Diamine Dihydrochloride Research Articles

Toxoplasma gondii Prevents Neuron Degeneration by Interferon-γ-Activated Microglia in a Mechanism Involving Inhibition of Inducible Nitric Oxide Synthase and Transforming Growth Factor-β1 Production by Infected Microglia

Interferon (IFN)-gamma, the main cytokine responsible for immunological defense against Toxoplasma gondii, is essential in all infected tissues, including the central nervous system. However, IFN-gamma-activated microglia may cause tissue injury through production of toxic metabolites such as nitric oxide (NO), a potent inducer of central nervous system pathologies related to inflammatory neuronal disturbances. Despite potential NO toxicity, neurodegeneration is not commonly found during chronic T. gondii infection. In this study, we describe decreased NO production by IFN-gamma-activated microglial cells infected by T. gondii. This effect involved strong inhibition of iNOS expression in IFN-gamma-activated, infected microglia but not in uninfected neighboring cells. The inhibition of NO production and iNOS expression were parallel with recovery of neurite outgrowth when neurons were co-cultured with T. gondii-infected, IFN-gamma-activated microglia. In the presence of transforming growth factor (TGF)-beta1-neutralizing antibodies, the beneficial effect of the parasite on neurons was abrogated, and NO production reverted to levels similar to IFN-gamma-activated uninfected co-cultures. In addition, we observed Smad-2 nuclear translocation, a hallmark of TGF-beta1 downstream signaling, in infected microglial cultures, emphasizing an autocrine effect restricted to infected cells. Together, these data may explain a neuropreservation pattern observed during immunocompetent host infection that is dependent on T. gondii-triggered TGF-beta1 secretion by infected microglia.

Quantitation of tolnaftate by spectrophotometric methods in pharmaceutical formulations

Two selective spectrophotometric methods are described for the assay of tolnaftate in single and​/or combined pharmaceutical formulations. The first one depends on the formation of a methylene blue dye (λmax 665 nm) by the reaction of N,​N-​di-​Me p-​phenylene diamine dihydrochloride in the presence of ceric ammonium sulfate with sodium sulfide resulting from the alk. hydrolysis of the thiono ester-​tolnaftate. All variables affecting hydrolysis of tolnaftate were studied. Also other parameters affecting the color development as sulfuric acid and reagent concns., reaction time, temp. and diln. solvents were optimized. The second method depends on the simultaneous estn. of tolnaftate and clioquinol in the presence of gentamycin sulfate and betamethasone by the measurement of the first deriv. spectrum in

Role of melanoidins in sweet wines

Melanoidins from several Spanish sweet wines were isolated by dialysis. Browning indexes (absorbances at 420 and 345 nm) and CIELab parameters of the wines and their dialysed fractions were measured. The antioxidant activity, which was expressed as Trolox equivalent antioxidant activity (TEAC), was determined using the N, N-dimethylphenylene diamine dihydrochloride (DMPD) method. Results showed a good correlation of colour parameters L ∗, h ∗ and absorbances at 345 and 420 nm between the dialysed fractions and the original sweet wines. However, the TEAC of dialysed fractions did not show any significant correlation with TEAC of the original wines. So brown polymers of high molecular weight (>12000 Da) isolated by dialysis, which could be mainly melanoidins, play an important role on the colour of these sweet wines, but not in their antioxidant activity.

SPECTROPHOTOMETRIC DETERMINATION OF NITRITE AFTER PRECONCENTRATION ON AN SDS COATED ALUMUN COLUMN

Determination of traces of nitrite in water samples is of importance. In the present work sulfanilic acid, as the diazotizable and N-(1-naphtyl) ethylene diamine dihydrochloride, as the coupling agent, were added to nitrite sample to form the azo dye. The azo dye was collected on the sodium dodecyl sulphate coated alumina column and eluted with 7 mL HCL:CH3COOH (2:3).The absorbance of the effluent was measured spectrophotometrically at 553 nm. The calibration graph was linear in the range 0.4–24 ng mL−1 and the preconcentration factor was 70. The detection limit (3 σ) for 500 mL of sample solution was 0.173 ng mL−1 and the relative standard deviation for six replicate determinations of 10 ng mL−1 nitrite was calculated to be 0.36%. The interferences from various ions were investigated and the effects of interfering ions were removed by using the appropriate masking agents. The method has also been extended to the simultaneous determination of nitrite and nitrate by using cadmium–copper reductor column to convert nitrate to nitrite.

