scholarly journals MICROFLUORIMETRIC STUDIES ON THE FORMALDEHYDE-INDUCED FLUORESCENCE OF NORADRENALINE IN ADRENERGIC NERVES OF RAT IRIS

1969 ◽  
Vol 17 (11) ◽  
pp. 714-723 ◽  
Author(s):  
GÖSTA JONSSON
Keyword(s):  
Fluorescence Intensity ◽  
Linear Part ◽  
Fluorescence Yield ◽  
Histochemical Demonstration ◽  
Adrenergic Nerves ◽  
Noradrenaline Concentration ◽  
Amine Storage ◽  
Rat Iris ◽  
Gaseous Formaldehyde

The fluorescence concentration relationship of formaldehyde-induced fluorescence of noradrenaline in adrenergic nerves of rat iris was investigated by the use of isotope and microfluorimetric techniques. The irides first were depleted of their endogenous stores of noradrenaline either by reserpine or by the methylester of α-methyl- p-tyrosine (H 44/68) and then were incubated in vitro in a physiologic medium containing 3H-noradrenaline for partial replenishment of the nerves of their transmitter. The incubated irides were prepared as whole amounts and were exposed to gaseous formaldehyde for histochemical demonstration of noradrenaline. Microfluorimetric and isotope measurements were performed on the same preparations. The fluorescence intensity was found to be proportional to the noradrenaline concentration up to a value corresponding to 30-40% of the endogenous level, above which a concentration-dependent quenching of the fluorescence occurred. In the linear part of the relation, it was possible to perform fairly safe estimations of the fluorescence intensity by eye, but, if the nerves contained more than 40% of the endogenous content, usually no differentiation could be made, probably as a result of quenching effects. The quenching appears somewhat earlier and the relative fluorescence yield is lower when noradrenaline is stored in the intraneuronal amine storage granules, compared with the situation when the amine mainly is distributed extragranularly in the axoplasm. It can be concluded that, if changes in fluorescence intensity as compared with the control are observed, this reflects true changes in amine concentrations, but changes in amine concentration may escape detection when the concentration of amine is so high that quenching occurs.

scholarly journals ACID CATALYSIS OF THE FORMALDEHYDE CONDENSATION REACTION FOR SENSITIVE HISTOCHEMICAL DEMONSTRATION OF TRYPTAMINES AND 3-METHOXYLATED PHENYLETHYLAMINES

1970 ◽  
Vol 18 (11) ◽  
pp. 794-802 ◽  
Author(s):  
ANDERS BJÖRKLUND ◽  
ULF STENEVI
Keyword(s):  
Acid Catalysis ◽  
Condensation Reaction ◽  
Fluorescence Yield ◽  
Histochemical Demonstration ◽  
Formaldehyde Treatment ◽  
Hcl Gas ◽  
Fluorescent Products ◽  
Acid Catalyzed ◽  
Gaseous Formaldehyde ◽  
Related Compounds

Hydrochloric acid catalyzes the formation of fluorophores in the histochemical condensation reaction between gaseous formaldehyde and certain phenylethylamines and indolylethylamines. Thus, when the formaldehyde reaction is carried out in the presence of minute amounts of HCl gas, 3-methoxy-4-hydroxyphenylethylamine, 3,4-dimethoxyphenylalanine and tryptamine displayed a fluorescence yield approximately 20-200 times higher than that obtained after standard formaldehyde treatment in normal air ( i.e., the conditions of the Falck-Hillarp method). This fluorescence intensity was nearly twice as high as that obtained from noradrenaline and dopamine under the standard conditions. The results indicate that the acid catalyzes the first step of the histochemical reaction, i.e., the Pictet-Spengler condensation reaction. In this step low fluorescent tetrahydroisoquinolines and tetrahydro-β-carbolines are formed, which are subsequently dehydrogenated to strongly fluorescent products. Low reactive aromatic amines and amino acids, such as phenylalanine, tyrosine, amphetamine and melatonin, gave no or only very low visible fluorescence after this treatment. Thus, the acid-catalyzed histochemical formaldehyde reaction described in this paper exhibits a good specificity for indolylethylamines and 3-hydroxylated or 3-methoxylated phenylethylamines and will also allow the distinction between these structurally related compounds on the basis of their reactivity in the condensation reaction.

