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At least 1,369 records · Page 76Linked to original sources
PubMed1995

Renal masses: assessment of corticomedullary-phase and nephrographic-phase CT scans.

PURPOSE: To evaluate the role of thin-section helical computed tomography (CT) performed during the corticomedullary phase (CMP) and nephrographic phase (NP) of contrast enhancement in the detection and characterization of renal masses. MATERIALS AND METHODS: Renal CT scans and medical records of 33 patients were retrospectively reviewed. In all examinations, 5-mm-thick, contiguous, helical-mode scans were obtained before and 40 seconds after initiation of dynamic bolus injection of contrast material (CMP images); 5-mm-thick, contiguous, axial-mode scans were obtained after completion of CMP scanning (NP images). RESULTS: At review of CMP, NP, and combination images, 259, 389, and 417 lesions, respectively, were identified. The greatest difference in detection occurred in the renal medulla, with 25 lesions identified on CMP images and 111 lesions identified on NP images. False-positive results occurred when CMP images were reviewed without NP images. CONCLUSION: CT scans obtained only during the CMP of contrast enhancement fail to depict many renal masses that are easily seen on NP images.

False Positive Reactions↗
PubMed1994

Smoke inhalation injury in sheep is caused by the particle phase, not the gas phase.

The inhalation of smoke can produce severe lung injury, particularly to airways. We assessed the role of the toxic compounds in the particle phase vs. those in the gas phase of smoke in the injury process by filtering out all particles > 0.3 micron diam before exposure. Adult sheep (n = 16) were insufflated with a well-characterized cellulose smoke. Mean particle size was 3 +/- 0.4 micron diam. A standardized dose of 12 breaths of whole or filtered smoke (n = 8/group) was given to sheep under anesthesia with a tidal volume of 20 ml/kg. Sheep were awakened and monitored for 24 h and then killed. Peak carboxyhemoglobin levels were 40-45% in both groups. Severe respiratory failure occurred only in the whole-smoke group, as evidenced by an increase in shunt fraction from a control of 0.04 +/- 0.02 to 0.28 +/- 0.05, a decrease in lung compliance of 50%, and histological evidence of severe airway mucosal edema, ulceration, and bronchorrhea. No significant physiological, histological, or biochemical changes were noted in the filtered-smoke group.

Animals↗
PubMed2000

Phase I Clinical Trial of a Day-1, -3, -5 Every 3 WeeksPhase I Clinical Trial of Day-1, -3, -5 Every 3 Weeks Schedule with Titanocene Dichloride (MKT 5) in Patients with Advanced Cancer. (Phase I Study Group of the AIO of the German Cancer Society).

BACKGROUND: Titanocene dichloride (TD) is an organometallic compound with antiproliferative properties in vitro and promising antitumor activity in preclinical in vivo models. The drug interferes with DNA, blocks the S/G(2) phase of the cell cycle and shows antiangiogenic properties. The purpose of this study was to determine the maximum tolerated dose (MTD) and the dose-limiting toxicity (DLT) of a 'split' dose administration schedule (days 1, 3, 5 q 3 weeks). PATIENTS AND METHOD: Patients with progressive advanced cancer and a creatinine clearance > 60 ml/min qualified for a treatment with TD after standard therapies (radio-, chemo-, hormone therapy) failed. A total of 10 patients (4 females, 6 males) with a median age of 58 (range 49-68) years were treated with 80 mg/m(2) TD at days 1, 3 and 5 (repeated at day 22). The drug was administered as light-protected infusion within 1 h. RESULTS: Significant side effects were as follows: nausea/vomiting, appetite loss, renal toxicity (elevation of serum creatinine and proteinuria) and liver toxicity (bilirubin and alkaline phosphatase elevation), but no myelosuppression. At the starting dose (3 x 80 = 240 mg/m(2) TD), renal (3 patients) or liver toxicity (1 patient) of grade 3 was judged as DLT. No further dose escalation was possible. No objective tumor remission was observed. CONCLUSION: The tolerability of TD cannot be improved by splitting the total dose in to three treatments every other day. Compared to previous phase I data using a 3-weekly and a 1-weekly schedule, the 'split' dose administration allowed no further increase of the total drug dose per treatment cycle. Thus, dose intensification by alterations of the application mode does not seem to be possible. Copyright 2000 S. Karger GmbH, Freiburg

Journal Article↗
PubMed2001

Characterization of Ascaris-induced biphasic skin allergic reaction model in mice: possible roles of mast cells in early-phase and CD4-positive T cells in late-phase reactions.

