Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “systematic analysis”

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 1,171 records · Page 65Linked to original sources
PubMed1996

Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity.

Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity: PEPTIDES 17(6) 995-1002, 1996.-Systematic analysis of fragment derivatives of the superpotent alpha-MSH analogue. Ac-Ser.Tyr-Ser-Nle4-Glu- His-DPhe7-Arg-Trp-Gly-Lys-Pro-Val-NH2(NDP-MSH), led to the discovery of tripeptide agonists possessing prolonged bioactivity in the frog skin assay. Of particular significance to this discovery was Ac-DPhe-Arg-DTrp-NH2, which was the most potent tripeptide in this series exhibiting sustained melanotropic activity. Different pharmacophore models appear to exist that are dependent on the substructure and stereochemistry of the MSH(6-9) "active site." The tripeptides Ac-DPhe-Arg-Trp-NH2, Ac-DPhe-Arg-DTrp-NH2, and Ac-DPhe-DArg-Trp-NH2 stereo-chemical combinations require only Phe7-Xaa8-Trp9, whereas Ac-DPhe-DArg-DTrp-NH2, Ac-Phe-Arg-DTrp-NH2, and Ac-Phe-Arg-Trp-NH2 additionally require His4 for minimal biological activity. Ac-DPhe-Arg-DTrp-NH2 represents a novel prototype lead for the development of MSH-based peptidomimetic agonists.

Amino Acid Sequence↗
PubMed1985

Complexity of minor histocompatibility loci.

Allografts can be rejected as a result of major histocompatibility antigen disparity or as a result of differences at any of a number of minor histocompatibility antigens. In many cases, rejection due to multiple minor histoincompatibility is as difficult to control as that induced by major histoincompatibility. Although an understanding of the molecular, biochemical, and functional parameters of the major histocompatibility loci and their products is increasing at an exponential rate, little is known about these same facets of minor histocompatibility loci and their products. It is generally accepted that minor histocompatibility loci in the murine model have a degree of polymorphism similar to that of H-2K or H-2D. This conclusion was based on typing alleles by the classic F1-skin graft test. Based on these allelic assignments, numerous unexpected findings of CTL specificity were made. Therefore, a systematic analysis was made comparing CTL specificity, F1-complementation, and allograft rejection. Based on these three parameters, the data presented using strains of mice that were bred to, and therefore presumed to, differ only at H-3 indicate that the antigen disparity of these congenic strains and the parental B10 strain as defined by CTL specificity and skin graft rejection is much more complex than originally described. One especially interesting chromosomal region is H-3/beta 2-microglobulin in the fifth linkage group of chromosome 2. Using CTL, ten specificities are defined, three of which appear to be specific for beta 2-microglobulin-A, -B, and -C. These findings raise the question of whether any minor histocompatibility locus is polymorphic or is instead a composite of multiple minor H-loci which are masquerading as a single locus.

Alleles↗
PubMed1982

[Emergence and development of the tuberculosis control system in France between 1900 and 1940].

In industrialised countries the treatment of tuberculosis was one of the first public health services to appear at the beginning of the 20th century. This initiative represented a departure from the usual measures set up by public health specialists for improving living and environmental conditions, as new knowledge about the process of infection meant that action could be taken on the population directly. The processes which served to stratify and differentiate living standards characteristic of this period of industrialisation are reflected in the epidemiology of tuberculosis: the hierarchy of mortality rates runs parallel to that of the social groups. Many authors now question the role of the health service in the regression of infectious diseases, which they attribute more to changes in lifestyle. This text attempts to analyse the context and the objectives which surrounded the establishment of the service to combat tuberculosis in France, with reference to the various theories which seek to explain the emergence of social services in health or in education. Hence three theses are examined with reference to the actual history of the tuberculosis service. In this service an instrument of the ruling class, owners of the means of production, who thereby assure the reproduction of the workforce at a time when industrialisation demands an increase in the workforce, and when additional reserves of manual labour are being exhausted? Was the use of techniques arising out of new knowledge accompanied by an extension of the power of doctors into areas which had hitherto been outside their field of intervention? Did medical activity lead to new norms being introduced into everyday life in the name of scientific values? An interpretation in terms of social control is put forward to explain both the public health movement, compulsory education and urbanisation. Is this helpful in understanding how the organisation of the struggle against tuberculosis came about? This research is based on the systematic analysis of documents and journals on tuberculosis published in France during the period under study. Support is found for elements of all the these examined without any one being able to account for all aspects of the establishment of this service. The service represents the meeting point of a number of different forces: economic forces; political forces, as witnessed in the debate between the social and technical approach before the first World War; and professional forces, given the transformation of medical practice with the introduction of public health services and national insurance.

