Will there be any hope for the poor?
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Delivery of Health Care↗
Biomedical subjects
A Sen
Publications and source records attributed to A Sen.
Imino proton exchange in DNA catalyzed by ammonia and trimethylamine: evidence for a secondary long-lived open state of the base pair.
The base-pair opening kinetics of the self-complementary oligomer d(CGCGAATTCGCG)(2) has been derived from NMR measurements of the imino proton exchange. In general, it has previously been found that imino proton exchange in duplex DNA is limited by the proton-transfer step from the open state and that the dependence of the exchange times on the inverse concentration of an added exchange catalyst is linear. In the present study, a curvature is observed for, in particular, the innermost AT base pair with both ammonia and trimethylamine (TMA) as exchange catalysts. The two catalysts act on the same open states, but the accessibility of TMA is reduced by a factor of 2-3 compared to ammonia. Assuming that ammonia accesses the imino proton equally in the open state of the base pair and in the mononucleoside, the curvature is consistent with 7-9% of the openings ending in open states with lifetimes of about 1 micros while the bulk of open-state lifetimes fall in the nanosecond range. A curvature is also found for the exchange times of the imino protons in the A-tract sequence CGCA(8)CGC/GCGT(8)GCG. This curvature becomes increasingly pronounced from the 5'-end toward the center of the tract and hereby seems to be correlated with the contraction of the minor groove. Thus, while the base-pair lifetimes deduced from the present study are in accordance with previous measurements, a substantial fraction of the open states formed by the central AT-base pairs in the two oligomers exhibits microsecond lifetimes in contrast to previous estimates in the nanosecond range. These findings may be of relevance for the way sequence specific recognition is accomplished by proteins and ligands.
Ammonia↗
Activation of a rel-A/CEBP-beta-related transcription factor heteromer by PGG-glucan in a murine monocytic cell line.
PGG-Glucan is a soluble beta-glucan immunomodulator that enhances a variety of leukocyte microbicidal activities without activating inflammatory cytokines. Although several different cell surface receptors for soluble (and particulate) beta-glucans have been described, the signal transduction pathway(s) used by these soluble ligands have not been elucidated. Previously we reported that PGG-Glucan treatment of mouse BMC2.3 macrophage cells activates a nuclear factor kappa-B-like (NF-kappaB) transcription factor complex containing subunit p65 (rel-A) attached to an unidentified cohort. In this study, we identify the cohort to be a non-rel family member: a CCAAT enhancer-binding protein-beta (C/EBP-beta)-related molecule with an apparent size of 48 kDa, which is a different protein than the previously identified C/EBP-beta p34 also present in these cells. C/EBP-beta is a member of the bZIP family whose members have previously been shown to interact with rel family members. This rel/bZIP heteromer complex activated by PGG-Glucan is different from the p65/p50 rel/rel complex induced in these cells by lipopolysaccharide (LPS). Thus, our data demonstrate that PGG-Glucan uses signal transduction pathways different from those used by LPS, which activates leukocyte microbicidal activities and inflammatory cytokines. We further show that heteromer activation appears to use protein kinase C (PKC) and protein tyrosine kinase (PTK) pathways, but not mitogen-activated protein kinase p38. Inhibitor kappa-B-alpha (IkappaB-alpha) is associated with the heteromer; this association decreases after PGG-Glucan treatment. These data are consistent with a model whereby treatment of BMC2.3 cells with PGG-Glucan activates IkappaB-alpha via PKC and/or PTK pathways, permitting translocation of the rel-A/CEBP-beta heteromer complex to the nucleus and increases its DNA-binding affinity.
Adjuvants, Immunologic↗
Salivary fistulae.
Three cases of unusual cervical fistulae are presented with a review of the literature to caution against labelling all lateral cervical fistulae as simple branchial fistulae or midline ones as dermoid cysts.
Child↗
Further immunochemical and biocatalytic characterization of CYP1A1 from feral leaping mullet liver (Liza saliens) microsomes.
