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PubMedDate not supplied

Luminol chemiluminescence catalysed by colloidal platinum nanoparticles.

Platinum colloids prepared by the reduction of hexachloroplatinic acid with citrate in the presence of different stabilizers were found to enhance the chemiluminescence (CL) of the luminol-H(2)O(2) system, and the most intensive CL signals were obtained with citrate-protected Pt colloids synthesized with citrate as both a reductant and a stabilizer. Light emission was intense and reproducible. Transmission electron microscopy and X-ray photoelectron spectroscopy studies were conducted before and after the CL reaction to investigate the possible CL enhancement mechanism. It is suggested that this CL enhancement is attributed to the catalysis of platinum nanoparticles, which could accelerate the electron-transfer process and facilitate the CL radical generation in aqueous solution. The effects of Pt colloids prepared by the hydroborate reduction were also investigated. The application of the luminol-H(2)O(2)-Pt colloids system was exploited for the determination of compounds such as uric acid, ascorbic acid, phenols and amino acids.

Catalysis↗
PubMed2002

Electrochemical behavior of Au colloidal electrode through layer-by-layer self-assembly.

Electrodes formed by Au colloidal nanoparticles have been obtained by layer-by-layer self-assembly using 1,6-hexanedithiol as cross-linkers. Cyclic voltammograms show that the peak-to-peak separation decreases as the number of Au colloidal layers increases. After seven layers of Au colloidal particles have been deposited, the multilayer electrodes have the electrochemical properties of metallic Au and show ideal microelectrode behavior. An equivalent circuit for the electrochemical impedance spectroscopy was established to model the working electrode. It is evident that by increasing the layer number of Au colloidals, the interfacial electron transfer is promoted, implying the electron-transfer process changes from a kinetically limited process to a diffusionally limited process.

Colloids↗
PubMed1982

Deposition of small 99mTc-labelled colloids in bone marrow and lymph nodes.

The degree of deposition of small-particle colloids such as 99mTc-antimony sulfide colloids (ASC-group) and 99mTc-rhenium colloid (Tc-Re) in the bone marrow and lymph node was studied. H-ASC that was prepared in our laboratory was concentrated to a higher degree both in the bone marrow and lymph nodes, compared with other colloids. The H-ASC were mostly from 5 to 12.5 nm and the shape was uniform and spherical. The degree of deposition of Tc-Re in rabbit lymph nodes was not higher, however, the label was considered to be valuable clinically. The degree of deposition of Tc-Re in the bone marrow was not satisfactory. The size of Tc-Re was much smaller than H-ASC, ranging from 3 to 5 nm. From these results, it is considered that factors affecting deposition in the marrow are not identical to those in the lymph nodes.

Animals↗
PubMed1981

Cell labelling with colloidal substances in whole blood.

A method for the labeling of leucocytes with 99mTc-colloid is described. The labelling can be done in samples of whole blood, because the colloid is only taken up by the phagocytosing cells, the monocytes and the granulocytes. The part of the colloid that is not phagocytosed is brought to a soluble state with Na-citrate, so that only the phagocytosed colloid is reinjected. The labelling efficiency with this method is between 80% and 90%. Measurements of the activity in the leucocytes 3 h after reinjection, have shown that at least 50% of the labelled cells are at this time still available in the blood pool. The clinical results on 32 patients with the tentative diagnosis of an abdominal abscess and on 42 patients with the tentative diagnosis of septic loosening of an endoprosthesis have shown that the labelled leucocytes are very well suited to show up local foci of inflammation.

Adolescent↗
PubMed1984

Intrathecal therapy with 198Au-colloid for meningosis prophylaxis.

