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PubMed1977

Relationship between colloid osmotic pressure and plasma protein concentration in the dog.

This study was done to establish the correct relationship between protein concentration and plasma colloid osmotic pressure in the dog and to determine the possible influence of the relative albumin and globulin content (A:G ratio). Plasma samples from dogs, rats, and humans were evaluated for total protein concentration, globulin concentration, and colloid osmotic pressure. Samples were concentrated and diluted by ultrafiltration to provide a range of total protein concentrations from 1 to 12 g/dl. Rat and human plasma samples had A:G ratios of 1.4 and 2.1, respectively, and the relationship between protein concentration and colloid osmotic pressure was in agreement with the Landis-Pappenheimer equation. In contrast, dog plasma samples consistently exhibited lower colloid osmotic pressures for any given protein concentration. Two forms of empirical equations were derived to relate these parameters in the dog. Dog plasma samples had higher concentrations of globulin and the A:G ratio averaged 0.59 +/- 0.35 SD. There was a significant relationship between the A:G ratio and the plasma colloid osmotic pressure. Analysis of the possible effect of this altered relationship on glomerular filtration dynamics predicted that efferent plasma colloid osmotic pressure was not specifically affected and was dependent only on the filtration fraction and the plasma colloid osmotic pressure.

Animals↗
PubMed2002

Physico-chemical characterisation and biological evaluation of 188-Rhenium colloids for radiosynovectomy.

BACKGROUND: Radiosynovectomy is a type of radiotherapy used to relieve pain and inflammation from rheumatoid arthritis. In this study, 188-Rhenium (188Re) colloids were characterized by physical and biological methodologies. This was used to assess which parameters of the kit formulation would be the basis in the development of a more effective radiopharmaceutical for synovectomy. Intraarticular injection in knees of rabbits assessed cavity leakage of activity. METHODS: The physical characteristics of tin (Sn) and sulphur (S) colloids were determined to assess the formulation with suitable properties. Particles were grouped in three ranges for analyzing their distribution according to their number, volume and surface. The ideal particle size range was considered to be from 2 to 10 microns. Membrane filtration and laser diffraction characterization methodologies were used. RESULTS: While membrane filtration could give misleading data, laser diffraction proportions more reliable results. The Sn colloid showed a better distribution of particle volume and surface than S colloid, in the 2 to 10 microns range. The 188Re-Sn colloid was obtained with a radiochemical purity higher than 95% after 30 minutes of autoclaving. While Sn colloid kit stability was verified for 60 days, the 188Re-Sn preparation was stable in the first 24 hrs. No significant intrabatch variability (n = 3) was detected. Biodistribution and scintigraphic studies in rabbits after intraarticular injection showed relevant activity only in knee, being 90% at 48 hours. CONCLUSION: The 188Re-Sn colloid is easy to prepare, is stable for 24 hours and shows minimal cavity leakage after intraarticular injection into rabbit knees, suggesting this radiotherapeutical agent has suitable physical properties for evaluation for joint treatment in humans.

Journal Article↗
PubMed2004

188Re radiopharmaceuticals for radiosynovectomy: evaluation and comparison of tin colloid, hydroxyapatite and tin-ferric hydroxide macroaggregates.

BACKGROUND: Radiosynovectomy is a therapy used to relieve pain and inflammation from rheumatoid arthritis and related diseases. In this study three 188Re particulate compounds were characterized according to their physico-chemical properties and their biological behavior in rabbits. The results were compared in order to establish which was the radiopharmaceutical that better fits the requirements of this kind of radiotherapy. METHODS: Three radiopharmaceutical formulations, tin colloid, hydroxyapatite particles (HA) and ferric hydroxide macroaggregates coated with tin colloid (FHMA), were physically characterized (number, volume and surface of the particles). For this purpose laser diffraction methodology was used. To evaluate cavity leakage of activity the following studies in New Zealand rabbits were performed: scintigraphic images for 48 hr after intraarticular injection of each radiopharmaceutical, biodistribution at 48 hr and urine samples collection during the first 24 hr post-radiopharmaceutical administration. RESULTS: Labeling procedures for 188Re-HA and 188Re-Sn-FHMA were labour intensive while 188Re-Sn was easily prepared. Furthermore, 188Re-Sn colloid offered the greatest surface area in the 2-10 microm range and was obtained with a radiochemical purity over 95%, while percentage of bound activity for 188Re-HA and 188Re-Sn-FHMA were 55% and 92% respectively. Stability was verified for the three radiopharmaceuticals for 24 hr. Scintigraphic studies and biodistribution in rabbits after intraarticular administration of the radiopharmaceuticals showed relevant activity only in the knee, this being over 90% of the residual activity in the whole body at 48 hr in every case. Renal elimination of 188Re-Sn colloid and 188Re-Sn-FHMA was detected by activity measurements in urine samples, during the first 12 hr post-radiopharmaceutical injection.The percentage of activity retained in the knee was 69.1% for 188Re-Sn colloid, 55.1% for 188Re-Sn-FHMA and 33.6% for 188Re-HA. CONCLUSION: The 188Re-Sn colloid was easy to prepare, minimum facilities were required, was stable for 24 hr and showed minimal leakage from the joint after intraarticular injection into the rabbit's knee. Furthermore, 188Re-Sn colloid has greater retention in the knee when it is compared with the other radiopharmaceuticals, so it could provide the best therapeutic effect/absorbed dose ratio for the patient.

