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Biomedical subjects

E Ruch

Publications and source records attributed to E Ruch.

16 recordsLinked to original sources
PubMed1989

Effect of heterocyclic amines and beef extract on chromosome aberrations and sister chromatid exchanges in cultured human lymphocytes.

Two of the major bacterial mutagens formed in heated meat products, 2-amino-3-methylimidazo[4,5-f]quinoline and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline or the basic fraction of beef extract induced a low frequency of sister chromatid exchanges in human lymphocyte cultures in the presence of metabolic activation. Structural chromosome aberrations were not induced at comparable high concentrations in human lymphocytes with intact repair system, suggesting that repair or induction of point mutations are involved in the DNA-damaging effect of heterocyclic amines rather than structural chromosome aberrations. Accordingly it may be concluded that mammalian cells with both intact repair and enzyme systems are more relevant than bacterial systems for evaluating the carcinogenic potential of heterocyclic amines.

Animals↗
PubMed1985

The effect of delta-9-tetrahydrocannabinol on rat cerebrospinal fluid.

The effect of delta-9-tetrahydrocannabinol (THC) on cerebrospinal fluid (CSF) flow in rats was studied. The ventricular system of rats anesthetized with ketamine sulfate was cannulated via cisternal puncture, and CSF production was recorded. When administered in doses of 25 mg/kg to 45 mg/kg intraperitoneally, THC caused inhibition of CSF flow; in larger doses a smaller response was noted. In response to THC, CSF flow showed an initial drop, a return toward baseline, and a secondary decrease. It is postulated that this biphasic effect is due to a combination of THC's sympathomimetic effects on the CNS plus the local action that this drug has on choroidal synaptosomal neurotransmitters.

Animals↗
PubMed1985

Instant and brewed coffees in the in vitro human lymphocyte mutagenicity test.

Incubation of instant and 'home brew' coffees (caffeinated and decaffeinated) and of coffee aroma with cultured human lymphocytes in the presence and absence of S-9 increased the number of total aberrations. However, the increase was smaller in the presence of S-9 than in its absence. Pure caffeine tested with or without S-9 at doses equivalent to levels in caffeine-containing coffee did not give statistically significant increases of any type of aberration when compared with controls. In all in vitro test systems used to date, coffee and coffee aroma or their reactive compounds were metabolically deactivated in the presence of S-9. This could explain the negative results obtained in mutagenicity assays in vivo.

Animals↗
PubMed1984

Investigation of coffee in sister chromatid exchange and micronucleus tests in vivo.

Administration of a single oral dose of instant coffee to Chinese hamsters at levels up to 2.5 g/kg body weight did not increase the frequency of sister chromatid exchanges. Furthermore, five consecutive daily oral doses of instant coffee given to Swiss OF-1 mice up to 3 g/kg/day did not induce increases in micronuclei above spontaneous levels. Similarly, no effect was observed in the micronucleus test after mice received two oral doses of coffee aroma of up to 50 ml/kg.

Animals↗
PubMed1983

5-Fluorouracil concentrations in rat plasma, parotid saliva, and bile and protein binding in rat plasma.

The pharmacokinetics of 5-fluorouracil were studied over a 60-min period in rats that received 12.5, 25.0, and 50.0 mg/kg iv. The plasma concentration-time relationship and the detectability in bile and parotid saliva (a route of elimination heretofore given little or no attention) were examined. Protein binding of 5-fluorouracil at concentrations chosen to approximate those found in plasma was determined by equilibrium dialysis. Bile-plasma and parotid saliva-plasma concentration ratios were calculated. 5-Fluorouracil concentrations were quantitated by high-performance liquid chromatography. Plasma concentrations at all doses studied appeared to rapidly decline. The half-life, however, at the 50.0-mg/kg dose (27 min) was significantly longer (p less than 0.025) than the corresponding half-life at the 25.0-mg/kg dose (22 min). This may be attributed to an easily saturable hepatic degradation. Although an observed decline in bile-plasma and parotid saliva-plasma concentration ratios at higher doses may represent saturation of these excretary routes, the small amounts of 5-fluorouracil detected in bile and parotid saliva probably contribute negligibly to the elimination of the total drug equivalents administered. Parotid saliva-plasma concentration ratios were not useful in predicting plasma protein binding as determined by equilibrium dialysis. Excretion of intravenously administered 5-fluorouracil in saliva, however, exposes the upper GI tract to this agent and may play a part in causing stomatitis in patients receiving the drug by this route.

Animals↗
PubMed1983

Doxorubicin and 5-fluorouracil plasma concentrations and detectability in parotid saliva.

Doxorubicin and 5-fluorouracil pharmacokinetics were studied in 19 volunteers with various advanced neoplastic diseases who received 50-90 mg doxorubicin or 600-1000 mg 5-fluorouracil intravenously, followed by plasma and parotid saliva collection over a 75 min period. The extent to which these chemotherapeutic agents are bound to plasma proteins, at concentrations chosen to approximate plasma concentrations, was measured by equilibrium dialysis. Both agents were quantitated by high-performance liquid chromatography. As reported previously, a wide range of plasma levels were found among patients receiving similar doses of either doxorubicin or 5-fluorouracil. It appears that in addition to being quickly cleared from the plasma both chemotherapeutic agents are excreted in detectable amounts in parotid saliva, a route of elimination heretofore given little or no attention. Excretion in the saliva exposes the mucosa of the upper gastrointestinal tract to 5-fluorouracil after intravenous administration and may play a part in causing stomatitis in patients receiving it by this route. Since there are huge interindividual and pronounced intraindividual differences in S/P ratios mostly not systematically related to the drugs' concentration in plasma, the concentration in parotid saliva was not useful in predicting the level of free doxorubicin or 5-fluorouracil in plasma.

