New ruthenium complexes containing salicylic acid and derivatives induce triple-negative tumor cell death via the intrinsic apoptotic pathway.

In this work we present the synthesis and characterization of six new ruthenium compounds with general formulae [Ru(L)(dppb)(bipy)]PF6 and [Ru(L)(dppe)2]PF6 where L = salicylic acid (Sal), 4-aminosalicylic acid (AmSal) or 2,4-dihydroxybenzoic acid (DiSal), dppb = 1,4-bis(diphenylphosphino)butane, dppe = 1,2-bis(diphenylphosphino)ethane and bipy = 2,2'-bipyridine. The complexes were characterized by elemental analysis, molar conductivity, cyclic voltammetry, NMR, UV-vis and IR spectroscopies, and two by X-ray crystallography. The 31P{1H} NMR spectra of the complexes with the general formula [Ru(L)(dppe)2]PF6 showed that the phosphorus signals are solvent-dependent. Aprotic solvents, which form strong hydrogen bonds with the complexes, inhibit the free rotation of the salicylic acid-based, modifying the diphosphine cone angles, leading to distortion of the phosphorus signals in the NMR spectra. The cytotoxicity of the complexes was evaluated in MCF-7, MDA-MB-231, SKBR3 human breast tumor cells, and MCF-10 non-tumor cell lines. The complexes with the structural formula [Ru(L)(dppe)2]PF6 were the most cytotoxic, and the complex [Ru(AmSal)(dppe)2]PF6 with L = 4-aminosalicylic acid ligand was the most selective for the MDA-MB-231 cell line. This complex interacts with the transferrin and induces apoptosis through the intrinsic pathway, as demonstrated by increased levels of proteins involved in apoptotic cell death.

Selective GABA-receptor actions of amobarbital on thalamic neurons.

1. We studied amobarbital's effects on membrane properties and currents, and electrically evoked inhibitory postsynaptic currents (IPSCs) mediated by gamma-aminobutyric acid (GABA) in rat thalamic slices. Using concentration-response relationships, we compared amobarbital's effects in nociceptive nuclei and non-nociceptive nucleus reticularis thalami (nRT). 2. Amobarbital decreased input resistance by activating GABA(A) receptors. Amobarbital produced a larger decrease in ventrobasal than nRT neurons. 3. Amobarbital depressed burst and tonic firing. Depression of burst firing was more effective, particularly in ventrobasal and intralaminar neurons. Depression was reversed by GABA(A) antagonists, and surmountable by increasing current injection, implicating a receptor-mediated shunt mechanism. 4. Amobarbital did not affect the tetrodotoxin-isolated low threshold Ca(2+) spike during GABA(A) blockade. Amobarbital reduced excitability without altering outward leak, or hyperpolarisation-activated inward currents. 5. Amobarbital increased mean conductance and burst duration of single GABA(A) channels. Consistent with this, amobarbital increased amplitude and decay time of IPSCs with distinct EC(50)s, implicating actions at two GABA(A) receptor sites. 6. Activation of GABA(A) receptors by low concentrations, fast IPSC amplitude modulation, and failure to affect intrinsic currents distinguished amobarbital's mechanism of action from previously characterised barbiturates. The selective actions of amobarbital on GABA(A) receptor may have relevance in explaining anaesthetic and analgesic uses.

The central nervous effects of Mitragyna africanus (Willd) stembark extract in rats.

The acute toxicity and the central effects of Mitragyna africanus (M. africanus) stembark methanol extract were studied in rats. The extract did not produce any death in the treated rats even at the highest dose (6400 mg kg(-1)) used. It produced depressant effects on the central nervous system. The stembark extract potentiated amylobarbitone sleeping time in rats dose-dependently, induced sleep in rats and also produced significant local anaesthetic effect on rabbits, the effects being comparable to that of xylocaine. The extract protected rats treated with a convulsive dose of strychnine (2 mg kg(-1)) and increased the period of onset of convulsions and decreased the number of spasms.

Effect of venotropic drugs on the respiratory activity of isolated mitochondria and in endothelial cells.

