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At least 1,063 records · Page 59Linked to original sources
PubMed1984

Mono(adenosine diphosphate ribosyl) transferase in Xenopus tissues. Direct demonstration by a zymographic localization in sodium dodecyl sulfate--polyacrylamide gels.

A semiquantitative method to measure mono(adenosine diphosphate ribosyl) transferase activity [mADPRT] in tissue extracts is described. After electrophoretic separation in sodium dodecyl sulfate (SDS)--polyacrylamide gels, renatured enzymatic activity is demonstrated in situ by incubation of the slab gels with radiolabeled NAD+ and histones. Precipitation of the radiolabeled product in the gel allows localization of the enzyme by autoradiography. This method is suitable for two-dimensional gel electrophoresis, whereby proteins are electrofocused in the presence of 9 M urea and subsequently subjected to electrophoresis in SDS. A single major band showing mADPRT activity of Mr approximately 30 Kda was observed in all crude extracts of Xenopus tissues examined. Accumulation of acid-insoluble radiolabeled products was dependent on added histones and was specifically inhibited by agmatine. The ADPRT activity of cholera toxin A fragment could also be demonstrated by this technique. Reducing agents stimulated the activity of cholera toxin A fragment while depressing that of Xenopus mADPRT.

Animals↗
PubMed1985

Calcium-dependent potassium-stimulated release of neurokinin A and neurokinin B from rat brain regions in vitro.

The release of the tachykinins neurokinin A (NKA) and neurokinin B (NKB) from superfused slices of rat brain was studied. For radioimmunoassay of superfusates and tissue extracts an antiserum which reacts with both NKA and NKB but not with substance P was used. The released immunoreactive material, as well as the immunoreactive material in extracts of the tissue slices, was characterized by cation exchange chromatography and reversed phase high performance liquid chromatography (reversed phase-HPLC). Potassium (50 mM) evoked a calcium-dependent release of tachykinin-like immunoreactivity from slices of frontal cortex and striatum. Reversed phase-HPLC accumbens, striatum and the ventral part of the mesencephalon revealed two major immunoreactive components which co-eluted with synthetic NKA and NKB. Furthermore, the superfusates also contained three minor unidentified immunoreactive components.

Amino Acid Sequence↗
PubMed1992

Studies on carbohydrates extracted from native and chemically treated Biomphalaria alexandrina snails.

1. Carbohydrates were extracted from total tissue extracts of Biomphalaria alexandrina snails and were analyzed to their monosaccharides using GLC. 2. The snails were chemically treated with thioxanthone derivatives (compounds I, II, III) and the change in the monosaccharide constituents of their carbohydrates was investigated. 3. The isolated monosaccharides from native and chemically pretreated snails were injected into mice and their protective effects were examined after infection of mice with cercariae of Schistosoma mansoni. 4. The results showed that the main monosaccharides in carbohydrates of snails were galactose, glucose, fucose and mannose and that chemical treatment caused a drop in the galactose content. 5. Moreover, monosaccharide fractions from snails treated with compound III were the most effective in inducing protection against Schistosoma infection in mice.

Animals↗
PubMed1986

A new subtype of a natural viral inhibitor (CVI) that is stable in the gastrointestinal tract.

A virus inhibitor found in gastric secretions and in extracts from gastrointestinal tissues is described. The inhibitor shares a number of characteristics with the recently described contact-blocking virus inhibitor (CVI), which is produced by unstimulated cells in culture, and occurs naturally in some body fluids. The new inhibitor, which we have designated gastrointestinal-CVI (GI-CVI) is similar to the originally described CVI in its resistance to denaturation by acid and alkali, stability at 100 degrees C, and broad antiviral action. GI-CVI can be distinguished from the previously described material by its resistance to proteolytic inactivation and enhanced heat stability, however. This new virus inhibitor has been found in significant titers in gastrointestinal secretions and tissue extracts from three mammalian species.

Animals↗
PubMed2006

Fluorescence imaging and phototoxicity effects of new formulation of chlorin e6-polyvinylpyrrolidone.

