in ethanol droplets were self-assembled into compactly packed silica colloidal crystals in spherical shapes, whereas polystyrene latex spheres in toluene droplets self-assembled into spherical colloidal crystal shells with hollow cores. The silica colloidal assemblies reflected diffraction colors according to the three-dimensionally ordered arrangement of silica spheres.

Colloids↗
PubMed2003

Effects of dietary fibre-rich juice colloids from apple pomace extraction juices on intestinal fermentation products and microbiota in rats.

Effects of colloids isolated from apple pomace extraction juices (so-called B-juices) produced by enzymic liquefaction on food intake, body and faecal weights, short-chain fatty acid (SCFA) profile and selected intestinal microbiota were investigated in rats. Ten male Wistar rats per group were fed diets without any apple dietary fibre (DF) (control) or supplement with 5 % B-juice colloids or an alcohol-insoluble substance (AIS) from apples for 6 weeks. Rats fed with apple DF (5 % B-juice colloids or AIS) gained less weight than control rats (P<0.05). B-juice colloids did not affect food intake, whereas feeding AIS resulted in a 10 % higher food consumption than in control rats. Both juice colloids and AIS increased the weight of caecal contents in rats and lowered luminal pH values (P<0.05). In addition, SCFA concentrations and total yields were also raised (P<0.05) in caecum of these rats indicating good fermentability of apple substrates by gut microflora. Distinctly higher concentrations of acetate and propionate were found in intestinal contents of juice colloid-fed rats (P<0.05), whereas AIS also increased butyrate yield. Changes in microbiota due to apple DF in diets were restricted in the caecum to the Eubacterium rectale cluster (AIS; P<0.05) and in faeces to the Bacteroidaceae (juice colloids and AIS; P<0.05). The present study shows the physiological effects of apple DF isolated from pomace extraction juices produced by enzymic liquefaction on intestinal fermentation. Results may be helpful for the development of such innovative juice products that are rich in DF of fruit origin.

Animals↗
PubMedDate not supplied

Effect of protective colloids on the induction of polymorphic changes in indomethacin agglomerates after solvent evaporation from o/w emulsions.

Indomethacin (IMC) agglomerates were prepared by the solvent evaporation process from o/w emulsions containing different protective colloids in the external aqueous solution. The types of protective colloids inducing the polymorphic transformation of IMC in the agglomerates without wall material were investigated. The composition and its polymorphs were evaluated from the X-ray diffraction patterns, IR spectra and DSC thermograms. The results indicate that when pectin, beta-cyclodextrin, sodium alginate or sodium dodecyl supphase acted as a protective colloid, the respective IMC agglomerates consisted only of the alpha form of IMC. When gelatin or hydroxypropyl methylcellulose was used as a protective colloid, the amorphous, alpha and gamma forms as well as methylene chloride solvates of IMC were found in the IMC agglomerates. There was only methylene chloride solvate of IMC with a small amount of amorphous form in the IMC agglomerates prepared from albumin as a protective colloid, while IMC agglomerates prepared from methylcellulose, polyvinyl alcohol or biosoluble polymer consisted of the mixture of amorphous and alpha forms, and methylene chloride solvate of IMC. When polyvinyl pyrrolidone was applied to act as a protective colloid, the mixture of methylene chloride solvate and gamma form of IMC with less quantity of amorphous form was found in its IMC agglomerates. This strongly suggests that the composition of IMC agglomerates prepared from the solvent evaporation process was significantly influenced by the type of protective colloids used.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Use of low-dose technetium Tc 99m sulfur colloid to locate sentinel lymph nodes in melanoma of the head and neck: preliminary study.