France↗
PubMed1990

Patient careers in end-stage renal failure.

This paper argues that coping with end-stage renal failure can be analysed in terms of status structures. Biographical narratives from 68 cases of British male married patients of working age and data from four follow-ups covering a time period of up to 12 years are interpreted as evidence of structured career patterns. The method of data interpretation is adapted from Max Weber's ideal type venturing a systematic analysis of life-history (qualitative) material.

Adaptation, Psychological↗
PubMed1987

Factors affecting the choice of preamplification for ultrasonic hydrophone probes.

This paper gives a systematic analysis of the effects of including an integrated (built-in) preamplifier into the ultrasonic piezoelectric probes (hydrophones) that are finding increasing use in biomedical applications. The design parameters considered include the end-of-cable sensitivity, gain, dynamic range, power supply requirements, construction intricacy, and cost. The rationale behind the inclusion of a preamplifier is given, and it is shown that the additional complexity introduced with the preamplifier into the measurement chain may not be warranted in all applications. Both the drawbacks and advantages of hydrophone preamplification are demonstrated, especially for the case of high pressure amplitude ultrasonic field measurements. Guidelines are developed for the potential user to identify the need for preamplification and the factors that influence the selection of the appropriate circuitry.

Amplifiers, Electronic↗
PubMed1994

Depositional and tectonic setting of the Archean Moodies Group, Barberton Greenstone Belt, South Africa.

The 3.22-3.10 Ga old Moodies Group, uppermost unit of the Swaziland Supergroup in the Barberton Greenstone Belt (BGB), is the oldest exposed, well-preserved quartz-rich sedimentary sequence on earth. It is preserved in structurally separate blocks in a heavily deformed fold-and-thrust belt. North of the Inyoka Fault, Moodies strata reach up to 3700 m in thickness. Detailed mapping, correlation of measured sections, and systematic analysis of paleocurrents show that the lower Moodies Group north of the Inyoka Fault forms a deepening- and fining-upward sequence from a basal alluvial conglomerate through braided fluvial, tidal, and deltaic sandstones to offshore sandy shelf deposits. The basal conglomerate and overlying fluvial facies were derived from the north and include abundant detritus eroded from underlying Fig Tree Group dacitic volcanic rocks. Shoreline-parallel transport and extensive reworking dominate overlying deltaic, tidal, and marine facies. The lithologies and arrangement of Moodies Group facies, sandstone petrology, the unconformable relationship between Moodies strata and older deformed rocks, presence of at least one syndepositional normal fault, and presence of basaltic flow rocks and airfall fall tuffs interbedded with the terrestrial strata collectively suggest that the lower Moodies Group was deposited in one or more intramontane basins in an extensional setting. Thinner Moodies sections south of the Inyoka Fault, generally less than 1000 m thick, may be correlative with the basal Moodies Group north of the Inyoka Fault and were probably deposited in separate basins. A northerly derived, southward-thinning fan-delta conglomerate in the upper part of the Moodies Group in the central BGB overlies lower strata with an angular unconformity. This and associated upper Moodies conglomerates mark the beginning of basin shortening by south- to southeast-directed thrust faulting along the northern margin of the BGB and suggest that the upper Moodies Group was deposited in a foreland basin. Timing, orientation, and style of shortening suggest that this deformation eventually incorporated most of the BGB into a major fold-and-thrust belt.

Aluminum Silicates↗
PubMed1995

A critical appraisal of intratracheal instillation of benzo[a]pyrene to Syrian golden hamsters as a model in respiratory tract carcinogenesis.

Several experimental models have been developed to study respiratory tract carcinogenesis. The most widely applied in vivo model uses Syrian golden hamsters which receive intratracheal instillations of a suspension of benzo[a]pyrene (B[a]P) particles attached to ferric-oxide (Fe2O3) particles in saline; it was first described by Saffiotti et al. [1]. This model has several benefits compared with other experimental models; however, the large number of variables affecting the tumour response is a clear disadvantage because the tumour response is difficult to control. In this review, we describe a systematic analysis of various variables that may influence the tumour response of the respiratory tract with the aim to further standardize the method and increase, through that, its suitability and predictability. The most important variables influencing the tumour response, as shown by statistical analysis of 29 representative studies, turned out to be the administered dose and the particle size. Both these variables influence the actual dose and the contact-time of the B[a]P particles with the target cells. The present study does not support the widespread opinion that ferric-oxide particles enhance the tumour response of the respiratory tract. In conclusion to the present analysis, some recommendations are made which probably increase the predictability of the model.

