Colloidal gold as a permanent marker of cells

Summary We have demonstrated that colloidal gold-labelled serum proteins are taken up by a number of cells in cultures established from the postnatal rodent neopallium. The colloidal gold enters and remains within secondary lysosomes over extended periods of time and, as well, persists after the subculture of these cells. The cell types that readily take up the label in our culture system are type-1 astrocytes, glial precursor cells and macrophages, whereas, only a small number of oligodendrocytes take up the label. The use of serum proteins to introduce colloidal gold into cells therefore seems to be a convenient and easy way to permanently mark cells.     

Colloidal gold as a permanent marker of cells.

We have demonstrated that colloidal gold-labelled serum proteins are taken up by a number of cells in cultures established from the postnatal rodent neopallium. The colloidal gold enters and remains within secondary lysosomes over extended periods of time and, as well, persists after the subculture of these cells. The cell types that readily take up the label in our culture system are type-1 astrocytes, glial precursor cells and macrophages, whereas, only a small number of oligodendrocytes take up the label. The use of serum proteins to introduce colloidal gold into cells therefore seems to be a convenient and easy way to permanently mark cells.     

A colloidal gold prepared with ultrasonics

Summary With the application of ultrasonic energy a colloidal gold may be easily prepared with a particle diameter of less than 10 nm and suitable for use as an immunological marker for TEM-studies. This new approach replaces the use of phosphorus, traditionally used for producing gold sols of the smallest diameter.     

Cholera toxin B-subunit incorporation into synaptic vesicles of the neuromuscular junction of the rat

The B-subunit of cholera toxin, a nontoxic macromolecule which binds specifically to GM1 ganglioside, was conjugated to colloidal gold and injected into skeletal muscle of the rat. It was taken up rapidly in vesicles in the terminal axons at the neuromuscular junctions. Injection of albumin-colloidal gold conjugates resulted in an insignificant uptake. The results indicate that uptake of extracellular macromolecules into the terminal axon of the neuromuscular junction may be greatly enhanced by binding to gangliosides at the presynaptic membrane, and that it may occur without association with vesicular recycling related to transmitter release.     

Receptors for thymosin fraction V on rat thymic lymphocytes

Summary Binding by rat thymus lymphocytes of thymosin V, labeled with colloidal gold, was studied. Under the experimental conditions employed at least 2.8% cells exhibited thymosin binding sites. Supported by Polish Academy of Sciences. Fellows of Humboldt's Fellowship. The authors thank Dr A.L. Goldstein for the gift of thymosin. Also are grateful to Dr J. Jaroszewski for helpful discussion.     

Receptors for thymosin fraction V on rat thymic lymphocytes

Summary Binding by rat thymus lymphocytes of thymosin V, labeled with colloidal gold, was studied. Under the experimental conditions employed at least 2.8% cells exhibited thymosin binding sites.This article originally appeared in Experientia 38 (5) 1982, p. 618 but was accompanied by imporperfigures. Supported by Polish Academy of SciencesThe authors thank Dr A.L. Goldstein for the gift of thymosin. Also are grateful to Dr J. Jaroszewski for helpful discussion.     

Cholera toxin B-subunit incorporation into synaptic vesicles of the neuromuscular junction of the rat

Summary The B-subunit of cholera toxin, a nontoxic macromolecule which binds specifically to GM1 ganglioside, was conjugated to colloidal gold and injected into skeletal muscle of the rat. It was taken up rapidly in vesicles in the terminal axons at the neuromuscular junctions. Injection of albumin-colloidal gold conjugates resulted in an insignificant uptake. The results indicate that uptake of extracellular macromolecules into the terminal axon of the neuromuscular junction may be greatly enhanced by binding to gangliosides at the presynaptic membrane, and that it may occur without association with vesicular recycling related to transmitter release.The study was supported by grants from the Swedish Medical Research Council (proj. No. 07122).—Part of this study was performed at INSERM U-153, Paris, headed by Dr M. Fardeau.     

