Inorganic substances and their uses in Nikolaos Myrepsos' Dynameron. Recent applications in modern therapy.

Inorganic compounds have been known and used since antiquity. Dynameron is the largest Byzantine medical manuscript divided into 24 sections, in accordance with the letters of the Hellenic alphabet, which contains 2667 recipes. The majority of them contain ingredients of plant origin, followed by animal origin, while fewer inorganic substances are quoted. In the present study, the latter ones are listed. Moreover, the information on the uses of inorganic ingredients in the treatment of many diseases in the late Byzantine era is presented and their evaluation in light of the modern Pharmacology and Toxicology.

Remedies of animal origin and their indications in Nikolaos Myrepsos׳ Dynameron.

ETHNOPHARMACOLOGICAL RELEVANCE: Dynameron is a Byzantine medical compendium, divided into 24 sections, in accordance with the letters of the Greek alphabet. Being the largest medical and pharmaceutical book ever written in Byzantium, Dynameron contains 2667 recipes intended to treat many pathological conditions. A lot of information convey to us through prescriptions. In addition to plants, Nikolaos Myrepsos proposes the use of many animals, animal parts and animal by-products, for the treatment of various diseases. This article presents for the first time a full account of the animal products included in Dynameron. AIM OF THE STUDY: In continuation to our previous studies, this paper focuses on the use of animal products in composite medicines described in Dynameron. An effort was made to trace down the use of similar or identical animal products in texts of earlier medical writers. Recording recipes with animals or animal products intended for use in everyday medical practice highlights the timeless belief in their healing properties. MATERIALS AND METHODS: Our main source of material is the recent digital edition of Nikolaos Myrepsos' Dynameron. This huge treatise was written in the 13th century and reflects in many ways the long medical tradition of the Greek, the Hellenistic and the Roman eras, having also received influences from the materia medica of Arabic medicine. In addition, information from dictionaries and databases were cross-checked to confirm and classify the animals and their products and to identify them. For the various pathological conditions these products are meant for, we have used the current medical terminology. RESULTS: In the present study, we could identify the therapeutic use of 93 animals. In several instances, Myrepsos suggests the use of specific organs of an animal, and for that reason he includes in his treatise 16 anatomical parts of different animals. Moreover, Dynameron comprises also 34 animal by-products, such as milk and honey. Medicines of animal origin are used in recipes concerning diseases of the respiratory, the digestive, the cardiovascular and the urinary system, as well as gynecological diseases, and ailments of the eyes, the ears and the skin. CONCLUSIONS: Of the 2667 recipes of Dynameron, 344 recipes contain medicines of animal origin, which can be detected in totally 769 citations. In addition, 626 citations for animal by-products are found in 268 recipes. Honey and milk are quoted in 2136 recipes, mostly as excipients. Dietary instructions are present on many occasions, reflecting the attitude for a healthy everyday life, similar to the modern beliefs pertaining to food as an essential factor for a good health.

Ethnopharmacological approach to the herbal medicines of the "Elements Alpha to Delta" in Nikolaos Myrepsos׳ Dynameron. Part II.