Improvement of a monitoring tape for nitrogen dioxide in air

A porous cellulose tape containing a silica gel that was previously impregnated with a processing solution containing p-toluenesulfonic acid, sulfanilic acid, N-1-naphthyl ethylene diamine dihydrochloride, ethylene glycol and methanol has been developed to provide a highly sensitive detection of nitrogen dioxide in air. When the sample including nitrogen dioxide was passed through the tape, the color of tape changed to red, and the degree of color change could be recorded by measuring the intensity of reflecting light (555 nm). The calibration graph was linear up to ∼0.10 ppm. The detection limit was 0.5 ppb for nitrogen dioxide with a sampling time of 8 min and a flow rate of 60 ml min −1. No interferences were observed from ammonia (40 ppm), sulfur dioxide (51 ppm), carbon dioxide (21%), ozone (0.75 ppm), hydrogen sulfide (27 ppm) or nitrogen monoxide (99 ppm).

Solid-Phase Extraction and Spectrophotometric Determination of Iodate in Table Salt after Azo Dye Formation

Abstract A new reaction for determining iodate in table salt is proposed. It is based on oxidation of phenylhy-drazine-4-sulfonic acid by iodate in acidic medium to the 4-diazobenzenesulfonic acid cation and its electrophilic coupling with N-(1-naphthyl)ethylene- diamine dihydrochloride to give an azo dye, which is measured spectrophotometrically at 545 nm. Maximum molar absorptivity was 8.41 ×104 L/mol cm. A rectilinear calibration graph was obtained for iodate in the range 0.25–5 mg/L. The azo dye could be preconcentrated at least 40-fold by solid-phase extraction on C18 sorbent. The limit of detection was 0.6 μg iodate/L. The method was used to determine iodate in laboratory-prepared and commercially available table salt samples. Up to 5 mg bromate/kg and 10 mg iron(lll)/kg in table salt did not interfere.

Spectrophotometric determination of azathioprine in pharmaceutical formulations

Four simple and sensitive visible spectrophotometric methods (A–D) have been described for the assay of azathioprine (ATP) either in pure form or in pharmaceutical formulations. Methods A and B are based on the oxidation of ATP with excess N-bromosuccinimide (NBS) or chloramine-T (CAT) and determining the consumed NBS or CAT with a decrease in colour intensity of celestine blue (CB) (method A) or gallocyanine (GC) (method B), respectively. Methods C and D are based on the diazotisation of reduced azathioprine (RATP) with excess nitrous acid and estimating either the consumed nitrous acid (HNO 2) with cresyl fast violet acetate (CFVA) (method C) or by coupling reaction of the diazonium salt formed with N-1-naphthyl ethylene diamine dihydrochloride (NED) (method D). All of the variables have been optimized and the reactions presented. The concentration measurements are reproducible within a relative standard deviation of 1.0%. Recoveries are 99.2–100.3%.

Synthesis of a tritium labelled analog of the novel hematoregulatory agent SB 209978

[3H]SB 209978 (10) was synthesized in 6 steps from phenylene diamine dihydrochloride. A key aspect was the regioselective synthesis of 6-chloropicolinic acid (7). This was condensed with diamine 6 and the resulting product was deprotected to give 9. Palladium catalyzed 3H-hydrogenolysis of the chloropyridine rings gave the final product 10. © John Wiley & Sons, Ltd.