Journal Article↗
PubMed1980

Protein composition of the thyroid colloid in patients with hyperthyroidism.

Analysis of the protein composition of the thyroid colloid was performed in 28 patients operated on for hyperthyroidism. Fifteen of the patients were treated before the operation with carbimazole combined with thyroxine and 13 were treated with propranolol alone. Colloid was collected by micropuncture of single follicles in peroperative thyroid biopsies. The protein composition was analysed by microgel electrophoresis and densitometry, both in the colloid samples and in the supernatant fraction of homogenates of microbiopsies from the thyroid specimens. The analyses showed that, during treatment with carbimazole and thyroxine, the relative amount of the larger thyroglobulin aggregates (S-TG) was decreased compared with the relative amount observed in the colloid from normal thyroid tissue. In the hyperfunctioning thyroid tissue from the propranolol-treated patients the protein composition of the colloid was similar to that observed in normal tissue and the relative amount of the S-TG fractions was significantly higher than in the carbimazole- and thryoxine-treated group. It may be concluded that the increased release of thyroid hormones in hyperthyroidism is not combined with changes in the protein composition of the thryoid colloid. The decreased relative amount of the S-TG fractions in the thyroid colloid from patients treated with carbomazole and thryoxine was probably due to an insufficient capacity to iodinate thyroglobulin.

Carbimazole↗
PubMed2003

Ion-exchange properties of colloidal particle consisting of polyaniline and poly(vinyl alcohol) fixed on silica-gel powder.

A colloidal powder was prepared by fixing polyaniline (PANI, conducting polymer), poly(vinyl alcohol) (PVA, surfactant stabilizer) and a suitable dopant anion to silica-gel powder. This hydrophilic composite colloidal particle incorporates anions with the protonation of PANI in an acidic solution. The anion can be exchanged with other anions when the colloid is immersed in an acidic solution. Thus, the PANI colloid works as an ion exchanger. The ion-exchange properties on the composite colloidal powder were investigated. Anions were successfully and easily exchanged in the order Br- < Cl- < NO3- < ClO4- < SCN-. This ion-exchange selectivity corresponds largely to the ion-exchange equilibrium constants, which are based on a hydrophobic interaction between the anion and colloid. However, this ion-exchange selectivity does not agree simply with the lipophilic order, but is instead explainable by a gap in the effective ion-exchange capacity due to a size effect between the micropore on the colloidal particle formed by the dopant anion in polymerization and anion sizes in the hydrophobic environment.

Journal Article↗
PubMed2004

Structure of hybrid colloid-polymer xerogels.

Crack-free monolithic gels were prepared from different mixtures of colloidal silica with a sol solution containing tetraethoxysilane, under powerful ultrasonic agitation (sonosol). Recently, information on the structure of these gels, inferred from N2 adsorption and mercury intrusion porosimetry, was presented. In the present paper, these data were used to construct structural models of the gels using Monte Carlo calculations on the basis of random close packing (RPC) premises. In addition, the structure of gels under study was investigated by transmission and scanning electron microscopy. The material can be described as a composite in which the sonogel is the matrix and the colloid particles the reinforcing phase. For low colloid content, the colloid forms discrete clusters, and the main structural characteristic of sonogels, i.e., a network of uniformly sized particles of approximately 3-4-nm radius, remains unmodified. However, for high colloid silica content, a multimode distribution appears, the structure is discontinuous, and only colloid aggregates larger than 100 nm are observed. For medium colloid content, aggregates of approximately 50-100 nm can be seen, but the sonogel structure extends throughout the whole material. By the processing method and election of a suitable precursor concentration, it is possible to design the composite for specific purposes.