Gold nanoparticles induce nuclear damage in breast cancer cells,which is further amplified by hyperthermia

Gold nanoparticles have emerged as promising tools for cancer research and therapy, where they can promote thermal killing. The molecular mechanisms underlying these events are not fully understood. The geometry and size of gold nanoparticles can determine the severity of cellular damage. Therefore, small and big gold nanospheres as well as gold nanoflowers were evaluated side-by-side. To obtain quantitative data at the subcellular and molecular level, we assessed how gold nanoparticles, either alone or in combination with mild hyperthermia, altered the physiology of cultured human breast cancer cells. Our analyses focused on the nucleus, because this organelle is essential for cell survival. We showed that all the examined gold nanoparticles associated with nuclei. However, their biological effects were quantitatively different. Thus, depending on the shape and size, gold nanoparticles changed multiple nuclear parameters. They redistributed stress-sensitive regulators of nuclear biology, altered the nuclear morphology, reorganized nuclear laminae and envelopes, and inhibited nucleolar functions. In particular, gold nanoparticles reduced the de novo biosynthesis of RNA in nucleoli, the subnuclear compartments that produce ribosomes. While small gold nanospheres and nanoflowers, but not big gold nanospheres, damaged the nucleus at normal growth temperature, several of these defects were further exacerbated by mild hyperthermia. Taken together, the toxicity of gold nanoparticles correlated with changes in nuclear organization and function. These results emphasize that the cell nucleus is a prominent target for gold nanoparticles of different morphologies. Moreover, we demonstrated that RNA synthesis in nucleoli provides quantitative information on nuclear damage and cancer cell survival.     

Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method

A 1-step silver-staining technique, requiring only 2 min to perform, is described for the differential staining of nucleolus organizer regions. A protective colloidal developer is used to control the reduction of the silver.     

Colloidal carbon as a multilevel marker for experimental lesions

The use of colloidal carbon for the anatomical marking of experimental lesions is proposed. Visualization of the lesion site may be readily performed through this procedure at the macroscopic, light microscopic, and ultrastructural levels in the same specimen. The chemical inertness of the marker and its relative permanency greatly add to its usefulness.     

Colloidal carbon as a multilevel marker for experimental lesions

Summary The use of colloidal carbon for the anatomical marking of experimental lesions is proposed. Visualization of the lesion site may be readily performed through this procedure at the macroscopic, light microscopic, and ultrastructural levels in the same specimen. The chemical inertness of the marker and its relative permanency greatly add to its usefulness.     

Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method

Summary A 1-step silver-staining technique, requiring only 2 min to perform, is described for the differential staining of nucleolus organizer regions. A protective colloidal developer is used to control the reduction of the silver.This research was supported by the National Science Foundation, grant Nos PCM-76-82828 and DEB-76-84195 to WMH.     

Construction of a thin film PO2-electrode using gold paste

A thin film gold electrode for biological oxygen consumption was constructed using gold paste. This electrode is easy to construct, has high sensitivity and is disturbed only slightly by bubbling of the surrounding fluid. As an application, the electrode was used to measure oxygen consumption of the skin and yielded a reasonable value.     

A relevant in vitro rat model for the evaluation of blood-brain barrier translocation of nanoparticles

Poly(MePEG₂₀₀₀cyanoacrylate-co-hexadecylcyanoacrylate) (PEG-PHDCA) nanoparticles have demonstrated their capacity to reach the rat central nervous system after intravenous injection. For insight into the transport of colloidal systems across the blood-brain barrier (BBB), we developed a relevant in vitro rat BBB model consisting of a coculture of rat brain endothelial cells (RBECs) and rat astrocytes. The RBECs used in our model displayed and retained structural characteristics of brain endothelial cells, such as expression of P-glycoprotein, occludin and ZO-1, and immunofluorescence studies showed the specific localization of occludin and ZO1. The high values of transendothelial electrical resistance and low permeability coefficients of marker molecules demonstrated the functionality of this model. The comparative passage of polyhexadecylcyanoacrylate and PEG-PHDCA nanoparticles through this model was investigated, showing a higher passage of PEGylated nanoparticles, presumably by endocytosis. This result was confirmed by confocal microscopy. Thanks to a good in vitro/in vivo correlation, this rat BBB model will help in understanding the mechanisms of nanoparticle translocation and in designing new types of colloidal carriers as brain delivery systems.Received 4 March 2005; accepted 14 April 2005     

Technical note about simultaneous recording of oxygen partial pressure and neuronal activity in cat cortex.