Animals↗
PubMed1987

Monoaminergic fibers form conventional synapses in the cerebral cortex.

The morphological characteristics of the monoaminergic axon-terminals in the mammalian cerebral cortex have been the subject of controversy in recent years. Systematic analysis of serial ultrathin sections, immunocytochemically stained with antibodies against noradrenaline and serotonin, has shown that nearly all stained terminals form synapses characterized by specialized junctional appositions. These results suggest that, contrary to the widely held view, monoamines in the cortex are released at specialized junctions.

Animals↗
PubMed1985

Distribution of enzymes of purine metabolism in lymphocytes of horse, Equus caballus.

A microassay requiring as few as 2 X 10(5) cells per assay was developed for systematic analysis of 9 purine enzymes in lymphocytes from equine peripheral blood, spleen, lymph node, thymus and bone marrow. The activities of adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenosine kinase (AK), deoxyadenosine kinase (dAK), deoxycytidine kinase (dCK), 5'-nucleotidase (5'-N), AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase (HGPRT or HPRT), and adenine phosphoribosyl transferase (APRT) were measured by this microassay in lymphocytes from peripheral blood from four different breeds of horses (Arabian, Quarter Horse, Thoroughbred and Shetland Pony). There were no significant differences in the enzyme activities among the various breeds. Peripheral blood lymphocytes (PBL) from foals exhibited enzyme activities similar to those observed for adult animals. All lymphoid tissue contained similar levels of activity for each kinase (AK, dAK and dCK). Spleen had the highest activity for ADA, PNP, 5'-N, and HGPRT. The lowest activity for ADA, APRT, PNP and AMP deaminase was found in thymus. Enzymatic activities that varied the most among the tissue were 5'-N, ADA, APRT, HGPRT and AMP deaminase.

5'-Nucleotidase↗
PubMed1992

Improved methods for determination of variability in patient positioning for radiation therapy using simulation and serial portal film measurements.

Variability in patient positioning was determined by analyzing simulation and portal film measurements for 318 portals in 51 patients treated with external beam radiotherapy to the head and neck. Several indicators of error in patient positioning were examined: random error, a measure of the deviation of all portal films from the average portal film position, systematic error, a measure of the difference between the average portal film and the simulation film, and total uncertainty, a measure of the overall deviation, including both random and systematic uncertainties. The median differences noted were 0.4 cm, 0.6 cm, and 0.7 cm, for Random Error, Systematic Error, and Total Uncertainty, respectively. The treatment fields analyzed in this study show a substantial treatment-to-treatment and simulation-to-treatment variability in patient positioning. The methods described provide an improved means for the systematic analysis of variability in patient positioning.

Head and Neck Neoplasms↗
PubMed1992

Contouring structures for 3-dimensional treatment planning.

Three-dimensional (3-D) treatment planning is a labor-intensive process with contouring of the target volume and critical normal tissues being a significant time-consuming component. The use of 3-D treatment planning on a routine basis may be limited by the time required to complete treatment plans. Despite the need to increase the efficiency of the process, there is little literature addressing the speed and accuracy of contouring systems. In an attempt to initiate systematic analysis of the contouring process, data sets consisting of 10 CT images each were developed on two patients with esophageal carcinoma. Nine different operators manually contoured structures (target volume, spinal canal, lungs) on the data sets using four different contouring systems present in our department. These included both commercially available systems and those developed by the authors. There was a wide variation in the hardware and software characteristics of these systems. The time required to contour the CT data sets was recorded and analyzed. The contouring accuracy was assessed by comparison with a standard template derived from the CT data set for each image. The contouring time was found to be dependent on the system design, previous contouring experience, and the type of drawing instrument (lightpen vs mouse). The mean contouring time ranged from 26 minutes per patient for the fastest system to 41 minutes for the slowest. Potential clinically significant errors in contouring were rare for the spinal canal and lungs but present at a greater rate for the target volume (30.3%). The implications of this finding are discussed.