Journal Article↗
PubMed1996

[Preliminary study of colloid osmotic pressure for cardiopulmonary bypass].

The ideal colloid osmotic pressure is beneficial to decrease the fluid accumulated in the pulmonary and other tissue during cardiopulmonary bypass. Schupbach reported the proper colloidosmotic pressure for cardiopulmonary bypass was 2.1 kPa (16 mmHg). Colloid osmotic pressures of blood and priming fluid during cardiopulmonary bypass were measured in 28 patients with heart disease by using colloid osmotic pressure detection apparatus. The value of colloid osmotic pressure suitable for the designed standard was apparently different among the Gelofusine group and other groups. P value was 0.005. Priming fluid for cardiopulmonary bypass needs to satisfy the quality and the quantity of colloid osmotic pressure. Using Albumin isn't economical. Whole blood and plazma are not suitable for increasing colloid osmotic pressure. Hydroxyethyl starch or Gelofusine is best choice in priming to get designed standard of colloid osmotic pressure. The ratio of hydroxyethyl starch or Gelofusine in priming fluid should beyond 1/2.

Adolescent↗
PubMed1987

Absolute quantification of pharmacokinetic distribution of RES colloids in individuals with normal liver function.

Estimates of the radiation dose resulting from liver-spleen scintigraphy 99Tcm-labelled colloids are based on pharmacokinetic data mainly determined in animals. The aim of this study was to check the pharmacokinetic data by direct, absolute in vivo quantification in man. For this purpose appropriate methods of measurement were developed, or procedures taken over from literature were modified. Liver and spleen activities were directly measured using a double-energy window technique. Activities in other organs were quantified by conjugate whole-body scans. All measurement procedures were checked using the whole-body Alderson phantom. Pharmacokinetic data for sulphur colloid, tin colloid, human serum albumin (HSA) millimicrospheres, and phytate were obtained in 13 to 20 normal subjects for each type of colloid. Depending on the colloid type liver uptake was between 54 and 75% of the total administered dose (TAD) and spleen uptake was 3.5 to 21% TAD. Activity measured in blood, urine, lung and thyroid proved to be far from negligible. The results of this work suggest a correction of the animal-based data of colloid distribution and radiation dose on the basis of the direct measurement of absolute uptake in man.

Adult↗
PubMed2000

Colloid in the pituitary pars distalis of viscacha (Lagostomus maximus maximus): ultrastructure and occurrence in relation to season, sex, and growth.

Randomly distributed extracellular colloidal accumulations were observed in the pars distalis of viscacha (Lagostomus maximus maximus). They were preferentially located in the peripheral zone of the gland and showed variability in shape and size. Two different types of colloidal accumulations were found by electron microscopy: 1) those surrounded by nongranulated follicular cells that correspond to characteristic follicles, and 2) those surrounded by granulated cells. In the follicles lined by nongranulated follicular cells, long, prominent microvilli and cytoplasmic processes protruded into the lumen. The frequency of these accumulations varies during the year in adult male animals, showing an increase in number during summer and a decrease during winter. The lowest value was registered in August (winter). The mean follicular diameter did not vary seasonally. The number of colloidal accumulations did not vary seasonally in adult female viscachas, but a significant difference in the mean follicular diameter between pregnant and non-pregnant females was observed. Pituitaries of immature animals contain fewer colloidal accumulations than those of adults. In fetuses, these accumulations were absent. The administration of melatonin provoked a decrease in the number of these structures. The numeric changes of the colloidal accumulations observed in this study are associated with: 1) the seasonal reproductive activity in adult males, and 2) the reproductive condition, body weight and sexual maturity in males and females. The fact that melatonin administration decreases the population of colloidal accumulations in males suggests participation of the pineal gland in these changes.

Age Factors↗
PubMed2006

One- and two-photon induced fluorescence of Pacific Blue-labeled human serum albumin deposited on different core size silver colloids.

We studied one- and two-photon induced fluorescence of Pacific Blue (PB)-labeled human serum albumin (HSA) in the presence of different size silver colloids. The PB fluorescence emission intensity was observed with small (30-40 nm) and large (about 120 nm) colloids and compared with PB emission in absence of colloids. For the system with a small core size colloids we did not detect any fluorescence enhancement with one-photon excitation and the enhancement observed with two-photon excitation was about 2.5-fold. In contrast, for large silver colloids we observed about a 2-fold increase in PB fluorescence brightness for one-photon excitation, and the enhancement with two-photon excitation excided 13-folds. Much stronger increases in brightness observed with two-photon excitation, compared to one-photon excitation, indicate a dominant role of enhanced local field in fluorescence enhancement on silver colloids in solutions.

