Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Valerates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70Linked to original sources

Ultrastructural study of the cardiotoxicity and light-microscopic findings of the skin after treatment of golden hamsters with seven different anthracyclines.

Golden hamsters were administered seven anthracyclines: adriamycin (ADM), detorubicin (DTR), daunorubicin (DNR), 4'-epi-adriamycin (eADM), rubidazone (RBZ), aclacinomycin (ACM), and N-trifluoroacetyladriamycin-14-valerate (AD-32), three times a week during 4 weeks, at doses equivalent to 3/4 of those which are optimally oncostatic on murine L1210 leukemia. We examined their myocardia by electron microscopy (EM) and their skin by light microscopy (LM), and report here the findings of these two examinations. The mortality was very high for the groups of hamsters treated with ADM, DTR, DRB, eADM, and RBZ (all treated hamsters died before the end of the fourth week) and very low for those treated with ACM and AD-32 (for each drug, only one of the 21 treated animals died after 4 weeks of treatment). After the first week of treatment and chiefly after the second week, all treated hamsters, except those treated with ACM, showed very severe EM alterations of their myocardia. EM detected almost no early myocardial lesions in ACM-treated hamsters but, after 4 weeks of treatment, severe cardiac lesions also appeared which, like those after AD-32, were nonlethal and reversible. LM of the skin detected degenerative lesions with atrophy of all epidermic layers and a loss of the hair (alopecia) in all treated hamsters except those treated with ACM and AD-32; the skin in these two groups preserved its normal histologic structure. These observations agree with phase I-II clinical ACM studies in which the rate of ECG abnormalities was 4.5% and the rate of alopecia 0%, and with an early AD-32 clinical study conducted by Blum [3].

Animals↗

Opposing effects on blood pressure following the activation of metabotropic and ionotropic glutamate receptors in raphe obscurus in the anaesthetized rat.

The microinjection of L-glutamate (1-6 nmol/rat) and N-methyl-D-aspartate (NMDA 1-10 nmol/rat), ionotropic glutamate receptor (iGluR) agonists, into the nucleus raphe obscurus caused a concentration -dependent increase of arterial blood pressure. In contrast, (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (t-ACPD, 14-42 nmol/rat), a metabotropic glutamate receptor (mGluRs) agonist, caused a concentration-dependent decrease in blood pressure. Pretreatment with D,L-2-amino-phosphono valeric acid (2-APV, 5 nmol/rat) a selective NMDA iGluR antagonist, and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,b] cyclohepten-5,10-imine hydrogen maleate (MK801, 0.9 nmol/rat), a noncompetitive NMDA iGluR antagonist, blocked both the glutamate and NMDA pressor responses, while pretreatment with (+)-alpha-methyl-4-carboxyphenylglycine (MCPG, 0.05 nmol/rat), a mGluR1 antagonist, increased the glutamate-induced pressor effects and blocked the fall in blood pressure induced by t-ACPD. 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX, 0.4 nmol/rat) a non-NMDA iGluR antagonist, did not affected the glutamate-induced hypertension. These observations indicate opposing roles for ionotropic and metabotropic receptors in the glutamate-induced blood pressure changes elicited from the nucleus raphe obscurus. Moreover, we suggest that the glutamate-induced hypertension may be due to the activation of NMDA ionotropic receptor subtypes and the metabotropic receptors may influence this activation through a reduction of excitability at level of synapses.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

Nucleoside incorporation as a function of hormone levels during the early phases of estrogen-induced genesis of medullary bone in the Japanese quail, Coturnix coturnix.

The sequence of changes in RNA synthesis during the early phases of genesis of medullary bone induced in male Japanese quail by estrogen treatment was studied by 3H-uridine uptake. Analyses of plasma estrogen and testosterone were done by radioimmunoassay at 12, 24, 38 and 61 h. A dose of 5 mg kg-1 estradiol-17 beta was found to stimulate the same 3H-uridine uptake 15 h after hormone treatment as a dose of 20 mg kg-1 of estradiol valerate. The uptake of 3H-uridine rose as the dose of estradiol-17 beta increased. Plasma estrogen levels, which were highest 12 h after injection, declined sharply during the next 12 h, returning to control levels between 38 and 61 h. Testosterone levels declined after estrogen administration and remained below control values at all time points. Following estrogen administration, 3H-uridine uptake declined from control values for the first 8 h. Twelve hours after hormone administration control levels were again reached, with maximum 3H-uridine uptake occurring 16 h after hormone treatment. The 16-h maximum was followed by a steady decline to below control levels at 20, 24 and 28 h, the time at which the experiment was discontinued. Maximum 3H-uridine uptake following estrogen stimulation is similar to that observed for the stimulated immature rat uterus.

