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At least 127 records · Page 7Linked to original sources
PubMed2004

Schedule-dependent cytotoxic interaction between epidoxorubicin and gemcitabine in human bladder cancer cells in vitro.

PURPOSE: The aim of the study was to evaluate the activity of epidoxorubicin (EPI) and gemcitabine (GEM) and to define the most effective schedule in human bladder cancer cells. EXPERIMENTAL DESIGN: The study was performed on HT1376 and MCR cell lines. Cells were exposed for 1 and 24 h to drugs used in different schemes. Cytotoxic activity was evaluated by the sulforhodamine B assay, potential clinical activity was estimated by relative antitumor activity, and the type of drug interaction was assessed using the method of Chou and Talalay. Cell cycle perturbations and apoptosis were assessed by flow cytometry; BAX, BCL-2, and P53 expression was evaluated by Western blot; and DNA damage was assessed using the alkaline Comet assay. RESULTS: EPI and GEM produced a cytotoxic effect in both cell lines, with 50% inhibitory concentration and relative antitumor activity values suggestive of a high clinical activity. Simultaneous treatment with EPI and GEM and the sequence GEM-->EPI caused an antagonistic interaction (combination index > 1) after both 1- and 24-h treatments. Conversely, the inverse sequence, EPI-->GEM, produced a synergistic interaction that was more pronounced in MCR cells than in HT1376 cells. The increase in DNA-damaged cells from 10% to 20% after single-drug exposure to 40-60% at the end of EPI-->GEM treatment may explain the synergistic interaction produced by the anthracycline-antimetabolite sequence. CONCLUSIONS: Our findings show that the efficacy of the EPI and GEM combination is highly schedule dependent and indicate that the most active scheme is EPI followed by GEM, which is currently being validated in an ongoing intravesical Phase I-II clinical protocol.

Antibiotics, Antineoplastic↗
PubMed1992

Use of fluid-attenuated inversion-recovery pulse sequences for imaging the spinal cord.

Fourteen patients with disease of the spinal cord were imaged with fluid-attenuated inversion-recovery (FLAIR) sequences in which the inversion time was chosen to substantially reduce or null the signal from CSF. Lesions were seen with greater conspicuity than with conventional contrast-enhanced and -unenhanced T1- and T2-weighted sequences in 11 cases.

Adult↗
PubMed1996

Acyl carrier protein of Azospirillum brasilense: properties of the purified protein and sequencing of the corresponding gene, acpP.

Acyl carrier protein (ACP) plays a crucial role in bacterial fatty acid synthesis. Cloning genes encoding ACPs from Gram-negative bacteria in Escherichia coli is difficult due to adverse effects of the cloned gene on host cell viability, and we were unsuccessful in cloning the full length ACP gene (acpP) from Azospirillum brasilense using conventional methods. Therefore, ACP from A. brasilense was purified to homogeneity and a part of the acpP gene was cloned using the polymerase chain reaction (PCR) technique with two primers, one designed from the N-terminal amino acid sequence of the purified ACP and the other from the highly conserved amino acid sequence of bacterial ACPs. The nucleotide sequence of the gene was obtained by cloning and sequencing inverse PCR products containing the acpP region generated by two oppositely oriented internal primers designed from the partial acpP gene sequence using restriction-enzyme-digested, self-circularized chromosomal DNA fragments as templates. Characterization of the purified ACP and analysis of the derived amino acid sequence of the acpP gene of A. brasilense revealed that: (a) the mature ACP, composed of 78 amino acids, is a highly expressed protein (about 2.0-3.0 x 10(4) molecules per cell), (b) compared to E. coli ACP, it has a more compact structure and contains significantly more hydrophobic amino acid residues and (c) the potential mRNA sequence of the ACP gene has some structural features typical of a stable mRNA.

Acyl Carrier Protein↗
PubMed2006

[Efficacy and safety of two dosing regimens with Tadalafil in Spanish men with erectile dysfunction: results from the SURE study in 14 European countries].