ETHNOPHARMACOLOGICAL RELEVANCE: Dynameron is a Byzantine medical compendium, divided into 24 sections, the "Elements", containing 2667 recipes, most of which inherited by previous physicians of the classic ancient Greek and Hellenistic, and imperial Roman periods. AIM OF THE STUDY: In continuation to our previous study concerning the first and largest chapter of the "Element Alpha" of Nikolaos Myrepsos׳ Dynameron (Valiakos et al., 2015), this paper focuses on the plants quoted in the recipes of the eight following chapters entitled "About Salts", "About Honeypacks" and "About Spreads", all belonging to the same "Element Alpha"; "About Antitussives" and "About Suppositories" belonging to the "Element Beta"; "About women's Cathartics" belonging to the "Element Gamma"; "About Drossaton" and "About Diachrisma", both belonging to the "Element Delta". MATERIALS AND METHODS: Our main primary source material was the codex kept in the National Library of France (in Paris) under the number grec. 2243, which is the older and larger codex of Dynameron (Valiakos et al., 2015). RESULTS: The present study led us to the interpretation of 277 plants under different names, among which we recognized 57 medicinal plants listed by the European Medicines Agency, one of them with negative monograph (i.e. Chelidonium majus). In addition, there are identified taxa related to those quoted by EMA as herbal medicines. The plants appearing in the examined Elements belong to various families of which the most frequent are: Apiaceae 10.11%; Lamiaceae 7.22%; Asteraceae 6.86%; Rosaceae 6.5% and Fabaceae 6.14%. CONCLUSIONS: A total of 277 species have been catalogued, most of which are referred in our previous publication (Valiakos et al., 2015). Among them, 56 plants still play a very important role in medical practice, as they are used as traditional herbal medicines (www.ema.eu). This evidence is a proof that the use of medicinal plants remains valuable from the ancient times until today. The recipes, in contrast to older medical compendia, contain precise measurements of ingredients and dosages for every drug, which seem to reflect empirical logic.

Dopamine D2-Receptor Antagonists Down-Regulate CYP1A1/2 and CYP1B1 in the Rat Liver.

Dopaminergic systems regulate the release of several hormones including growth hormone (GH), thyroid hormones, insulin, glucocorticoids and prolactin (PRL) that play significant roles in the regulation of various Cytochrome P450 (CYP) enzymes. The present study investigated the role of dopamine D2-receptor-linked pathways in the regulation of CYP1A1, CYP1A2 and CYP1B1 that belong to a battery of genes controlled by the Aryl Hydrocarbon Receptor (AhR) and play a crucial role in the metabolism and toxicity of numerous environmental toxicants. Inhibition of dopamine D2-receptors with sulpiride (SULP) significantly repressed the constitutive and benzo[a]pyrene (B[a]P)-induced CYP1A1, CYP1A2 and CYP1B expression in the rat liver. The expression of AhR, heat shock protein 90 (HSP90) and AhR nuclear translocator (ARNT) was suppressed by SULP in B[a]P-treated livers, whereas the AhRR expression was increased by the drug suggesting that the SULP-mediated repression of the CYP1 inducibility is due to inactivation of the AhR regulatory system. At signal transduction level, the D2-mediated down-regulation of constitutive CYP1A1/2 and CYP1B1 expression appears to be mediated by activation of the insulin/PI3K/AKT pathway. PRL-linked pathways exerting a negative control on various CYPs, and inactivation of the glucocorticoid-linked pathways that positively control the AhR-regulated CYP1 genes, may also participate in the SULP-mediated repression of both, the constitutive and induced CYP1 expression. The present findings indicate that drugs acting as D2-dopamine receptor antagonists can modify several hormone systems that regulate the expression of CYP1A1, CYP1A2 and CYP1B1, and may affect the toxicity and carcinogenicity outcome of numerous toxicants and pre-carcinogenic substances. Therefore, these drugs could be considered as a part of the strategy to reduce the risk of exposure to environmental pollutants and pre-carcinogens.

Metronomic vinorelbine: Anti-angiogenic activity in vitro in normoxic and severe hypoxic conditions, and severe hypoxia-induced resistance to its anti-proliferative effect with reversal by Akt inhibition.