Animals↗

Regulation of dopamine levels in intrastriatal grafts of fetal mesencephalic cell suspension: an in vivo voltammetric approach.

An in vivo voltammetric technique was used to monitor dopamine (DA) release in the 6-hydroxydopamine (6-OHDA)-lesioned rat striatum reinnervated by grafts of ventral mesencephalon containing DA neurons. Extracellular levels of DA were measured during the administration of D1 or D2 DA receptor antagonists. In addition, changes in DA levels induced by agonists and antagonists of excitatory amino acid (EAA) receptors were studied to verify the possible existence of a host glutamatergic control on the grafted DA cells in the 'transplanted' rats. Two months after the grafts were performed, the voltammetric signal measured under baseline conditions in the grafted striata was found to be almost similar to that recorded on the contralateral control side. Likewise, in another group of transplanted rats, the turnover of the amine, as expressed by the DO-PAC/DA tissue level ratio, was found to have become "normalized" after grafting, compared with the lesion-only group. The increase in the voltammetric signal observed after administering the D2 antagonist sulpiride (100 mg/kg i.p.) was lower in the grafted striata than on the contralateral side, however. This suggests that some D2 autoreceptor subsensitivity may have helped to maintain the baseline level of dopaminergic transmission. Adaptive processes of this kind might compensate for the partial DA reinnervation of the host striatum found to occur on the basis of the tyrosine hydroxylase immunostaining patterns. After administration of either the D1 antagonist SCH 23390 (0.1 mg/kg s.c.), or injection of EAA receptor agonists--1-glutamate, quisqualate and N-methyl-D-aspartate (all 10 nmol i.c.v.)--and antagonists--amino-phosphono-valeric acid (10 nmol i.c.v.) and dizocilpine (MK801, 0.2 mg/kg i.p.)--no significant differences between the two striata were detected in the voltammetric signals. These results suggest that, in the grafted rats, neurons belonging to the host population, such as the striatal cells bearing D1 receptors or the corticostriatal afferents presumed to contain glutamate, might modulate the DA levels, as was found to occur under normal conditions.

2-Amino-5-phosphonovalerate↗

The role of the anterior intralaminar nuclei and N-methyl D-aspartate receptors in the generation of spontaneous bursts in rat neocortical neurones.

The nature of spontaneous unitary activity of rat neocortex was investigated during slow wave sleep and urethane anaesthesia. Neurones in layer IV and V locations fired in a burst-pause pattern at a low burst repetition rate (0.5-4 per second) during both stage 3/4 sleep and urethane anaesthesia. Occasionally an alternative mode of firing (spindle clusters), associated with focal spindle wave activity, was also found to occur in both states. Using dual microelectrode implants it was found that the onset times of bursts (but not spindle clusters), coincided in the same and opposing cortices, whether in functionally similar or disparate areas. The highest probability was that burst onsets occurred simultaneously (resolution = 2.56 ms, interquartile range = 40 ms). Spontaneous unitary activity was investigated in the thalamus for temporal correlation with spontaneous unitary activity in neocortex under urethane anaesthesia. Neurones of the anterior intralaminar group (aIL) consistently fired in a burst-pause pattern such that each aIL burst showed a strong tendency to precede a cortical burst. Unilateral electrical stimulation of the aIL nuclei evoked widespread bilateral entrainment of cortical bursts. In contrast stimulation of VPl, or cutaneous sites, evoked only short duration spike responses together with burst abolition in the appropriate restricted Sml area. Ionophoresis of NMDA (N-Methyl D-Aspartate) onto Sm1 neurones increased the probability of cortical burst responses to aIL stimulation in addition to decreasing the latency by 20-40 ms (n = 11). Ionophoresis of 2APV (2-amino 5-phosphono valeric acid) caused simultaneous abolition of spontaneous cortical bursts and bursts evoked by aIL stimulation. Short latency responses to cutaneous and VPl stimulation were unaffected by ionophoresis of 2APV sufficient to cause burst elimination, suggesting that this pathway does not operate via a 2APV sensitive receptor mechanism. Anatomical features of the aIL nuclei and their overall cortical projection pattern are discussed in relationship to these findings. The activation of cortical NMDA/APV sensitive receptors by aIL afferents in the "spontaneous" generation of bursts in cortical cells is discussed.