OBJECTIVES/HYPOTHESIS: Because sentinel lymph nodes are the first lymph nodes that drain a primary cancer site, results of sentinel lymph node (SLN) biopsy indicate status of the regional lymph nodes. Preoperative lymphoscintigraphy and intraoperative combined application of the handheld gamma probe and blue-dye technique (i.e., the "combined technique") was used previously to accurately identify the SLN, mostly in melanoma of the extremities and trunk and, sometimes, in melanoma of the head or neck, which is anatomically complex. Because of this complexity, melanoma in the head or neck is inherently problematic to treat: Localization of the SLN can be difficult or impossible because the primary cancer site can be near or overlapping the nodal basin. The objective of the present study was to determine the technical modifications and other considerations that can make SLN localization feasible in cases of melanoma occurring near or overlapping the nodal basin in the head or neck. STUDY DESIGN/METHODS: In a retrospective study of clinical records containing our database of melanoma diagnoses made between January 1996 and December 1999, we identified 27 patients diagnosed with stage I or II primary melanoma of the head or neck with clinically negative neck nodes who also had had preoperative lymphoscintigraphy. Of the 27 patients (17 male and 10 female patients; mean age, 54 y), 24 had SLN biopsy by intraoperative localization using both the handheld gamma probe and the blue-dye technique. RESULTS: Among the 27 patients who had SLN mapping, a median Breslow thickness of 1.8 mm was noted. Sentinel lymph node was noted at preoperative lymphoscintigraphy in 26 (96%) of the 27 patients. Activity of technetium Tc 99m (Tc-99m) sulfur colloid injected ranged from 10 to 1000 microCi (0.37 to 37 megabecquerel [MBq]). Intraoperative use of the combined technique for sentinel lymphadenectomy was successful in 92% of patients. Sentinel lymph nodes were identified in all 14 patients who received Tc-99m sulfur colloid at an activity level less than 60 microCi (2.2 MBq); mean activity level of injected TC-99m sulfur colloid was 28 microCi (1.04 MBq). Sentinel lymph nodes were identified in 8 (80%) of 10 patients who received Tc-99m sulfur colloid at an activity level greater than 100 microCi (3.7 MBq); mean activity of injected Tc-99m sulfur colloid in these patients was 482 microCi (17.8 MBq). A mean number of 1.4 sentinel lymph nodes per patient was identified at preoperative lymphoscintigraphy, and a mean number of 3 sentinel lymph nodes per patient was identified intraoperatively using the combined technique. Tumor recurrence was seen in 2 (10%) of the 19 patients who had cancer-free SLN at mean follow-up of 18 months (range, 1 to 47 mo). Sentinel lymphadenectomy of the parotid region did not injure the facial nerve in any patients. CONCLUSIONS: For patients with primary melanoma that is near or overlaps the nodal basin in the head or neck, SLN biopsy can be accurately performed using Tc-99m sulfur colloid at low activity levels (10 microCi to 60 microCi [0.37 to 2.2 MBq]. However, background radiation from the primary injection site can incorporate the SLN, making localization at preoperative lymphoscintigraphy difficult if not impossible; therefore, the high doses commonly used for melanoma of the extremities and trunk (500 to 2000 microCi [18.5 to 74 MBq]) should not be used for melanoma of the head or neck if the primary site is near or overlaps the nodal basin. In addition, absorption of Tc-99m sulfur colloid by salivary glands increases background radiation in the nodal basin; therefore, use of the handheld gamma probe for intraoperative localization of SLN can be problematic in regions where lymph nodes are adjacent to or within the substance of the salivary gland (i.e., the submandibular and parotid glands).

Female↗
PubMed2001

Inhomogeneous model colloid-polymer mixtures: adsorption at a hard wall.

We study the equilibrium properties of inhomogeneous model colloid-polymer mixtures. By integrating out the degrees of freedom of the ideal polymer coils, we derive a formal expression for the effective one-component Hamiltonian of the (hard sphere) colloids that is valid for arbitrary external potentials acting on both the colloids and the polymers. We show how one can recover information about the distribution of polymer in the mixture given knowledge of the colloid correlation functions calculated using the effective one-component Hamiltonian. This result is then used to furnish the connection between the free-volume and perturbation theory approaches to determining the bulk phase equilibria. For the special case of a planar hard wall the effective Hamiltonian takes an explicit form, consisting of zero-, one-, and two-body, but no higher-body, contributions provided the size ratio q=sigma(p)/sigma(c)<0.1547, where sigma(c) and sigma(p) denote the diameters of colloid and polymer respectively. We employ a simple density functional theory to calculate colloid density profiles from this effective Hamiltonian for q=0.1. The resulting profiles are found to agree well with those from Monte Carlo simulations for the same Hamiltonian. Adding very small amounts of polymer gives rise to strong depletion effects at the hard wall which lead to pronounced enhancement of the colloid density profile (close to the wall) over what is found for hard spheres at a hard wall.