We established an Ascaris-induced biphasic skin allergic reaction in mice. In the early-phase reaction (EPR), mast cell degranulation was observed, and tranilast inhibited ear edema. In mast-cell-deficient mice (WBB6F(1)-W/W(V) mice), ear edema in the EPR disappeared, whereas that in the late-phase reaction (LPR) remained. Eosinophils increased, and CD4-positive T cells tended to increase in the LPR. Anti-CD4 antibody, anti-IL-4 antibody and anti-IL-5 antibody all inhibited ear edema and had a tendency to inhibit eosinophil infiltration in the LPR. These data suggest that the EPR is induced by histamine released from mast cells, whereas the LPR is induced by IL-4 and IL-5 produced from CD4-positive T cells.

Animals↗
PubMed1981

Effects of triamterene and its phase I and phase II metabolities on sodium transport of the isolated frog skin.

We studied the effects of triamterene (TA) on its phase I and phase II metabolites, p-hydroxytriamterene (OH-TA) and p-hydroxytriamterene sulfuric acid ester (OH-TA ester), on sodium transport in the isolated frog skin. While TA applied to the inside (corial side) surface had no effects on potential difference (PD) and short-circuit current (SCC), TA, OH-TA, and OH-TA ester at a concentration of 10(-5) mol/l significantly decreased SCC by 19, 24 and 16%, respectively, when added to the solution bathing the outside (epithelial side) surface of the skin. In vasopressin-treated skins TA was more effective than OH-TA or OH-TA ester. In aldosterone-treated skins all compounds significantly suppressed SCC, the strongest effect was again exerted by TA. Only minor and transient changes in PD were noted. Inhibition of sodium transport was rapidly reversible when skins were washed with fresh Ringer solution. Thus, OH-TA and OH-TA ester possess qualitatively similar pharmacological activity as TA. The quantitatively smaller effects of OH-TA and OH-TA ester in the hormone-stimulated skin as compared to TA agrees well with their relative natriuretic potency observed in vivo.

Aldosterone↗
PubMed1987

[Remission in phase II and phase III studies: criteria and prerequisites].

We identify factors of influence for the observed variability of published rates of remission and we derive from these findings prerequisites and criteria for the assessment of remission in cancer therapy. As a consequence we postulate a separate assessment of patients with measurable and with non-measurable disease and a complete documentation of those patient characteristics in order to compare rates of remission of different studies. Several methods for the determination of sample sizes in phase II and phase III clinical trials are presented and discussed.

Antineoplastic Agents↗
PubMed1978

Measurement of acetate in aqueous solutions and plasma by gas phase chromatography using a porous polymer stationary phase.

A method of acetate determination by gas phase chromatography using a porous polymer stationary phase is reported that is suitable for use with aqueous and plasma samples. It is linear up to 100 mmol/l and has a coefficient of variation of less than 4% for acetate values of greater than 1 mmol/l. The recovery of acetate from plasma is 92% and sample retention time is 3 minutes. The reference range of plasma acetate in a group of 40 apparently healthy subjects was from less than 0.1 to 0.35 mmol/l. The frequently encountered problem of absorption and ghosting of volatile fatty acids is overcome without the addition of formic acid vapour to the carrier gas.

Acetates↗
PubMed1986

Speckle reduction in pulse echo imaging using phase insensitive and phase sensitive signal processing techniques.

In conventional B-scan imaging, speckle often distorts the true representation of small structures and lesions and hence reduces the diagnostic potential of the technique. Considerable speckle reduction has been achieved with an f/2.4, cone hybrid system by cutting the large aperture transducers into sectors, and using either phase insensitive sector addition (PISA), phase insensitive sector multiplication (PISM), or an rf multiplicative processing technique. We have compared two modes of operation with the hybrid system. In the first, the cone acts as transmitter, and each sector of the f/2.4 spherical aperture is a receiver. In the second mode, the f/2.4 sphere acts as transmitter, and each sector of the cone is a receiver. Quantitative assessment using the contrast to speckle ratio developed by Patterson et al, indicates that processing under both modes results in reduced speckle noise and improved image quality, with the cone sector receive (rx) geometry offering the greatest improvement.

Breast↗
PubMed1989

Temperature dependence of phase response curves for drug-induced phase shifts.

The effectiveness of drugs active in phase-shifting the circadian rhythm of bioluminescent glow in the unicellular dinoflagellate Gonyaulax polyedra differs, depending upon the time of drug exposure (as pulses). For two drugs tested--cycloheximide and anisomycin, both inhibitors of cytosolic protein synthesis--this function, referred to as the drug phase response curve (dPRC), differs, depending upon the ambient temperature. Since dPRCs may differ at different drug concentrations, the effects observed may be attributable to differences in the effectiveness of or recovery from the drugs at different temperatures.

Animals↗
PubMed2005

Gene expression in the conversion of early-phase to late-phase long-term potentiation.

