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Biomedical subjects

R Eckard

Publications and source records attributed to R Eckard.

12 recordsLinked to original sources
PubMed1994

Effects of pentachlorophenol (PCP) on the pituitary and thyroidal hormone regulation in the rat.

Investigations on rats after repeated application of pentachlorophenol (PCP) should clarify whether thyroid side effects caused by this xenobiotic can be seen in a dose range which does not cause major toxic effects. Female rats of the Wistar strain were treated with 3 and 30 mg PCP/kg body wt. daily by gavage for 28 days. To assess the potential impact of impurities the study was performed both with pure and technical grade PCP at the dosage of 3 mg.kg-1.day-1, and at a level of 30 mg.kg-1.day-1 with pure PCP only. The effects in animals on normal iodine diet were compared to those in animals on a low iodine diet. No decrease of body wt. was noticed, only the liver weights were increased slightly in animals treated with 30 mg.kg-1.day-1 PCP. However distinct effects on thyroid hormones as well as on thyrotropin (TSH) were observed: a pronounced fall of circulating thyroxine (T4) and triiodothyronine (T3) levels was accompanied by lower levels of both free thyroid hormones and TSH, and the T4:T3 ratio was decreased in serum. Furthermore the intrathyroidal hormone stores were reduced. An interference of PCP at pituitary or hypothalamic level is assumed as a major mode of action. Additional effects of the test substance on peripheral conversion can be suspected.

Administration, Oral↗
PubMed1993

Environmental specimen banking and poisons control--a new challenge.

Today clinical toxicology and poisons control are widely lacking objective criteria, e.g., analytical data, figures of kinetics and metabolism in acute and chronic poisoning. Co-operation between clinical toxicology and an environmental specimen bank for human tissue will help to overcome many difficulties and complement one another. The possible power of such a co-operation is demonstrated by the example of the institutions in Münster, Germany. The successful strategies used for setting-up an environmental specimen bank for human tissue may also be applied in clinical toxicology and experimental toxicology. The frame of a university medical clinic seems to be the ideal basis of an effective co-operation of an Environmental Specimen Bank for Human Tissue, a Poisons Control Centre and clinical toxicology. In general a co-operation of an environmental specimen bank for human tissue and a poisons control centre will be cost-saving and beneficial to both and an environmental specimen bank for human tissue will gain the status of a unique tool for risk assessment of xenobiotics.

Animals↗
PubMed1992

Pharmacokinetics of vinyldithiins, transformation products of allicin.

The pharmacokinetic behaviour of vinyldithiins, the main constituents of oily preparations of garlic (Allium sativum L.), was investigated after oral administration of 27 mg 2-vinyl-4H-1,3-dithiin and 9 mg 3-vinyl-4H-1,2-dithiin to rats. In serum, kidney, and fat tissue, both vinyldithiins could be detected by GC-MS over a period of 24 h, whereas in liver only 1,3-vinyldithiin was found. Pharmacokinetic parameters (t1/2, ke, Cltot, AUC, and Vd) were determined using compartment models, elucidating the different pharmacokinetic behaviour of both vinyldithiins. 1,3-Vinyldithiin seems to be less lipophilic and is rapidly eliminated from serum, kidney, and fat tissue, whereas 1,2-vinyldithiin is more lipophilic and shows a tendency to accumulate in fat tissue. Experiments with liver homogenate confirmed the in vivo findings on the different degradation rates of both vinyldithiins. Allicin, the precursor of the vinyldithiins, is metabolized more rapidly in liver homogenate than the vinyldithiins.

Adipose Tissue↗
PubMed1992

Metabolism of garlic constituents in the isolated perfused rat liver.

The metabolic and kinetic behaviour of different garlic (Allium sativum L., Alliaceae) constituents were investigated in the isolated perfused rat liver, using aqueous extracts of garlic powder as well as isolated allicin, the main product of the enzymatic degradation of alliin. Allicin (allyl thiosulfinate) showed a remarkable first pass effect and passed the liver unmetabolized only at high concentrations which caused considerable cell injuries. Diallyl disulfide and allyl mercaptan were identified as metabolites of allicin, whereby diallyl disulfide probably is the metabolic precursor of allyl mercaptan as shown by perfusion with diallyl disulfide alone. The metabolites diallyl disulfide and allyl mercaptan could be determined in the perfusion medium as well as in the bile and the liver tissue. Other degradation products of garlic were also investigated in this model. Ajoenes and vinyldithiins were detected in perfusion medium after liver passage but no metabolites of them could be identified up to now.

Animals↗
PubMed1991

Influence of color on odor identification and liking ratings.