Evaluations of the efficiency of a new formulation of chlorin consisting of a complex of trisodium salt chlorin e6 (Ce6) and polyvinylpyrrolidone (PVP) in photodynamic therapy (PDT) and fluorescence diagnosis was performed on poorly differentiated human bladder carcinoma murine model with the following specific aims: (i) to qualitatively evaluate the fluorescence accumulation in human bladder tumor, (ii) to determine fluorescence distribution of Ce6-PVP using the tissue extraction technique and fluorescence imaging technique, (iii) to compare the fluorescence distribution of Ce6, Ce6-PVP and Photofrin in skin of nude mice, and (iv) to investigate phototoxicity caused by different parameters (drug-light interval, drug dose, irradiation fluence rate and total light fluence) in PDT. The fluorescence of the Ce6-PVP formulation was determined either by fluorescence imaging measurements or by chemical extraction from the tissues displaying similar trends of distribution. Our results demonstrated that the Ce6-PVP formulation possesses less in vivo phototoxic effect compared to Ce6 alone. The phototoxicity revealed a strong dependence on the drug and light dosimetry as well as on the drug-light interval. In PDT, the Ce6-PVP compound was most toxic at the 1h drug-light interval at 200J/cm(2), while Ce6 alone was most toxic at a light dose of more that 50J/cm(2) at the 1 and 3h drug-light interval. We also confirmed that Ce6-PVP has a faster clearance compared to Ce6 alone or Photofrin. This eliminates the need for long-term photosensitivity precautions. In conclusion, the Ce6-PVP formulation seems to be a promising photosensitizer for fluorescence imaging as well as for photodynamic treatment.

Animals↗
PubMed2002

Earthworm species of the genus Eisenia can be phenotypically differentiated by metabolic profiling.

The universality of low molecular weight metabolites allows rapid and straightforward investigation of the biochemistry of genetically uncharacterised species. Thus ex vivo metabolic profiling in combination with multivariate data analysis (metabonomics) offers great potential in comparative biology. Here we present the first use of high resolution nuclear magnetic resonance (NMR) spectroscopy to distinguish closely related animal species via their metabolic phenotype (metabotype). We have profiled the three Eisenia (Oligochaeta, Lumbricidae) species Eisenia fetida, Eisenia andrei and Eisenia veneta using tissue extracts and coelomic fluid analysis. The low molecular weight biochemical profiles of tissue extracts were highly conserved for all three species, with E. fetida and E. andrei being more similar to each other than to E. veneta. However the metabolic profiles of the coelomic fluid of the different species were highly distinctive - the NMR spectra allowed unequivocal identification of species. Multivariate statistics were also used to quantify these spectral differences and to enable simplified graphical visualisation of species similarity. These results show that two morphologically undistinguishable species (E. fetida and E. andrei) differ markedly in their biochemical profiles despite apparently occupying the same ecological niche, and indicate that metabolic phenotype profiling can be used as a powerful functional genomics tool.

Animals↗
PubMed1998

Preliminary observations on ascidian and echinoderm neurons and neural explants in vitro.

As part of a study on echinoderm and ascidian neural regeneration, attempts were made to develop a system for the maintenance of their neurons in vitro. It was found that neurons and neural tissue explants from the starfish, Asterias rubens, and the brittlestar, Ophiura ophiura, and explants from the brain of the ascidian, Ciona intestinalis, could be cultured for up to 6 weeks in a modified L15-based medium. Some cells extended axonal projections and produced growth cones under certain conditions. Attempts were made to stimulate neuron survival and outgrowth of echinoderm cultures with conditioned media containing growth factors or tissue extracts and with various substrates including extracellular matrix extracts from native tissue. Ascidian brain explants from both normal and regenerating animals were cultured in the standard conditions established for echinoderm tissue, with outgrowth being observed in 25% of explants. In these cultures labelling with bromodeoxyuridine suggested that regeneration continues in vitro, although results using substance P immunocytochemistry indicate neuronal differentiation may be impeded. These preliminary studies suggest it is possible to maintain adult echinoderm and ascidian neurons in vitro.