In Vitro Incorporation of Sodium Acetate-l-C14 into Leukocyte Lipids of Normal and Leukaemic Subjects as a Function of Incubation Time

1962 ◽  
Vol 02 (02) ◽  
pp. 165-172
Author(s):  
C Miras ◽  
G Lewis ◽  
J Mantzos
Keyword(s):  
Sodium Acetate ◽  
Linear Part ◽  
Lipid Synthesis ◽  
Normal Subjects ◽  
Cytostatic Agents ◽  
Time Intervals ◽  
Total Blood ◽  
Effect Of Treatment ◽  
Product Relation

Summary1. Separated leukocytes or total blood from normal subjects, untreated leukaemic patients and from leukaemic patients treated with cytostatic agents were incubated with CH3COONa-l-C14. Radioactivity of mixed lipids was measured at standard time intervals.2. The time incorporation curve observed with leukocytes from treated leukaemic patients showed after an initial linear part, a more rapid levelling off than the curves observed with leukocytes from untreated and normal subjects.3. Therefore, an indirect effect of treatment on leukocyte lipid synthesis seems to be present.4. Phospholipid and neutral lipid synthesis by leukaemic leukocytes was also studied. The results give no evidence that these fractions as a whole have any precursor-product relation.

scholarly journals Effects of tacrolimus on autophagy protein LC3 in puromycin-damaged mouse podocytes

2020 ◽  
Vol 48 (12) ◽  
pp. 030006052097142
Author(s):  
Xiao-qing Yang ◽  
Sheng-you Yu ◽  
Li Yu ◽  
Lin Ge ◽  
Yao Zhang ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Light Chain ◽  
In Vitro Model ◽  
Group Versus ◽  
Podocyte Injury ◽  
Apoptosis Rate ◽  
Protein Levels ◽  
Vitro Model ◽  
Intercellular Connections

Objective To investigate the mechanism through which tacrolimus, often used to treat refractory nephropathy, protects against puromycin-induced podocyte injury. Methods An in vitro model of puromycin-induced podocyte injury was established by dividing podocytes into three groups: controls, puromycin only (PAN group), and puromycin plus tacrolimus (FK506 group). Podocyte morphology, number, apoptosis rate and microtubule associated protein 1 light chain 3 alpha ( LC3) expression were compared. Results Puromycin caused podocyte cell body shrinkage and loose intercellular connections, but podocyte morphology in the FK506 group was similar to controls. The apoptosis rate was lower in the FK506 group versus PAN group. The low level of LC3 mRNA observed in untreated podocytes was decreased by puromycin treatment; however, levels of LC3 mRNA were higher in the FK506 group versus PAN group. Although LC3-I and LC3-II protein levels were decreased by puromycin, levels in the FK506 group were higher than the PAN group. Fewer podocyte autophagosomes were observed in the control and FK506 groups versus the PAN group. Cytoplasmic LC3-related fluorescence intensity was stronger in control and FK506 podocytes versus the PAN group. Conclusions Tacrolimus inhibited puromycin-induced mouse podocyte damage by regulating LC3 expression and enhancing autophagy.

Amitriptyline and imipramine inhibit the release of acetylcholine from parasympathetic nerve terminals in the rat iris

1984 ◽  
Vol 62 (7) ◽  
pp. 857-859 ◽  
Author(s):  
J. S. Richardson ◽  
T. G. Mattio ◽  
E. Giacobini
Keyword(s):  
Nerve Terminals ◽  
Dependent Manner ◽  
Parasympathetic Nerve ◽  
Drug Concentrations ◽  
Release Of Acetylcholine ◽  
Rat Iris ◽  
Anticholinergic Side Effects ◽  
Dose Dependent ◽  
Drug Free