The effects of color on odor identification were tested under color appropriate, inappropriate, and blindfolded conditions. Subjects made fewer errors in identifying solutions that were colored appropriately (e.g., red-cherry) than in either the blindfolded condition, where there were no color cues, or the inappropriate color condition (e.g., red-lemon). Identification accuracy was greatest for typical odor-color combinations (e.g., red-cherry) compared with appropriate but nontypical odor-color combinations (e.g., red-watermelon). Response latencies were fastest for odors in the appropriately colored solutions. Subjects also rated appropriate color-odor combinations as most pleasant. However, this effect is probably due to the increase in identification accuracy of the appropriately colored solutions. In all three conditions, correctly identified odors were liked more than odors that were not correctly identified. Thus, color is an important perceptual variable in odor identification because it biases subjects toward a color category that facilitates identification if the color is "correct". This ability to identify an odor in turn influences the affective response to the odor.

Adult↗
PubMed1986

[Expansion behavior of intravitreous sulfur hexafluoride in exposure to nitrous oxide].

In experiments with 19 rabbits the changes in volume and concentration of intravitreously instilled sulfur hexafluoride were investigated under normal air conditions (10 rabbits in group A) and with application of laughing, gas to the inspiration system for 3 hours (9 rabbits in group B). Under normal air conditions the SF6 gas bubble attained its greatest volume after 24 hours (twice its initial volume). With the addition of 67% laughing gas to the inspiration system the largest expansion in volume (260%) was found after 3 hours, i.e., at the end of application of laughing gas, and was followed by another peak after 24 hours. With regard to the sulfur hexafluoride concentration in the gas bubble, the results in the two groups were similar. The authors conclude that in retinal surgery with application of sulfur hexafluoride general anesthesia should not include laughing gas.

Animals↗
PubMed1985

Pharmacokinetics of bencyclane after single dose administration to healthy volunteers.

The pharmacokinetics of bencyclane were studied in 4 healthy volunteers. In a randomized cross-over design, 35 and 70 mg of bencyclane were infused intravenously and 71 and 143 mg were given orally as a solution in water. After intravenous application bencyclane is distributed very rapidly into tissues (t1/2 approx. 7 min). The volume of distribution is about 600 l. In almost every subject the plasma levels rose again after this distribution phase. Bencyclane is eliminated mainly by metabolism. At the most 3% of the dose is excreted as unchanged drug in the urine. Total clearance is appr. 44 l/h, the elimination half-life approx. 12 h. Oral bioavailability ranges between 18 and 84%.

Adult↗
PubMed1980

Ultrastructural morphometric investigations on rat liver of young and adult rats after treatment with technical pentachlorophenol (PCP).

Age-dependent effects of technical pentachlorophenol (PCP) on male rat livers were investigated after a 15 day treatment with PCP, 30 mg/kg/d body weight. The liver tissues were investigated morphometrically at light and electron microscopical levels. Statistically significant alterations of nuclei and organelles of the hepatocytes were described.

Adipose Tissue↗
PubMed1979

Identification of S-(carboxymethyl)-L-cysteine and thiodiglycolic acid, urinary metabolites of 2,2'-bis-(chloroethyl)-ether in the rat.

S-(carboxymethyl)-L-cysteine (CMC) and thiodiglycollic acid (TGA) were identified by gas chromatographic-mass spectrometric measurements in the urine of rats after intraperitoneal injections of 2,2'-bis-(chloroethyl)-ether (BCEE). It is therefore probable that BCEE is O-dealkylated by a mixed-function oxidation. The hepatocarcinogenic effect of BCEE may be explained by the liberation of chloroacetaldehyde in vivo.

Animals↗
PubMedDate not supplied

[Disorder of the blood-brain barrier caused by mannitol poisoning in an infant with encephalotoxicosis].

The clinical course of a mannitol intoxication in a 5-month-old infant is reported. Mannitol measurements were performed by gas-chromatographic-mass-spectrometric analysis. The role of the osmolal gap as a simple diagnostic tool in mannitol intoxication was underlined by comparison to serum mannitol levels. Mannitol elimination was analysed by measuring mannitol levels in urine, ultrafiltrate, and peritoneal dialysis outflow. The highest concentrations were found in urine (approx. 300% serum values) and the lowest in peritoneal dialysis outflow (approx. 50% serum levels). "Total body Mannitol" was calculated each day from body weight, hydration, and serum mannitol levels and opposed to the amount eliminated via urine, ultrafiltration, and peritoneal dialysis. The results were only compatible with a volume of distribution of approx. 5.3 1, representing total body water at a lean body weight of 7 kg. It could thus be demonstrated that the sudden fall of serum mannitol levels from 19.6 mg/ml to 5.5 mg/ml without dialysis treatment in an anuric patient was due to a leak of mannitol into the intracellular compartment.

Acute Kidney Injury↗