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At least 757 records · Page 42Linked to original sources
PubMed1982

Location on chitin in the cyst wall of Entamoeba invadens with colloidal gold tracers.

Chitin was located in the cyst wall of Entamoeba invadens with colloidal gold-linked wheat germ agglutinin. Cysts stained differentially from trophozoites when encysting cultures were treated with the gold tracer; cysts acquired a wine-red coloration while, in general trophozoites remained unstained. Observation of cells with the electron microscope revealed that the tracer particles were bound specifically to the walls of the surface of the cyst when cells were exposed in suspension, and to the cyst wall cross-section, when cells were exposed to the tracer in thin section, indicating that chitin fibers were distributed on the surface as well as throughout the matrix of the cyst wall.

Animals↗
PubMed1995

Characterisation of the neurosensory elements of the feline cranial cruciate ligament.

The identification and distribution of mechanoreceptors in the cranial cruciate ligament of the cat (analogous to the anterior cruciate ligament in other species) was studied histologically using a modified celloidin embedding technique to achieve serial sectioning of bone-ligament-bone preparations with gold chloride staining. We identified distinctive large elongated structures situated between the collagen bundles of the ligament (resembling endings described as Freeman and Wyke type III; also termed Golgi tendon receptors). These endings were found near the middle of the ligament well away from the bone-ligament junction. Axons seen entering only one end of each type III ending helped to confirm its neural basis. While we saw structures resembling types I and II endings (i.e. Ruffini and pacinian endings, respectively) in individual sections, serial sections failed to reveal convincing evidence of their existence. Such structures almost always appeared to be vascular in nature on adjacent sections, with vessels entering and exiting. We conclude that serial sections are critical to interpreting the presence or absence of mechanoreceptors.

Animals↗
PubMed1994

A method for selective radiolabeling of lung endothelium plasmalemmal vesicles, in situ.

Albumin-gold complex (Alb-Au) was previously shown to bind selectively to plasmalemmal vesicles of capillary endothelium. Based on these findings, as well as on the ability of lactoperoxidase (LPO) to mediate the radioiodination of proteins, we have prepared a complex of gold particles bearing both albumin and anionized lactoperoxidase (Alb-Au-aLPO). The complex had a pI of 5.8, largely preserved aLPO enzymatic activity (approximately 74%), and was able to catalyze protein radioiodination. Upon washing out the blood, the complex was perfused in the mouse lung, the excess tracer removed, and a Na125I/H2O2 solution was introduced in the vasculature. After extensive washing, lung fragments were processed for either electron microscopy (EM), or to prepare a membrane-enriched fraction. In control experiments, lungs were perfused with native LPO (pI 9.3), or with a LPO-Affi Gel conjugate and further radioiodinated as described for Alb-Au-aLPO. By EM, it was found that both in tissue and in the isolated membrane fraction, only Alb-Au-aLPO labeled markedly and preferentially some uncoated pits and most plasmalemmal vesicles. Analysis by SDS-PAGE and autoradiography of a membrane-enriched fraction prepared from lungs perfused with Alb-Au-aLPO had some major identified 125I-labeled polypeptides of apparent molecular masses of 16, 18, 31, 36, 55, and 77 kDa. A different subset of polypeptides was labeled in lungs perfused with LPO, whereas after administration of LPO-Affi Gel the major radiolabeled polypeptides had a molecular mass of 33, 55 kDa and several peptides in the range of 77 to 160 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Electron microscopic demonstration of transcription of ram sperm chromatin.

Transcription of ram sperm chromatin was examined by two electron microscopic techniques, namely spreading and thin sections. Labelling by Streptavidin-gold particles permits identification of transcription complexes, that have previously incorporated biotinylated uridine triphosphate. This supports previous electron microscopic data for randomly distributed transcription complexes and the presence of polymerase II molecules, documented by means of specific antibody using immunoelectron microscopy. Labelling of transcripts with biotin permits exact visualization of the transcription process, as well as identification of regions, where transcription occurs.