Telecobalt irradiation in combination with intrathecal (IT) methotrexate has been replaced by IT 198Au-colloid and methotrexate for meningosis prophylaxis in leukemia. Seventy-seven children received 56-200 MBq 198Au-colloid. The distribution was measured with a scintillation camera having a data processing facility. The radiopharmaceutical is adsorbed at the surface of the spaces with cerebrospinal fluid (CSF) 10-20 h after application. The normal retention of the administered radioactivity in the intracranial subarachnoid space (ISS) and in the spinal subarachnoid space (SSS) were 52 +/- 10% and 26 +/- 9%, respectively. An impairment of the normal distribution was observed after IT methotrexate and also postinjection CSF leakage. The calculated radiation absorbed doses in the cerebral and spinal meninges at a depth of 0.01 cm, i.e. the thickness of the pia, were 45 +/- 17 mGy and 189 +/- 91 mGy, respectively, for 1 MBq administered 198Au-colloid. The dosimetry shows that an effective radiation absorbed dose of 18 Gy can be delivered to the cerebral meninges by the application of 400 MBq 198Au-colloid.

Acute Disease↗
PubMed1996

Huge colloid cyst of the third ventricle associated with calcification in the cyst wall.

Giant or huge colloid cysts of the third ventricle up to of more than 3 cm in diameter are extremely rare. The patient presented with symptoms of increased intracranial pressure, including headache, vomiting, and papilledema. Computerized tomographic (CT) scan revealed a hypodense, huge colloid cyst of the third ventricle associated with calcification in the cyst wall. Both hypodensity and calcification are uncommon roentgenological findings for colloid cysts of the third ventricle. The patient was operated on by the transcortical/transventricular approach and the colloid cyst was completely excised.

Adult↗
PubMed1983

Cationic cacodylate iron colloid for the detection of anionic sites on cell surface and the histochemical stain of acid mucopolysaccharides.

Stable cationic iron colloid solution was prepared by mixing the Hale's iron colloid (Hale 1946; Mowry 1963) with sodium cacodylate buffer solution. The colloid particles obtained were 30-50 A in size and kept their positive charges in a wide range of pH 1.8-7.6. Observations made on rat kidney tissues proved that this iron colloid solution is promising for the detection of anionic sites of cell surface in fixed tissues as well as in living cells in place of cationic ferritin.

Animals↗
PubMed1990

Comparison of technetium 99m-phytate and technetium 99m-sulphur colloid in primary bone tumours.

Eleven patients with proven primary bone tumour (five Ewing sarcomas, six osteosarcomas) and two cases of metastatic bone involvement (primary other than bone) were investigated with 99mTc-phytate and 99mTc-sulphur colloid to compare the behaviour of the two radiopharmaceuticals at the tumour site. After intravenous administration of the respective radiopharmaceutical, imaging of the tumour site and its contralateral part was carried out at 15 min and 1 h intervals. The data were stored in our computer. Bone scanning was also carried out in all patients. 99mTc-phytate uptake was observed at the tumour site in ten cases. The 99mTc-sulphur colloid study revealed sparse or no significant uptake in eight cases. In two patients, with osteosarcoma 99mTc-sulphur colloid investigation showed uptake at the primary tumour site. However, the distribution pattern is different from that of 99mTc-phytate. No significant uptake of either 99mTc-phytate or 99mTc-sulphur colloid was observed in the two patients with metastatic skeletal disease. It may be concluded that the unusual accumulation of 99mTc-phytate at the tumour site is not due to any generalized reticuloendothelial phenomenon and that the radiopharmaceutical itself is responsible for this.

Adolescent↗
PubMed1980

Colloid osmotic and hydrostatic pressures in chronic subdural haematomas.

Intracranial pressure (ICP) has been measured in eight patients with chronic subdural haematomas (CSH) for 24 hours prior to and for 24 hours following evacuation of the haematomas. In all patients ICP was increased prior to surgery (mean: 23 mm Hg), and it rose again to the preoperative level following evacuation of the haematomas in spite of disappearance of most symptoms and signs. In two of these patients and in another eight patients with CSH, colloid osmotic pressures were measured in samples obtained simultaneously from haematoma fluid and venous blood during surgery. The colloid osmotic pressure in haematoma fluid varied considerably between patients (lowest: 11.8 mm Hg, highest: 60 mm Hg), and thus the difference between colloid osmotic pressures in haematoma fluid and plasma also varied considerably. We suggest that the increased ICP in patients with CSH is the consequence of an increased resistance to absorption of cerebrospinal fluid due to compression of the underlying subarachnoid space. The findings with regard to colloid osmotic pressures suggest that osmotic gradients may be maintained across the boundaries of a chronic subdural haematoma.

