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Biomedical subjects

E Richter

Publications and source records attributed to E Richter.

At least 271 records · Page 15Linked to original sources
PubMed1982

Effects of dietary paraffin, squalane and sucrose polyester on residue disposition and elimination of hexachlorobenzene in rats.

Previous studies have shown addition of light liquid paraffin to enhance the elimination of organochlorine xenobiotics. In the present study the effect of paraffin on the elimination of [14C]hexachlorobenzene (HCB) was compared with the effect of possible alternative compounds, squalane and sucrose polyester (SPE). Four groups of 7 rats were fed a diet containing 1.5 ppm [14C]HCB for 4 days followed by 10 days on HCB-free diet. Thereafter one group (control) remained on this diet whereas the other 3 groups received a diet supplemented with 8% (w/w) paraffin, squalane or SPE, respectively. Radioactivity in urine and faeces was measured daily and at the end of the experiment in samples of abdominal fat, muscle, liver, kidney and blood. Dietary treatment with either paraffin, squalane or SPE markedly enhanced faecal excretion of [14C]HCB, whereas urinary excretion was not affected. Both the time course as well as the extent of faecal [14C]HCB elimination were similar in the treated groups. After 3 weeks of treatment the amount of [14C]HCB excreted with faeces was about three times higher in treated animals than in controls. The half-life (t1/2) of [14C]HCB elimination from the body was markedly decreased in treated animals (mean 34--38 days) compared to controls (110 days). [14C]HCB concentrations in some major tissues were significantly reduced to the same extent by all three dietary regimens. Thus squalane and SPE are as effective as paraffin in removing HCB from contaminated animals.

Adipose Tissue↗
PubMed1982

Iron absorption during the development of hexachlorobenzene-induced porphyria in rats.

The absorption of iron [59Fe-(FeSO4)] from jejunal loops was studied in rats after acute and subacute exposure to hexachlorobenzene (HCB). Female rats were given orally 100 mg HCB/kg body weight or fed a diet with 0, 500, 1,000, or 2,000 parts/10(6) HCB for 1 and 4 weeks. Male rats were fed on diets with 0 and 2,000 parts/10(6) HCB only. An increase in total urinary porphyrins and a decrease in the ratio of coproporphyrin to uroporphyrin in individual 24-h urine samples indicated different stages of porphyria in the rats at the time of determination of iron absorption. After acute oral administration of HCB, iron absorption decreased to about 70% of control values. After feeding the animals on HCB-containing diets, relative liver weight as well as total plasma protein increased depending on time and dose. The absorption of iron was not altered after 1 week of HCB exposure. After 4 weeks, the uptake of iron into the carcass decreased to less than 40% of control values, independently of dose and sex. The uptake of iron into the liver, expressed as percentage of the amount absorbed by the intestine, decreased significantly after 1 and 4 weeks of HCB feeding. No correlation could be observed between iron metabolism and urinary porphyrin excretion. The development of HCB-induced porphyria in rats is apparently not accelerated by an increased iron absorption.

Acute Disease↗
PubMed1982

Effect of squalane on hexachlorobenzene (HCB) concentrations in tissues of mice.

Female mice were given 100 mg HCB/kg body weight i.p. and fed diets containing 0, 2.5, 5.0, and 7.5% of squalane. After 3 weeks samples of liver, blood and abdominal fat were analysed for HCB as well as for squalane. HCB concentrations were significantly lowered as compared to controls in all tissues and at all dietary concentrations of squalane to a maximum of about 36% in fat, 44% in liver and 47% in blood. The effect of squalane upon HCB concentrations was strongly dose dependent in abdominal fat. In contrast, no significant differences were seen with liver and blood between animals fed 5.0 or 7.5% of squalane. Squalane was detected in considerable amounts in the livers (50-100 ppm) but not in abdominal fat (less than 1 ppm) of mice fed squalane.

Adipose Tissue↗
PubMed1982

[Investigations about late effects of exclusive radiotherapy of tumors of the epipharynx].

The late effects of ionizing radiation after radiotherapeutic healing of malignant tumors are of great interest. A report is given on sixteen patients with a malignant tumor of the epipharynx, who had been exclusively treated by radiotherapy and are regarded as cured. Only four of these patients had no complaints when examined, the others presented symptoms which were partly due to radiotherapy. The most important symptoms were rhinitis sicca and pharyngitis sicca induced by radiation. The complaints now indicated by the patients and the results of thorough clinical examinations are discussed and compared to communications of literature.

Humans↗
PubMed1982

Renal bile acid excretion as a cause of neoplastic lesions in the urinary tract after total portacaval shunt in the normal rat?

Rats with a total portacaval anastomosis (PCA, PC-SS) develop preneoplastic and neoplastic lesions in the urinary tract. In contrast to this, animals with a modified shunt (mPCA) do not develop these lesions. To evaluate the possible role of bile acids excreted with the urine for tumor development, total plasma bile acid concentration and 24 hours urinary bile acid excretion were measured radioimmunologically in rats with total and modified shunts. Additionally the renal 14C-glycocholic acid excretion into the urine was studied after oral administration. Total plasma BA increased from 4.89 +/- 1.0 mumol/l in sham-operated controls to 77.7 +/- 39 mumol/h in PCA and 52.9 +/- 36.7 mumol/l in mPCA rats (p less than 0.001 vs controls, PCA vs mPCA = n.s.). Urinary bile acid excretion rose from 0.2 +/- 0.29 mumol/24 hours in controls to 4.47 +/- 4.49 in PCA and 2.55 +/- 2.22 mumol/24 hours in mPCA rats (p less than 0.001 vs control; PCA vs mPCA = n.s.) 14C-glycocholic acid was excreted within 24 hours into the urine in 13.6 +/- 11.5% in PCA and 26.3 +/- 23.5% of the administered dose in mPCA-rats (controls; 2.98 +/- 0.67%, p less than 0.001; PCA vs mPCA = n.s.). Since renal BA-excretion is similar in both shunted groups, urinary BA does not seem to be of primary significance for cancer development in the urinary tract of totally shunted rats.