Action Potentials↗

Radioactive species in rat urines and tissues after [14C] AD 32 administration.

[14-14C]N-Trifluoroacetyldoxorubicin-14-valerate [( 14C]AD 32) was synthesized and administered IV to male rats at 9.09 mg/kg. Urinary radioactivity excreted in the 0-24 h interval was only 2.3% of the dose, N-trifluoroacetyldoxorubicin (AD 41), 13-dihydro-N-trifluoroacetyldoxorubicin (AD 92), and doxorubicin being the major urinary metabolites identified. Doxorubicin and AD 32 were the main radioactive species extracted from tissues at 24 h after treatment. The amount of doxorubicin present in the analysed tissue samples is in agreement with the relatively low toxicity of AD 32 compared with doxorubicin.

Animals↗

Comparative effects of adriamycin and DNA-non-binding analogues on DNA, RNA, and protein synthesis in vitro.

Drug-DNA binding is claimed to be the basis by which the antitumor antibiotic adriamycin (doxorubicin) inhibits DNA and RNA synthesis in vitro. However, in preliminary studies the DNA-non-binding adriamycin analogue N-trifluoroacetyladriamycin-14-valerate (AD 32) showed somewhat greater inhibition of DNA and RNA synthesis than adriamycin under identical conditions. The kinetics of macromolecule synthesis inhibition induced by adriamycin and AD 32, and the two principal DNA-non-binding metabolites of AD 32, N-trifluoroacetyladriamycin (AD 41) and N-trifluoroacetyladriamycinol (AD 92), have now been subjected to comparative study in cultured CEM (human leukemic lymphoblastic) cells. At equimolar concentrations (10 microM), or at concentrations related to their 50% growth-inhibitory values vs CEM cells, AD 32 was consistently found to be more inhibitory than adriamycin of DNA and RNA synthesis, as measured by the incorporation of tritiated thymidine and uridine, respectively, into acid-precipitable fractions relative to untreated controls. Marked inhibitory activity was apparent with 10 microM AD 32 even at the earliest sampling time (15 min); with adriamycin at the same concentration the maximal effect was not achieved until 3 h. AD 32 at 4.8 microM concentration continued to show strong inhibition of nucleic acid synthesis, whereas adriamycin at 1.0 microM was essentially inactive. Like AD 32, AD 41 and AD 92 showed greater inhibition than adriamycin of DNA and RNA synthesis at the early sampling times, although in all instances the effects of AD 32 were more profound. AD 32 at 10 microM concentration produced a moderate but significant inhibition of the incorporation of tritiated methionine into protein compared with adriamycin, which at this concentration was not active. Parallel HPLC analytical studies with similar drug-treated cultures indicated that, while small amounts of adriamycin were found in cells treated with 10 microM AD 32, the amount of adriamycin present at 15 min was only a small fraction (less than 5%) of the amount of adriamycin achieved at 3 h in cultures treated with 1.0 microM adriamycin, a concentration already shown to be only slightly inhibitory of nucleic acid synthesis under the culture conditions. The present study thus confirms the marked DNA and RNA synthesis-inhibitory effects of AD 32, and establishes that this inhibitory activity is not due to conversion of AD 32 into adriamycin. These findings accordingly call into question the validity of the drug-DNA binding mechanism as the explanation for the nucleic acid synthesis inhibitory effects seen with ADR.

Cell Survival↗

Hindgut fermentation in the wombats: two marsupial grazers.