Adenosine Triphosphate↗
PubMed1995

[Crystalline and molecular structure of the K+-complex of meso-valinomycin, cyclo(-(D-Val-L-Hyi-L-Val-D-Hyi)3-).KAuCl4].

Crystal structure of the complex of meso-valinomycin with KAuCl4 (C60H102N6O18KAuCl4) was determined using direct X-ray diffraction analysis. The conformational state of the complex is similar to that determined earlier for free meso-valinomycin. Characteristic of it is the centrosymmetric bracelet shape stabilized by six intramolecular NH...OC hydrogen bonds of 4 --> 1 type. The K+ ion is located in an inner negatively charged octahedral cavity formed by six carbonyl oxygen atoms of ester groups. The observed differences in conformational angles of the complex and free are caused by readjustment of the geometry of the ion-binding cavity to the size of the ion bound during complexation.

Amino Acid Sequence↗
PubMed1996

Sonochemical formation of gold particles in aqueous solution.

Gold(III) ions in aqueous solutions of NaAuCl4 were reduced to form gold particles by ultrasonic irradiation. The rate of formation of gold particles was accelerated in the presence of certain organic additives such as surfactants, water-soluble polymers and aliphatic alcohols and ketones. The rates of formation of gold particles from 1 mM Au(III) ions in pure water were 3 microM min-1 under argon atmosphere and approximately zero under air, and in solutions containing additive the rates were 9-133 microM min-1 under argon and 8-40 microM min-1 under air. Surfactants stabilized the particles as colloidal state for more than several months. The rates of formation of both hydrogen atoms and hydroxyl radicals were estimated to be equal to 25 microM min-1 in the sonolysis of pure water under argon. Three reaction pathways leading to the reduction of metal ions were proposed: (1) reduction by hydrogen atoms; (2) reduction by reducing radicals formed via reactions of hydroxyl radicals or hydrogen atoms with the additives; (3) reduction by radicals formed from thermal reaction of the additives at the interfacial region between cavitation bubbles and bulk solution and/or in the cavities. The order of the contribution of these three pathways to the reduction of gold ions was (3) > (2) > (1) in most cases. The number averages of the size of gold particles formed in surfactant solutions under argon atmosphere were about 10 nm with a fairly narrow size distribution.

Argon↗
PubMed1996

Effect of amniotic fluid in corneal sensitivity and nerve regeneration after excimer laser ablation.

To examine the effect of topical application amniotic fluids on the recovery of corneal sensitivity and nerve regeneration after excimer laser photokeratectomy, excimer laser was applied to 18 rabbits (VISX 20/20, 5 Hz, 7 microns depth: nine rabbits; 100 microns depth: nine rabbits). Human amniotic fluid (AF) was topically applied to the right eyes (AF group), and a balanced salt solution (BSS) was applied to the left eyes (BSS group). Corneal sensitivity was measured by using a Cochet-Bonnet aesthesiometer after weeks 1, 2, 4, 5, 8, and 12. Nerve-regeneration status was evaluated after weeks 2, 4, 5, 8, and 12 by gold chloride staining. Corneal sensitivity was initially subnormal and recovered close to the normal level at week 8. The sensitivity was higher in the AF group than in the BSS control group, except at week 2. Subepithelial nerve regeneration at the laser site was detected both at week 4 in the AF group and at week 5 in the BSS group. There was no significant correlation between the nerve-regeneration state and sensitivity changes. Long striated nerve regeneration from the deep stromal nerve was remarkable at the third month, especially in the BSS group. The BSS group showed more marked scarring of the superficial stroma, compared with the AF group. The nerve regeneration at the scar site was discontinued and delayed. Subepithelial leash nerves in the AF group were more abundant than those in the BSS group. The recovery of sensitivity and nerve regeneration were faster in the AF cornea than in the BSS cornea. These results suggest that the factors in AF helped the recovery of corneal sensitivity, nerve regeneration, and reduced scar formation.