Animals↗
PubMed2007

The influence of pharmacogenetics on fatty liver disease in the wistar and kyoto rats: a combined transcriptomic and metabonomic study.

Although fatty liver disease is caused by a number of toxicological insults and the metabolic syndrome, the exact mechanisms by which many of these pathophysiological stimulii induce fatty liver are unknown. The rapid and profound steatosis caused by orotic acid, resulting from an impairment in the production of ApoB, has been investigated in the Wistar strain rat using a combined transcriptomic and metabonomic/metabolomic approach. Analysis of liver tissue from rats exposed to orotic acid for 1, 3, and 14 days was performed by DNA microarrays and high resolution 1H NMR spectroscopy based metabonomics of both tissue extracts and intact tissue (n = 3). Data were analyzed using a combination of ANOVA and principal components analysis, used as a data reduction tool to visualize the most perturbed transcripts and metabolites. Orotic acid produced a profound 8-fold increase in total lipids, and in particular increases in resonances associated with polyunsaturated fats (CH=CH and CH2CH=CH groups). This was accompanied by increases in the concentrations of trimethylamine-oxide (TMAO), betaine, choline, and phosphocholine, as well as a relative decrease in glucose and glycogen. At the transcriptional level, perturbations were detected in both oxidative stress and osmoregulation/pH homeostasis. However, this contrasts with a previous transcriptomic/metabolic study of fatty liver disease in a combined data set of Wistar (out-bred) and Kyoto (in-bred) strains of rats, with only 4 transcripts being found to be in common between the two analyses. This emphasizes the need to understand how strain background interacts with a given toxic lesion or genetic modification.

Animals↗
PubMed2001

Indications for post-translational regulation of Vitis vinifera L. arginine decarboxylase.

In order to study arginine decarboxylase regulation, we produced an antiserum against a hybrid of a 615 amino acid residue fragment of grapevine arginine decarboxylase cDNA with maltose-binding protein. The antiserum generated recognized mainly a protein band of ca. 80 kDa in extracts from grapevine tissues. Extracts from leaves and internodes in different developmental stages showed differences in the quantity of the 80 kDa band recognized by the antiserum. However, these differences did not correspond with changes in arginine decarboxylase specific activity. Furthermore, western blot analysis of extracts from cell cultures, where enzyme-specific activity was induced or repressed, did not reveal respective changes in the quantity of the 80 kDa protein band. Digestion of the hybrid by the specific protease factor Xa resulted in a polypeptide of 90 kDa instead of the expected two polypeptides of 43 and 66 kDa. Finally, western blot analysis of shoot extract incubated with factor Xa or the hybrid protein previously digested by factor Xa revealed that factor Xa-digested hybrid protein cleaved the 80 kDa band, resulting in two bands of ca. 38 and 40 kDa, whereas factor Xa alone did not affect it. These results suggest that arginine decarboxylase protein levels and/or activity is post-translationally regulated, as has been shown for other enzymes of polyamine biosynthesis.

Animals↗
PubMed1996

Testis-specific protein, Y-encoded (TSPY) expression in testicular tissues.

TSPY, the 'testis-specific protein, Y-encoded', is the product of a tandem gene cluster on human proximal Yp. In order to gain insight into the function of this locus, we have analysed (I) the diversity of RNAs transcribed from the cluster, (II) the sequence homology of the deduced TSPY to other proteins, and (iii) its protein properties both in tissue extracts and in tissue sections, using a TSPY-specific antiserum. We have identified a set of distinct TSPY transcripts with diverse exon compositions. We show that TSPY has homology with other human and non-human proteins, including SET and NAP, factors that are suggested to play a role in DNA replication. Protein analysis revealed TSPY to occur mainly in a modified, putatively phosphorylated form. By immunostaining it was detected in distinct subsets of spermatogonia. TSPY was also strongly immunostained in early testicular carcinoma in situ (CIS), while seminomatous tumour cells stained less intensely. The spermatogonial cells of two XY-TFM-females gave a strong immune response. The data presented here point to a phosphorylation-dependent TSPY-function in early spermatogenesis, immediately prior to the spermatogonia-to-spermatocyte transition, and in early testicular tumorigenesis.