Adult↗
PubMed1996

The silver anniversary of gold: 25 years of the colloidal gold marker system for immunocytochemistry and histochemistry.

Since 1971, when W.P. Faulk and G.M. Taylor published "An immunocolloid method for the electron microscope", colloidal gold has become a very widely used marker in microscopy. It has been used to detect a huge range of cellular and extracellular constituents by in situ hybridization, immunogold, lectin-gold, and enzyme-gold labeling. Besides its use in light microscopic immunogold and lectin-gold silver staining, colloidal gold remains the label of choice for transmission electron microscopy studying thin sections, freeze-etch, and surface replicas, as well as for scanning electron microscopy. The year 1996 is the 25th anniversary of the introduction of colloidal gold as a marker in immunoelectron microscopy and this overview outlines some of the major milestones in the development of the colloidal gold marker system.

Animals↗
PubMed2003

Postdural puncture headache in a parturient with sickle cell disease: use of an epidural colloid patch.

PURPOSE: To report the injection of a colloid in the epidural space as an alternative to an epidural blood patch in a woman with sickle cell disease. CLINICAL FEATURES: A Cesarean delivery was performed under spinal anesthesia in a 32-yr-old woman with severe sickle cell disease and a past medical history of vaso-occlusive crisis. In the postoperative period, the patient complained of postdural puncture headache resistant to symptomatic treatment. Because there were no data concerning the safety of a blood patch in this condition, a colloid (a modified fluid gelatin heated to 37 degrees C) was injected in the epidural space instead of blood. Headaches decreased immediately after the epidural injection of the colloid and disappeared totally within 12 hr. CONCLUSION: Data concerning the safety of epidural blood patches in patients with sickle cell disease are lacking. Injection of colloids in the epidural space could be an alternative.

Adult↗
PubMed2006

The effects of colloid solutions on hemostasis.

PURPOSE: Colloid solutions are widely used to prevent or to correct hypovolemia in surgical patients. Although more efficacious than crystalloids, they are more expensive and can be associated with adverse effects, in particular when they interfere with the hemostatic system. METHODS: This narrative review focuses on the effects of albumin and synthetic colloids on the biological markers of coagulation and their clinical consequences. RESULTS: All colloidal plasma substitutes interfere with the physiological mechanisms of hemostasis either through a non-specific effect correlated to the degree of hemodilution or through specific actions of these macromolecules on platelet function, coagulation proteins, and the fibrinolytic system. Albumin has the least effect, while high molecular weight (Mw) dextrans and hydroxyethyl starches (HES) have the most significant effects. Gelatins and medium Mw HES with a low molar substitution ratio have moderate and, probably, comparable effects. The use of dextrans and high in vivo Mw HES may be associated with increased bleeding, while gelatins and low in vivo Mw HES are unlikely to have such an effect. CONCLUSIONS: In most cases, the clinical consequences of the biological effects of colloids on hemostasis are limited, provided that safety considerations are observed (maximum daily dosage, duration of treatment, patient's hemostatic status, clinical conditions). The implications may be different in patients with hemostatic disorders, either inherited or related to preoperative antiplatelet or anticoagulant treatment. In these patients, crystalloids, gelatins or even albumin solutions should be preferred when hemodilution exceeds 30% of the circulating blood volume.

Animals↗
PubMed1998

[Excessive tissue storage of colloids in the reticuloendothelial system].

In addition to renal elimination and gastrointestinal metabolism (amylase; splenic and hepatic dextranase) colloid plasma solutions like dextran and hydroxyethyl starch deposit in tissues, especially in the reticuloendothelial system (RES). This tissue storage is limited in time (weeks to months), is influenced by the employed solution and other factors (lysosomes) and has usually no clinical importance (no RES blockade). We report here a case study of a patient with sepsis (lung, liver and kidney failure) who had an overload of the RES with colloids while being treated with dextran (molecular weight 40,000 and 70,000 daltons) and hydroxyethyl starch (mw 450,000 daltons, molar substitution 0,7) for 5 weeks. Autopsy showed parenchymal and reticuloendothelial cells of liver, lung, kidney and spleen with a large amount of colloid mass inclusions and altered organ morphology. This storage may have impaired ventilation, transport of bile acids and renal function. A possible role of tissue storage of colloids in organ failure is discussed.