The electrically stimulated release of [3H]acetylcholine from the parasympathetic nerve terminals of the rat iris in vitro is increased in a dose-dependent manner by scopolamine but is decreased by the tricyclic antidepressants amitriptyline and imipramine. The increased release in the presence of scopolamine seems to be due to the blockade of a presynaptic muscarinic autoreceptor that, in the drug-free state, inhibits the release of acetylcholine. However, at drug concentrations that should have comparable antimuscarinic potency, the antidepressants inhibit the release of acetylcholine. This suggests that the anticholinergic side effects of the antidepressants may be due to the reduced release of acetylcholine from parasympathetic nerve terminals as well as a possible direct postsynaptic muscarinic receptor blocking action. Whatever the mechanism of this action, the antidepressants do not have the same effect as scopolamine at the presynaptic muscarinic autoreceptor in the rat iris.

scholarly journals RUBELLA INFECTION OF SYNOVIAL CELLS AND THE RESISTANCE OF CELLS DERIVED FROM PATIENTS WITH RHEUMATOID ARTHRITIS

1970 ◽  
Vol 131 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Arthur I. Grayzel ◽  
Carolyn Beck
Keyword(s):  
Fluorescence Intensity ◽  
Growth Stimulation ◽  
Cell Level ◽  
Pronounced Increase ◽  
Binding Reaction ◽  
Major Histocompatibility Locus ◽  
Histocompatibility Locus ◽  
Protein Moiety ◽  
Mechanism Of Growth

The mechanism of growth stimulation in allogeneic lymphocytes mixed in vitro was studied at the cell level by means of cytophotometric techniques. A pronounced increase in fluorescence intensity of fixed and acridine orange (AO) stained lymphocytes was observed as soon as after 1–3 hr in mixed culture. No increase in the amount of DNA took place during this time. The higher fluorescence intensity was due to an increased accessibility of AO binding sites in the deoxyribonucleoprotein (DNP) complex, most probably as a result of weakened bonds between the DNA and the protein moiety in the DNP complex. Similar DNP changes have been found in other systems of growth stimulation and may be one prerequisite for later induction of cellular synthetic processes. Increased AO binding only occurred when the lymphocyte donors were incompatible at the major histocompatibility locus (HL-A); there was no change in AO binding in cases of HL-A identity. The AO binding reaction probably reflects a specific recognition of HL-A antigens, whereas other antigenic discrepancies between the individuals do not seem to cause an analogous response.

Quantum Dots CdSe/ZnS-Loaded Poly(D,L-Lactide-Co-Glycolide) Nanoparticles: Physicochemical Characterization and Application

2006 ◽  
Vol 505-507 ◽  
pp. 667-672 ◽  
Author(s):  
Chih Hui Yang ◽  
Kuo Chin Lin ◽  
Yu Huai Chang ◽  
Yu Cheng Lin
Keyword(s):  
Quantum Dots ◽  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Uv Light ◽  
Physicochemical Characterization ◽  
Plga Nanoparticles ◽  
Optimum Concentration ◽  
Cellular Internalization ◽  
Optimum Concentration Range

This paper described and characterized the quantum dots (QDs) with/without the polymeric PLGA applied in MC3T3E-1 delivery. Neat QDs were treated with various solvents, temperatures, exposure time and concentration to evaluate their stability and efficacy. We found that the intensity degree of fluorescence spectra (QDs) in different solvents follows the order: ether > THF > acetone > chloroform > methanol. Importantly, the QDs become inactive after 8-hr dissolution in the solvents of ether, THF or chloroform. According to this result, acetone and methanol are ideal solvents for QDs. The optimum concentration range of QDs in acetone is 5 to 10 mg/mL. We found that no obvious difference of fluorescence intensity was detected in QDs stored respectively at 4 °C, 24 °C and 44 °C (8-hour). When QDs were exposed to UV light (312 nm) for 2 hr, serious decay of fluorescence intensity was observed. In order to extend the application of QDs in medical areas, we encapsulated them in individual biocompatible poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles for in-vitro imaging of endocytosis in MC3T3E-1 cells. We demonstrated that the polymeric PLGA have the ability to permeate the cells for cellular internalization; the endocytotic activity could be enhanced by the polymeric QDs-encapsulated PLGA.

scholarly journals Spectrofluorometric determination of nicardipine, nifedipine and isradipine in pharmaceutical preparations and biological fluids