Metronomic chemotherapy is the protracted, dense administration of low sub-toxic doses of chemotherapy, to inhibit tumor angiogenesis. Vinorelbine is an orally bioavailable vinca alkaloid shown to be useable for metronomic administration. In clinical trials, metronomic vinorelbine has been demonstrated to generate sustainable antitumor efficacy at low nanomolar (nM) concentrations with negligible toxicity. We sought to determine whether the clinically relevant metronomic concentration of vinorelbine is anti-angiogenic in vitro and whether hypoxia, often induced by anti-angiogenic therapy, modifies its effectiveness. We found that the metronomic concentration of 10 nM vinorelbine inhibited human umbilical vein endothelial cell (HUVEC) proliferation, migration, tube formation and sprouting. Severe hypoxia, did not affect the inhibitory effect of metronomic vinorelbine on migration, tube formation and sprouting. However, severe hypoxia reduced its anti-proliferative effect by decreasing its ability to induce G2/M block as it shifted the cell population to the G1 phase and decreased the fraction of the cells in the DNA synthesis S phase. Furthermore, the pro-apoptotic effects of 10 nM vinorelbine were also decreased. Metronomic vinorelbine decreased the Bcl-2/Bax ratio in normoxia whereas the ratio was reduced in severe hypoxia but unaltered by vinorelbine treatment. Akt signals to an anti-apoptotic pathway and we demonstrated that the Akt inhibitor V reversed the protective effect of severe hypoxia. Thus, we provide evidence for the anti-angiogenic basis of metronomic vinorelbine and we show that severe hypoxia mediates resistance to its anti-proliferative effect on endothelial cells. Akt warrants further investigation as a potential target to circumvent this hypoxic resistance.

Ethnopharmacological approach to the herbal medicines of the "Antidotes" in Nikolaos Myrepsos׳ Dynameron.

ETHNOPHARMACOLOGICAL RELEVANCE: This paper focuses on the plants quoted in the recipes of the first chapter entitled "About the Antidotes" belonging to the first and largest section "Element Alpha" of Nikolaos Myrepsos׳ Dynameron, a medieval medical manuscript. Nikolaos Myrepsos was a Byzantine physician at the court of John III Doukas Vatatzes at Nicaea (13th century). He wrote in Greek a rich collection of 2667 recipes, the richest number known in late Byzantine era, conventionally known as Dynameron and divided into 24 sections, the "Elements". The only existing translation of this work is in Latin, released in 1549 in Basel by Leonhart Fuchs. Since no other translation has ever been made in any language, this work still remains poorly known. MATERIALS AND METHODS: Our primary source material was the codex written in 1339 and kept in the National Library of France (in Paris) under the number grec. 2243. For comparison, all the other codices, which contain the entire manuscript, have also been studied, namely the codices EBE 1478 (National Library of Greece, Athens), grec. 2237 and grec. 2238 (both in Paris), Lavra Ε 192 (Mont Athos, Monastery of Megisti Lavra), Barocci 171 (Oxford) and Revilla 83 (Escorial). RESULTS: The exhaustive study of the "About the Antidotes" led us to the interpretation of 293 plant names among which we recognized 39 medicinal plants listed by the European Medicines Agency, (Herbal Medicines, www.ema.eu); the therapeutic indications of some of them provided by Myrepsos were similar or related to their current ones, as given in their monographs. The plants belong to various families of which the most frequent are: Apiaceae 10.6%; Lamiaceae 9.2%; Asteraceae 8.9%; Fabaceae 6.8% and Rosaceae 5.1%. The most frequently mentioned plants even under several different names are the following: Apium graveolens L., Crocus sativus L., Nardostachys jatamansi (D. Don) DC., Zingiber officinale Roscoe, Rosa centifolia L., Syzygium aromaticum (L.) Merr. & L.M. Perry, Papaver somniferum L., Costus sp., Petroselinum crispum (Mill.) Fuss, Anethum graveolens L., Foeniculum vulgare Mill., Daucus carota L. CONCLUSIONS: This research led us to the conclusion that the content of "About the Antidotes" is a valuable source for the study of recipes based mainly on medicinal plants, most of them inherited from classic ancient Greek and Hellenistic periods.

Intracellular signalling via the AKT axis and downstream effectors is active and prognostically significant in cancer of unknown primary (CUP): a study of 100 CUP cases.