Several drugs used in the treatment of chronic peripheral ischaemic and venous diseases, i.e. aescine, Cyclo 3, Ginkor Fort, hydroxyethylrutosides, naftidrofuryl, naphthoquinone and procyanidolic oligomers, were tested on the mitochondrial respiratory activity. The results show that all these drugs protected human endothelial cells against the hypoxia-induced decrease in ATP content. In addition, they all induced a concentration-dependent increase in respiratory control ratio (RCR) of liver mitochondria pre-incubated with the drugs for 60 min. The drugs were divided into two groups according to their effects. The first group (A), comprising aescine, Ginkor Fort, naftidrofuryl and naphthoquinone, increased RCR by decreasing state 4 respiration rate. The second group of drugs (B), comprising hydroxyethylrutosides, procyanidolic oligomers and Cyclo 3, increased RCR by increasing state 3 respiration rate. The drugs of group A were able to prevent the inhibition of complexes I and III respectively by amytal and antimycin A while the first two drugs of group B increased adenine nucleotide translocase activity. Cyclo 3 inhibited the carbonylcyanide m-chlorophenyl hydrazone (mCCP)-induced uncoupling of mitochondrial respiration. None of these seven drugs could protect complexes IV and V, respectively, from inhibition by cyanide and oligomycin. When tested on endothelial cells the drugs of group A, in contrast to group B, prevented the decrease in ATP content induced by amytal or antimycin A. The present results suggest that the protective effects on mitochondrial respiration activity by these venotropic drugs may explain their protective effect on the cellular ATP content in ischaemic conditions and some of their beneficial therapeutic effect in chronic vascular diseases.

Control of cardiac energy turnover by cytoplasmic phosphates: 31P-NMR study.

Energy flux, estimated from the cardiac work index (pressure-rate product) and the rate of oxygen consumption, was varied in different ways; and the free concentrations of cytosolic phosphates were detected by the 31P-nuclear magnetic resonance method. A reversible decrease in phosphocreatine (PCr) and concomitant increase in [ADP] at nearly constant Pi were induced by 2-deoxyglucose (2-DG) treatment and its subsequent washout and were followed by a reversible suppression of pressure-rate product and elevation of end-diastolic pressure. 2-DG treatment also resulted in an irreversible and severe reduction of the cytosolic adenine nucleotide pool (to approximately one-third of control value) that did not recover during 2-DG washout. Reduction of the energy turnover rate, either by suppression of the PCr shuttle with iodoacetamide or by inhibition of the respiratory chain with amytal, was associated with a drop of PCr level, an elevation of both [ADP] and [Pi], and a rise of end-diastolic pressure. In contrast, a decrease in energy flux by reduction of perfusate Ca2+ led to a PCr rise and a fall in [ADP] and [Pi]. Most of these experimental groups were exposed to two types of loads, isoproterenol stimulation and coronary flow (CF) elevation. Iodoacetamide-treated hearts showed a poor mechanical response to both types of loads compared with other groups. The metabolic response to isoproterenol was uniform in all groups and was associated with some decrease in PCr and increase of [ADP] and [Pi], implying limitations in the respiratory chain.(ABSTRACT TRUNCATED AT 250 WORDS)

[Mechanism of decreased oxygen tension in tissue during hyperoxia and criteria of hyperoxygenation dosage]. / O mekhanizme snizheniia napriazheniia kisloroda v tkaniakh pri giperoksii i kriteriiakh dozirovki giperoksigenatsii.

Experiments on white rats were made to study the effect of normo- and hyperbaric oxygenation on the total oxygen consumption, its tension in tissues, and the course of oxidative processes in liver mitochondrial preparations from animals exposed to oxygen under positive pressure. It was found that the time of the development of the protective reaction to hyperoxia in the mitochondria was in agreement with the onset of a progressive fall of oxygen tension in the tissues. Experiments with hyperbaric oxygenation in the presence of artificial inhibition or stimulation of the oxidative processes in the body demonstrated a pathogenic relationship between the fall of oxygen tension in the tissues and intensification of its recovery in the mitochondria. The recommendations are given as to the use of the results obtained for the elaboration of more effective regimens of oxygen therapy.

[Electron transport particles from bovine heart as a test system in toxicological studies]. / Elektronentransportpartikeln aus Rinderherz als Testsystem für toxikologische Untersuchungen.