Blood Substitutes↗
PubMed2007

Concentrations of metals in water, sediment, biofilm, benthic macroinvertebrates, and fish in the Boulder River watershed, Montana, and the role of colloids in metal uptake.

To characterize the partitioning of metals in a stream ecosystem, concentrations of trace metals including As, Cd, Cu, Pb, and Zn were measured in water, colloids, sediment, biofilm (also referred to as aufwuchs), macroinvertebrates, and fish collected from the Boulder River watershed, Montana. Median concentrations of Cd, Cu, and Zn in water throughout the watershed exceeded the U.S. EPA acute and chronic criteria for protection of aquatic life. Concentrations of As, Cd, Cu, Pb, and Zn in sediment were sufficient in the tributaries to cause invertebrate toxicity. The concentrations of As, Cu, Cd, Pb, and Zn in invertebrates from lower Cataract Creek (63, 339, 59, 34, and 2,410 microg/g dry wt, respectively) were greater than the concentrations in invertebrates from the Clark Fork River watershed, Montana (19, 174, 2.3, 15, and 648 microg/g, respectively), that were associated with reduced survival, growth, and health of cutthroat trout fed diets composed of those invertebrates. Colloids and biofilm seem to play a critical role in the pathway of metals into the food chain and concentrations of As, Cu, Pb, and Zn in these two components are significantly correlated. We suggest that transfer of metals associated with Fe colloids to biological components of biofilm is an important pathway where metals associated with abiotic components are first available to biotic components. The significant correlations suggest that Cd, Cu, and Zn may move independently to biota (biofilm, invertebrates, or fish tissues) from water and sediment. The possibility exists that Cd, Cu, and Zn concentrations increase in fish tissues as a result of direct contact with water and sediment and indirect exposure through the food chain. However, uptake through the food chain to fish may be more important for As. Although As concentrations in colloids and biofilm were significantly correlated with As water concentrations, As concentrations in fish tissues were not correlated with water. The pathway for Pb into biological components seems to begin with sediment because concentrations of Pb in water were not significantly correlated with any other component and because concentrations of Pb in the water were often below detection limits.

Animals↗
PubMedDate not supplied

Tc-99m sulfur colloid scintigraphy for detecting perigraft flow following endovascular aortic aneurysm repair: A feasibility study.

PURPOSE: To determine if scintigraphy with Tc-99m sulfur colloid can be used to detect perigraft flow after stent-graft repair of abdominal aortic aneurysm (AAA). METHODS: Twenty-three men and two women aged 56-84 years (mean 71 years) underwent endoluminal AAA repair as part of the EVT Phase II trial [EVT = Endovascular Technologies (Menlo Park, CA, USA)]. Aneurysm size averaged 5.4 cm (range 3-8 cm). Sixteen bifurcated, seven tube, and two aorto-uniiliac grafts were placed. Two days after stent-graft placement, patients underwent both contrast-enhanced computed tomography (CT), including delayed views, and Tc-99m sulfur colloid scintigraphy. RESULTS: Perigraft flow was found in only one patient at completion of angiography. Four additional patients had perigraft flow, discovered during their postoperative follow-up CT. Four patients had leaks at an attachment site and one had retrograde branch flow. Tc-99m sulfur colloid scintigraphy failed to diagnose any of the five leaks prospectively. In two of these patients, however, some abnormal paraaortic activity was noted in retrospect. CONCLUSION: Tc-99m sulfur colloid scintigraphy was unable to demonstrate endoleak with either rapid flow (attachment site leak) or slow filling (branch flow).

Aged↗
PubMed2001

Reversible nephrotoxicity after overdose of colloidal bismuth subcitrate.