CYP1A is known to play important roles in the metabolism, detoxification and bioactivation of carcinogens and other xenobiotics in animals including fish. In our laboratory, CYP1A1 was obtained in a highly purified form with a specific content of 15-17 nmol P450 per mg protein from liver microsomes of feral fish, leaping mullet (Liza saliens). Purified mullet CYP1A1 showed a very high substrate specificities for 7-ethoxyresorufin and 7-methoxyresorufin in a reconstituted system containing purified fish P450 reductase and lipid. In addition, effects of each individual components of the reconstituted system, i.e., CYP1A1 and P450 reductase on 7-methoxyresorufin O-demethylase (MROD) activity were studied. 7-ethoxyresorufin O-deethylase (EROD) activity was strongly inhibited by alpha-naphthoflavone (ANF). At 0.5 and 2.5 microM. ANF inhibited EROD activity by 90 and 98%, respectively. Mullet CYP1A1 did not catalyze monooxygenations of other substrates such as aniline, ethylmorphine, N-nitrosodimethylamine and p-nitrophenol. Antibodies produced against CYP1A1 orthologues in fish such as trout and scup showed strong cross-reactivity with the purified mullet CYP1A1. In addition, anti-L. saliens liver CYP1A1 produced in our laboratory inhibited both the EROD and MROD activities catalyzed by L. saliens liver microsomes but stronger inhibition was observed with EROD activity. On the other hand, anti-mullet CYP1A1 antibodies showed very weak cross-reactivity with two proteins (presumably CYP1A1 and CYP1A2) in 3MC-treated rat liver microsomes. Moreover, 3MC-treated rat liver microsomal EROD activity was weakly inhibited by the anti-L. saliens liver CYP1A1. These results strongly suggested that the purified mullet CYP1A1 is structurally, functionally and immunochemically similar to the CYP1A1 homologues purified from other teleost species but functionally and immunochemically distinct from mammalian CYP1A1.
Animals↗
Sense organ identity in the Drosophila antenna is specified by the expression of the proneural gene atonal.
We have shown that the basic helix-loop-helix transcription factor Atonal is sufficient for specification of one of the three subsets of olfactory sense organs on the Drosophila antenna. Misexpression of Atonal in all sensory precursors in the antennal disc results in their conversion to coeloconic sensilla. The mechanism by which specific sense organ fate is triggered remains unclear. We have shown that the homeodomain transcription factor Cut which acts in the chordotonal-external sense organ choice does not play a role in olfactory sense organ development. The expression of atonal in specific domains of the antennal disc is regulated by an interplay of the patterning genes, Hedgehog and Wingless, and Drosophila epidermal growth factor receptor pathway.
Animals↗
A system for determination of 3D vessel tree centerlines from biplane images.
With the increasing number and complexity of therapeutic coronary interventions, there is an increasing need for accurate quantitative measurements. These interventions and measurements may be facilitated by accurate and reproducible magnifications and orientations of the vessel structures, specifically by accurate 3D vascular tree centerlines. A number of methods have been proposed to calculate 3D vascular tree centerlines from biplane images. In general, the calculated magnifications and orientations are accurate to within approximately 1-3% and 2-5 degrees, respectively. Here, we present a complete system for determination of the 3D vessel centerlines from biplane angiograms without the use of a calibration object. Subsequent to indication of the vessel centerlines, the imaging geometry and 3D centerlines are calculated automatically and within approximately 2 min. The system was evaluated in terms of the intra- and inter-user variations of the various calculated quantities. The reproducibilities obtained with this system are comparable to or better than the accuracies and reproducibilities quoted for other proposed methods. Based on these results and those reported in earlier studies, we believe that this system will provide accurate and reproducible vascular tree centerlines from biplane images while the patient is still on the table, and thereby will facilitate interventions and associated quantitative analyses of the vasculature.
Coronary Angiography↗
Electroporation-enhanced gene delivery in mammary tumors.