BACKGROUND: Hypothesising that cancer of unknown primary (CUP) may harbour unique characteristics, we present a translational study of the immunohistochemical expression and clinical correlation of key PTEN/AKT pathway molecules. PATIENTS AND METHODS: We collected 100 paraffin-embedded CUP tissue blocks. We studied using tissue microarrays the expression of PTEN, phospho-AKT, Cyclin D1, p21, phospho-RPS6. From the percentage of staining tumour cells and the literature, we selected cut-offs to classify the expression of each biomolecule. We correlated IHC expression with clinical data. RESULTS: PTEN, pAKT, and pRPS6 showed frequent expression. At univariate analysis, high IHC expression of pAKT and pRPS6 displayed statistically significant association with worse survival. Prognosis was worse upon concurrent high IHC expression of pMAPK and pAKT {median overall survival = 8 months [95% confidence interval (CI) 5.3-10.7] versus 17 months [95% CI 13.1-20.9]}. In multivariate analysis, high p21 was associated with better survival (risk ratio [RR] = 0.34 [95% CI 0.16-0.73], P = 0.005). High expression of pAKT (RR = 2.39 [95% CI 1.23-4.66], P = 0.01) or pRPS6 (RR = 2.76 [95% CI 1.31-5.84], P = 0.008) was associated with worse survival. CONCLUSIONS: p21 expression conferred favourable prognosis, while high pAKT or pRPS6 expression predicted worse prognosis. Concurrent MAPK and pAKT expression had a marked adverse impact on survival.

Inhibition of rat hepatic CYP2E1 by quinacrine: molecular modeling investigation and effects on 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced mutagenicity.

Increased activity of CYP2E1 has been associated with increased risk of chemically-mediated cancers, through enhanced activation of a variety of procarcinogens. In this context, inhibition of CYP2E1 is potentially of significance in xenobiotic toxicity. The aim of the present study was to test the hypothesis that quinacrine inhibits hepatic CYP2E1. For this purpose, disulfiram (75 mg/kg i.p) as an inhibitor and isoniazid (100 mg/kg i.p) as an inducer of CYP2E1, as well as quinacrine (50 mg/kg i.p) were administered to Wistar rats and the hepatic activity of CYP2E1 was measured. The expression of CYP2E1 was further assessed by Western blot analysis. As expected, disulfiram inhibited, while isoniazid induced the activity and expression of the enzyme. Interestingly, treatment with quinacrine resulted in a significant decrease of CYP2E1 activity and expression. To investigate any similarities in the inhibition of CYP2E1 by quinacrine and disulfiram, molecular modeling techniques were adopted and revealed that quinacrine molecule anchors inside the same binding pocket of the protein where disulfiram is also attached. Finally, as assessed by the sister chromatid exchanges (SCE) assay, quinacrine was demonstrated to reduce the mutagenic effects of the tobacco-specific N-nitrosamine 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which is known to be converted to active mutagen in the liver principally through CYP2E1. We suggest that these antimutagenic effects of quinacrine could be possibly attributed, at least in part, to its ability to block the bioactivation of NNK, mainly by the inhibition of CYP2E1. Our results, even preliminary, indicate that quinacrine as an inhibitor of CYP2E1 might be protective against chemically-induced toxicities such as NNK-induced mutagenicity.

A dose escalation and pharmacokinetic study of biweekly pegylated liposomal doxorubicin, paclitaxel and gemcitabine in patients with advanced solid tumours.

To determine the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of pegylated liposomal doxorubicin (PLD), paclitaxel (PCX) and gemcitabine (GEM) combination administered biweekly in patients with advanced solid tumours. Twenty-two patients with advanced-stage solid tumours were treated with escalated doses of PLD on day 1 and PCX plus GEM on day 2 (starting doses: 10, 100 and 800 mg m(-2), respectively) every 2 weeks. DLTs and pharmacokinetic (PK) parameters of all drugs were determined during the first cycle of treatment. All but six (73%) patients had previously received at least one chemotherapy regimen. The DLT dose level was reached at PLD 12 mg m(-2), PCX 110 mg m(-2) and GEM 1000 mg m(-2) with neutropaenia being the dose-limiting event. Of the 86 chemotherapy cycles delivered, grade 3 and 4 neutropaenia occurred in 20% with no cases of febrile neutropaenia. Non-haematological toxicities were mild. The recommended MTDs are PLD 12 mg m(-2), PCX 100 mg m(-2) and GEM 1000 mg m(-2) administered every 2 weeks. The PK data revealed no obvious drug interactions. Biweekly administration of PLD, PCX and GEM is a well-tolerated chemotherapy regimen, which merits further evaluation in various types of solid tumours.