Changes in gene expression associated with different forms of synaptic plasticity in rat hippocampus were investigated. Microarray analysis revealed differential expression of hundreds of genes 30 min after synaptic or antidromic stimulation in different patterns. Results of selected genes were verified by LightCycler RT-PCR. Synaptic activation in a theta burst protocol, which induced long-term potentiation (LTP), increased the mRNA abundance of BDNF-exon 1, but antidromic stimulation in the presence of CNQX, APV, and MCPG (to block glutamatergic synapses) decreased the level of mRNA of this transcript, as did 1 Hz synaptic stimulation. The opposite regulation of this BDNF transcript after firing of the postsynaptic neuron, coincidently or uncorrelated with synaptic firing, is consistent with the effects of BDNF on synaptic transmission, suggesting possible involvement in strengthening and weakening CA1 synapses after correlated versus uncorrelated firing of the postsynaptic neurons with its synaptic inputs. Possible involvement of transcriptional regulation of BDNF in the conversion of early-phase LTP to late-phase LTP are discussed in the context of previous studies by Dudek & Fields (Proc. Natl. Acad. Sci. USA 99: 3962-3967) showing that this conversion can be induced by antidromic stimulation of CA1 neurons in the absence of excitatory synaptic activity.

Animals↗
PubMed1980

Evidence that the dopaminergic prolactin-inhibiting factor mechanism regulates only the depletion-transformation phase and not the release phase of prolactin secretion during suckling in the rat.

We have compared the effectiveness of stalk-median eminence (SME) extracts, dopamine, and bromocriptine (CB-154) in inhibiting the release of PRL into the plasma during suckling when injected before depletion with that when the injections were given after the pituitary stores of PRL had been depleted and transformed by 10 min of suckling. We found that a single injection of either neutralized acidic extracts of SME at a dose of one or two SME equivalents per rat or 625 ng dopamine effectively prevented both the depletion of PRL within the pituitary and the subsequent rise in plasma PRL when given 1-3 min before the onset of suckling. Likewise, a single injection of bromocriptine (0.5 mg) given 20-30 min before the onset of suckling totally blocked pituitary depletion and the subsequent release of PRL into the circulation. However, the PRL concentration rose normally in the plasma in response to suckling when either SME extract or bromocriptine was given after PRL depletion had first been effected by prior short term (10 min) suckling. These data indicate that the depletion-transformation phase but not the release phase (into the circulation) of PRL secretion is under inhibitory control by a dopaminergic PRL-inhibiting factor system.

Animals↗
PubMed1999

The Caenorhabditis elegans gene ncc-1 encodes a cdc2-related kinase required for M phase in meiotic and mitotic cell divisions, but not for S phase.

We have identified six protein kinases that belong to the family of cdc2-related kinases in Caenorhabditis elegans. Results from RNA interference experiments indicate that at least one of these kinases is required for cell-cycle progression during meiosis and mitosis. This kinase, encoded by the ncc-1 gene, is closely related to human Cdk1/Cdc2, Cdk2 and Cdk3 and yeast CDC28/cdc2(+). We addressed whether ncc-1 acts to promote passage through a single transition or multiple transitions in the cell cycle, analogous to Cdks in vertebrates or yeasts, respectively. We isolated five recessive ncc-1 mutations in a genetic screen for mutants that resemble larval arrested ncc-1(RNAi) animals. Our results indicate that maternal ncc-1 product is sufficient for embryogenesis, and that zygotic expression is required for cell divisions during larval development. Cells that form the postembryonic lineages in wild-type animals do not enter mitosis in ncc-1 mutants, as indicated by lack of chromosome condensation and nuclear envelope breakdown. However, progression through G1 and S phase appears unaffected, as revealed by expression of ribonucleotide reductase, incorporation of BrdU and DNA quantitation. Our results indicate that C. elegans uses multiple Cdks to regulate cell-cycle transitions and that ncc-1 is the C. elegans ortholog of Cdk1/Cdc2 in other metazoans, required for M phase in meiotic as well as mitotic cell cycles.

Amino Acid Sequence↗
PubMed1995

Characterization of the execution phase of apoptosis in vitro using extracts from condemned-phase cells.