Dibenzoyl Methane—A New Coupling Agent for Nitrite Determination

Abstract Dibenzoyl methane is introduced as a new coupling agent for the determination of nitrogen dioxide in air and for nitrite in water and soil samples. Nitrogen dioxide is fixed as nitrite in NaOH–sodium arsenite trapping solution and also in triethanoamine trapping solution. The method is based on the diazo coupling reaction of p-nitro aniline with a new coupling agent, dibenzoyl methane. The azo dye formed under aqueous alkaline condition has an absorption maximum at 520 nm and obeys Beer’s law over a range of 0–20 μg nitrite per 10 ml analyte. The dye formed is stable for 40 h. The relative standard deviation is 2.8% for 10 determinations at 10 μg nitrite per 10 ml analyte. The color system upon extraction with isobutyl methyl ketone–amyl alcohol (1+1) shows a λ max at 520 nm and a Beer’s law range of 0–4 μg nitrite. The developed color is stable for 7 h in the organic phase. The relative standard deviation is 3.0% for 10 determinations at 2 μg nitrite. The molar extinction coefficient of the color system is 3.6 × 104 L/(mol·cm). The effect of interfering gases and ions on the determination is described. The method was applied to the determination of residual amounts of nitrogen dioxide present in the laboratory fume cupboard and in automobile exhaust gas. The method was also applied to the determination of nitrite and nitrate in water and soil samples. The results obtained were compared with the standard sulfanilamide–NEDA (N-1 naphthyl ethylene diamine dihydrochloride) method. The method can be used to determine levels as low as 0.5 μg nitrite in aqueous medium and 0.1 μg nitrite upon extraction.

Colorimetric methods for the assay of nomifensine maleate

Two colorimetric methods are reported for the assay of nomifensine maleate. The methods are based on the coupling between the diazotised form of nomifensine maleate and (i) N-(1-naphthyl)-ethylene diamine dihydrochloride (Bratton—Marshall reagent) and (ii) p-aminosalicylic acid (PAS). The optimum conditions for the reactions were investigated. The coupled products exhibit maximum absorbance at 470 and 435 nm for the Bratton—Marshall and PAS reagents, respectively. With PAS, a linear relationship has been established between absorbance ( A max) and concentration of nomefensine maleate over the range 2–12 μg ml −1. Similarly, with the Bratton—Marshall reagent, a linear relationship exists in the concentration range 2–16 μg ml −1. The calculated mean percent recoveries for nomifensine maleate in the commercial capsules (Merital® 25 mg) using the Bratton—Marshall and PAS reagents were 97.53 ± 0.71 and 100.28 ± 1.32, respectively. Similarly, for the added recoveries, the percentage obtained were 99.01 ± 0.46 and 100.03 ± 1.03, respectively.

Synthesis of 3H‐labelled levamisole

AbstractLevamisole, the levo isomer of tetramisole, is a potent anthelmintic also showing immunotropic properties. Renewed interest in the latter domain necessitated the synthesis of specifically 3H‐labelled levamisole of high specific activity.Racemic 1‐(2‐bromophenyl)‐1,2‐ethane diamine dihydrochloride (V) was obtained via bromination of 1‐(2‐bromophenyl)ethanone (I), followed by reaction with 2,5‐pyrrolidinedione, Leuckart amination and hydrolysis. The racemate was then resolved by successive salt formation with (S)‐(‐) and (R)‐(+) tartaric acid. The liberated (S)‐(+)‐base of VI was dehalogerated with approximately 30 Ci of tritium gas and immediately ring‐closed with carbon disulfide to VIII. The HPLC‐purified material was finally cyclized with 1,2‐dibromo ethane to (S)‐(‐)‐2,3,5,6‐tetrahydro‐6‐[2‐T]phenyl‐imidazo‐(2,1‐b)‐thiazole IX and the isomerically ringclosed (S)‐2,3,5,6‐tetrahydro‐5‐[2‐T] phenyl‐imidazo‐(2,1‐b)‐thiazole X, of which levamisole IX was isolated via HPLC. The radiochemical yield over the cyclization steps was 28.2 %, the specific activity was 10.82 Ci/mmol, and the product was 99.9 % HPLC pure.

The cyclization of N,N′‐bis[2‐(dialkoxy)ethyl]‐p‐xylene‐α,α′‐diamine dihydrochloride to pyrido[3,4‐g]isoquinoline and 3,8‐phenanthroline

AbstractThe ring closure of N,N′‐bis[2‐(dialkoxy)ethyl]‐p‐xylene‐α,α′‐diamine dihydrochloride in fuming sulfuric acid has been investigated and the cyclization products have been identified as the linear pyrido[3,4‐g]isoquinoline as well as the previously reported angular 3,8‐phenanthroline.