Adsorption↗
PubMed2006

The effects of colloidal nanotopography on initial fibroblast adhesion and morphology.

Colloidal lithography offers a simple, inexpensive method of producing irregular nanotopographies, a pattern not easily attainable utilizing conventional serial writing processes. Colloids with 20- or 50-nm diameter were utilized to produce such an irregular topography and were characterized by calculating the percentage area coverage of particles. Interparticle and nearest neighbor spacing were also assessed for the individual colloids in the pattern. Two-way analysis of variance (ANOVA) indicated significant differences between the number of fibroblasts adhering to planar, 20-, and 50-nm-diameter colloidal topographies, the number of fibroblasts adhering to the substrates at the time intervals studied, namely 20 min, 1 h, and 3 h and significant interaction between time and topography on fibroblast adhesion (P < 0.01). Tukey tests were utilized for sensitive identification of the differences between the sample means and compounded ANOVA results. Cytoskeletal and general cell morphology were investigated on planar and colloidal substrates, and indicated cells in contact with irregular nanotopographies exhibit many peripheral protrusions while such protrusions are absent in cells on planar control surfaces. These protrusions are rich in microtubules on 20-nm-diameter colloidal surfaces while microfilaments are prevalent on 50-nm-diameter surfaces. Moreover, by 3 h, cells on the colloidal substrates initiate cell-cell adhesions, also absent in controls.

Cell Adhesion↗
PubMed1989

Electron microscopic study of the colloid-like substance in solar elastosis.

We have made electron microscopic studies on the elastotic material of solar elastosis which developed in cutis rhomboidalis nuchae taken from 10 males, 50-83 years of age. It was revealed that this material of the cutis rhomboidalis nuchae contained a colloid-like substance consisting of both a fine granular and an amorphous component. The colloid-like substance closely resembled that which is seen in the adult-type colloid milium, and could not be distinguished from it under light microscopy. In view of the morphological similarity at the ultrastructural level between the elastotic material and the colloid-like substance, it was proposed that normal elastic fibers can change into elastotic material and then further degenerate into the colloid-like substance, eventually becoming the typical colloid substance seen in colloid milium.

Aged↗
PubMed2005

Cytoplasmic colloid inclusions in thyroid lesions: a cytomorphological study based on fine needle aspiration.

INTRODUCTION: Intracytoplasmic lumens (ICL) with or without magenta material and transgressing vessels are features of Hürthle cell neoplasms (HCN). After detection of intracytoplasmic colloid inclusions (CIs) including targetoid (magenta) body-like structures in the Hürthle cells (HC) in a case of Hashimoto's thyroiditis (HT), we reviewed cases of HT, thyroid neoplasms, hyperplastic nodules (HN) and colloid goitres to determine the frequency of these structures. Further, an attempt was made to find out the significance of CIs. METHODS: FNA smears of 120 HT, 101 colloid goitres, 11 HN, and 76 neoplastic goitres were examined. The presence of CIs and empty ICL were noted in epithelial cells in these lesions. An attempt was made to find out the difference between HT with and without CIs in respect of various cytomorphologic features. The groups were compared using the Fisher's exact test of probability. RESULTS: The CIs were present in 36 (30.0%) of HT, 26 (34.2%) of neoplastic goitres, 3 (27.3%) of HN, and 4 (4.0%) colloid goitres. As compared to colloid goitres, CIs were present in a significant higher number of cases in HN (P = 0.0202), neoplastic goitres (P < 0.0001), and HT (P < 0.0001). Among neoplasms the frequency of CIs in HCN (75.0%) was significantly higher than that of papillary thyroid carcinoma (PTC) (33.3%, P = 0.0466), and follicular neoplasm (14.3%, P = 0.0083). The CIs were more frequent in HC in HT and HCN but in follicular cells (FC) in other lesions. The HT cases with CIs differed significantly from those without CIs in respect of HC and their cellularity, cellularity of reactive lymphoid cells, extracellular colloid and empty ICL. CONCLUSION: Care should be taken not to diagnose HT cases with an excessive Hürthle cell component and CIs, and PTC cases with Hürthlization and CIs, as HCN in FNA smears. Based on review of the literature and our findings, it is suggested that the Hürthle cell metaplasia in HT is a survival response of FC and the presence of CIs in Hürthle cell may represent their limited ability to synthesize colloid.