Apoptotic cell death is characterized by a dramatic morphological transformation during which apparently healthy cells suddenly initiate a comprehensive program of motility changes and degradative activities that culminates in disassembly of the cell into membrane-enclosed vesicles. The mechanism of the cellular changes during this spectacular execution phase of apoptosis is just now yielding to biochemical analysis. In our laboratory, we have applied a novel in vitro system to the study of these events. In this system, nuclei isolated from healthy cells undergo the characteristic changes of apoptosis rapidly and synchronously. Using this system we have identified the first substrates for interleukin-1 beta-converting enzyme (ICE)-like proteinases during apoptotic execution. One of these, the nuclear enzyme poly (ADP-ribose) polymerase is cleaved very early in the apoptotic process. A second class of proteins, the nuclear lamins, is cleaved later in the pathway. Lamin cleavage requires a second ICE-related proteinase, and is essential for the complete dissolution of nuclei into apoptotic bodies. Studies with our cell-free extracts reveal that the various proteinases and nucleases that operate during the execution phase of apoptosis do so largely in independent parallel biochemical pathways. However, all of these pathways require the action of ICE-related proteinases for their initiation.

Amino Acid Sequence↗
PubMed1994

Basic fibroblast growth factor stimulates the competence phase of subcultured endothelial cells and the progression phase of primary cultured smooth muscle cells from rat aorta.

The proliferative effects of basic fibroblast growth factor (bFGF) on the cell cycle were compared in subcultured endothelial cells (EC) and primary cultured smooth muscle cells (SMC) from rat aorta by monitoring the starting time (an index of the competence phase) and rate (an index of the progression phase) of [3H]thymidine incorporation. Persistent treatment with bFGF (1, 10 and 30 ng/ml) reduced the starting time of EC proliferation in the presence of 1% fetal bovine serum (FBS) in a concentration-dependent manner. The starting time of [3H]thymidine incorporation into EC was reduced by a maximum of 4 h by pretreatment with bFGF for 12 h but not for 3 h. DNA synthesis in EC was inhibited by pretreatment with bFGF for 24 h. The rate of [3H]thymidine incorporation into SMC was accelerated both by persistent treatment with bFGF and pretreatment for 3 h in the presence of 3% FBS. In serum-free medium, bFGF (30 ng/ml) stimulated [3H]thymidine incorporation into SMC but not into EC after incubation for 36 h. Together, bFGF (10 ng/ml) and insulin (10 micrograms/ml) synergistically stimulated [3H]thymidine incorporation into EC, but insulin alone did not. These findings indicate that bFGF is a competence factor in EC and a progression factor in SMC from rat aorta.

Animals↗
PubMed2000

Analyses of polyphenols in cacao liquor, cocoa, and chocolate by normal-phase and reversed-phase HPLC.

The antioxidant polyphenols in cacao liquor, a major ingredient of chocolate and cocoa, have been characterized as flavan-3-ols and proanthocyanidin oligomers. In this study, various cacao products were analyzed by normal-phase HPLC, and the profiles and quantities of the polyphenols present, grouped by molecular size (monomers to approximately oligomers), were compared. Individual cacao polyphenols, flavan-3-ols (catechin and epicatechin), and dimeric (procyanidin B2), trimeric (procyanidin C1), and tetrameric (cinnamtannin A2) proanthocyanidins, and galactopyranosyl-ent-(-)-epicatechin (2alpha-->7, 4alpha-->8)-(-)-epicatechin (Gal-EC-EC), were analyzed by reversed-phase HPLC and/or HPLC/MS. The profile of monomers (catechins) and proanthocyanidin in dark chocolate was similar to that of cacao liquor, while the ratio of flavan-3-ols to the total amount of monomeric and oligomeric polyphenols in the case of pure cocoa powder was higher than that in the case of cacao liquor or chocolate.

Anthocyanins↗
PubMed2002

Double-phase holograms implemented with phase-only spatial light modulators: performance evaluation and improvement.

We propose modified hologram cells (or macropixels) for the computer-generated double-phase holograms (DPHs), based on pixelated phase-only spatial light modulators (SLMs). Such modified DPHs exhibit a substantially improved signal-to-noise ratio, in comparison with the conventional ones. The modified macropixels are formed by arrays of either 1 x 2 or 2 x 2 SLM pixels.

Journal Article↗
PubMed2004

Effects of phase change on reflection in phase-measuring interference microscopy.

We show by analytical and numerical calculations that the phase change on reflection that occurs in interference microscopy is almost independent of the numerical aperture of the objective. The shift of the microscope interferogram response due to the phase change on reflection, however, increases with the numerical aperture. Measurements of the interferogram shift are made with a Linnik interference microscope equipped with various numerical-aperture objectives and are reported and compared with theory.

Journal Article↗
PubMed2004

Duplication of phase key for random-phase-encrypted volume holograms.

Holographic memory encrypted by an optical random-phase key and decrypted by either the original phase key or a duplicate key is proposed and demonstrated. The duplicate key is made by recording the encryption wave front with angle multiplexing during writing of the hologram. The amount of three-dimensional shifting that is tolerable in the duplicate key is analyzed.

Journal Article↗