14 standard respiratory inhibitors and substances of toxicological interest were tested on the NADH oxidase and the succinate-cytochrome c oxidoreductase systems of beef heart electron transfer particles (ETP) in the presence and absence of human serum albumin (HSA). HSA did not influence the half-inhibition concentrations by cyanide, amytal and antimycin A. It had little effect on the inhibition by rotenone or carboxin, whereas the inhibition by free fatty acids and monoglyceride was greatly decreased. Lindan and DDT exerted a marked inhibition of the NADH oxidase system in the absence of HSA; the inhibition was weaker but still considerable in the presence of HSA. In the presence of HSA 10(-4) M DDT but not Lindan inhibited also the succinate-cytochrome c reductase system. The results show that ETP may be a useful test object in toxicological studies.

The effects of chlordesmethyldiazepam on behavioral performance and subjective judgment in normal subjects.

Eight normal subjects were tested on a battery of subjective and psychological tests 12 hours after a hypnotic dose of chlordesmethyldiazepam (1 or 2 mg), amylobarbitone sodium (100 mg), and a placebo. The tests included self-ratings of hypnotic effects and alertness; reactiontime, card-sorting, coding and cancellation tasks; arithmetic; and tapping. Before each task, test anxiety and performance expectation was self-rated; and after the task, judgment of performance was self-rated. Residual effects were definitely detectable after the 2-mg dose of benzodiazepine with both behavioral impairment and subjective hangover. Both the 1-mg dose and the barbiturate were almost devoid of such effects. Very few drug effects on test anxiety and performance judgment were discerned. Plasma concentrations of amylobarbitone were related to decreases in test anxiety and of chlordesmethyldiazepam with ratings of sleepiness.

Shifts in ATP synthesis during preimplantation stages of mouse embryos.

The actual and potential activities of the cyochrome system were studied in cleavage-stage mouse embroys. Activities were determined by assaying embroys for total ATP and the rates of [32-P]ATP synthesis both before and after their incubation in medium supplemented either with an energy coupling site inhibitor (antimycin, amytal or cyanide) or with the FADH-linked substrate, succinate. The data indicate that there are three major shifts in the mode of ATP production during preimplantation stages: the first, between the two-cell and late four-cell stages; the second, between the eight-celland late morula stages; and the third, between the late morula and late blastocyst stages. These data are discussed in relation to studies on the energy metabolism of cleavage and blastocyst stage mouse embryos.

Studies on the nature and mode of action of the insulin-sensitive glucoregulator receptor in the central nervous system.

In vivo studies were undertaken in rats to provide evidence of the neural nature, tentative localization and mode of excitation of the insulin-sensitive central nervous system (CSN) glucoregulator center. In rats under light barbiturate anesthesia minute amounts of insulin injected into the carotid artery resulted in an immediate decrease of the systemic blood sugar. This hypoglycemic action of regional insulinzation of the CSN was lost when the animals were subjected to prolonged, deep barbiturate narcosis. Competitive inhibition of glucose utilization in the CSN region by intracarotid administration of 2-deoxy-D-glucose did not block the systemic hypoglycemic effect of subsequent intracarotid insulin injection. Chronic endogenous hyperinsulinemia produced by daily growth hormone treatment resulted in an insensitivity of the CNS glucoregulator center to exogenous insulin. The ratio of the quantity of the injected insulin and the pre-existent plasma insulin concentration showed direct correlation with the systemic hypoglycemic response that followed intracarotid injection. Present data support the hypothesis that the insulin-sensitive glucoregulator center located in the area supplied by the carotid artery is neural in nature, because of its inhibition by barbiturate anesthesia. The data are compatable with the working hypothesis that the center is located in the hypothalamus, since light cortical barbiturate anesthesia did not, but deep anesthesia did have an inhibitory effect on it. Marked interference by chronic hyperinsulinemia suggests that the receptor center estimates the metabolic status of the animal through means related to physicochemical binding of insulin to specific receptors. However, since our attempt to inhibit glucose utilization in the CNS was without effect on the activity of the center, it appears that the singal for the glucoregulatory impulse is not insulin facilitation of glucose utilization in the receptor area, but another parameter of insulin action.