Photochemical and photocatalytic degradation of 1-propanol using UV/H2 O2 : Identification of malonate as byproduct.

1-propanol is a primary alcohol extensively used in the pharmaceutical, chemical, and food industries. It has been also found as a contaminant in the atmosphere and is considered a model compound to mimic the behavior and fate of aliphatic alcohols exposed to environmental conditions. In order to understand that role of relevant variables, this paper presents results obtained with a simple experimental set-up to investigate the reactivity of 1-propanol under mild oxidizing conditions. Coupling this system with CE-C4 D allowed the quantification of the carboxylic acids formed. For the described experiments, aqueous solutions of 1-propanol were placed inside a photoreactor and oxidized upon the addition of TiO2 and/or H2 O2 . According to the described results, the addition of H2 O2 (0.1% w/w) was the most significant variable, roughly tripled the amount of carboxylic acids generated and led to the conversion of up to 70% of the initially available 1-propanol (1 mmol/L). More importantly, the reaction yielded the formation (within 10 min) of propionate (50 µmol/L), acetate (400 µmol/L), formate (50 µmol/L), and malonate (200 µmol/L). The latter is critically important because it represents the first example of the photochemical oxidation of both terminal carbons of the C3 -chain of 1-propanol under mild conditions, and opens new avenues for the production of this important chemical building block.

[Endotheliotropic effects of venotonic drugs in treatment of patients with varicose veins]. / Éndoteliotropnye éffekty venotoniziruiushchikh preparatov pri lechenii bol'nykh s varikoznoi bolezn'iu.

The authors analysed the effect of Venarus on the endothelial function in patients suffering from lower limb varicose veins. Our open-label prospective study included a total of 100 patients diagnosed as having CEAP class C1-C2 varicose veins and divided into two equal groups. Dynamic assessment of the clinical course of the disease in Group One patients was carried out on the background of taking Venarus and compression therapy, with Group Two patients evaluated without taking Venarus. At defined stages we determined the level of biochemical markers of endothelial function. The obtained findings demonstrated that the use of phlebotonic Venarus resulted in decreased activity of lipid peroxidation processes and reduced activity of antioxidant system enzymes. Using Venarus was followed by a statistically significant decrease in the concentration of malonic dialdehyde (from 1.220±0.190 µmol/l at baseline to 0.858±0.231 µmol/l after 2 months of treatment), whereas in Group Two patients the changes were insignificant (1.191±0.204 µmol/l before treatment and 1.138±0.175 µmol/l at 2 months thereafter). Patients taking Venarus were also found to have a higher level of nitric oxide metabolites compared with the patients treated by compression therapy alone (51.646±11.757 and 36.310±6.921 µmol/l in Groups One and Two, respectively). Hence, an evidence-based conclusion was drawn that Venarus proved efficient and may therefore be prescribed as pharmacotherapy for correction of endothelial dysfunction.

Response to medical and a novel dietary treatment in newborn screen identified patients with ethylmalonic encephalopathy.

Ethylmalonic encephalopathy (EE) is a devastating neurodegenerative disease caused by mutations in the ETHE1 gene critical for hydrogen sulfide (H2S) detoxification. Patients present in infancy with hypotonia, developmental delay, diarrhea, orthostatic acrocyanosis and petechiae. Biochemical findings include elevated C4, C5 acylcarnitines and lactic and ethylmalonic acid (EMA) in body fluids. Current treatment modalities include metronidazole and N-acetylcysteine (NAC) to lower the production and promote detoxification of toxic H2S. Patients are typically identified after the onset of clinical symptoms and there is limited information about long term response to treatment. We report the findings of two unrelated patients with EE, identified through newborn screening, who were managed with conventional treatment (NAC, metronidazole alternated with neomycin) and in patient 2, a novel dietary treatment restricting sulfur containing amino acids. Pathogenic mutations were confirmed in the ETHE1 gene (homozygous splice site mutation in patient 1, c.505 + 1G > A; compound heterozygous mutations in patient 2, c.131_132delAG + c.566delG). Both patients were started on metronidazole and NAC by 10 weeks of age and treated for 23 months. Patient 1 did not accept the metabolic formula due to palatability and parental refusal for gastrostomy tube placement. She demonstrated improved biomarkers (EMA, lactic acid and thiosulfate) and an attenuated clinical course. Patient 2 was started on a low methionine and cysteine diet at 8 months of age utilizing SOD Anamix® Early Years, (Nutricia). Baseline EMA levels were (642 mg/g Cr; n = 2) and decreased with medical treatment by 38% to a mean of 399 (n = 4, SD = 71, p 0.0013). With dietary treatment EMA levels were further reduced by 42% to a mean of 233 (n = 8, SD = 52, p 0.0030). Lactic acid, thiosulfates and clinical outcomes were also improved. Our long-term follow-up confirms previous reports of clinical improvement with NAC and metronidazole treatment. Additionally, our studies suggest that a diet restricted in sulfur-containing amino acids results in further improvement in clinical outcomes and biochemical markers.