OBJECTIVE: [corrected] To compare the efficacy and safety of tadalafil 20 mg administered 3 times/week (SCH) vs. on demand (OD) in a cohort of Spanish men with erectile dysfunction (ED), since Tadalafil period of responsiveness lasts up to 36 hours post-dosing. MATERIAL AND METHODS: The 418 Spanish patients participating in the European multicenter, crossover, open-label SURE clinical trial (comprising 4262 men) were randomly assigned to one of the treatment sequences: tadalafil 20 mg SCH for 5-6 weeks followed by tadalafil 20 mg OD for 5-6 weeks, or the inverse sequence. At completion, patients were asked to select the regimen they preferred to receive in an extension phase. RESULTS: In both regimens, tadalafil led to a similar improvement in erectile function compared to baseline. However, the SCH regimen showed statistically significant higher scores for several IIEF questions (i.e. sexual desire domain). Normal erectile function (IIEF EF domain score > or = 26) was achieved by 69.3% of patients on SCH and 64.3 % on OD, with a sexual intercourse success rate (SEP3) of 75.6% and 72.2% respectively (p<0.05). Nevertheless, more patients preferred to receive tadalafil OD for the extension phase (55.9% vs 44.1%, p<0.05). Tadalafil was well tolerated in both regimens. The most common TEAEs (> or = 5%) were headache, dyspepsia and back pain. There were no clinically significant differences in the incidence of TEAEs between regimens. CONCLUSIONS: Tadalafil 20 mg is efficacious and well tolerated for the treatment of ED, regardless the regimen of administration (OD or SCH). Patients can choose the pattern of administration that fits better with their expectations.

Adult↗
PubMed1993

Effectiveness of the Short TI Inversion Recovery (STIR) sequence in MR imaging of intramedullary spinal lesions.

A Short TI Inversion Recovery (STIR) sequence with spin-echo data collection was compared to a conventional cardiac gated long TR spin-echo (SE) sequence for detecting intramedullary signal abnormalities. The cervical (n = 48), cervico-thoracic (n = 1), and thoraco-lumbar (n = 18) spinal cord was imaged in a sagittal plane with a 0.5 T (n = 61) or 1.5 T (n = 6) MRI unit in 67 patients with clinical evidence of myelopathy of different etiologies (e.g., multiple sclerosis, trauma, herniated intervertebral disk, spondylosis, etc.). In all patients, ungated double or quadruple echo STIR images (TR 1000-1400 msec, TI 100 msec, TE 30-60 or 30-60-90-120 msec) were compared with cardiac gated long TR (1400-2100 msec), double echo (30-100, 50-100, or 50-150 msec) SE images with first order flow compensation for the second echo. Although STIR images appeared "noisier" than long TR SE images, they showed fewer ghost artifacts. In 55 patients, single or multiple, focal or diffuse, hyperintense areas within the spinal cord were observed on both long TR SE and (magnitude reconstructed) STIR images. Lesion conspicuity was better on the STIR images in 25 patients, better on the SE images in 14 patients, and equal in 16. STIR sequence provides a valuable alternative to gated long TR SE sequence for the MRI investigation of intramedullary spinal lesions.

Adolescent↗
PubMed1987

Mechanism of anion permeation through channels gated by glycine and gamma-aminobutyric acid in mouse cultured spinal neurones.