Aged↗
PubMed1982

Nonmutagenicity in vivo of the food flavonol quercetin.

Mice given quercetin per os at concentrations that were about 10(3) times greater than the estimated average human intake of total flavonols were tested for mutagenicity with 2 complementary in vivo mutagenicity/carcinogenicity screening tests--the micronucleus test and the host-mediated assay employing the Ames Salmonella tester strain TA 98 as indicator organism. No mutagenic effect was detected with either test.

Animals↗
PubMed1980

Human whole blood and parotid saliva concentrations of oral and intramuscular promethazine.

Ten healthy male subjects received 25 mg of promethazine intramuscularly, followed within 3 weeks by oral administration of 25 mg. Whole blood and parotid saliva were collected over a 12-hr period after drug administration. Promethazine was quantitated by high-performance liquid chromatography. After intramuscular administration, the promethazine concentrations were 3.0-22.4 ng/ml in blood and 0.9-2.8 ng/ml in parotid saliva. After oral administration, the promethazine concentrations were 1.4-5.5 ng/ml in blood and 0.2-0.8 ng/ml in parotid saliva. The peak blood promethazine concentration after the intramuscular dose was four times higher than that following the oral dose, which indicates that promethazine possesses an extensive first-pass effect. The mean parotid saliva to whole blood ratio (S/B) was calculated to be 0.24 after the intramuscular route an 0.20 after the oral route over the 12-hr period. The calculated percentage of free drug in the blood was 20-24% of the whole blood concentration determined from the S/B ratio.

Administration, Oral↗
PubMed1979

Correlations of parotid saliva and plasma lidocaine concentrations in rats.

The concentration ratios of parotid saliva to plasma lidocaine were determined in rats after a single dose (10 mg of lidocaine/kg) and constant infusion (60 micrograms of lidocaine/kg/min). Parotid saliva and plasma samples were obtained at 10, 20, and 30 min after single-dose lidocaine administration and at 70, 80, and 90 min after the initiation of a lidocaine infusion. The saliva/plasma concentration ratios for lidocaine after single-dose administration decreased from 1.13 +/- 0.03 at 10 min to 0.51 +/- 0.06 at 30 min, whereas the ratios determined during the lidocaine infusion remained constant (0.43 +/- 0.03, 0.45 +/- 0.03, and 0.43 +/- 0.04) over the time period tested. The variable saliva/plasma concentration ratios obtained after single-dose administration may be associated with rapid drug distribution between the plasma and peripheral compartments and variation in lidocaine binding to plasma proteins. However, during constant lidocaine infusion, a steady-state concentration was achieved within 70 min, as demonstrated by the constant saliva/plasma concentration ratios.

Animals↗
PubMed1979

In vitro study of antispasmodic effects of dicyclomine hydrochloride on vesicourethral smooth muscle of guinea pig and rabbit.

Dicyclomine inhibition of acetylcholine-induced and barium chloride-induced isotonic contractions of the smooth muscle from three segments of the lower urinary tract (bladder body, bladder base, and proximal urethra) of the guinea pig and the rabbit was studied in vitro. In the guinea pig dicyclomine caused competitive inhibition of acetylcholine-induced contraction of the bladder body (1 x 10(-7) M to 1 x 10(-5) M) and the bladder base (1 x 10(-6) M, 1 X 10(-5) M) and was less potent than atropine and propantheline. In the rabbit significant blockade of acetylcholine-induced contractions occurred at dicyclomine concentrations of 5 x 10(-6) M to 3 x 10(-5) M in the bladder body and at 1 x 10(-5) M and 3 x 10(-5) M in the bladder base. In both species dicyclomine inhibitory effects were most marked in the bladder body, moderate in the bladder base, and minimal in the proximal urethra. Dicyclomine failed to cause inhibition of the barium chloride-induced contractions in the guinea pig vesicourethral smooth muscle. In rabbits, however, significant antagonism P less than 0.01) of barium chloride-induced muscle contraction was observed with dicyclomine at concentration 1 x 10(-5) M in both bladder body and the bladder base. The clinical implication of such properties of dicyclomine are discussed.

Acetylcholine↗
PubMed1977

An autosomal dominant midline cleft syndrome resembling familial holoprosencephaly.

We have detected a previously unrecognized autosomal dominant syndrome characterized by: mental retardation, microcephaly; craniofacial anomalies including cleft lip and anterior cleft palate, hypotelorism and antimongoloid slant; skeletal anomalies, notably of the foot and spine; and chronic constipation. Despite similarities to familial holoprosencephaly, this disorder appears to be a distinct entity. Incomplete penetrance and variable expressivity accompany transmission of the abnormal allele through four generations of a large kindred. Three of the four affected males survived past 20 years of age; the fourth is an infant. All three affected females died very early in infancy.

Abnormalities, Multiple↗