Subpicogram determination of malondialdehyde by gas-liquid chromatography with nitrogen phosphorus detector. I. Standardization.

A method for the measurement of malondialdehyde (MDA) using GLC with a nitrogen phosphorus detector (GLC/NPD) is described and evaluated. The method uses 2-hydrazinobenzothiazole (HBT) which forms condensation derivatives with MDA, acetoacetaldehyde, and acetylacetone (AA). GC/MS and 13C NMR studies of the three derivatives obtained showed that they are 2-(pyrazol-1'-yl)benzothiazoles and that they can be separated by GLC/NPD. Any one of these derivatives can be used as an internal standard for the measurement of the other two. The optimal conditions for the measurement of MDA were studied. At pH 2.5 and 70 degrees C, the condensation derivative is quantitatively formed in 30 min. Its extraction is obtained by a mixture of n-hexane/isoamyl alcohol 98/2 (v/v) containing HBT-AA as internal standard. The GLC detection limit is 0.04 pmol. Inter- and intrassay coefficients of variation were 2.9 and an average of 4.0%, respectively. The method is specific, and there was no interference from other carbonyl compounds. The artifactual formation of MDA from carbohydrates during the derivatization reaction is negligible. The method is proposed as a reference method for the standardization of working solutions of MDA or MDA-generating solutions.

Analysis of free malondialdehyde in photoirradiated corn oil and beef fat via a pyrazole derivative.

Malondialdehyde (MA) formed in linolenic acid, linoleic acid, corn oil and beef fat upon photoirradiation was determined by gas chromatography (GC). The MA produced was reacted with methylhydrazine to give 1-methylpyrazole and was subsequently analyzed on a GC equipped with a nitrogen-phosphorus specific detector and a fused silica capillary column. MA values determined by this method correspond to free or unbound MA levels. Linolenic and linoleic acids produced 867 micrograms MA/g and 106 micrograms MA/g, respectively. Oleic and stearic acids did not produce detectable levels of MA upon photoirradiation. Amounts of MA produced after eight hour irradiations of corn oil and beef fat were 56.24 micrograms/g and 25.01 micrograms/g, respectively. Some photoreaction products in irradiated corn oil also were identified as methylhydrazine derivatives.

Hydroxyl-radical-induced iron-catalysed degradation of 2-deoxyribose. Quantitative determination of malondialdehyde.

The degradation of 2-deoxyribose to thiobarbituric acid-reactive material was investigated with two hydroxyl-radical-generating systems: (i) a defined gamma-radiolysis method and (ii) incubation with FeSO4 in phosphate buffer. In each case the thiobarbituric acid-reactive material can be accounted for by malondialdehyde, as measured by an h.p.l.c. method for free malondialdehyde. In the radiolysis system there is a large post-irradiation increase in free malondialdehyde if iron ions are added to the samples. It is proposed that this is due to iron ions catalysing the formation of hydroxyl radicals from radiolytically generated H2O2 as well as stimulating the breakdown of an intermediate deoxyribose degradation product. A mechanism for the formation of malondialdehyde during deoxyribose degradation is proposed.

Penetration of malonic dialdehyde on filtration of tobacco smoke.

It has been found that malonic dialdehyde penetrates through the filters of cigarettes. The filter cigarettes, such as "Club", "F6", "Cabinet", "Semper" and "Kenton" as well as non-filter cigarettes, namely "Salem", "Real" and "Karo" generate malonic dialdehyde during smoking, in amounts ranging from 15.6 to 44.3 mg/kg, i.e. from 20.4 to 44.3 mg/kg for cigarettes with filters and from 15.6 to 27.1 mg/kg for non-filter cigarettes.

Quantitation of methylmalonic acid and other dicarboxylic acids in normal serum and urine using capillary gas chromatography-mass spectrometry.