Weekday on-weekend off oral capecitabine: a phase I study of a continuous schedule better simulating protracted fluoropyrimidine therapy.

BACKGROUND: Although protracted intravenous 5-fluorouracil is superior to bolus regimens in terms of tumour exposure to the drug during DNA synthesis as well as activity and safety, the oral fluoropyrimidine capecitabine is administered intermittently. In this phase I study, we investigated an alternative, dose-intense continuous regimen. MATERIALS AND METHODS: Oral capecitabine was administered twice daily continuously with weekend breaks, in patients with advanced solid tumours refractory to standard therapy. Dose escalation proceeded from 1,331 to 2,510 mg/m(2) daily. Dose limiting toxicity (DLT) consisted of any grade-3 or 4 adverse event except for alopecia and skin toxicity resolving within 7 days. RESULTS: Twenty-five heavily pretreated patients participated in the study. No DLT occurred in the first four cohorts. Two out of four patients developed grade III diarrhoea in the fourth week of capecitabine at 2,510 mg/m(2) (DLT). The most common toxic episodes during all cycles of treatment were grade 1-2 fatigue, skin erythema, abdominal cramps, nausea, constipation and neutropenia. Disease regression was seen in three and stabilisation with clinical benefit in ten patients (clinical benefit response 54%). Pharmacokinetic studies of capecitabine and metabolites in four patients at 2,250 mg/m(2 )daily showed rapid absorption, short plasma half-lives with the exception of FBAL and absence of accumulation or conversion saturation during the course of therapy. At this dose, administered dose intensity in eight patients was 99.3% of the planned one. CONCLUSIONS: Weekday on-weekend off capecitabine maximizes cytotoxic impact on tumour cells during S-phase by safely simulating protracted fluoropyrimidine therapy at a recommended dose (2,250 mg/m(2)) close to that of the intermittent schedule and clearly higher than the continuous one of 1,331 mg/m(2).

Behavioral pharmacological properties of a novel cannabinoid 1',1'-dithiolane delta8-THC analog, AMG-3.

Newly developed cannabinoids may hold the promise of the development of useful and safe drugs. This study aimed to investigate the behavioral effects of the novel 1',1'-dithiolane delta8-HC analogue AMG-3, a cannabinomimetic molecule with high affinity for CB1/CB2 receptors. This analog was chosen for its binding affinity to these receptors, which is higher than that reported for delta8-tetrahydrocannabinol (delta8-THC). Behavioral responses were assessed after the administration of AMG-3 (1, 2, 4, 8 mg/kg, i.p.) in the open field, on the bar test, on the hot plate and in the intracranial self-stimulation procedure. AMG-3 increased the reactivity time on the hot plate in a dose- and time-dependent manner, indicating a long-lasting analgesic effect (at least 24 h). The substance was found dose-dependently to decrease spontaneous motor activity and to induce catalepsy, particularly at the highest dose (8 mg/kg). AMG-3 did not affect the rewarding value of intracranial self-stimulation, except to increase the reward threshold at the highest dose (8 mg/kg). The effects of the highest dose of AMG-3 on spontaneous activity and on the self-stimulation paradigm were completely reversed by pre-treatment with the CB1 receptor antagonist AM-251. These findings indicate that the administration of AMG-3 to rats elicits a specific behavioral profile, most probably associated with the activation of CB1 receptors and without effects indicating abuse potential.

A dose-escalation and pharmacokinetic study of gemcitabine and oxaliplatin in patients with advanced solid tumors.