Animals↗
PubMed1981

Simultaneous determination of blood concentrations of methohexital and its hydroxy metabolite by gas chromatography and identification of 4'-hydroxymethohexital by combined gas--liquid chromatography--mass spectrometry.

A simple, sensitive and selective method is described for the simultaneous determination of low concentrations (less than 50 ng/ml) of underivatized methohexital and its hydroxy metabolite in small (0.1 ml) samples of human and rat plasma or whole blood by gas chromatography with nitrogen-selective detection. Moreover, the main metabolite in rat and man was identified as 4'-hydroxymethohexital by comparison of chromatograms from gas--liquid chromatography (GLC) with data obtained from GLC--mass spectrometry and 1H-nuclear magnetic resonance spectrometry of this metabolite, produced both by incubating methohexital with isolated rat liver microsomes and by isolating this metabolite from rat urine.

Animals↗
PubMed1981

Intestinal excretion of hexachlorobenzene.

1. The intestinal excretion of hexachlorobenzene (HCB) was studied in rats using the method of pendular perfusion. One and four weeks after i.p. application of 100 micrograms HCB/kg body weight segments of jejunum, ileum and colon were perfused with light liquid paraffin or squalane for 5 h. 2. The highest amount of HCB was excreted into jejunum, followed by ileum and colon. After 5 h HCB concentration in jejunal perfusion medium equals that in plasma. 3. Serosal tissue of intestinal segments contained higher HCB concentrations as compared to mucosa. 4. Paraffin treatment decreased the HCB content in both serosal and mucosal tissue of jejunum and ileum but not of colon.

Animals↗
PubMed1981

Scarpa's ganglion in the cat one year after labyrinthectomy.

One year after membraneous labyrinthectomy in three cats a quantitative analysis of neurons in Scarpa's ganglion was performed under the light microscope. Total numbers of neurons were found 30% lower than in the respective contralateral ears. Although remaining perikarya showed signs of degeneration, such as shrinkage and vacuoles the proportions of large and small neurons remained unchanged after this procedure.

Animals↗
PubMed1981

Metabolism of beta-hexachlorocyclohexane-14C in rats following low dosing in the daily diet.

beta-Hexachlorocyclohexane-14C (1.5 ppm) was administered in the diet to rats for one week. During the elimination phase three therapeutic agents were fed to enhance the clearance. Renal and fecal excreted radioactive products were collected for 8 weeks and extracted. Although significant differences in the total excreted amount of radioactivity were registered between controls and treated rats, there were no quantitative differences in the extractability of the excreta and no differences in the chemical nature of metabolites found. Radioactivity in urine consisted to 100% of conversion products, about 30% of which were unextractable residues. In the organic soluble fraction the 2,4,6-trichlorophenol was the major metabolite in urine and the only metabolite detected in feces. Minor conversion products of beta-HCH in urine were a trichlorohydroxyme-thoxybenzene, a dichlorophenol and a trace of a tetrachlorocyclohexane-isomer.

Animals↗
PubMed1981

Hexobarbitone disposition at different stages of intensive care treatment.

The pharmacokinetics of hexobarbitone were investigated in 22 patients in an intensive care unit. The results were compared with those obtained in a healthy group for three time periods: 3rd or 4th day (I), 5-8th days (II) and 13-29th days (III) of treatment. Hexobarbitone 7.32 mg per kg of body weight was administered by i.v. infusion in 60 min. At the end of the infusion, the mean plasma concentration of group I was 71% greater than control group; groups II and III were near to control. In all patients the post-infusion concentration-time course of hexobarbitone could be described by two-compartment kinetics. The biphasic decrease in plasma concentration of hexobarbitone was more rapid in groups II and III, than in either the control group or in group I. At the beginning of treatment patients generally showed an unchanged hexobarbitone half-life, a slightly decreased plasma clearance, a reduction of approximately 50% of the initial distribution volume. (V1) and a reduction of 44% of the distribution volume at steady state. In groups II and III the mean of these values were comparable to control. However, plasma clearance had increased by about 87% in group II compared with control, and after 2-3 weeks (group III) by about 143%. Correspondingly, half-life was reduced by 45% and 58% respectively. The pharmacokinetics were not related to change in liver function. The presence of clinical and bacteriological signs of septicaemia was closely associated with an enhanced hexobarbitone clearance.

Adult↗
PubMed1981

Post mortem changes in drug-metabolizing enzymes of rat liver and human liver.

The aim of this investigation was to obtain information on the time-dependent decrease of the drug-metabolizing system in autolysing rat liver, and also in human cadaver liver. Rat liver, divided into three parts, was tested immediately after removal and 6 and 12 hrs later. Parameters investigated were: microsomal protein, cytochrome P-450, NADPH cytochrome C reductase, glucose-6-phosphatase, aminopyrine-N-demethylation and aniline-p-hydroxylation. In human liver, samples taken from 0.5 up to 3.5 hrs after death, microsomal protein cytochrome P-450, NADPH cytochrome C reductase and phospholipids were tested. Nearly all parameters based on microsomal protein decrease during autolysis, but by different amounts. Interestingly, the cytochrome P-450 content of patients with signs of shock 12 hrs before death is significantly lower than in patients without shock.

Adult↗