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K Hult

Publications and source records attributed to K Hult.

65 records · Page 4Linked to original sources
PubMed1978

Ochratoxin A as the cause of spontaneous nephropathy in fattening pigs.

At a number of slaughters nephropathy and high ochratoxin A contents in kidneys have been observed in fattening pigs from two Swedish farms. In one herd the source of contamination was barley grown on the home farm and stored under such conditions that the growth of fungal species (Penicillium verrucosum var. verrucosum) producing ochratoxin A occurred, with the subsequent formation of the toxin. In this case high ochratoxin A levels in fattening pigs were found during a period of about 18 months. In the second herd, where compounded feed was used, it was impossible to locate the source of contamination. It was presumed that a consignment of feed was damaged by rain during storage at the farm. Ochratoxin A was found in fattening pigs from this herd for a period of about 2 months. Ochratoxin A appeared in the kidneys of all investigated pigs. In some animals the livers, whole blood, and plasma were analyzed, too. The livers contained somewhat lower amounts of ochratoxin A than the kidneys, whereas the content in whole blood and plasma, respectively, was 5 and 13 times greater. Kidneys spontaneously contaminated with ochratoxin A, when stored for 10 months at -70 degrees C, showed no systematic decrease in toxin content.

Animal Feed↗
PubMed1977

Analysis of ochratoxin B alone and in the presence of ochratoxin A, using carboxypeptidase A.

A method is described for ochratoxin B analysis, which is adapted to the earlier described method of ochratoxin A analysis, using carboxypeptidase A (K. Hult and S. Gatenbeck, J. Assoc. Off. Anal. Chem. 59:128-129, 1976). The fluorescence spectra of ochratoxins A and B coincide too much to allow direct discrimination of the two compounds. A method using the differences in kinetic parameters of the enzymatic hydrolysis of the two compounds is suggested for the analysis of mixtures of the ochratoxins.

Carboxypeptidases↗
PubMed1976

Degradation of ochratoxin A by a ruminant.

The fate of ochratoxin A during incubation with contents from the four stomachs of the cow was studied. It was concluded that ochratoxin A was cleaved into the nontoxic ochratoxin alpha and phenylalanine by the contents from all but the abomasum.

Animals↗
PubMed1976

Regulation and metabolic background of polyketide formation. I. Effects of (-)-hydroxycitrate and metabolic roles of citrate and malate in fatty acid and polyketide formations.

The effects of (-)-hydroxycitrate on fatty acid and alternariol syntheses from glucose and acetate in Alternaria alternata were investigated. Fatty acid synthesis from glucose and acetate was inhibited by (-)-hydroxycitrate. The inhibition could partly be removed by the addition of malate or isocitrate. Alternariol synthesis from glucose was also inhibited by (-)-hydroxycitrate. This inhibition was not influenced to the same extent by malate addition as was that of fatty acid synthesis. It is shown that ATP -citrate lyase is essential not only for the production of cytoplasmic acetyl-CoA but also for the production of NADPH by supplying malate via oxaloacetate.

Acetates↗
PubMed1976

A spectrophotometric procedure, using carboxypeptidase A, for the quantitative measurement of ochratoxin A.

In the method described, ochratoxin A is eleaved into ochratoxin alpha (free isocoumarin chromophore) and phenylaline, using carboxypeptidase. Detection is based on the difference in fluorescence excitation spectra of ochratoxin A (380 NM, maximum) and ochratoxin alpha (340 nm, maximum). The quantitation of ochratoxin A is based on the loss of fluorescence intensity at 380 nm. The method has been used for the quantitative determination of as little as 4 mug ochratoxin A/kg barley and barley meal but it could be extended to other products.

Carboxypeptidases↗
PubMedDate not supplied

Plasma ochratoxin A levels in three Swedish populations surveyed using an ion-pair HPLC technique.

