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Biomedical subjects

I Lewandowska

Publications and source records attributed to I Lewandowska.

At least 19 recordsLinked to original sources

Several mutations including two novel mutations of the glucose-6-phosphate dehydrogenase gene in Polish G6PD deficient subjects with chronic nonspherocytic hemolytic anemia, acute hemolytic anemia, and favism.

DNA sequencing revealed seven different glucose-6-phosphate dehydrogenase (G6PD) mutations in G6PD deficient subjects from 10 Polish families. Among them we found two novel mutations: 679C-->T (G6PD Radlowo, class 2) and a 1006A-->G (G6PD Torun, class 1). Variant G6PD Radlowo was characterized biochemically. Both novel mutations were analyzed using a model of the tertiary structure of the human enzyme. The main chain of G6PD Torun is different from the wild-type G6PD. The remaining mutations identified by us in deficient Polish patients were: 542A-->T (G6PD Malaga), 1160G-->A (G6PD Beverly Hills), 1178G-->A (G6PD Nashville), 1192G-->A (G6PD Puerto Limon), and 1246G-->A (G6PD Tokyo). Variant Tokyo was found in four families. In one of them favism was the first clinical sign of G6PD deficiency and chronic nonspherocytic hemolytic anemia (CNSHA) was diagnosed later. Variants G6PD Nashville and G6PD Puerto Limon were accompanied by the silent mutation 1311C-->T of the G6PD gene.

Acute Disease↗

Regulation of folate-dependent enzyme levels in Aspergillus nidulans: studies with regulatory mutants.

The synthesis of folate-dependent enzymes in Aspergillus nidulans appears to be regulated by intracellular pools of homocysteine and methionine. The results are consistent with the view that homocysteine acts as an inducer and methionine as a corepressor, but the molecular mechanism of the regulation is still unknown. Methionine-requiring mutants, metH2 and metD10, apparently allelic, show deregulation of folate-dependent enzymes. Most characteristic of the mutants is a repressed level of folylpolyglutamate synthetase. New mutations suppressing the metH2 lesion which render folate enzymes insensitive to methionine-mediated repression have been isolated. These mutations are likely to identify new regulatory genes in folate metabolism.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗

[A method of determining global migration from plastic packing materials into model fluids simulating food products containing fat according to directives of the EWG Commission].

A method is described for determination of global migration into model fluids simulating food products with fat of isooctane, 50% and 96% ethanol from 33 samples of foils and laminates used for food packing. Bag, chamber, immersion and padding methods were used. Most samples complied with the requirements of the EEC Directives and the used method is simple and convenient. It should be introduced promptly for routine control of packing materials in the laboratories of the Province Sanitary-Epidemiological Stations.

Ethanol↗

[A method for determining global migration into model fluids from plastic packaging materials, in accordance with recommendations of the EWG commission].

Samples of polypropylene, polyethylene, polystyrene foils, softened polyvinyl chloride foils and laminates, in which polyethylene or EVA copolymer or SULRYN ionomer formed the inner layer were subjected to tests for determination of the global migration to aqueous fluids using model methods: chamber test, bag test, immersion test and lining test. The tested materials comprised 37 samples of packaging materials. The tested samples were not exceeding the range of permitted global migration into aqueous model fluids as recommended by the EEC directives. The obtained results fell significantly below the accepted limit of 10 mg/dm2.

Food Contamination↗

[Formaldehyde determination in packing paper for food products by the colorimetric method with acetylacetone].

Papers used for food packing were studied for formaldehyde migration from them by the colorimetric method with acetylacetone. The studied material comprised 14 samples of paper of Polish or foreign production: pergamenous paper, offset and sulphite papers and one sample from waste paper imported from Germany. Formaldehyde migration from these samples differed but never exceeded 1 mg/dm2, with the exception of the recycled paper from which it was 1.77 mg/dm2.

Colorimetry↗

[Determination of formaldehyde content in artificial cellulose casings by the colorimetric method with acetylacetone].

Artificial cellulose casings destined for production of processed pork were studied for their ability of formaldehyde release by a colorimetric method with acetylacetone. The studied material comprised 24 samples of colourless imported cellulose casings. The migration of formaldehyde into distilled water under conditions laid down in the BGA regulations (Empfehlung XLIV) was not exceeding 0.5 mg/dm3.

Animals↗

[Determination of unbound formaldehyde in protein coverings using the colorimetric method with chromotropic acid].

In the period 1989-1991 in a control of health quality of packing material and utility objects in contact with food 1964 samples of protein coverings for processed food were analysed, determining the content of formaldehyde, lead, arsenic and copper according to the requirements of Production Standard ZN-76/MPSS-M-19-149. It was found that in about 40% of covering samples formaldehyde level exceeded the acceptable level of 1000 mg/kg. In about 90% of the samples the level of formaldehyde was below 1800 mg/kg. In 14% of the samples the lead level was increased. Arsenic and copper were within normal range in most analysed coverings.

Colorimetry↗

[Examination of plastic food-packaging materials].

The aim of the work was evaluation of the hygienic quality of plastic packaging material and its elements intended for direct contact with food products. The study carried out in the years 1986-1989 comprised 3066 samples taken from 20 provinces. A considerable number of the studied materials had no attest of the State Institute of Hygiene (19.54%). The proportion of samples with such attest accepted as unsuitable was lower than that without attest (unacceptable organoleptic features--4.83%, or results of chemical investigations--2.87%). In some materials high amounts of cadmium and lead were found which suggested that they had been made of technical plastic materials containing unacceptable stabilizers or dyes derived from these metals. The obtained results indicate the necessity of control of plastic materials intended for contact with food products to eliminate these which would have a negative effects on the health.

Cadmium↗

[Determining acebutolol level in the blood serum].

A simple method for isolation of acebutolol from blood serum, and conditions of thin-layer chromatography for detection of this drug in blood are reported. An own colorimetric method has been developed for the determination of acebutolol after its isolation and hydrolysis in the medium of sulphuric acid. Results of the determinations were subjected to statistical analysis. The methods were elaborated using model samples prepared by addition of the acebutolol working standard to blood serum. Sensitivity of the acebutolol detection by thin-layer chromatography under elaborated conditions proved to reach the level of 0.5 microgram.

Acebutolol↗

Effect of prolonged acetylcholinesterase inhibition on postnatal brain development in rabbit. I. Level of serotonin in different brain regions.

Studies were performed on young rabbits treated with dichlorvos (organophosphorus pesticide) 9 mg/kg/day by oral gavage. Pesticide was given for 10 days starting on the 6th day of life or as a single dose on the 16th day of life. Animals were sacrificed 30 min, 3 und 24 h after treatment. The spinal cord and the brain were removed and 6 regions (neocortex, hippocampus, basal ganglia, mesencephalon, brain stem, cerebellum) were isolated. Acethylcholinesterase activity was estimated by biochemical and histochemical methods. The concentration of serotonin in brain regions was determined. Acute and prolonged intoxication with dichlorvos inhibited acethylcholinesterase activity. As revealed the histochemical studies, single dose decreased activity of enzyme mainly in neuropil. Prolonged intoxication decreased the acethylcholinesterase in neuropil and in neurons. The single dose of dichlorvos caused the increase of serotonin concentration in all brain regions. After prolonged intoxication the decrease of serotonin concentration in brain stem, mesencephalon and hippocampus for 78, 74, 41% respectively was observed. The cholinergic-serotonergic link is discussed.

Acetylcholinesterase↗