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A J Baars

Publications and source records attributed to A J Baars.

11 recordsLinked to original sources
PubMed1992

[Lead poisoning in cattle in Northern Netherlands. Follow-up study of 2 farms].

The after-effects of a serious lead intoxication were studied. This intoxication was caused by contaminated feed. Calves and cows of two dairy farms were examined up to half a year after the incident with the contaminated feed in October 1989. Clinical signs were observed and blood samples were taken. Blood parameters like zinc-protoporphyrin (ZPP), haemoglobin, RBC, WBC, MCV, haematocrit, MCHC, and the blood lead levels were analysed. Cattle of one of the most afflicted farms showed severe effects of lead intoxication: blindness, muscle twitching and hyperirritability. Two animals died. Forty percent of the affected cows had to be slaughtered. The ZPP levels in calves of this farm were still elevated after six months. The zinc-protoporphyrin level in blood seemed to coincide better with the clinical signs than the blood lead level. Animals with less than 3 mg ZPP/l RBC showed no irreversible effects of the lead intoxication. It is suggested that ZPP could be a useful predictor for the after-effects of lead intoxication.

Animals↗
PubMed1992

Increased metallothionein in the liver and kidney of patients with amyotrophic lateral sclerosis.

To evaluate the putative role of metals and trace elements in the pathogenesis of classic amyotrophic lateral sclerosis, we studied the metallothionein levels in liver and kidney samples obtained at autopsy from 24 patients with amyotrophic lateral sclerosis and 18 controls. To assay metallothioneins and copper, cadmium, and zinc bound to metallothioneins, we used high-performance liquid chromatography directly coupled to flame atomic absorption spectrometry. Total cadmium, zinc, and copper concentrations were determined separately with the use of graphite furnace atomic absorption spectrometry with Zeeman background correction. The median liver metallothionein level was 60.3 mg/kg (range, 9 to 318 mg/kg) in the patients with amyotrophic lateral sclerosis and 12.6 mg/kg (range, 0 to 104.5 mg/kg) in the controls. In the kidney, median metallothionein levels were 126.9 mg/kg (range, 44 to 387 mg/kg) in the patients with amyotrophic lateral sclerosis and 64 mg/kg (range, 13.1 to 187 mg/kg) in the controls. Total zinc, cadmium, and copper concentrations, as measured by atomic absorption spectrometry, were not significantly different in patients vs controls. Our finding of elevated metallothionein levels in organs from patients with amyotrophic lateral sclerosis may indicate an increased exposure to metals.

Adolescent↗
PubMed1979

Xenobiotica-metabolizing enzymes in Drosophila melanogaster: activities of epoxide hydratase and glutathione S-transferase compared with similar activities in rat liver.

Activities of epoxide hydratase and glutathione (GSH) S-transferase were investigated in subcellular fractions of Drosophila melanogaster, and these activities were compared with analogous enzymic activities in extracts from rat liver. Microsomes of Drosophila were active in the hydratation of styrene oxide catalyzed by epoxide hydratase. The post-microsomal supernatant of Drosophila catalyzed the conjugation of GSH with 1-chloro-2,4-dinitrobenzene. However, GSH S-transferase activity with styrene oxide as the electrophilic substrate was not measurable. The respective specific activities of epoxide hydratase (per mg microsomal protein) and GSH S-transferase (per mg cytosolic protein) were factors of 5- and 10-fold lower than the corresponding activities in rat liver. However, when expressed per gram body weight, activities of both epoxide hydratase and GSH S-transferase were 3 times higher for Drosophila enzymes. The apparent Km values for the two Drosophila enzymes were higher, whereas the apparent Km values were lower, than the values found for the rat-liver enzymes. Among 3 different Drosophila strains (a wild-type, a white eye-color carrying mutant strain and a DDT-resistant strain), preliminary experiments showed no differences as far as these two enzymic activities were concerned. It is concluded that the results obtained in genetic toxicology testing with Drosophila are probably relevant to effects to be expected in mammalian systems with compounds requiring metabolic processes involving the enzymes investigated here.

Animals↗
PubMedDate not supplied

Lead intoxication in cattle: a case report.

During the autumn of 1989 a feed contamination induced a widespread lead intoxication of cattle in the northern provinces of The Netherlands (Groningen and Friesland). Over 300 farms were involved, affecting about 15,500 animals (mostly dairy cattle). For a period of one to four weeks these animals took up a thousand kg of lead. This resulted in lead levels in milk, livers, and kidneys above the regulatory safety limits. Due to the chelating therapy, which was rapidly applied by the local veterinarians, only about 30 animals died of an acute lead intoxication. A joint action of the governmental and private authorities prevented exposure of consumers to lead-contaminated animal products. Based on observations, measurements and literature data, predictions were made of the lead levels to be expected in animal products and the time needed for depletion of these levels. The appropriate animals were ear-tagged to ensure their identification, and the decline in time of the lead levels in milk and offals was conscientiously monitored. In the second week of 1990 the lead concentrations were decreased to levels well below the regulatory limits, and hence the tags were removed. The present paper reports our observations and conclusions, especially regarding treatment, predictions and outcome of this incident.

Animal Feed↗