Colloids↗
PubMed2006

Nanomachining by colloidal lithography.

Colloidal lithography is a recently emerging field; the evolution of this simple technique is still in progress. Recent advances in this area have developed a variety of practical routes of colloidal lithography, which have great potential to replace, at least partially, complex and high-cost advanced lithographic techniques. This Review presents the state of the art of colloidal lithography and consists of three main parts, beginning with synthetic routes to monodisperse colloids and their self-assembly with low defect concentrations, which are used as lithographic masks. Then, we will introduce the modification of the colloidal masks using reactive ion etching (RIE), which produces a variety of nanoscopic features and multifaceted particles. Finally, a few prospective applications of colloidal lithography will be discussed.

Colloids↗
PubMed1993

Human fetuin/alpha 2 HS glycoprotein in colloid and parenchymal cells in human fetal pituitary gland.

An immunohistochemical study was undertaken, in an attempt to identify the acidic glycoprotein(s) present in colloid and in parenchymal cells in human fetal pituitary gland. As the colloid has been proposed to represent disintegrating cells, a series of antibodies against plasma glycoproteins and plasma proteins was applied; their presence intracellularly would generally be an indicator of plasma membrane leakage in dying parenchymal cells. In tissue sections from 9- to 20-week-old fetuses, the colloid showed prominent staining with an antibody to human fetuin/alpha 2 HS glycoprotein. Anti-alpha 2-HS glycoprotein labelled parenchymal cells in pars anterior and intermedia. Apart from a minor immunoreactivity for alpha 1 beta glycoprotein, no other plasma glycoprotein was seen in colloid or parenchymal cells. An antibody against bovine fetuin showed staining of the colloid and of some parenchymal cells in pars distalis and intermedia; the plasma and stroma of the pituitary gland were unstained. In contrast, the anti-human plasma protein antibodies all stained the stroma. The presence of alpha 2 HS glycoprotein in parenchymal cells and absence of other plasma glycoproteins imply integrity of the parenchymal cell plasma membrane. Thus, alpha 2 HS glycoprotein is either synthesized locally or taken up specifically in the parenchymal cells, which are proposed to participate in the formation of colloid. It is suggested that alpha 2 HS glycoprotein is part of a homeostatic system, which controls remodelling and physiological cell death during development.

Animals↗
PubMed1980

Mechanism of hepatic extraction of gelatinized 99m technetium sulfur colloid.

Hepatic extraction, cellular and subcellular localization of gelatin stabilized Tc-99m sulfur colloid was studied in the rat model with time sequenced microautoradiography from 15 min to 24 h following I.V. administration of the tracer. Hepatic lobular and cellular distribution, quality and quantity of focal grain pattern, grain clusters, remained essentially constant for the period of study. Grain clusters were associated predominantly with Kupffer cells lining the peripheral segment of hepatic lobular sinusoids. Subcellular localization of gelatinized Tc sulfur colloid, stained prior to the I.V. administration with osmium tetroxide, was demonstrated with a transmission electron microscope in unosmicated liver tissue. Extracted Tc sulfur colloid particles were attached in groups to cytoplasmatic membranous intrasinusoidal projections of activated Kupffer cells. Intracytoplasmatic phagocytosis was not demonstrated. The kinetic arrest and en groupe extraction of Tc sulfur colloid particles at the Kupffer cell membrane suggests a specific membrane receptor site and specific Tc sulfur colloid particle-plasma protein interaction at the time of extraction. Hepatic extraction of gelatinized Tc sulfur colloid thus reflects primarily extra and intra hepatic hemodynamics and does not serve as an indicator of phagocytic hepatic reticuloendothelial system function.

Animals↗
PubMed2002

Colloid infusion in the perinatal period and abnormal neurodevelopmental outcome in very low birth weight infants.

UNLABELLED: In very low birth weight (VLBW) infants, colloid infusion is associated with impaired perinatal lung function and increased oxygen dependency duration. The aim of this study was to determine whether perinatal colloid infusion was associated with abnormal neurodevelopmental outcome. All perinatal fluid input (crystalloid and colloid) given to VLBW infants entered into a randomised trial was recorded. At 1 and/or 2 years, the neurodevelopmental status of VLBW infants was routinely assessed. Of 131 survivors, median gestational age 27 weeks (range 23-33 weeks), 95 were seen at follow-up. Nineteen had abnormal neurodevelopmental outcome and differed significantly from the rest of the cohort with regard to their birth weight, magnitude of colloid infusion received and the proportions who had received postnatal steroids, suffered prolonged oxygen dependency or having had intracerebral haemorrhage/periventricular leucomalacia development. Regression analysis demonstrated that only colloid infusion related significantly to abnormal neurodevelopmental outcome independent of other variables. CONCLUSION: These data suggest that colloid infusion should be used with caution in the perinatal period.