Although toxicity due to acute and chronic use of bismuth salts is well known, nephrotoxicity after ingestion of colloidal bismuth has been reported in few cases so far. Here we report the first case of acute renal failure (ARF) due to colloidal bismuth subcitrate overdosage in childhood. A 2-year-old boy was admitted to the hospital 6 h after ingestion of 28 De-Nol tablets (colloidal bismuth subcitrate 8.4 g). On admission, physical examination was unremarkable and he showed no signs of encephalopathy. Initially gastric lavage was performed then appropriate fluid therapy was started. ARF associated with uremia and oliguria developed on day 2 and peritoneal dialysis therapy was prescribed on day 4 for 10 days. Blood and urine bismuth levels were 739 micrograms/l and 693 micrograms/l, respectively, 10 days after the pills had been taken. His urine volume gradually increased and plasma BUN and creatinine levels decreased during peritoneal dialysis. On day 20 post-admission, plasma BUN and creatinine were 14 mg/dl and 0.7 mg/dl, respectively. Blood bismuth levels were 96 micrograms/l on day 60 and 12 micrograms/l on day 105. Now the patient is well and has no problem. This case suggests that ARF may develop in children following colloidal bismuth subcitrate overdosage; the prognosis is good, and peritoneal dialysis may be useful in these cases.

Acute Kidney Injury↗
PubMed1998

On the chemical characterization of colloid cyst contents.

Colloid cysts of the third ventricle have been investigated by chemical characterization of the cyst contents using ELISA with monoclonal antibodies for certain carbohydrate epitopes as well as a polyclonal antiserum against peptide domains, and immunohistochemistry on the cyst wall using the same antibodies. Furthermore, the carbohydrate composition of one sample has been determined after gel filtration. The cyst contents reacted strongly with the monoclonal antibody for the sulfo-Lewis epitope, and with the antimucin polyclonal antiserum. In one case the cyst fluid exhibited a blood group A antigen. A sample of cyst wall obtained by biopsy showed strong immunoreactivity against sulfo-Lewis antigen, and the sialo-Lewis antigen. The presence of the S atom with its high atomic number relative to that of C, H, and O atoms, may contribute to the high density appearance of colloid cysts on CT-scans. The sulfo-Lewis and sialo-Lewis carbohydrate epitopes are known as ligands for selectins, involved in inflammatory processes, and may well account for the aseptic meningeal reaction that may follow spilling of cyst contents during operative evacuation. The carbohydrate epitopes exhibited by colloid cysts and their contents, have also been reported for the mucins of salivary glands, uterine cervix, gall bladder and colon, and therefore, are not inconsistent with the assumption of an endodermal origin of colloid cysts.

Biopsy↗
PubMed1999

Colloidal blood volume expansion during high intracranial pressure.

This study tested the hypothesis that colloidal blood volume expansion could improve the cerebral circulation during high intracranial pressure. We studied cerebrovascular haemodynamic variables during high intracranial pressure with and without colloidal blood volume expansion in 12 pigs, whereas five pigs served as controls with intracranial pressure increase twice without colloidal blood volume expansion. Cerebral blood flow was measured with ultrasonic flowmetry on the internal carotid artery, and cerebral microcirculation with laser Doppler flowmetry. High intracranial pressure was induced by infusion of artificial cerebrospinal fluid into the cisterna magna. Blood volume expansion was obtained by infusion of albumin, 1 gram/kg. Albumin infusion caused increases in internal carotid artery blood flow (P < 0.05) and cerebral perfusion pressure (P < 0.005), while cerebral microcirculation and cerebrovascular resistance was unchanged. High intracranial pressure albumin infusion caused internal carotid artery blood flow (P < 0.05) and cerebral perfusion pressure (P < 0.001) to increase compared to high intracranial pressure without albumin infusion, while cerebrovascular resistance was unchanged. Cerebral micro-circulation tended to increase, but this was not statistically significant (P = 0.07). Augmentation of the intravascular blood volume during high intracranial pressure increased the arterial inflow to the brain and possibly the cerebral microcirculation by increasing the cerebral perfusion pressure. Our results tend to support that the effect of colloidal blood volume expansion is beneficial for the cerebral circulation during high intracranial pressure.

Animals↗