1. The ion-selective and ion transport properties of glycine receptor (GlyR) and gamma-aminobutyric acid receptor (GABAR) channels in the soma membrane of mouse spinal cord neurones were investigated using the whole-cell, cell-attached and outside-out patch versions of the patch-clamp technique. 2. Current-voltage (I-V) relations of transmitter-activated currents obtained from whole-cell measurements with 145 mM-Cl- intracellularly and extracellularly, showed outward rectification. In voltage-jump experiments, the instantaneous I-V relations were linear, and the steady-state I-V relations were rectifying outwardly indicating that the gating of GlyR and GABAR channels is voltage sensitive. 3. The reversal potential of whole-cell currents shifted 56 mV per tenfold change in internal Cl- activity indicating activation of Cl(-)-selective channels. The permeability ratio of K+ to Cl- (PK/PCl) was smaller than 0.05 for both channels. 4. The permeability sequence for large polyatomic anions was formate greater than bicarbonate greater than acetate greater than phosphate greater than propionate for GABAR channels; phosphate and propionate were not measurably permeant in GlyR channels. This indicates that open GlyR and GABAR channels have effective pore diameters of 5.2 and 5.6 A, respectively. The sequence of relative permeabilities for small anions was SCN- greater than I- greater than Br- greater than Cl- greater than F- for both channels. 5. GlyR and GABAR channels are multi-conductance-state channels. In cell-attached patches the single-channel slope conductances close to 0 mV membrane potential were 29, 18 and 10 pS for glycine, and 28, 17 and 10 pS for GABA-activated channels. The most frequently observed (main) conductance states were 29 and 17 pS for the GlyR and GABAR channel, respectively. 6. In outside-out patches with equal extracellular and intracellular concentrations of 145 mM-Cl-, the conductance states were 46, 30, 20 and 12 pS for GlyR channels and 44, 30, 19 and 12 pS for GABAR channels. The most frequently occurring main state was 46 pS for the GlyR and 30 pS for the GABAR channel. 7. Single-channel conductances measured in equal 140 mM concentrations of small anions on both membrane faces revealed a conductance sequence of Cl- greater than Br- greater than I- greater than SCN- greater than F- for both channels. This is nearly the inverse sequence of that found for the permeability of these ions indicating the presence of binding sites for ions in the channel.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1982

Recombination between two TnA transposon sequences oriented as inverse repeats is found less frequently than between direct repeats.

Inverse repeats of the transposon Tn2660 in either a ColE1 or an R6K replicon, with or without inversions of the parental DNA sequences between the repeats, show no detectable (less than 2%) evidence of recombination between the repeats after 60 generations of growth in either recA or RecA+ hosts. In contrast, attempts made to construct plasmids which carry two direct repeats by in vitro cleavage and ligation in the recA host were unsuccessful, although homologous plasmids with inverse repeats could be constructed, and other plasmids were found consistent with products of recombination between the direct repeats of the transient intermediate structure. It is concluded that in recA or recA+ hosts recombination between direct repeats of a transposon is frequent, whereas recombination between inverse repeats of a homologous structure has not been observed. A model to explain this difference depends upon a mechanisms that produces a nick in only one of the pair of strands at the internal resolution site (IRS) sequence of the transposon.

Cloning, Molecular↗
PubMed1994

Isolation and analysis of the breakpoint sequences of chromosome inversion In(3L)Payne in Drosophila melanogaster.

Chromosomal rearrangements constitute a significant feature of genome evolution, and inversion polymorphisms in Drosophila have been studied intensely for decades. Population geneticists have long recognized that the sequence features associated with inversion breakpoints would reveal much about the mutational origin, uniqueness, and genealogical history of individual inversion polymorphisms, but the cloning of breakpoint sequences is not trivial. With the aid of a method for rapid recovery of DNA clones spanning rearrangement breakpoints, we recover and examine the DNA sequences spanning the breakpoints of the cosmopolitan inversion In(3L)Payne in Drosophila melanogaster. By examining the sequence diversity associated with six standard and seven inverted chromosomes from natural populations, we find that the inversion is monophyletic in origin, the sequences are genetically isolated from recombination at the breakpoints, and there is no association with features such as transposable elements. The inverted sequences show 17-fold less nucleotide polymorphism, but there are eight fixed differences in the region spanning both breakpoints. This suggests that this inversion is not recently derived. Finally, Northern analysis and transcript mapping find that the distal breakpoint has disrupted three transcripts that are normally expressed in the standard arrangement. Incidentally, the method introduced here can be used to isolate breakpoint sequences of arrangements associated with many human diseases.