Administration, Topical↗
PubMed1997

Sensitive in situ hybridization with catalyzed reporter deposition, streptavidin-Nanogold, and silver acetate autometallography: detection of single-copy human papillomavirus.

The usefulness of standard in situ hybridization for viral nucleic acid detection is occasionally limited by its sensitivity limit of 10 to 50 copies per cell. A modified version of the recently described signal amplification method, catalyzed reporter deposition (CARD), and its application to formalin-fixed cells and tissue sections is presented. Deposition of the reporter is facilitated by using horseradish peroxidase catalyzing the deposition of biotinylated tyramide on the location of the probe target. The biotin accumulation created is usually detected with streptavidin-labeled enzymes or fluorochromes. In the present investigation, this step was replaced by streptavidin-Nanogold and combined with silver acetate autometallography. This resulted in deep-black precipitation at positive in situ hybridized reaction sites. The sensitivity of this new approach was tested with a biotinylated, genomic probe specific for human papillomavirus (HPV)-16/18. SiHa cells, a cervical carcinoma-derived cell line with one to two HPV16 copies per cell, and 10 histologically confirmed cervical carcinomas were used for the study. All samples were previously HPV16 positive with solution polymerase chain reaction, but only two of the cervical carcinomas were positive with standard in situ hybridization with barely visible signals. When employing CARD-Nanogold, SiHa cells and 9 of 10 biopsies proved positive with marked signals. It is concluded that this nonisotopic method can detect single viral copies in situ in routinely fixed material and may have the potential to replace in situ polymerase chain reaction in many applications.

Acetates↗
PubMed1996

Neural structures within the sheep temporomandibular joint.

To better understand pathologic processes associated with arthritis of the temporomandibular joint (TMJ), detailed information on the innervation of TMJ tissues in normal as well as arthritic joints is needed. The aim of this study was to describe the normal innervation of the sheep TMJ in preparation for using this animal as a model for the study of the effects of arthritis on joint innervation. The macroscopic and microscopic appearance plus the distribution of neural structures within the TMJ were examined using fluorescence histochemistry (glyoxylic acid), immunohistochemistry (calcitonin gene-related peptide), silver, and gold chloride techniques. Joints from 10 mature merino sheep were studied. Calcitonin gene-related peptide-immunoreactive nerve fibers were found in the capsule and the synovial membrane, but not in the disc. Nerve bundles and single nerve fibers in the capsule, synovial membrane, and the peripheral 2 to 3 mm of the disc were stained by glyoxylic acid. Ruffini, paciniform-type, and Golgi organ nerve endings plus free nerve endings were located in the capsule, with the highest density of nerve endings occurring at the site of attachment of the disc to the capsule. The highest density of neural structures (using gold chloride) was in the posterior part of the joint. The highest density of autonomic fibers (using glyoxylic acid) was in the anterior capsule. The highest density of sensory fibers (using calcitonin gene-related peptide) was in the synovial and subsynovial tissues of the anterior capsule. These results confirm the existence of autonomic and sensory nerves in the capsule, synovial membrane, and peripheral disc in healthy adult sheep.

Animals↗
PubMedDate not supplied

Commonly used disease-modifying antirheumatic drugs in the treatment of inflammatory arthritis: an update on mechanisms of action.

Although disease-modifying drugs are extensively used in the treatment of inflammatory arthritides such as rheumatoid arthritis (RA), the actual underlying mechanisms of action of these agents remains somewhat unclear. Many investigators have studied the effects of these agents, often with particular attention being paid to alterations in inflammatory cytokine production, cell proliferation and activation, signal transduction pathways, and enzyme inhibition. By gaining a more complete understanding of these mechanisms, further information may be had regarding the pathophysiology of RA as well as other autoimmune diseases. In the following review we will examine some of the more recent studies of drug mechanisms, focusing on the most commonly used anti-rheumatic medications in the treatment of RA.

Antirheumatic Agents↗