Brain↗
PubMed1987

Caseins are cross-linked through their ester phosphate groups by colloidal calcium phosphate.

Artificial casein micelles were prepared by adding 30 mM calcium, 22 mM phosphate and 10 mM citrate to sodium caseinate solutions, and the content of the casein aggregates cross-linked by colloidal calcium phosphate was determined by high-performance gel chromatography on a TSK-GEL G4000SW column in the presence of 6 M urea. The content of the casein aggregates cross-linked by colloidal calcium phosphate in artificial whole casein micelles was 48% of total casein, and their relative casein composition determined by high-performance ion-exchange chromatography was 53.1% for alpha s1-casein, 15.8% for alpha s2-casein, 31.1% for beta-casein and 0% for kappa-casein. The order of cross-linking by colloidal calcium phosphate agreed with that of the ester phosphate content of casein constituents. The content of the casein aggregates cross-linked by colloidal calcium phosphate was higher in alpha s1-kappa-casein micelles than in beta-kappa-casein micelles. kappa- and gamma-caseins and dephosphorylated alpha s1-casein were not cross-linked by colloidal calcium phosphate. Although kappa-casein was not cross-linked, chemically phosphorylated kappa-casein, of which the average phosphate content was 8.5 per molecule, was cross-linked. It is concluded that caseins are cross-linked through their ester phosphate groups by colloidal calcium phosphate.

Animals↗
PubMed1986

Preparation of 99mTc-tin-phosphate polyvinyl pyrollidone stabilized colloid and distribution in bone marrow.

Technetium-99m-Sn-phosphate colloid was prepared in the presence of polyvinylpyrollidone(PVP), molecular weight 44,000, for bone marrow imaging. Size of the colloidal particles, as determined by coulter counter, microphotographic and electron microscopic studies was 15-35 nm. The colloid preparation was checked for the presence of any soluble components by Sephadex G-25 chromatography. Scintigraphy in rabbits showed a high concentration of the colloid in the bone marrow. Tissue distribution studies in rabbits showed 26.7% of the injected dose at 1 h post-injection in the bone marrow collected from femoral shaft and head. Although liver and spleen showed considerable levels of activity, kidneys and compact bone did not show any uptake. The colloid cleared from the blood exponentionally with a first phase showing a relatively fast clearance while in the second phase it disappeared more slowly. Uptake of the colloid in human bone marrow was close to that in the rabbit and thus clinical evaluation is warranted.

Animals↗
PubMed1991

Effect of size fractionation on the distribution of an albumin colloid in the reticuloendothelial system of the mouse.

To study if by varying the particle size of a 99mTc albumin colloid preparation its relative bone marrow accumulation could be increased, it was separated by gel filtration and different fractions were injected into mice. Particles around and smaller than the peak size of the colloid, 31 nm, exhibited a higher bone marrow/liver-spleen uptake ratio than larger particles but the uptake ratio was similar to that of the unseparated colloid. An antimony sulphide colloid showed a similar particle size distribution, but the corresponding uptake ratio was half of the albumin colloid. This indicates that characteristics other than size determine the distribution of a colloid in the reticuloendothelial system.

Animals↗
PubMed1989

Crystalloid or colloid: does it matter?

The modern version of the crystalloid-colloid debate has continued for more than 25 years, and a current appraisal of the debate is presented here. Although the effect of crystalloids and colloids on intravascular volume is important, their effect on interstitial fluid volume after hemorrhage and hemorrhagic shock is central to the debate. If reduced, crystalloids are appropriate as part of the resuscitation regime; if increased, colloid therapy is more logical. A brief review of the distribution of crystalloids and currently used colloids (albumin, polygeline, dextran 70, and hydroxyethyl starch) is presented. The problems of pulmonary and peripheral edema also are presented, as is an appraisal of adverse reactions to colloids together with a cost comparison of crystalloids and colloids. The results of a survey of attitudes at the major Australian anesthetic departments are given, and a personal approach to fluids in resuscitation is outlined.

Colloids↗