The wombats Vombatus ursinus and Lasiorhinus latifrons have a capacious proximal colon with only a vestigial caecum. The pattern of microbial fermentation in the hindgut of both species was studied in captive animals fed a pelleted straw diet and in wild wombats feeding on their natural winter diets. Digesta pH was low in the stomach but near neutrality along the hindgut, indicating effective absorption and/or buffering of the colonic contents. Initial proportions and production rates of short chain fatty acids in vitro reflected the fermentation of plant cell walls. Proportions of isobutyrate, isovalerate and n-valerate increased towards the distal colon indicating proteolysis and subsequent fermentation of amino acids. The low ammonia content of digesta fluid suggested that ammonia released from these amino acids was absorbed and utilized by the wombats and their gut microbes. Wild wombats had higher concentrations and production rates of short chain fatty acids than captive animals, which was consistent with the higher apparent digestibility of their natural diet. The energy from short chain fatty acids in captive animals was 30-33% of digestible intake. Energy intakes were low and similar to resting metabolic rates estimated for marsupials. Actual resting metabolic rates of the wombats are probably lower than these estimates, and the proportion of energy derived from fermentation substantially higher than the 53-61% estimated in wild wombats. The energy from fermentation clearly enables wombats to utilize diets high in fibre.

Animals↗

Drug-induced intrahepatic cholestasis: characterization of different pathomechanisms.

The pathogenesis of intrahepatic cholestasis in rats was studied using isolated perfused livers as an experimental model. Three basic mechanisms were differentiated: Permeabilization of the bilio-sinusoidal barrier associated with electron microscopic alterations of the tight junctional complexes was found in livers of rats treated with alpha-naphthylisothiocyanate (ANIT, 250 mg/kg body weight). Consequences of these alterations were: reflux of bile constituents such as taurocholate and sulfobromophthalein and increased access to the biliary space of paracellular markers such as inulin and sucrose. The clear-cut mechanism of ANIT cholestasis was used to distinguish other mechanisms of intrahepatic cholestasis. Inhibition of the basic process of fluid secretion was found to be the primary event in the development of cholestasis induced by estrogens. After 5 days of treating rats with ethinyl estradiol (5 mg/kg/day), bile flow was diminished in isolated livers while the permeability of the biliary tract to sucrose and inulin was not affected. Accordingly, the maximal concentration of taurocholate in bile was increased, indicating that its secretion was sustained. The same effect was observed after 1 week of treatment with the depot estrogen estradiol valerate (1 mg/kg/week). After 3 weeks of treatment, however, the taurocholate concentration in bile was lowered and the clearance of sucrose was increased. Bile flow remained at the same cholestatic level for 20 weeks. These results suggest that estrogens have the potency to increase tight junctional permeability only in a second step in the development of cholestasis, following the inhibition of bile flow. An additional mode of secretory inhibition was induced by lowering the concentration of Ca2+ in the perfusate of isolated liver.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Naphthylisothiocyanate↗

alpha-Isopropylmalate synthase from Alcaligenes eutrophus H 16. II. Substrate specificity and kinetics.

The purified isopropylmalate synthase of Alcaligenes eutrophus H 16 reacted with the following alpha-keto acids and acyl-coenzyme A derivatives (in the sequence of decreasing affinities): alpha-ketoisovalerate, alpha-keto-n-valerate, alpha-ketobutyrate and pyruvate; acetyl-CoA, propionyl-CoA, butyryl-CoA, malonyl-CoA, valeryl-CoA, and crotonyl0CoA. alpha-Ketoisocaproate, however, is a strong inhibitor of the enzyme. All reactions catalyzed by isopropylmalate synthase were inhibited to the same extent by the endproduct L-leucine. The substrate saturation curves of alpha-ketoisovalerate or other alpha-keto acids and of acetyl-coenzyme A or other acyl-CoA derivatives had intermediary plateau regions; the Hill coefficient alternated between nH-values higher and lower than 1.0, indicating changes from positive to negative and from negative to positive cooperativity for the substrates. The products, isopropylmalate and free coenzyme A, showed competitive inhibition patterns against both substrates (alpha-ketoisovalerate and acetyl-CoA). Free coenzyme A (1 micronM) inactivated the enzyme irreversibly. The 3'-phosphate of coenzyme A and the free carboxyl group of alpha-ketoisovalerate were involved in optimal binding of these substrates, but 3'-dephospho-acetyl-coenzyme A and the methylester of alpha-keto-isovalerate were also converted by this enzyme. A CH3--CH2-grouping of the alpha-keto acids seemed to be necessary for binding this substrate.

