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At least 1,495 records · Page 83Linked to original sources
PubMed1999

Enhanced tumor targeting by an intratumoral injection of colloidal chromic 32P in two human tumors (AsPC-1 pancreas and Ls174T colon) in nude mice.

BACKGROUND AND OBJECTIVES: To find the mechanisms of the ongoing clinical trials in intralesional colloidal chromic 32P (32P-CP) brachytherapy, the cellular uptake of 32P-CP, changes in tumor interstitial fluid pressure (TIFP), and tumor blood flow (TBF) using two (AsPC-1, Ls174T) human tumors were measured. METHODS: After exposure to 32p-CP using exponential and plateau-phase cells, cells were trypsinized at various time intervals, then measured for the levels of radioactivity using a y-counter. Also measured were TIFP using the WIN technique and TBF with laser Doppler flowmetry. RESULTS: The plateau growth-phase of both tumors showed the maximal uptake of 32P-CP at approximately 100 min. TBF decreased within 10 min after an intratumoral (i.t.) injection of 32P-CP, and reached 75% of control value by 1 h. CONCLUSIONS: If 32P-CP was introduced i.t., it maintained highly efficient tumor targeting, mainly due to two physiological mechanisms: the high adherence of 32P-CP to the infused regions and the reduction in TBF by this therapeutic colloid.

Adenocarcinoma↗
PubMed1982

Meningosis prophylaxis with intrathecal 198Au-colloid and methotrexate in childhood acute lymphocytic leukemia.

Since 1972, telecobalt irradiation plus intrathecal methotrexate (ITMTX) has been successfully replaced in Jena by intrathecal colloidal radioactive gold (198Au) plus ITMTX for meningosis prophylaxis in leukemia. Seventy-three children with acute lymphocytic leukemia (ALL) were given 1.24-4.89 mCi (45.8-181 MBq) of colloidal 198Au IT after successful initiation of remission. During cytostatic therapy, the following relapses occurred: meningosis leucaemica, five patients (6.8%); bone-marrow relapse and the meningosis leucaemica, one patient; and bone-marrow relapse, 20 patients (27.4%). In 18 children, combination chemotherapy was terminated after two and a half or three years of treatment. After that time, one meningeal relapse and six bone-marrow relapses occurred. Within the first 24 hours after application of radioactive gold, headaches, vomiting, and fever occurred in less than 10% of the children. An apathy syndrome, leukecephalopathy, or severe infections, were not observed in a single case. Radioactive gold spreads in the subarachnoid space and is phagocytized by the arachnoidea. The tumoricide effect extends selectively over the space of distribution of the latent meningosis leucaemia. The cerebral parenchyma remains unaffected by radiation. Thus, radioactive gold may be preferable to telecobalt irradiation in preventing central nervous system leukemia.

Bone Neoplasms↗
PubMed1985

Radionuclide lymphoscintigraphy with technetium 99m antimony sulfide colloid to identify lymphatic drainage of cutaneous melanoma at ambiguous sites in the head and neck and trunk.

Frequently the primary lesion of high-risk cutaneous melanoma (level III, greater than or equal to 1.5mm; greater than or equal to 1.0 mm with ulceration) is in an ambiguous lymphatic drainage site on the trunk, pelvic and shoulder girdles, and head and neck area. Lymphoscintigrams were performed by a circumferential intradermal injection of the biopsy site using technetium 99m (99mTc) antimony sulfide colloid in a total dose of 0.2 to 0.6 mCi in a volume of 0.1 to 0.5 ml. Imaging was done with a large-field gamma camera with high-resolution parallel hole collimator. Technetium 99m antimony sulfide colloid is an ideal agent for lymphoscintigrams because of small particle size (3-30 micron), which permits early migration into the interstitial space and lymphatics and rapid pickup by lymph nodes. Although it is a gamma emmitter with high activity, it has a short half-life and does not induce tissue necrosis. It does not localize the site of lymph node metastases, but indicates only the drainage pattern. Images were obtained at 1, 5, 10, 15, 30, and 60 minutes, respectively, and then three times every hour. Surgery was usually performed 24 hours later. The majority of patients had lesions with ambiguous drainage sites: head and neck (4 of 5 patients) and trunk (9 of 13 patients). The drainage by scan was to unpredictive sites in 72%, and resulted in a change of treatment planning by location and extent of ablation with node dissection in 9 of 18 patients. Ambiguous dissection sites included: (1) question of preauricular dissection with parotidectomy versus posterior auricular and cervical dissection for selected scalp lesions; (2) low-neck with or without axillary dissection for upper chest and shoulder lesions; and (3) axillary versus groin dissections for midflank lesions at zone of ambiguity between axilla and groin. It was concluded that preoperative 99mTc antimony sulfide lymphoscintigraphy is a highly useful planning technique in determining the appropriate lymphatic drainage basin for dissection in selected melanoma patients.