Electroporation was applied to enhance gene transfer into subcutaneous MC2 murine breast tumors. Cultured MC2 cells were also transfected by electroporation or by cationic liposomes in the presence of serum using pSV-luc plasmids. Electroporation parameters and liposome formulation were optimized to achieve the highest relative levels of transfection. An electric field threshold for successful electrotransfection in cultured cells appeared around 800-900 V/cm. The liposomes used contained the cationic lipid dioleoyl-3-trimethylammonium propane (DOTAP). Multilamellar vesicles (MLV) had a 10-fold advantage over small unilamellar vesicles (SUV) in cell culture transfection. For in vivo gene delivery, the plasmids were injected either alone, or in complex with MLV or SUV DOTAP liposomes. A series of six electric pulses 1 ms long were applied across tumors, using caliper electrodes on the skin surface. Electric field strengths ranged from 400-2300 V/cm. Luciferase expression was approximately two orders of magnitude higher than controls in tumors treated with pulses > or =800 V/cm. Differences between enhanced relative levels of transfection using uncomplexed plasmid and lipoplexes were not statistically significant. Distribution of DNA into tumor tissues was monitored by fluorescence in situ PCR. The highest numbers of fluorescent cells were found in tumors electroporated following the injection of plasmid. The significant transfection improvement shows that in vivo electroporation is a powerful tool for local gene delivery to tumors.
Animals↗
Transcribing in triage: the Wrexham experience.
The Manchester triage methodology and the practice of analgesic transcribing were introduced to the Accident & Emergency Department of the Wrexham Maelor Hospital in April 1998. The concept of nurse led transcribing is relatively new and its introduction was not without an element of administrative caution. The project was successfully implemented owing to the strategic input from a multidisciplinary group and elaborate steps towards quality assurance through audit. This paper describes the steps of implementation of this transcribing project and its successful completion through a prospective audit. Although there is a paucity of published literature in this topic, the Wrexham Pain Triage Group wishes to extend this implementation methodology into other areas of innovative nursing practice.
Analgesics↗
Bayesian inference for kappa from single and multiple studies.
Cohen's kappa coefficient is a widely popular measure for chance-corrected nominal scale agreement between two raters. This article describes Bayesian analysis for kappa that can be routinely implemented using Markov chain Monte Carlo (MCMC) methodology. We consider the case of m > or = 2 independent samples of measured agreement, where in each sample a given subject is rated by two rating protocols on a binary scale. A major focus here is on testing the homogeneity of the kappa coefficient across the different samples. The existing frequentist tests for this case assume exchangeability of rating protocols, whereas our proposed Bayesian test does not make any such assumption. Extensive simulation is carried out to compare the performances of the Bayesian and the frequentist tests. The developed methodology is illustrated using data from a clinical trial in ophthalmology.
Bayes Theorem↗
Apoptosis induced by DNA uptake limits transfection efficiency.
Electrotransfection is an effective method for transfecting lymphoid cells. However, the transfection efficiency of certain lymphoid cells is low. L1210 subclones and NFS-70 pro-B cells, which are highly refractory to various transfection methods, were used to identify the limiting factors. Cells were electrotransfected with plasmids coding for green fluorescence protein or luciferase. The luciferase expression of L1210 subclone 3-3 was found to increase 6-12 h after electroporation, but decreased significantly from 12 to 48 h. The lower level of luciferase activity at later time periods correlated with decreases in cell viability, which was shown to be due to apoptosis, as determined by propidium iodide/acrindine orange staining, DNA laddering, and prevention of cell death by addition of caspase inhibitors. Similar results were observed with NFS-70 pro-B cells and select L1210 subclones. In contrast, L1210 parental and L1210 subclone 7-15.6 cells undergo only low levels of apoptosis (< or = 5%). Apoptosis occurred only when DNA (plasmids or salmon sperm DNA) was present during electroporation, but was not dependent on the conformation of the DNA used or the expression of transgenes. Cells pulsed in the presence of dextran sulfate (MW 500,000) did not apoptose. Similar results were observed when L1210 subclone 3-3 was transfected using the cationic lipid 1, 2-dioleoyl-3-trimethylammonium propane, although the transfection efficiency and corresponding rate of apoptosis were significantly lower. Applying the caspase inhibitor fluoromethyl ketone (Boc-ASP-FMK) dramatically improved cell viability and transgene expression of select L1210 subclones and NFS-70 pro-B cells.
Amino Acid Chloromethyl Ketones↗
Emergence of adult diarrhoea rotavirus in Calcutta, India.
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Adolescent↗
Time-dependent ultrastructural changes to porcine stratum corneum following an electric pulse.