Animals↗
PubMed1995

Partially saturated fluid attenuated inversion recovery (FLAIR) sequences in multiple sclerosis: comparison with fully relaxed FLAIR and conventional spin-echo.

Fluid attenuated inversion recovery (FLAIR) sequences produce selective cerebrospinal fluid (CSF) suppression by employing a very long inversion time (TI). We used the FLAIR sequence to study patients with multiple sclerosis (MS) at 0.6 T. So far, a very long TR (and long acquisition time) has been used in a fully relaxed (FR-FLAIR) system. To speed up the FLAIR sequences, we used a shorter TR, and demonstrated that complete CSF suppression can be maintained with partial saturation (PS-FLAIR) by reducing TI at the same time. The introduction of partial saturation, however, reduced the contrast between lesions and normal appearing white matter (NAWM). Suboptimal CSF suppression therefore had to be accepted to maintain sufficient lesion to NAWM contrast. Using a TE of 60 ms, the PS-FLAIR and FR-FLAIR performed equally well in the detection of MS-lesions, although the former provided poorer CSF suppression. Both FLAIR sequences, however, provided poorer constrast between lesions and NAWM compared to conventional spin-echo sequences. Although the long acquisition time of the FLAIR sequence can be reduced by using partial saturation, complete CSF suppression and good lesion to NAWM contrast are incompatible at short TRs. Using a TE of 60 ms, conventional spin-echo sequences detect more lesions and provide better contrast between lesions and NAWM than FLAIR sequences in MS patients.

Brain↗
PubMed2001

Catalytic decomposition of hydrogen peroxide and 2-chlorophenol with iron oxides.

The aim of this study was to examine the catalyzed decomposition of hydrogen peroxide and 2-chlorophenol (2-CP) in the presence of iron oxides. Granular ferrihydrite, goethite, and hematite were selected as catalysts in this study. 2-CP was used as the model compound because it is a typical toxic compound and has not been investigated in the catalytic decomposition by iron oxides. The catalytic activity for hydrogen peroxide decomposition followed the sequence: granular ferrihydrite > goethite > hematite. However, hematite exhibited the highest activity in catalyzing 2-CP oxidation. The oxidation efficiency of 2-CP corresponded with the inverse sequence of specific area and pHpzc of the iron oxides. The catalytic activity of granular ferrihydrite was affected significantly by the mixing speed and particle size for its large value of Thiele modulus (phi) and Damkohler number (Da). The strong diffusion resistance for granular ferrihydrite was attributed either to its microporous structure or to the formation of oxygen in the pores of the iron oxide leading to the unexpected catalytic activity of granular ferrihydrite to hydrogen peroxide and 2-CP.

Catalysis↗
PubMed1994

Screening for inversions in the factor VIII (F8) gene causing severe haemophilia A.

A total of 164 unrelated patients with severe haemophilia A were screened for partial inversions of the factor VIII (F8) gene resulting from recombination between the intronic F8A gene and one or other of two homologous upstream A gene sequences. Inversions were found in 69 (42%) patients. Most inversions (90%) involved the distal rather than the proximal A gene. This unique mutational mechanism is estimated to occur with a frequency of 7.2 x 10(-6) per gene per gamete per generation. Although two patients with an inversion possessed inhibitors (antibodies) against factor VIII, possession of inhibitors did not appear to be associated disproportionately with inversion-type mutations.

Blotting, Southern↗
PubMed1994

Technical note: use of a double inversion recovery pulse sequence to image selectively grey or white brain matter.

The design of a double inversion recovery (DIR) sequence, to image selectively grey or white brain matter, is described. Suitable choice of inversion times allows either cerebrospinal fluid (CSF) and white matter to be suppressed, to image the cortex alone, or CSF and grey matter to be suppressed, to image the white matter. The DIR sequence was found to give clear delineation of the cerebral cortex.