2008 ◽  
Vol 6 (2) ◽  
pp. 222-228 ◽  
Author(s):  
Sheikha Al-Ghannam ◽  
Abeer Al-Olyan
Keyword(s):  
Fluorescence Intensity ◽  
Reaction Pathway ◽  
Biological Fluids ◽  
Sodium Dodecyl ◽  
Pharmaceutical Preparations ◽  
Reduction Reaction ◽  
Factors Affecting ◽  
Plasma And Urine Samples

AbstractA simple and highly sensitive spectrofluorometric method was developed for the determination of some 1,4-dihydropyridine compounds namely, nicardipine, nifedipine and isradipine in pharmaceutical preparations and biological fluids. The method is based on the reduction of nicardipine, nifedipine and isradipine with Zn/HCl and measuring the fluorescence intensity obtained (λem/λex) at 460/364, 450/393 and 446/360 nm, respectively. The factors affecting the development of the fluorophore and its stability were studied and optimized. The effect of some surfactants such as β-cyclodextrin (βCD), carboxymethylcelullose (CMC), sodium dodecyl sulphate (SDS) and triton X-100, on the fluorescence intensity was studied. The fluorescence intensity-concentration plots of nicardipine, nifedipine and isradipine were rectilinear over the ranges 0.4–6.0, 0.2–4.0 and 0.1–9.0 μg ml−1 with detection limits of 0.0028, 0.017 and 0.016 μg ml−1, respectively. The proposed method was successfully applied to commercial tablets containing the compounds; the percentage recovery agreed well with those obtained using the official methods. The method was further extended to the in vitro determination of the compounds in spiked human plasma and urine samples. A proposal of the reduction reaction pathway was postulated.

scholarly journals HISTOCHEMICAL DEMONSTRATION OF PHOSPHOLIPASE B (LYSOLECITHINASE) ACTIVITY IN RAT TISSUES

1966 ◽  
Vol 14 (12) ◽  
pp. 907-914 ◽  
Author(s):  
ATHOS OTTOLENGHI ◽  
JOHN P. PICKETT ◽  
WILLIAM B. GREENE
Keyword(s):  
Fatty Acid ◽  
Incubation Medium ◽  
Copper Ions ◽  
Isotonic Saline ◽  
Histochemical Demonstration ◽  
Interstitial Tissue ◽  
Rat Tissues ◽  
Positive Staining ◽  
Phospholipase B

A method has been developed for the histochemical demonstration of phospholipase B (lysolecithinase) of rat tissues. The enzyme attacks lysolecithin with liberation of 1 mole of glycerylphosphorylcholine and 1 mole of fatty acid. The recommended procedure involves use of 6-10 µ frozen sections, fixed in cold calcium-formol and incubated at 37°C in Tris buffered medium at pH 6.6 containing 2.2 x 10–3 M lysolecithin and 1% cobalt acetate. The fatty acid liberated by enzymatic hydrolysis is trapped as a cobalt precipitate and is then converted to a blackbrown precipitate by treatment with dilute ammonium sulfide in cold isotonic saline. Equivalent amounts of fatty acid and glycerylphosphorylcholine are recovered by extraction and analysis of the incubated sections and of the incubation medium, thus proving that lysolecithin hydrolysis occurs under the proposed reaction conditions. Staining is reduced by treating the sections with copper ions, mercury compounds, alcohols, acetone and by heating at 60°C prior to incubation with substrate. Lowering of the pH of the incubation medium has similar effect. These findings are interpreted as evidence of the enzymatic nature of the reaction. Cells exhibiting a positive staining are found in the lamina propria of the intestinal villi and crypts, in the red pulp of the spleen and in the interstitial tissue of lung, liver and thymus. Similar elements are present in bone marrow smears and in leukocyte preparations obtained by peritoneal lavage. The morphologic and staining characteristics of these cells correspond to those of the eosinophilic leukocytes. Physical and chemical agents (x-irradiation corticosteroids) which sharply decrease the number of eosinophils also reduce the number of cells shown histochemically to hydrolyze lysolecithin. A correspondent. diminution of phospholipase B activity of homogenates of the same tissues can be shown in vitro. Differences in tissue distribution and chemical properties distinguish the phospholipase B from less specific esterases and lipases.

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