Adolescent↗
PubMed1986

Immunohistochemical studies on colloid bodies (Civatte bodies) in oral lesions of discoid lupus erythematosus.

By electron microscopy colloid bodies have been shown to be derived from epithelial cells. It has been suggested, however, that connective tissue cells or components from the basement membrane zone contributed to the formation of colloid bodies. In order to examine these possibilities we stained oral lesions of discoid lupus erythematosus (DLE) with antibodies against intermediate filaments (keratin, vimentin), basement membrane components (laminin, collagen type IV) and fibronectin. IgM was used as a marker for colloid bodies. Colloid bodies were stained positive for keratin, whereas vimentin was never found in colloid bodies. Laminin and collagen type IV were occasionally seen in their periphery probably owing to adherence of basement membrane fragments during apoptosis. Fibronectin was frequently seen at the entire periphery of colloid bodies which may facilitate their elimination by macrophages. In conclusion, connective tissue cells or basement membrane components do not seem to contribute to the formation of colloid bodies in oral DLE.

Antibodies, Monoclonal↗
PubMedDate not supplied

The effect of hetastarch on serum colloid oncotic pressure in hypoalbuminemic dogs.

The purpose of this study was to determine the duration of action of a single dose of hetastarch, a synthetic colloid, in hypoalbuminemic dogs. Thirty hypoalbuminemic dogs (albumin concentration, < or = 2.0 g/dL) received 1 dose of hetastarch each, with an average dose of 18.1 mL/kg. Doses ranged from 7.7 to 43.9 mL/kg, with the majority of doses (n = 26) in the range of 10 to 25 mL/kg. Dogs were allotted to one of several groups: all dogs, dogs with acute gastrointestinal protein loss, dogs with chronic gastrointestinal protein loss, all dogs with gastrointestinal protein loss, and dogs with nongastrointestinal protein loss. Colloid oncotic pressure was measured immediately before and immediately after hetastarch administration, and 12 hours after hetastarch administration. There was a significant (P < .001) increase in the mean colloid oncotic pressure after hetastarch treatment in all groups, except in the group with acute gastrointestinal protein loss. Twelve hours after hetastarch treatment, the mean colloid oncotic pressure had decreased significantly (P < .001) from the immediate post-treatment value in all groups, except in dogs in the groups with acute and chronic gastrointestinal protein loss. Twelve hours after hetastarch treatment the mean colloid oncotic pressure was not significantly (P < .001) different from the baseline mean colloid oncotic pressure in any of the groups. Twenty-three dogs (77%) survived their illness and were sent home, whereas, 7 (23%) died or were euthanized. The effect of a single dose of hetastarch on raising colloid oncotic pressure in dogs with hypoalbuminemia decreases significantly within 12 hours of administration, and is no longer significantly above baseline values. We conclude that multiple dosing is necessary to prolong the beneficial effects of hetastarch.

Animals↗
PubMed2002

Microdialysis in human skeletal muscle: effects of adding a colloid to the perfusate.