BACKGROUND: Gemcitabine and oxaliplatin have broad antineoplastic activity and favorable toxicity. We conducted a phase I study to determine the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of the combination in patients with advanced solid tumors. PATIENTS AND METHODS: Sixty-eight patients with advanced stage solid tumors were enrolled. Treatment was first-line for 35% of patients, second-line for 27%, and third-line for 38%. Gemcitabine was administered at escalating doses of 1000-2000 mg/m(2) as a 30-min intravenous (i.v.) infusion on days 1 and 8 and oxaliplatin at 60-130 mg/m(2) as a 4-h i.v. infusion on day 8 every 21 days without growth factor support. RESULTS: The MTD was defined at gemcitabine 1800 mg/m(2) on days 1 and 8 and oxaliplatin 130 mg/m(2) on day 8. Twelve dose levels were evaluated and DLTs occurring during the first cycle consisted of grade 4 neutropenia, grade 3 asthenia or mucositis and grade 1-3 neutropenia or thrombocytopenia resulting in treatment delays. A total of 266 cycles were administered with only one episode of febrile neutropenia and no toxic deaths. Seven (3%) and 26 (10%) cycles were complicated by grade 4 and 3 neutropenia, respectively, three (1%) and 13 (5%) by grade 4 and 3 thrombocytopenia, and eight (3%) by grade 3 anemia. The most common non-hematological toxicity was grade 2/3 asthenia observed in 23% of cycles. Responses were observed in patients with a variety of epithelial neoplasms. The pharmacokinetic study revealed no significant interaction between the two drugs. CONCLUSIONS: The combination of gemcitabine and oxaliplatin has excellent tolerability and promising activity in patients with advanced solid tumors. As the MTD exceeds the recommended single-agent dose for gemcitabine, and a dose-response effect has not been established, we recommend using both drugs at full doses, e.g. gemcitabine 1200-1400 mg/m(2) on days 1 and 8 and oxaliplatin 130 mg/m(2) on day 8 for further phase II studies.

Evaluation of the cytotoxicity of selected systemic and intravitreally dosed drugs in the cultures of human retinal pigment epithelial cell line and of pig primary retinal pigment epithelial cells.

The cytotoxicity of the selected systemic and intravitreally dosed drugs tamoxifen, toremifene, chloroquine, 5-fluorouracil, gentamicin and ganciclovir was studied in retinal pigment epithelium (RPE) in vitro. The cytotoxicity was assayed in the human RPE cell line D407 and the pig RPE cell culture using the WST-1 test, which is an assay of cell proliferation and viability. The effects of experimental conditions on the WST-1 test (cell density, serum content in the culture medium, the exposure time) were evaluated. The EC50 values in tamoxifen-treated D407 cells ranged between 6.7 and 8.9 micromol/l, and in pig RPE cells between 10.1 and 12.2 micromol/l, depending on the cell density used. The corresponding values for toremifene were 7.4 to 11.1 micromol/l in D407 cells and 10.0 to 11.6 micromol/l in pig RPE cells. In chloroquine-treated cells, the EC50 values were 110.0 micromol/l for D407 cells and 58.4 micromol/l for pig RPE cells. Gentamicin and ganciclovir did not show any toxicity in micromolar concentrations. The exposure time was a significant factor, especially when the drug did not induce cell death, but was antiproliferative (5-fluorouracil). Serum protected the cells from the toxic effects of the drugs. Both cell cultures were most sensitive to tamoxifen and toremifene, and next to chloroquine. The drug toxicities obtained in the present study were quite similar in both cell types; that is, the pig RPE cells and the human D 407 cell line, despite the differences in, for example, the growth rate and melanin contents of the cell types. Owing to the homeostatic functions important for the whole neuroretina, RPE is an interesting in vitro model for the evaluation of retinal toxicity, but, in addition to the WST-1 test, more specific tests and markers based on the homeostatic functions of the RPE are needed.

Effects of 3-methylcholanthrene and aspirin co-administration on ALDH3A1 in HepG2 cells.