A new HPLC method for the analysis of ochratoxin A in plasma samples is described. The analysis is performed at an alkaline pH using an ion-pair technique, fluorescence detection at an excitation wavelength 380 nm, and an emission wavelength 420 nm. The detection and quantification limits are 0.02 ng and 0.05 ng ochratoxin A/ml plasma, respectively. The method was used to determine the ochratoxin A content of human plasma samples, collected in three districts of Sweden. The Visby district had a significantly higher proportion of ochratoxin A positive samples and higher levels than the other two districts--Uppsala and Ostersund. The calculated daily intake of ochratoxin A in the Visby district (0.35 ng/kg body weight), exceeds the lower tolerable daily intake (TDI) value suggested by Kuiper-Goodman and Scott (1989). The calculated daily intake by the population on the mainland of Sweden (0.04 ng/kg body weight) is below the proposed TDIs.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Ochratoxin A occurrence in slaughter-pigs in Sweden and its use as a tool for feed screening programs.

The occurrence of ochratoxin A in pig blood can be used as a measure of ochratoxin A contamination of the feed. A method for ochratoxin A analysis in pig blood, suitable for screening programs, is presented. The relationship between ochratoxin A contents in the blood of pigs and the feed given is investigated with feeding experiments. Blood samples from pigs originating from 279 herds slaughtered in nine slaughter-houses in Sweden were analyzed for ochratoxin A. In total, 14% of the investigated pigs contained greater than or equal to 2 ng ochratoxin A per ml blood. The highest level found was 215 ng/mL. Correlations between the occurrence of ochratoxin A in the blood and parameters concerning the feed are investigated.

Abattoirs↗
PubMedDate not supplied

Human exposure to ochratoxin A in areas of Yugoslavia with endemic nephropathy.

Ochratoxin A is a mycotoxin with pronounced nephrotoxic potency in all species of single-stomach animals studied; it is a major disease determinant of porcine nephropathy and a disease occurring endemically in several countries. This disease is comparable with Balkan (endemic) nephropathy, suggesting a common causal relationship. Ochratoxin A has been found in foodstuffs in many countries, but the highest frequency of ochratoxin A contamination in foods (10.3% of 1,553 samples of foodstuffs) was encountered in an area of Yugoslavia, where Balkan (endemic) nephropathy is prevalent. Detection of ochratoxin A in human blood samples confirmed the prevalent exposure to this food contaminant. Relative risk calculations indicated a tendency to an association between this mycotoxin and Balkan (endemic) nephropathy, supporting the hypothesis of a causal role of ochratoxin A in this disease.

Balkan Nephropathy↗
PubMedDate not supplied

Ochratoxin A in blood of slaughter pigs.

The global ochratoxin A contamination of Swedish feed cereals was studied by analysis of pig blood samples from 122 different herds. The samples were collected at seven Swedish slaughterhouses. The ochratoxin A analysis showed 21% of the samples to contain greater than or equal to 2 ng ochratoxin A per ml. Samples from Visby showed a significantly higher frequency of contamination compared with the rest of the country.

Abattoirs↗
PubMedDate not supplied

Ochratoxin A in cow's milk and in human milk with corresponding human blood samples.

A method for determining ochratoxin A in milk has been elaborated in which the sample was subjected to a liquid-liquid extraction step and then purified on a silica gel column packed in a Pasteur pipet. The purified samples were analyzed by ion-pair liquid chromatography with fluorescence detection. The detection and quantitation limits for determination of ochratoxin A in cow's milk were 10 and 40 ng ochratoxin A/L milk, respectively. The same limits were valid for the analysis of human milk. A total of 36 cow's milk and 40 human milk samples were analyzed. All samples were collected in Sweden. Ochratoxin A was found in 5 (14%) of the cow's milk samples (range 10-40 ng/mL) and in 23 (58%) of the human milk samples (range 10-40 ng/L). Blood samples were collected from the mothers who gave milk samples. A total of 39 samples were analyzed. All blood samples contained ochratoxin A in concentrations exceeding the quantitation limit (60 ng/L blood). The mean concentration of ochratoxin A in the samples was 167 ng/L blood (range 90-940 ng/L). The concentration of ochratoxin A in human milk was < or = 0.1 of that in the human blood.

Animals↗