Adult↗
PubMed2005

Adsorption of 6-mercaptopurine and 6-mercaptopurine-ribosideon silver colloid: a pH-dependent surface-enhanced Raman spectroscopy and density functional theory study. II. 6-mercaptopurine-riboside.

Surface-enhanced Raman spectroscopy (SERS) has been applied to characterize the interaction of 6-mercaptopurine-ribose (6MPR), an active drug used in chemotherapy of acute lymphoblastic leukemia, with a model biological substrate at therapeutic concentrations and as function of the pH value. Therefore, a detailed vibrational analysis of crystalline and solvated (6MPR) based on Density Functional Theory (DFT) calculations of the thion and thiol tautomers has been performed. 6MPR adopts the thion tautomeric form in the polycrystalline state. The SERS spectra of 6MPR and 6-mercaptopurine (6MP) recorded on silver colloid provided evidence that the ribose derivative shows different adsorption behavior compared with the free base. Under acidic conditions, the adsorption of 6MPR on the metal surface via the N7 and possibly S atoms was proposed to have a perpendicular orientation, while 6MP is probably adsorbed through the N9 and N3 atoms. Under basic conditions both molecules are adsorbed through the N1 and possibly S atoms, but 6MP has a more tilted orientation on the silver colloidal surface while 6MPR adopts a perpendicular orientation. The reorientation of the 6MPR molecule on the surface starts at pH 8 while in the case of 6MP the reorientation starts around pH 6. Under basic conditions, the presence of the anionic molecular species for both molecules is suggested. The deprotonation of 6MP is completed at pH 8 while the deprotonation of the riboside is finished at pH 10. For low drug concentrations under neutral conditions and for pH values 8 and 9, 6MPR interacts with the substrate through both N7 and N1 atoms, possibly forming two differently adsorbed species, while for 6MP only one species adsorbed via N1 was evidenced.

Adsorption↗
PubMed2006

Engineering of protein thermodynamic, kinetic, and colloidal stability: Chemical Glycosylation with monofunctionally activated glycans.

In this work we establish the relationship between chemical glycosylation and protein thermodynamic, kinetic, and colloidal stability. While there have been reports in the literature that chemical glycosylation modulates protein stability, mechanistic details still remain uncertain. To address this issue, we designed and coupled monofunctional activated glycans (lactose and dextran) to the model protein alpha-chymotrypsin (alpha-CT). This resulted in a series of glycoconjugates with variations in the glycan size and degree of glycosylation. Thermodynamic unfolding, thermal inactivation, and temperature-induced aggregation experiments revealed that chemical glycosylation increased protein thermodynamic (Delta G(25 degrees C)), kinetic (t(1/2)(45 degrees C)), and colloidal stability. These results highlight the potential of chemical glycosylation with monofunctional activated glycans as a technology for increasing the long-term stability of liquid protein formulations for industrial and biotherapeutic applications.

Chemical Engineering↗
PubMed1981

High colloidal uptake in axillary nodes with metastatic disease.

Axillary lymphoscintigraphy using 99Tcm antimony sulphide colloid has been carried out in 29 patients with suspected breast cancer and was correlated with histology. Of the 23 with proved tumour, axillary node metastases were found in 19 and, although 10 did have diminished uptake on the side of the lesion, 5 had an equal uptake in both sides and 4 had an increased uptake on the side of the lesion. Further, some of the nodes in which the high uptake had occurred were those heavily infiltrated by tumour. It is concluded that: a, lymphoscintigraphy with antimony sulphide colloid is not a reliable technique for the detection of metastatic disease in the regional nodes; b, any lymphoscintigraphy with this or any other agent requires more meticulous histological correlation than hitherto before it can be assumed to have any proved clinical value.

Antimony↗
PubMed2006

Colloidal gold-based immunochromatographic assay for detection of diethylstilbestrol residues.