Adult↗
PubMed1986

Structural and functional analysis of chicken U4 small nuclear RNA genes.

Two distinct chicken U4 RNA genes have been cloned and characterized. They are closely linked within 465 base pairs of each other and have the same transcriptional orientation. The downstream U4 homology is a true gene, based on the criteria that it is colinear with chicken U4B RNA and is expressed when injected into Xenopus laevis oocytes. The upstream U4 homology, however, contains seven base substitutions relative to U4B RNA. This sequence may be a nonexpressed pseudogene, but the pattern of base substitutions suggests that it more probably encodes a variant yet functional U4 RNA product not yet characterized at the RNA level. In support of this, the two U4 genes have regions of homology with each other in their 5'-flanking DNA at two positions known to be essential for the efficient expression of vertebrate U1 and U2 small nuclear RNA genes. In the case of U1 and U2 RNA genes, the more distal region (located near position-200 with respect to the RNA cap site) is known to function as a transcriptional enhancer. Although this region is highly conserved in overall structure and sequence among U1 and U2 RNA genes, it is much less conserved in the chicken U4 RNA genes reported here. Interestingly, short sequence elements present in the -200 region of the U4 RNA genes are inverted (i.e., on the complementary strand) relative to their usual orientation upstream of U1 and U2 RNA genes. Thus, the -200 region of the U4 RNA genes may represent a natural evolutionary occurrence of an enhancer sequence inversion.

Animals↗
PubMed1998

Early diagnosis of herpes encephalopathy using fluid-attenuated inversion recovery pulse sequence.

This study describes the usefulness of fluid-attenuated inversion recovery (FLAIR) pulse sequence for early diagnosis and treatment of herpes encephalitis. An 8-year-old boy with suspected herpes simplex encephalitis was examined by magnetic resonance imaging at 3 days post-symptom onset. Lesions in the right thalamus and insular cortex were detected by conventional T2-weighted images and images from FLAIR pulse sequence. Bilateral temporal lesions, however, were only detected by FLAIR images.

Child↗
PubMed1985

Erabutoxin b. Initial protein refinement and sequence analysis at 0.140-nm resolution.

The crystal structure of the protein postsynaptic neurotoxin, erabutoxin b, has been refined at 0.140-nm resolution (R = 0.22) by restrained least-squares and interactive computer graphics. The study has established complete structural identity of the two sea-snake venom toxins, erabutoxin b and neurotoxin b, isolated from Laticauda semifasciata snakes taken in different Pacific Ocean waters. Two chemical-sequence inversion errors in erabutoxin b have been discovered during refinement, corrected and subsequently confirmed in both erabutoxin b and erabutoxin a by chemical analysis. The correct sequences are His6-Gln7, hitherto unsuspected, and Ser18-Pro19. The sequence correction His6-Gln7 explains the anomalous results of 1H NMR solution studies and those of early chemical modification experiments, which were in conflict with the previously published three-dimensional structure of erabutoxin b. On refinement, the five-stranded beta sheet described earlier is now shown to be discontinuous, split into a two-stranded beta loop and a three-stranded beta sheet. Unique features of the Pro44-Gly49 peripheral segment have now been identified. 51 water molecule positions have been located.

Amino Acid Sequence↗
PubMed1996

Genetic complementation of radiation response by 3' untranslated regions (UTR) of RNA.