On The Analysis of Procaine Hydrochloride By Diazotisation and Coupling Reaction

Abstract N-(1-naphthyl) ethylene diamine dihydrochloride, thymol, α-naphthol and β-naphthol are used as coupling agents for the determination of diazotised procaine hydrochloride in pure form and in pharmaceutical preparations. All the experimental conditions have been adjusted, the effect of interferring substances, sensitivity and the validity of the procedure have been studied.

Conversion of ethylene diamine dihydrochloride into ethylenediamine by electrodialytic water-splitting

The feasibility of water-splitting electrodialysis for the conversion of polyammonium salts into the corresponding amines and acids was demonstrated with the conversion of ethylenediamine dihydrochloride as an example. Two- and three-compartment cells were compared and their current efficiencies ascertained. The former was relatively low in current efficiency, with a roughly linear increase with conversion. The three-compartment cell operated at more than 80% current efficiency over most of the conversion range, with a voltage drop of 2·7 V per repeating unit at 400 Am−2 and 25° C.

On the Saltzman factor

The nitrite equivalent of nitrogen dioxide in its determination in polluted air by means of a Griess type reagent is commonly called the Saltzman factor. Values ranging from 0.5 to 1.000 have been reported, but discussion about the 'right' value continues. The results of experimental calculations are presented to demonstrate that there is no set right value, but that it depends on circumstances and may be more or less chosen at will. No explanation was found for the differences reported. The results are summarized, and illustrate that the Saltzman factor is not a constant, but is inversely related to NO production and varies according to the expectations based on the expounded reaction mechanisms. In practice, a method with a high and therefore more constant factor would be recommended, such as the use of sulfanilamide instead of sulfanilic acid and a NEDA (naphthylethylene diamine dihydrochloride) concentration as low as possible without decreasing the collection efficiency too much with the air flow rate and washing bottle. Chemicals/CAS: nitrogen dioxide, 10102-44-0

Prosthecae of Asticcacaulis biprosthecum: system for the study of membrane transport

Prosthecae removed from cells of Asticcacaulis biprosthecum were examined for their ability to accumulate proline, alanine, aspartate, glutamate, and glucose against a concentration gradient. The transport of all of these compounds into prosthecae was stimulated by the nonphysiological electron donors phenazine methosulfate and N,N,N',N'-tetramethyl-p-phenylene diamine dihydrochloride. Reduced pyridine nucleotides caused very slight stimulation of transport of proline and glucose. Other physiological electron donors did not stimulate uptake. Evidence is presented indicating that the failure of certain potential electron donors to drive respiratory chain-linked transport is due to the inabilityof these compounds to enter prosthecae rather than to the absence of enzymes for their oxidation in prosthecae. Inhibition of respiration and uncouplers of oxidative phosphorylation, with the exception of arsenate, inhibit active transport systems of prosthecae.

Evaluation of chromogens suitable for occult blood in faeces

The effect of normal diet, medicinal iron on O-tolidine, guiacum, dichlorophenol-indophenol, dimethyl naphthidine, phenolphthalein, N, N-dimethyl- p-phenylenediamine-monohydrochloride, and tetra-methyl- p-phenylene diamine dihydrochloride which can be used for occult blood testing in faeces are discussed. A normal diet was found to give false positives with all techniques, the guiacum and dimethyl naphthidine techniques being least affected. Oral iron gave a false positive with all chromogens except dimethyl naphthidine unless ether extraction was used. The sensitivity of the chromogens can be easily adjusted to suit individual requirements. The dimethyl naphthidine test-tube technique is recommended for routine use or the guiacum filter paper technique for side room testing.

Synthesis of Guanidine Compounds by the Cyanamide Condensation Method I. Preparation of Ethylenediguanidine and Tetramethylenediguanidine. (Studies on some derivatives of calcium cyanamide. XI)

Abstract (1) Ethylenediguanidine- and tetramethylenediguanidine dihydrochloride were prepared by the reaction of 3 mols of cyanamide with 1 mol of corresponding diamine dihydrochloride in fused state at about 140°C. The yield was about 100% of the theory. (2) The dihydrochlorides were purified by the extraction with acetone which dissolved dicyandiamide. (3) The method for preparing free diguanidines in crystal form is described. (4) Various salts of these diguanidines were prepared from dihydrochlorides and free diguanidines and the melting point and other properties of these salts are also described.