2-Isopropylmalate Synthase↗

The anaerobic decomposition of benzoic acid during methane fermentation. IV. Dearomatization of the ring and volatile fatty acids formed on ring rupture.

A possible pathway for the anaerobic utilization of benzoic acid by a methanogenic consortium is suggested. Cyclohexane carboxylic acid and 1-cyclohexene-1-carboxylic acid have been identified as intermediates before ring rupture. Suprisingly, 3-cyclohexene-1-carboxylic acid interferes with utilization of other cyclic acids. In addition, isobutyric acid or short chain acids containing carbon-carbon double bonds could not be used without induction periods of a week or longer. A number of volatile fatty acids (heptanoic, valeric, butyric, propanoic, and acetic) have been identified and are suggested intermediates.

Anaerobiosis↗

Epidermal thinning: evaluation of commercial corticosteroids.

Epidermal thinning of mouse tail skin was compared for commercial preparations of clobetasol propionate (Dermovate), clobetasone butyrate (Eumovate), fluocinonide (Metosyn), and hydrocortisone butyrate (Locoid). The thickness measurements were ranked with those for hydrocortisone (1%), betamethasone valerate (Betnovate), triamcinolone acetonide (Ledercort), fluocinolone acetonide (Synlar), and prednisolone stearoylglycolate (Sinistrone) obtained in a previous study (Spearman and Jarrett, 1975). All steroids caused epidermal thinning, except clobetasone butyrate. Some cream and ointment vehicles were also assayed. Epidermal thickening was caused by the cream and ointment vehicles used for Eumovate and also by the cream employed for Locoid formulation.

Administration, Topical↗

Contraluminal para-aminohippurate transport in the proximal tubule of the rat kidney. III. Specificity: monocarboxylic acids.

In order to study the specificity of the contraluminal para-aminohippurate (PAH) transport system, the inhibitory potency of monocarboxylates on the 3H-PAH influx from the interstitium into cortical tubular cells in situ has been determined. The following was found: if a homologous series of fatty acids with increasing chain length is tested, inhibition of contraluminal PAH influx is first seen with valerate (app. Ki 1.4 mmol/l), increasing up to nonanoate (app. Ki 0.06 mmol/l) and remaining in this range up to duodecanoate, the last compound of this series which is sufficiently water-soluble. Similarly, the inhibitory potency of aromatic monocarboxylates increases with increasing hydrophobicity. If the fatty acids are esterified, their inhibitory potency is lost. If they are transformed to the respective aldehydes their inhibitory potency is preserved at a reduced degree. Introduction of a hydrophobic methyl-, ethyl-, or propyl-group increases the inhibitory potency. A beta-, but not an alpha-oxo-group augments the inhibitory potency of phenylpropionate analogs, an OH group diminishes it, and a NH2 group abolishes it. Among phenyl-fatty acids an increase in affinity is observed from phenyl- less than benzoylamine- less than phenoxy- less than benzoyl-acetate and -propionate. All monocarboxylate compounds, so far tested, do not inhibit contraluminal sulfate and Na+/succinate influx. The data indicate that the PAH transporter interacts with monocarboxylates and also with aldehydes which have a hydrophobic moiety. An additional oxo-group facilitates the interaction. Thus, the benzoyl compounds show the highest affinity observed.

Aminohippuric Acids↗

Uptake of piperidine and pipecolic acid by synaptosomes from mouse brain.