The effects of two different protocols of 3-methylcholanthrene (3MC) and aspirin co-administration were studied in a well-established human hepatoma cell line (HepG2). During this work, we have performed toxicity tests for cell viability/cell proliferation as well as studies on the expression of ALDH3A1 after exposure of HepG2 cells to 3MC or/and aspirin. For the evaluation of toxic concentrations of 3MC and aspirin, the WST-1 test was used. WST-1 is a reliable cytotoxicity test which is based on the cleavage of the tetrazolium salt WST-1 to formazan by mitochondrial enzymes of living cells. A broad range of drug concentrations for either 3MC (0.25-50.0 microM) or aspirin (0.05-10.0 mM) were used for cell exposure, in several periods of time. The expression of ALDH3A1 in HepG2 cells showed typical time- and dose-response curves of induction after application of 3MC (1-5 days, 1.5-5.0 microM, respectively). When cells were firstly exposed to 3MC (2.5 and 5.0 microM) and then to aspirin (0.25 mM), the induced ALDH3A1 activity was further enhanced in a statistically significant way (P<0.05). On the contrary, when aspirin application was preceded 3MC exposuring a statistically significant decrease in ALDH3A1 inducibility was observed, as compared with the application of 3MC alone.

Phenobarbital inducibility and differences in protein expression of an animal model.

Aldehyde dehydrogenases (ALDHs) are a group of enzymes which catalyze the conversion of aldehydes to the corresponding carboxylic acids in a NAD(P)(+)-dependent reaction. In mammals, different ALDHs are constitutively expressed in liver, stomach, eye and skin. In addition, inducible ALDH-isoenzymes are detectable in many tissues; apart from other physico- and immuno-chemical differences, two cytosolic ALDHs (ALDH1A3 and ALDH3A1) are known to be activated in rat liver, by different types of inducers of drug metabolism. Phenobarbital-type inducers increase the ALDH1A3, while polycyclic hydrocarbons (such as BaP and TCDD) increase the expression of the two members of ALDH3A subfamily (3A1 and 3A2). In this study, we used two Wistar rat substrains which have been well-characterized for different inducibility of ALDH1A3 enzyme activity after treatment with phenobarbital. Animals that respond (RR) or do not respond (rr) to treatment have been inbred for almost 25 years, offering a useful experimental model. Apart from the level of ALDH1A3 induced enzyme expression after phenobarbital treatment, no other differences between the two substrains have been noticed, as far as drug metabolizing enzyme activities (like the pentoxy- and ethoxy-O-dealkylation rate) are concerned. According to the present results, the ALDH1A3 expression is still the only difference between the two substrains. Immunoblotting experiments with polyclonal antibodies raised against CYP2B1 or/and CYP1A1/1A2 showed no differences between the two substrains. Additionally, data concerning time- and dose-response induction of ALDH1A3 after phenobarbital and griseofulvin treatment are presented. It is concluded that these two Wistar rat substrains represent a unique animal model for studying what seems to be the only difference between these substrains - the genetic basis of the phenobarbital induction.

Differentiation of disulfiram effects on central catecholamines and hepatic ethanol metabolism.

Disulfiram is used in the treatment of chronic alcoholism, because of the unpleasant symptoms it provokes after ethanol intake. The underlying mechanism is believed to be the accumulation of acetaldehyde in the blood, due to inhibition of the liver aldehyde dehydrogenases. In addition, it is known that disulfiram also has some neurotoxic properties. The aim of our study was to investigate the relationship between the pharmacological and neurotoxicological properties of disulfiram with respect to the doses applied. Increasing doses of disulfiram (25, 50, 75, 100 and 150 mg/kg) were administered intraperitoneally to Wistar rats and the hepatic enzyme activities of alcohol and aldehyde dehydrogenases were measured. Also, in two brain subregions (midbrain and hypothalamus) the levels of noradrenaline, dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid were determined. The higher dose of disulfiram (150 mg/kg) produced lethal effects in all treated animals. Aldehyde dehydrogenase activities were inhibited by disulfiram in a dose-dependent way, while alcohol dehydrogenase was not affected at all. Concerning the levels of brain biogenic amines, disulfiram produced a significant reduction in noradrenaline and an increase in dopamine levels in both structures of the brain, in a dose-dependent way. However, the lowest dose applied (25 mg/kg) had no effects on brain catecholamines. It is known that high doses of disulfiram may cause severe encephalopathy and peripheral neuropathy in humans, which could be attributed to the impairment of the metabolism of brain biogenic amines, due to inhibition of dopamine-beta-hydroxylase. Our experimental data show that disulfiram affects the level of brain biogenic amines at dose levels higher than those inhibiting the activity of aldehyde dehydrogenase. Therefore, in clinical practice 'disulfiram reaction' could still be achieved with a low dosage regimen not producing neurotoxicity

Stress modulates the enzymatic inducibility by benzo[alpha]pyrene in the rat liver.