The molecular basis of radiosensitivity was studied using a cDNA complementation approach to correct radiosensitivity in cells. Four cDNAs of sizes 1.6, 2.0, 2.2 and 2.5 kb were isolated that corrected several aspects of the phenotype of cells from patients with the human genetic disorder ataxia-telangiectasia, characterized by hypersensitivity to ionizing radiation. The criteria used to assess correction included cell viability, induced chromosome aberrations, G2 phase delay and induction of p53 after exposure to radiation. One cDNA (2.5 kb) was identified as the complete sequence of the RNA helicase p68, which was capable of correcting radiosensitivity based on two of the above four criteria, with p53 induction post irradiation being partially corrected. The 2.2 kb cDNA was shown to correspond to the complete sequence of arginyl tRNA synthetase and the other two cDNAs were identical to the 3' untranslated regions (UTR) of the transcription factor TFIIS (1.6 kb) and phospholipase A2 (2.0 kb) respectively. Additional transfections with the 3'UTR (198 nucleotides) of p68 RNA helicase and its inverse sequence revealed that the 3'UTR had the same complementation capacity as the full-length cDNA, whereas the inverse construct failed to complement radiosensitivity. These data provide additional support for a novel role for 3'UTRs in the regulation of gene expression.

Ataxia Telangiectasia↗
PubMed1992

Developmental regulation and neuronal expression of the mRNA of rat n-chimaerin, a p21rac GAP:cDNA sequence.

Human n-chimaerin is a GTPase-activating protein (GAP) for p21rac and a phorbol ester receptor. We have isolated rat n-chimaerin cDNA and investigated the cellular and developmental pattern of mRNA expression in the brain. There is extensive sequence conservation with human n-chimaerin in the coding region and the first 400 nucleotides of the 3'-untranslated region (UTR) (90% and 83% identity respectively). The rat cDNA encodes an additional 35 N-terminal amino acids compared with the reported human cDNA, which has a 5'-UTR sequence inversion and a 41-nucleotide deletion including the putative initiator methionine. The rat cDNA encodes a 334-amino acid protein (38200 M(r), pI 8.04) with 97% amino acid sequence identity with the human protein, after correction of the human 5'-DNA sequence. n-Chimaerin mRNA was detectable in embryonic rat brain at day 15 and increased in amount postnatally from birth to 20 days, coincident with cellular differentiation and synaptogenesis. n-Chimaerin mRNA is restricted to neurons, with highest concentrations in hippocampal pyramidal cells, granule cells of the dentate gyrus and cortical neurons. In the cerebellum the mRNA was detected only in Purkinje neurons. The pattern and specificity of mRNA expression suggests an important role for n-chimaerin in neuronal signal-transduction mechanisms.

Amino Acid Sequence↗
PubMed2003

Highly organized structure in the non-coding region of the psbA minicircle from clade C Symbiodinium.

The chloroplast genes of dinoflagellates are distributed among small, circular dsDNA molecules termed minicircles. In this paper, we describe the structure of the non-coding region of the psbA minicircle from Symbiodinium: DNA sequence was obtained from five Symbiodinium strains obtained from four different coral host species (Goniopora tenuidens, Heliofungia actiniformis, Leptastrea purpurea and Pocillopora damicornis), which had previously been determined to be closely related using LSU rDNA region D1/D2 sequence analysis. Eight distinct sequence blocks, consisting of four conserved cores interspersed with two metastable regions and flanked by two variable regions, occurred at similar positions in all strains. Inverted repeats (IRs) occurred in tandem or "twin" formation within two of the four cores. The metastable regions also consisted of twin IRs and had modular behaviour, being either fully present or completely absent in the different strains. These twin IRs are similar in sequence to double-hairpin elements (DHEs) found in the mitochondrial genomes of some fungi, and may be mobile elements or may serve a functional role in recombination or replication. Within the central unit (consisting of the cores plus the metastable regions), all IRs contained perfect sequence inverses, implying they are highly evolved. IRs were also present outside the central unit but these were imperfect and possessed by individual strains only. A central adenine-rich sequence most closely resembled one in the centre of the non-coding part of Amphidinium operculatum minicircles, and is a potential origin of replication. Sequence polymorphism was extremely high in the variable regions, suggesting that these regions may be useful for distinguishing strains that cannot be differentiated using molecular markers currently available for Symbiodinium.

Animals↗