Piperidine is actively transported into the synaptosomal fraction of adult mouse brain. The transport mechanism appears to be Na+ independent but is temperature dependent and sensitive to ouabain. Analysis of kinetic experiments indicates only a "low-affinity" transport system to be present. By contrast the uptake of D,L-[(3)H]pipecolic acid at a concentration of 4 X 10(-7)M was temperature and Na+ dependent, ouabain sensitive, and revealed a two-component system with a Km = 3.9 plus or minus 0.17 X 10(-6)M, Vmax = 129 plus or minus 6 pmol/mg protein/3 min for the "high-affinity" system and a Km = 90.2 plus or minus 4.3 X 10 (-6)M, Vmax = 2.45 plus or minus 0.19 nmol/mg protein/3 min for the "low-affinity" system. Compounds structurally related to pipecolic acid such as glycine, L-proline, 4-amino-n-butyric acid, and 5-amino-n-valeric acid showed an inhibitory effect on uptake at a concentration of 10(-4)M. The demonstration of biosynthesis of pipecolic acid in mouse brain and the presence of a "high-affinity" sodium-dependent uptake system suggest a physiological role of this substance in the central nervous system.

Animals↗

Percutaneous absorption of steroids: relative contributions of epidermal penetration and dermal clearance.

The permeation of triamcinolone, hydrocortisone, prednisolone, corticosterone, triamcinolone acetonide, testosterone, and betamethasone-17-valerate through excised human stratum corneum was quantified. The time course of permeation could be adequately described by a simple diffusion model suggesting that shunt transport may not be important. The disappearance of these steroids from aqueous solutions applied to human and rat dermis was also monitored. The concentrations of unbound steroid in the viable epidermis appeared to be mainly related to the blood perfusion rate in the dermis and, more importantly, to the lipophilicity of the steroid. The most lipophilic steroids penetrated the human epidermis at the fastest rates but are cleared from the viable epidermis at rates comparable to those found for more polar steroids.

Diffusion↗

The establishment of an ovum donation program using a simple fixed-dose estrogen-progesterone replacement regimen.

Most ovum donation (OD) programs involve cycle synchronization between recipient and donor for normally cycling recipients and a complex estrogen-progesterone replacement regimen for recipients with ovarian failure. In 1987, Serhal and Craft (1) suggested the use of a fixed-dose estrogen-progesterone regimen for recipients who were normally ovulatory and to those with ovarian failure. Following this protocol, and simplifying it still, the authors administered 6 mg estradiol valerate (E2) daily orally starting on day 2-6 of induced withdrawal bleeding, augmented with 100 mg progesterone in ethyl oleate (P) intramuscularly daily, starting any time between 4 days prior to and the day of oocyte pickup. All recipients underwent embryo transfer at a 2-pronuclei (2PN)-10-cell stage. A group of 21 patients underwent 26 treatment cycles, resulting in 16 pregnancies. Twelve of the patients gave birth, one to triplets, two to twins, and nine to singletons. Four patients miscarried in the first trimester of pregnancy.

Adult↗

Formation of volatile compounds and brown products in the model system n-hexanal-glycine.

During the boiling of a mixture of n-hexanal and glycine in aqueous medium, pH value 9, both soluble and insoluble brown colored pigments and volatile compounds were formed. The following volatile compounds were identified by gas chromatography and mass spectrometry; hexanone, decenone, undecenone, undecan-5-one, undecenedione, dodecenone, tridecanone, dodecanedione, tridecenone, dodecenedione, hexenyl hexanoate, caproic, valeric and butyric acids. The brown coloured pigments insoluble in water contained 0.57% of nitrogen. The presence of conjugated double-bonds, carbonyl and carboxyl groups was confirmed by spectral methods. The pigments were also separated by thin-layer chromatography on silica gel.

Aldehydes↗

Pregnancy rate in an oocyte donation program.

Oocyte donation programs offer an alternative treatment for infertile women with ovarian failure or abnormal ovarian function. Seventeen cycles of in vitro fertilization and embryo transfer with donated oocytes were performed in 13 women, with a mean age of 34.8 years. The hormonal replacement therapy consisted of a fixed dose of oral estradiol valerate, 6 mg daily, and intramuscular progesterone in oil, 100 mg daily. Estrogen and progesterone were continued for 10 more weeks after embryo transfer if pregnancy was established. After 13 embryo transfers, 8 pregnancies were obtained, for a pregnancy rate per transfer of 61.5%. Today seven pregnancies are progressing normally, including one set of twins. This results suggest that an oocyte donation program using a fixed and simple hormonal replacement therapy is an adequate treatment for these infertile couples.

Adult↗