The role of stress on the inducibility by benzo[alpha]pyrene (B[alpha]P), a representative polycyclic aromatic hydrocarbon, of several drug-metabolizing enzymes was investigated in rats, using restraint stress and mild unpredictable stress as models of psychological stress. Restraint stress was found to significantly suppress basal ethoxyresorufin 7-dealkylase (EROD) and pentoxyresorufin 7-dealkylase (PROD) activities (two-fold). In contrast, mild unpredictable stress markedly increased basal EROD activity, while PROD activity was not affected. In addition, both types of stress resulted in a significant reduction of basal p -nitrophenol hydroxylation (PNP). It is worth noting that restraint stress greatly enhanced the inducibility of EROD, methoxyresorufin 7-dealkylase (MROD) and to a lesser extent PROD activities by B[alpha]P, while mild unpredictable stress had no, or only a mild effect on the inducibility of cytochrome P450s (CYPs) by B[alpha]P. In conclusion, psychological stress may modulate different enzymatic systems which are vital elements of the detoxification mechanisms of the body. The two distinct types of psychological stress used in this study appear to affect the enzymatic systems under investigation in a stress-specific manner at the basal level and at the induced state by B[alpha]P.

CYTOTOXIC ACTIVITY OF KAEMPFEROL GLYCOSIDES AGAINST HUMAN LEUKAEMIC CELL LINES IN VITRO.

Two kaempferol coumaroyl glycosides (i.e. platanoside and tiliroside) isolated from the methanolic extract of Platanus orientalis L. buds, were examined for their in vitro cytotoxic activity against a panel of human leukaemic cell lines. Platanoside (1) exhibited cytotoxic activity against most of the cell lines tested, while tiliroside (2) was active against two of the nine tested cell lines. Compound 1, was examined for its effect on the uptake of [(3)H]thymidine as a marker of DNA synthesis. Kaempferol was used as a control. 2000 Academic Press@p$hr Copyright 2000 Academic Press.

Noradrenaline, dopamine, serotonin: different effects of psychological stress on brain biogenic amines in mice and rats.

The effect of restraint stress on central neurotransmission was evaluated in mice and rats. Noradrenaline (NA), dopamine (DA) and serotonin (5-HT) levels and their primary metabolites were measured in discrete brain regions following exposure to stress. Mice and rats demonstrated a similar response to stress in some brain regions. Both species responded to stress with lower NA and 5-HT in the locus coeruleus compared to non-stressed controls. Dopaminergic activity, assessed by DA turnover, was elevated in the hypothalamus. While DA turnover was suppressed in the amygdala, 5-HT turnover was similarly elevated in both species. In most cases, however, there were differences in biogenic neurotransmission between mice and rats in response to stress. In particular, NA levels were suppressed by stress in the dorsal cortex of mice, but in the rats NA levels were decreased in the hypothalamus. While stress produced lower DA levels in the hypothalamus, DA levels demonstrated a marked increase in the amygdala of mice. Stress was also associated with a decrease in DA levels in the rat striatum and with an increase of DA turnover in the locus coeruleus of mice. On the other hand, 5-HT was suppressed in the mouse striatum and in the rat hypothalamus and amygdala, while 5-HT turnover was markedly decreased in the hippocampus and dorsal cortex of rats alone. In conclusion, the changes in the central neurotransmission which are evoked by stress appear to be species-specific in most cases, a fact which may trigger discrete alterations in homeostatic mechanisms.