A method is described for simultaneous measurements of pO2 and action potentials with microelectrodes using prefabricated gold wires. The construction and measuring with such gold electrodes is easier than with traditionally used platinum electrodes. Single electrodes recording is done with a specially adapted electronic circuit, allowing the separation of both signals (pO2 and action potentials. A measurement in cat brain illustrates this procedure.     

Investigating the relationship between gold and silver prices

This paper analyses the long-run relationship between gold and silver prices. The three main questions addressed are: the influence of a large bubble from 1979:9 to 1980:3 on the cointegration relationship, the extent to which by including error-correction terms in a non-linear way we can beat the random walk model out-of-sample, and the existence of a strong simultaneous relationship between the rates of return of gold and silver. Different efficient single-equation estimation techniques are required for each of the three questions and this is explained within a simple bivariate cointegrating system. With monthly data from 1971 to 1990, it is found that cointegration could have occurred during some periods and especially during the bubble and post-bubble periods. However, dummy variables for the intercept of the long-run relationships are needed during the full sample. For the price of gold the non-linear models perform better than the random walk in-sample and out-of-sample. In-sample non-linear models for the price of silver perform better than the random walk but this predictive capacity is lost out-of-sample, mainly due to the structural change that occurs (reduction) in the variance of the out-of-sample models. The in-sample and out-of-sample predictive capacity of the non-linear models is reduced when the variables are in logs. Clear and strong evidence is found for a simultaneous relationship between the rates of return of gold and silver. In the three type of relationships that we have analysed between the prices of gold and silver, the dependence is less out-of-sample, possibly meaning that the two markets are becoming separated. © 1998 John Wiley & Sons, Ltd.     

Construction of a thin film PO 2-electrode using gold paste

Summary A thin film gold electrode for biological oxygen measurement was constructed using gold paste. This electrode is easy to construct, has high sensitivity and is disturbed only slightly by bubbling of the surrounding fluid. As an application, the electrode was used to measure oxygen consumption of the skin and yielded a reasonable value.With leave from the department of gynecology, School of Medicine, Hokkaido University.Glass laboratory.     

Technical note about simultaneous recording of oxygen partial pressure and neuronal activity in cat cortex

Summary A method is described for simultaneous measurements of pO₂ and action potentials with microelectrodes using prefabricated gold wires. The construction and measuring with such gold electrodes is easier than with traditionally used platinum electrodes. Single electrode recording is done with a specially adapted electronic circuit, allowing the separation of both signals (pO₂ and action potentials. A measurement in cat brain illustrates this procedure.     

Fine structrual relation between pancreatic excretory ductules and intercellular spaces.

Horse-radish peroxidase injected into the femoral vein of intact rats, or infused at 30 cm H2o pressure into the main pancreatic duct of intact dogs, entered easily the interstitial spaces surrounding acini and acinar cells. The latter are interconnected at their luminal segments by zonulae occuldentes. These junctions form a barrier to tracer penetrating from the interstituim towards the lumen of terminal ductules. However, the intraductally infused peroxidase entered the interstitial spaces, probably through the pressure injured acinar cells, as did colloidal carbon particles when infused intraductally.     

Fine structural relation between pancreatic excretory ductules and intercellular spaces

Summary Horse-radish peroxidase injected into the femoral vein of intact rats, or infused at 30 cm H₂O pressure into the main pancreatic duct of intact dogs, entered easily the interstitial spaces surrounding acini and acinar cells. The latter are interconnected at their luminal segments by zonulae occludentes. These junctions form a barrier to tracer penetrating from the interstitium towards the lumen of terminal ductules. However, the intraductally infused peroxidase entered the interstitial spaces, probably through the pressure injured acinar cells, as did colloidal carbon particles when infused intraductally.