One-step membrane-based competitive colloidal gold-based immunoassays in immunochromatographic formats for the rapid detection of diethylstilbestrol (DES) were developed. Nitro-cellulose membrane strip was separately coated with goat anti-rabbit IgG (control line) and DES hapten-ovalubumin conjugate (test line). Anti-DES polyclonal antibody labeled with colloidal gold particles was first incubated with DES. A positive reaction as a result of the remaining antibody-gold conjugate combining with antigen coated on the membrane was obvious by visual detection, with detection limits for immunochromatographic of 0.5 microg/kg for detecting DES standard solution, and the limit of detection was 5 microg/kg for detecting the DES spiked in swine pork and liver. The assay time for test was less than 5 min, suitable for rapid testing on-site.

Animals↗
PubMed2003

Overcharging in colloids: beyond the Poisson-Boltzmann approach.

A broad range of manufactured products and biological fluids are colliods. The ability to understand and control the processes (of scientific, technological and industrial interest) in which such colloids are involved relies upon a precise knowledge of the electrical double layer. The traditional approach to describing this ion cloud around colloidal particles has been the Gouy-Chapman model developed on the basis of the Poisson-Boltzmann equation. Since the early 1980s, however, more sophisticated theoretical treatments have revealed both quantitative and qualitative deficiencies in the Poisson-Boltzmann theory, particularly at high ionic strengths and/or high surface charge densities. This review deals with these novel approaches, which are mostly computer simulations and approximate integral equation theories based on the so-called primitive model. Special attention is paid to phenomena that cannot be accounted for by the classic theory as a result of neglecting ion size correlations, such as overcharging, namely, the counterion concentration in the immediate neighborhood of the surface is so large that the particle surface is overcompensated. Other illustrative examples are the nonmonotonic behavior of the electrostatic potential and attractive interactions between equally charged surfaces. These predictions are certainly remarkable and, on paper, they can have an effect on experimentally measurable quantities (for instance, electrophoretic mobility). Even so, these new approaches have scarcely been applied in practice. Thus a critical survey on the relevance of ion size correlation in real systems is also included. Overcharging of macroions can also be brought about by adsorption of oppositely charged polyelectrolytes. Noteworthy examples and theoretical approaches for them are also briefly reviewed.

Colloids↗
PubMed2004

Separation and recovery of intact gold-virus complex by agarose electrophoresis and electroelution: application to the purification of cowpea mosaic virus and colloidal gold complex.

Colloidal gold has been coupled to a mutant cowpea mosaic virus (CPMV), which contains 60 cysteine residues on the surface. A purification process was developed to separate the gold-containing viral nanoblocks (VNBs) from the free gold. Agarose electrophoresis was utilized to separate the mixture followed by electroelution of the desired sample to recover the intact virus. Mobility of Au-VNB and free colloidal gold was facilitated by the addition of thioctic acid (TA). 30% of the gold-containing virus was recovered after electroelution as determined by absorbance measurements. Histogram analysis of transmission electron microscopy (TEM) images demonstrated the efficient separation of gold-containing virus from free gold. TEM and scanning electron microscopy (SEM) images indicated that the virus was recovered intact. Monodisperse spherical particles of nominal size of 45 nm were observed under SEM.

Comovirus↗
PubMed1987

Adsorbed behavior of spin-labeled silane coupling agent on colloidal silica studied by electron spin resonance.

The adsorption mechanism of silane coupling agent on the colloidal silica surface is studied with spin-labeled silane coupling agent using ESR method. The density of the adsorbed silane molecules was determined to be approximately 1.5-2 molecules per 100 A2 of the silica surface in 95% ethanol solution. In addition, ESR signal of spin-labeled agent adsorbed on the colloidal silica surface was composed of two components; slow component attributable to the agents adsorbed directly on the Si--OH groups of the silica surface through hydrogen bond formation and rapid one attributable to the agents interacted with such adsorbed silane molecules.

Acrylic Resins↗
PubMed2004

Urinary protein fraction in healthy subjects using cellulose acetate membrane electrophoresis followed by colloidal silver staining.