Microdialysis catheters (CMA-60 with a polyamide dialysis membrane; 20,000-molecular wt cutoff) were either immersed in an external medium or were inserted in the quadriceps femoris muscle of healthy subjects, using perfusate with or without dextran 70. Varying the position of the outflow tubing induced changes in hydrostatic pressure. The sample volumes were significantly smaller in catheters perfused without a colloid compared with those perfused with a colloid [11-50% (in vitro) and 8-59% (in vivo) lower than in colloid-perfused catheters with the same position of the outflow tubing]. The sample volumes were also significantly smaller when the dialysis membrane was influenced by maximal hydrostatic pressure (above position) compared with minimal hydrostatic pressure (below position) [7-38% (in vitro) and 3-46% (in vivo) lower than in catheters in the below position with the same perfusion fluid]. In vivo, glucose concentration at a perfusion flow rate of 0.33 microl/min was higher when the catheters were perfused without a colloid [18-28% higher than in colloid-perfused catheters with the same position of the outflow tubing (P < 0.001)] than with a colloid. A corresponding difference also tended to occur with lactate, glycerol, and urea. At 0.16 microl/min, the glucose concentration was the same irrespective of whether fluid loss had been counteracted by colloid inclusion or by lowering of outlet tubing. The mechanism behind the observed concentration difference is thought to be a higher effective perfusion flow rate when fluid loss is prevented at low-perfusion flows. This study shows that fluid imbalances can have important implications for microdialysis results at low-perfusion flow rates.

Adult↗
PubMed1982

Cimetidine and colloidal bismuth in treatment of chronic duodenal ulcer. Comparison of initial healing and recurrence after healing.

The aim of the study was to compare the use of cimetidine and colloidal bismuth in the initial healing of chronic duodenal ulcer and to note the recurrence rate over 1 year after healing induced by both forms of treatment. Cimetidine was administered in the dose of 200 mg three times daily and 400 mg at night and the dose of colloidal bismuth was 5 ml four times each day. 51 outpatients with chronic duodenal ulcers proven on endoscopy completed the initial study. At 3 weeks, healing was observed in 83% of the cimetidine group and 70% of the colloidal bismuth group (p greater than 0.10); at 6 weeks, 96% of patients in both groups had healed. 33 patients were followed up over 1 year, 16 having initially been treated with cimetidine and 17 with colloidal bismuth. 2 other patients originally treated with cimetidine were followed up for 6 months only. No further treatment was given. Endoscopy was performed at 6 and 12 months, or earlier if symptoms developed. At 6 months, 44% of patients in the cimetidine group had recurred compared to 47% in the colloidal bismuth group (p greater than 0.5). At 1 year, 75% of patients in the cimetidine group and 76% in the colloidal bismuth group had recurred (p greater than 0.5). It is concluded that both agents are equally effective in healing duodenal ulcers and the incidence of recurrence over 1 year is similar irrespective of whether the initial healing is induced with colloidal bismuth or cimetidine.

Bismuth↗
PubMed2004

Colloidal silver as an antimicrobial agent: fact or fiction?

OBJECTIVE: Colloidal silver preparations are marketed on the internet as omnipotent antimicrobial agents, but scientific support for these claims is lacking. This study reports the results of in vitro tests of colloidal silver's antimicrobial activity against several pathogenic or non-pathogenic microorganisms. METHOD: Three samples of colloidal silver were tested: one available commercially on the internet (silver concentration of 22 ppm) and two samples (concentrations of 403 and 413 ppm) which were prepared in our laboratory using standard chemical methods. RESULTS: In an agar-well diffusion assay none of the three colloidal silver solutions had any effect on the growth of the test organisms. All tested bacterial strains were sensitive to ciprofloxacin. Colloidal silver 22 ppm showed no bactericidal activity in phenol coefficient tests. CONCLUSION: As the tested colloidal silver solutions did not show any antimicrobial effect in vitro on the microorganisms, claims of colloidal silver's antimicrobial potency are misleading and there is no place for it as an antiseptic.

Anti-Infective Agents↗