The morphological changes to heat-stripped porcine stratum corneum following an electroporating pulse were studied by time-resolved freeze fracture electron microscopy. Pulses at a supra-electroporation threshold of 80 volts and 300 microseconds were applied across the stratum corneum with a pair of copper plate electrodes, which also served as cooling contacts. Multilamellar vesicles of 0.1-5.5 mm in diameter in the intercellular lipid bilayers of the stratum corneum appeared in less than milliseconds after pulsing. Pulsed samples exhibited aggregations of vesicles, whereas only occasional single vesicles were seen in the unpulsed samples. Aggregates form in less than a millisecond and disappear within minutes after the pulse. Their size ranged from 0.3 to 700 mm2. The size of individual vesicles, aggregate density, and size were analyzed as functions of postpulse time. These aggregate formations seem to be a secondary reaction to the pulse-induced skin permeabilization, determined by the resistance drop and recovery after the pulse. Heating the samples to 65 degrees C also caused vesicle aggregates of similar appearance to form, suggesting that these aggregations are related to the heating effect of the pulse. Hydration is thought to play an important role in aggregate formation.
Administration, Cutaneous↗
Antioxidant status and lipid peroxidation in human feto-placental unit.
The human feto-placental unit being in the environment of the materno-fetal circulation is very much susceptible to the danger of reactive oxygen species-induced oxidative damage. The present study reports the status of various antioxidants in the feto-placental system at birth. The activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase as well as concentrations of non-enzymic antioxidants viz, ascorbic acid, alpha-tocopherol, bilirubin and glutathione have been determined in term placental brush border membrane (BBM) and umbilical cord (UC) blood. The extent of lipid peroxidation in developing and term BBM and UC blood has been studied by estimation of malondialdehyde and conjugated dienes, both being the end products of lipid peroxidation. The results indicate the presence of a protective mechanism against oxygen toxicity in the feto-placental system at the time of parturition.
Antioxidants↗
Economics and health.
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Developed Countries↗
Detection of IgG antibody to bovine leukaemia virus in urine and serum by two enzyme immunoassays.
Four hundred blood sera from a cattle production unit were tested for BLV-(Bovine Leukaemia Virus) antibody with IP (Institut Porquier) and SB (Svanova Biotech) ELISA kits. Seventy-seven cattle with BLV-antibody (19.25%) and 77 without the antibody were used. No significant difference was found between O.D. of sera of PL+ (Persistent Lymphocytosis Positive) and PL- (Negative) cattle. The mean O.D. of urine samples of 77 seropositive cattle was significantly higher than that of 77 seronegative cattle (P < 0.01). There were also differences between urine O.D.s of seropositive (PL+) and seropositive (PL-) groups of cattle with IP (P < 0.05) and SB (P < 0.01) kits. All the results revealed the presence of BLV-antibody in the urine of the cattle without any urinary dysfunction.
Animals↗
Quantitative evaluation of vessel tracking techniques on coronary angiograms.
Accurate, automated determination of vessel center lines is essential for two- and three-dimensional analysis of the coronary vascular tree. Therefore, we have been developing techniques for vessel tracking and for evaluating their accuracy and precision in clinical images. After points in vessels are manually indicated, the vessels are tracked automatically by means of a modified sector-search approach. The perimeters of sectors centered on previous tracking points are searched for the pixels with the maximum contrast. The sector size and radius are automatically adjusted based on local vessel tortuosity. The performance of the tracking technique in regions of high-intensity background is improved by application of a nonlinear adaptive filtering technique in which the vessel signal is effectively removed prior to background estimation. The tracking results were evaluated visually and by calculation of distances between the tracked and user-indicated centerlines, which were used as the "truth." Two hundred and fifty-six coronary vessels were tracked in 32 angiograms. Vessels as small as 0.6 mm in diameter were tracked accurately. This technique correctly tracked 255/256 (>99%) vessels based on an average of 2-3 indicated points per vessel. The one incorrect tracking result was due to a low signal-to-noise ratio (SNR<2). The distance between the tracked and the "true" centerlines ranged from 0.4 to 1.8 pixels, with an average of 0.8 pixels. These results indicate that this technique can provide a reliable basis for 2D and 3D vascular analysis.
Coronary Angiography↗