We previously reported a rapid and highly sensitive colloidal silver staining solution suitable for the cellulose acetate membrane. This method was useful for detecting even very small amounts of urinary protein. In the present study, we examined urinary protein fractions in healthy subjects, using cellulose acetate membrane electrophoresis (CAE) with a highly sensitive colloidal silver staining, in an attempt to determine the clinical relevance of urinary protein fractions. Sixty unconcentrated spot urine specimens were analyzed by CAE and calculated by densitometry. All of the samples were separated into five fractions by CAE. The mean +/- 1 SD of the percentage of five fractions was 28.37 +/- 8.51 in albumin, 4.30 +/- 4.19 in alpha1-globulin, 14.41 +/- 6.14 in alpha2-globulin, 19.45 +/- 7.10 in beta-globulin, and 33.46 +/- 8.24 in gamma-globulin. The albumin/globulin (A/G) ratio was 0.41 +/- 0.17. These six items and the concentrations of total protein, albumin, and beta-N-acetyl-D-glucosaminidase (NAG) did not significantly differ between males and females. NAG is the marker of tubulointerstitial nephropathy. The results suggest that there are no gender-dependent differences in the urinary protein fractions of healthy subjects.

Adult↗
PubMed1991

Suitability of different silver enhancement methods applied to 1 nm colloidal gold particles: an immunoelectron microscopic study.

In order to exploit the recently introduced 1 nm gold colloids in routine electron microscopic labeling experiments, an efficient enhancement step for a better visualization of this small marker is a prerequisite. Efficiency and reproducibility of enhancement as well as growth homogeneity of gold particles were evaluated for three different silver intensifying solutions: silver lactate/hydroquinone/gum arabic (Danscher, 1981), Ilford L4/Metol (Bienz et al., 1986), and the commercially available IntenSE M silver enhancement kit (Janssen Pharmaceutica). The best results were obtained by using the silver lactate/hydroquinone/gum arabic mixture. The quality of enhancement of the IntenSE M kit was considerably increased by the addition of the protective colloid gum arabic.

Bacterial Outer Membrane Proteins↗
PubMed1995

Postembedding colloidal-gold immunocytochemistry of noncollagenous extracellular matrix proteins in mineralized tissues.

Immunocytochemistry is a powerful tool for investigating protein secretion, extracellular matrix assembly, and cell-matrix and matrix-matrix/mineral relationships. When applied to the tissues of bones (bone and calcified cartilage) and teeth (dentin, cementum, and enamel), where calcium phosphate-containing extracellular matrices are the predominant structural component related to their weight-bearing and masticatory roles, respectively, data from immunocytochemical studies have been prominent in advancing our understanding of mineralized tissue modeling and remodeling. The present review on the application of postembedding, colloidal-gold immunocytochemistry to mineralized tissues focuses on the advantages of this approach and relates them to conceptual, theoretical, and experimental data currently available discussing matrix-mineral interactions and extracellular matrix formation and turnover in these tissues. More specifically, data are summarized regarding the distribution and role of noncollagenous proteins in different mineralized tissues, particularly in the context of how they interface with mineral, and how this relationship might be affected by the various tissue-processing steps and immunocytochemical strategies commonly implemented to examine the distribution and function of tissue proteins. Furthermore, a technical discussion is presented that outlines several different possibilities for epitope exposure in mineralized tissues during preparation of thin sections for transmission electron microscopy. Cell biological concepts of protein secretion by cells of the mineralized tissues, and subsequent extracellular matrix assembly and organization, are illustrated by examples of high-resolution, colloidal-gold immunolabeling for osteopontin, bone sialoprotein, and osteocalcin in the collagen-based mineralized tissues and for enamel protein (amelogenin) in enamel.

Animals↗
PubMed1990

Use of colloidal silica (Sepracell-MN) for enrichment of dendritic cells from human peripheral blood: comparison with other methods.

Three methods are described for enrichment of dendritic cells from human peripheral blood. In method 1, mononuclear cells were incubated in plastic tissue culture flasks for two h. Nonadherent cells were removed. Adherent cells were washed to remove floating cells and incubated for 14 h at 37 degrees C in 5% CO2. Carbonyl iron was added, and the flasks were incubated for another 2 h. Nonadherent cells were subjected to centrifugation over metrizamide gradient. Phagocytic cells containing ingested carbonyl iron, small lymphocytes, and free carbonyl iron particles passed through the metrizamide, while the interface cell population was enriched for dendritic cells. The purity and yield of enriched dendritic cells were 52.8% and 0.05%, respectively. In method 2, adherent mononuclear cells were cultured overnight, and the released cells (released adherent cells) were centrifuged over metrizamide to separate low-density cells. Monocytes from this low-density cell population were removed by panning over human gamma globulin-coated plastic Petri dishes. In this method the average purity and yield of DC were 63.8% and 0.1%, respectively. In method 3, released adherent cells were treated with anti-CD5 and anti-CD14 monoclonal antibodies plus baby rabbit complement for 15 min, washed, and centrifuged with colloidal silica (Sepracell-MN). Centrifugation with Sepracell-MN was repeated three times. Low-density cells were panned twice over human gamma globulin-coated plastic Petri dishes. Nonadherent cells were highly enriched for DC. Contamination of T cells, B cells, and NK cells was undetectable by flow cytofluorometry. Contamination of monocytes was less than 2%. This method provided greater than 85.0% purity and 0.4% yield. This method (method 3) combines adherence, complement-dependent lysis, centrifugation with colloidal silica, and panning and provides the best yield and purity; it is therefore recommended for optimal purification of DC.