Adenocarcinoma↗
PubMedDate not supplied

Study of cortical spindles during sleep in the rat.

A systematic analysis of the dorsally accessible cortical areas has been undertaken so as to study the space-time distribution, the intrinsic characteristics and the physiological appearance modalities of cortical spindles in the rat. After falling asleep, the animal presents anterior spindles of which the number, duration and amplitude increase as sleep with slow waves deepens. These spindles are fully developed during intermediate state which precedes and follows paradoxical sleep, where they are associated with a theta rhythm in the hippocampus and the visual cortex. These spindles, at their maximum in anterior regions, lose intensity as one approaches the cerebellum. Uniquely during slow wave phase of sleep, the rat presents posterior spindles which are predominant in the occipital region, are less marked in parietal and cerebellar regions and disappear in the frontal cortex. Less frequent than anterior spindles, they are significantly distinguished by their lower amplitude, higher frequency and shorter duration.

Animals↗
PubMed1990

A novel expression assay to study transcriptional activators.

A novel assay to study transcriptional regulation in vivo designated trans-activation-dependent replication (TDR) assay is based on the modulation of a simian virus 40 (SV40)-derived replication system. A mixture of four plasmids (pPARA + pCIS + pTRANS + pREF) is co-transfected into vertebrate cells. After appropriate incubation, the replication of the pPARA plasmid (containing an SV40 origin of replication) is measured with a simple enzymatic test. We demonstrate that the level of replication is dependent on the differential trans-activation of the reporter pCIS (in which SV40 T-antigen is brought under control of the desired promoter) by the specific regulator protein encoded by the pTRANS plasmid. Three advantages make this assay a convenient tool for the systematic analysis of trans-activation in vivo: (1) remarkable sensitivity (higher than conventional assays); (2) rapid sample processing combined with a built-in standard (pREF-plasmid); (3) avoidance of expensive reagents such as freshly radiolabelled probes. We present the application of the TDR assay to the analysis of deletion mutants of the glucocorticoid receptor (GR) and other, GR-based chimeric trans-activators. The results demonstrate that the properties of protein domains are not always additive in a particular chimaera. Further application possibilities of the TDR assay are also discussed.

Animals↗
PubMed1990

Qualitative changes of general movements in preterm infants with brain lesions.

The aims of the study were (1) to replicate previous quantitative studies of motor activity in low-risk and high-risk preterm infants and (2) to apply a new method of systematic analysis of the qualitative characteristics of general movements in these two groups of infants. Sequential one-hour videorecordings of the unstimulated infants in the incubator were made during the preterm period and then continued during the postterm period until about 20 weeks. The high-risk group consisted only of infants with signs of haemorrhage and/or leucomalacia in the repeated ultrasonograms of the brain. The neurological follow-up continued up to a minimum of one and a maximum of three years of corrected age. The quantification of the various motor patterns in 12 matched pairs of low-risk and high-risk preterm infants revealed a slight but significant (P = 0.05) excess of isolated arm movements in the low-risk cases during the activity phase. No other movement pattern differed significantly. The qualitative assessment of general movements during the preterm period resulted in all but one of the 14 low-risk cases having a normal quality of general movements. In the lesion-group (N = 29) all the infants had an abnormal quality during the preterm period. Eight cases later became neurologically normal although 1 of them had strabism. In addition, one infant was blind (ROP) and retarded and one other had mental retardation. Nineteen infants later developed cerebral palsy (two monoplegia of a leg, three hemiplegia, 5 diplegia and 9 quadriplegia). Strabism was present in 48.3% of the whole group of 29 cases. A semi-quantitative estimation of various aspects of the abnormal general movements made a typology of abnormal patterns possible. A graphic display of developmental trajectories of individual cases, depicting the course of abnormal aspects along the time axis, helps document the evolution of abnormal signs. Their course is a better predictor of the neurological outcome than the nature and localization of the lesion, detected by imaging techniques. The qualitative assessment of general movements from videorecordings is a reliable, quick, cheap and totally non-intrusive method in neonatology for the early detection of functional impairment of the nervous system.

Brain Diseases↗
PubMedDate not supplied

Isolation of drugs from blood and tissues with XAD-2 bags.