Methylmalonic acid, succinic acid, and other dicarboxylic acids have been extracted and partially purified from serum and urine using ether extraction and high-performance liquid chromatography. The t-butyldimethylsilyl derivatives were prepared and analyzed using capillary gas chromatography-mass spectrometry with selected ion monitoring. The addition of [methyl-2H3]methylmalonic acid and [1,4-13C2]succinic acid to the starting samples made it possible to quantitate these two dicarboxylic acids. Normal ranges for methylmalonic acid and succinic acid were determined in human and rat serum and in human urine. The utilization of other internal standards would make it possible to quantitate malonic, dimethylmalonic, ethylmalonic, methylsuccinic, glutaric, and other dicarboxylic acids.

Malonaldehyde in cervical mucus associated with copper IUD.

PIP: Malonaldehyde was measured by a colorimetric assay in the cervical mucus specimens of 19 women wearing copper IUDs and 21 women wearing inert IUDs to determine the relationship between copper biochemistry and the potential production of this potential carcinogen. Malonaldehyde was detected in 8 of the 19 specimens from women fitted with copper IUDs but in none of the inert IUD group specimens. The concentrations of the component varied, but were generally in the range of 100 nmol/gm. Based on certain assumptions about the bioreactivity of malonaldehyde, it was estimated that the daily production rate of malonaldehyde associated with copper IUD is from .1-.9 mcmol (7-93 mcg) (this is the cervical rate measurement). Though malonaldehyde is associated with pelvic inflammatory exudates, it is concluded that since the epithelium of the uterus is shed monthly during menstruation, it is unlikely that malonaldehyde associated with the copper IUD is harmful; rather it may have something to do with the copper IUDs' mechanism of action.^ieng

Microassay for primidone and its metabolites phenylethylmalondiamide, phenobarbital and p-hydroxyphenobarbital in human serum, saliva, breast milk and tissues by gas chromatography--mass spectrometry using selected ion monitoring.

A method for the quantitative determination of primidone and its metabolites phenobarbital, phenylethylmalondiamide (PEMA) and hydroxyphenobarbital (free and conjugated) in serum, urine, saliva, breast milk and tissue has been developed. Following the addition of the methyl analogues of primidone, phenobarbital and PEMA as internal standards and of saturated ammonium sulphate, the samples (5--100 microliter) were extracted twice with ethyl acetate--benzene (20:80). The extracts were divided into two equal portions; one portion was ethylated by Greeley's method for the analysis of primidone, phenobarbital and hydroxy-phenobarbital, while the other was trimethylsilylated for the analysis of primidone and PEMA. A gas chromatographic--mass spectrometric system was used for the analysis of the derivatized extracts. Linear calibration curves were obtained in the concentration range studied (between 100 ng/ml and 30 microgram/ml). The recoveries of the drugs were between 80 and 93%. The relative standard deviations were between 3.2 and 5.9% (100-microliter serum samples containing 1 microgram/ml of the drugs). The lower detection limits were found to be between 1.4 and 3.7 ng/ml using serum samples of 100 microliter. These methods have been applied to the study of the placental transfer and neonatal disposition of primidone and its metabolites in the human.

[Metabolism of lipid peroxidation products in multiple sclerosis patients]. / Osobennosti obmena produktov perekisnogo okisleniia lipidov u bol'nykh rasseiannym sklerozom.

Concentration of dienic conjugates and malonic dialdehyde (metabolites of lipid peroxidation) were examined in the blood and the cerebrospinal liquor of patients suffering from disseminated sclerosis, CNS tumours complicated with neurological pathology, and osteochondrosis with the secondary radical syndrome at D4--D5 and D5--S1 levels. In patients with disseminated sclerosis no malonic dialdehyde was found in the cerebrospinal liquor, while its blood level exceeded normal 1.5 to 2 times. After hormonal therapy the situation was found to be reverse: malonic dialdehyde appeared in the cerebrospinal liquor, while its serum level dropped. This is, probably, due to a stabilization of the process and a fall of the concentrations of antioxidants in the liquor. An experiment with direct determination of the antioxidant activity in the liquor confirmed the hypothesis on migration of antioxidants from myelin to the liquor during process exacerbation. Since in cases of CNS tumours (contrary to disseminated sclerosis) malonic dialdehyde is regularly present in the cerebrospinal liquor, a test is suggested for diagnostic differentiation between atypic forms of disseminated sclerosis and CNS tumours.