Antibodies↗
PubMed2001

Gastrointestinal persorption and tissue distribution of differently sized colloidal gold nanoparticles.

The gastrointestinal uptake of micro- and nanoparticles has been the subject of recent efforts to develop effective carriers that enhance the oral uptake of drugs and vaccines. Here, we used correlative instrumental neutron activation analysis and electron microscopy to quantitatively and qualitatively study the gastrointestinal uptake and subsequent tissue/organ distribution of 4, 10, 28, and 58 nm diameter metallic colloidal gold particles following oral administration to mice. In our quantitative studies we found that colloidal gold uptake is dependent on particle size: smaller particles cross the gastrointestinal tract more readily. Electron microscopic studies showed that particle uptake occurred in the small intestine by persorption through single, degrading enterocytes in the process of being extruded from a villus. To our knowledge this is the first report, at the ultrastructural level, of gastrointestinal uptake of particulates by persorption through holes created by extruding enterocytes.

Administration, Oral↗
PubMed2005

Microemulsions as colloidal vehicle systems for dermal drug delivery. Part V: Microemulsions without and with glycolipid as penetration enhancer.

The aim of this study was to investigate the dermal administration of a highly hydrophilic model drug, diphenhydramine (DPH), in colloidal systems with an aqueous colloidal phase in the presence of a glycolipid (GL) as a penetration modifier. Dermal penetration of DPH, GL, and isopropylpalmitate (IPP) from ME systems without GL and with GL as well as from a hydrogel used as standard formulation were estimated in vitro using human skin. The penetration of the drug, the oil (IPP), and the GL was measured with highly sensitive HPLC, HPLC-MS, and GC-MS assays, respectively. It could be shown that penetration modifier GL is penetrating very fast, and to a high extent into and through the human skin. In contrast, the penetration of IPP used as oily phase in the ME is limited. When incorporated in the ME systems GL and DPH was accumulated in the viable epidermis and in the dermis. Using ME containing a penetration modifier such as GL, a slight additional enhancing effect could be observed, particularly concerning the penetration of DPH into the acceptor fluid when a highly hydrophilic drug such as DPH was applied.

Administration, Topical↗
PubMed1993

Submicron emulsions as colloidal drug carriers for intravenous administration: comprehensive physicochemical characterization.

Submicron injectable emulsions have been gaining more and more attention in the last few years, mainly as a vehicle for the intravenous administration of lipophilic drugs rather than as an improved delivery system for drug targeting. Submicron emulsions are available, clinically well accepted, and successfully marketed. Novel original emulsion formulations are being extensively investigated and already exhibit improved pharmacological activity; this fact underlines the promising therapeutic properties of these colloidal drug carriers as vehicles for potent lipophilic drugs. It is therefore essential to carry out a comprehensive physicochemical characterization of these submicron emulsions. It is the objective of the present review to emphasize the need for physicochemical studies in the design of new submicron emulsion drug delivery systems and to describe the different approaches available for carrying out such a complete examination of the emulsion colloidal drug carrier system.

Colloids↗
PubMed2004

High activity of enzymes immobilized in colloidal nanoreactors.

We present a novel type of nanoreactor suitable for the immobilization of enzymes. The particles used consist of a polystyrene core onto which long chains of poly(acrylic acid) are grafted ("spherical polyelectrolyte brush"). Proteins adsorbed spontaneously onto these particles from aqueous solutions if the ionic strength is low. We immobilized glucoamylase on these particles and showed that this enzyme keeps nearly its full activity. This is shown by analyzing the enzymatic activity in terms of the Michaelis-Menten kinetics. No leaching out of the enzyme takes place during the reaction and the colloidal stability is not impeded by the adsorbed biomolecules. The data presented here suggest that the principle of immobilizing enzymes on these particles may be of general use.The Figure shows a schematic representation of the colloidal nanoreactors.

Acrylic Resins↗