Amino Acid Sequence↗
PubMedDate not supplied

Detection of a novel compound after overdoses of aspirin and amoxapine.

The identification of a novel by-product in the tissue and fluid extracts of a victim of fatal overdoses of the tricyclic antidepressant amoxapine and aspirin is presented. Gas chromatography/mass spectrometry suggested that amoxapine was transacetylated by aspirin to form N-acetylated amoxapine. When standard N-acetylated amoxapine was prepared and subjected to the same analytical testing as extracted tissues and fluids, the metabolite was identified as N-acetylamoxapine. Quantitation of N-acetylamoxapine was obtained by gas chromatography. Concentrations of N-acetylamoxapine compared to those of amoxapine and salicylates in blood, liver, stomach, and small bowel are given.

Acetylation↗
PubMed1984

Purification of the chick eye ciliary neuronotrophic factor.

Dissociated 8-day chick embryo ciliary ganglionic neurons will not survive for even 24 h in culture without the addition of specific supplements. One such supplement is a protein termed the ciliary neuronotrophic factor (CNTF) which is present at very high concentrations within intraocular tissues that contain the same muscle cells innervated by ciliary ganglionic neurons in vivo. We describe here the purification of chick eye CNTF by a 2 1/2-day procedure involving the processing of intraocular tissue extract sequentially through DE52 ion-exchange chromatography, membrane ultrafiltration-concentration, sucrose density gradient ultracentrifugation, and preparative sodium dodecyl sulfate-polyacrylamide gradient electrophoresis. An aqueous extract of the tissue from 300 eyes will yield about 10-20 micrograms of biologically active, electrophoretically pure CNTF with a specific activity of 7.5 X 10(6) trophic units/mg protein. Purified CNTF has an Mr of 20,400 daltons and an isoelectric point of about 5, as determined by analytical gel electrophoresis. In addition to supporting the survival of ciliary ganglion neurons, purified CNTF also supports the 24-h survival of cultured neurons from certain chick and rodent sensory and sympathetic ganglia. CNTF differs from mouse submaxillary nerve growth factor (NGF) in molecular weight, isoelectric point, inability to be inactivated by antibodies to NGF, ability to support the in vitro survival of the ciliary ganglion neurons, and inability to support that of 8-day chick embryo dorsal root ganglionic neurons. Thus, CNTF represents the first purified neuronotrophic factor which addresses parasympathetic cholinergic neurons.

Animals↗
PubMed1987

Use of a novel type of rotating disc electrode and a flow cell with laminar flow pattern for the electrochemical detection of biogenic monoamines and their metabolites after Sephadex gel chromatographic purification and high-performance liquid chromatographic isolation from rat brain.

A novel type of rotating disc electrode and a flow cell with laminar flow pattern were developed and applied to the electrochemical detection of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, 3-methoxytyramine (3-MT), noradrenaline, 3-methoxy-4-hydroxyphenylethyleneglycol (MOPEG), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid after HPLC of these compounds. The active surface of the rotating disc working electrode was made from solid paraffin (40% wt/wt) and graphite powder (60% wt/wt). The sensitivity of the detector was proportional to the square root of the angular velocity and was practically independent of the flow rate of the mobile phase. The surface of the working electrode was very large (radius = 12 mm), and so the percentage of oxidation was 24-67% (flow rate = 1.0 ml/min), depending on the compound. Electrical noise between 20 and 40 pA and background current of 20-60 nA were observed. In practice, the sensitivity for the detection of the compounds examined here was 8-16 nA/ng, and so a detection limit of 5 pg/injection could be achieved, when the detector was combined with reversed-phase HPLC. Supernatants obtained from the extracts of the tissue samples (nine brain parts of rat brain were studied) were purified by using Sephadex G-10 gel chromatography. Before this procedure, the proteins of the tissue extracts were precipitated by 0.2 M HClO4, and the excess of HClO4 was precipitated by KOH/HCOOH buffer. Simultaneously, the pH of the extracts was set to 2.4 by the above buffer.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