Nylon bags containing 2-g portions of Amberlite XAD-2 resin were used for systematic analysis of drugs in biosamples. The procedure requires 10 or less grams of material, two XAD-2 bags, and enables rapid and economical isolation of most common drugs. The method was demonstrated on autopsy blood spiked withe 19 of the most common drugs, and was routinely used in cases of fatal and non-fatal poisoning. The eluates were clean and suitable for direct gas chromatographic and ultraviolet spectrophotometric analysis. The procedure used appeared more convenient than XAD-2 column extraction procedures. Classic solvent extraction methods were usually less efficient.

Chromatography, Gas↗
PubMed1993

Effect on coronary artery anatomy of radiofrequency catheter ablation of atrial insertion sites of accessory pathways.

OBJECTIVES: The purpose of this study was to analyze the effects of radiofrequency catheter ablation of the atrial insertion site of accessory pathways on the angiographic appearance of coronary arteries. BACKGROUND: Radiofrequency catheter ablation of accessory pathways requires the application of energy to the endocardial surface of the atrioventricular groove adjacent to the major epicardial coronary arteries. A systematic analysis of the effect of radiofrequency ablation on coronary arteries has not previously been demonstrated. METHODS: Seventy consecutive patients with 76 accessory pathways (7 right free wall, 44 left free wall, 12 posteroseptal, 8 anteroseptal and 5 midseptal) were studied. Quantitative coronary angiography was performed before, immediately after and a mean of 69 +/- 42 days after radiofrequency catheter ablation. RESULTS: Coronary artery diameter adjacent to the ablating electrode was 2.6 +/- 0.9 mm before ablation, 2.7 +/- 0.9 mm immediately after ablation and 2.7 +/- 1.0 mm at the time of follow-up study. Angiographic findings were unchanged from baseline in 69 of 70 patients immediately after ablation and in all 70 patients at the time of follow-up study. CONCLUSIONS: Radiofrequency catheter ablation of the atrial insertion site of accessory pathways does not result in short-term angiographic changes in coronary artery anatomy.

Adolescent↗
PubMed1991

Genomic DNA sequence of the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

The gene responsible for cystic fibrosis, the most common severe autosomal recessive disorder, is located on the long arm of human chromosome 7, region q31-q32. The gene has recently been identified and shown to be approximately 250 kb in size. To understand the structure and to provide the basis for a systematic analysis of the disease-causing mutations in the gene, genomic DNA clones spanning different regions of the previously reported cDNA were isolated and used to determine the coding regions and sequences of intron/exon boundaries. A total of 22,708 bp of sequence, accounting for approximately 10% of the entire gene, was obtained. Alignment of the genomic DNA sequence with the cDNA sequence showed perfect colinearity between the two and a total of 27 exons, each flanked by consensus splice signals. A number of repetitive elements, including the Alu and Kpn families and simple repeats, such as (GT)17, (GATT)7, and (TA)14, were detected in close vicinity of some of the intron/exon boundaries. At least three of the simple repeats were found to be polymorphic in the population. Although an internal amino acid sequence homology could be detected between the two halves of the predicted polypeptide, especially in the regions of the two putative nucleotide-binding folds (NBF1 and NBF2), the lack of alignment of the nucleotide sequence as well as the different positions of the exon/intron boundaries does not seem to support the hypothesis of a recent gene duplication event. To facilitate detection of mutations by direct sequence analysis of genomic DNA, 28 sets of oligonucleotide primers were designed and tested for their ability to amplify individual exons and the immediately flanking sequences in the introns.

Amino Acid Sequence↗
PubMed2006

Generation of a homology model for the human cytochrome P450, CYP24A1, and the testing of putative substrate binding residues by site-directed mutagenesis and enzyme activity studies.

A systematic analysis of conserved H-bonding patterns and tertiary structural motifs from 13 crystal structures was used to create a homology model for the human multicatalytic cytochrome P450, CYP24A1, involved in catabolism of 1alpha,25-dihydroxyvitamin D3. The substrate was docked in the active site and used to identify potential substrate contact residues in the B' helix, B'/C loop, F-helix and the beta-5 hairpin. Seven CYP24A1 mutants were created and studied by mammalian cell transfection and CYP24A1 activity assay. Mutants showed reduced metabolic rates and altered metabolite patterns compared to wild-type. We conclude that: Ile-131 positions substrate via A-ring and cis-triene contacts; Trp-134 and Gly-499 are determinants of substrate access; Leu-148 contacts the substrate side-chain; Met-246 is important in mediating regioselectivity. Our findings validate the new model of CYP24A1, which can now be used to predict structural modifications for rational vitamin D drug design.

Amino Acid Substitution↗