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At least 757 records · Page 42Linked to original sources
PubMed1993

Establishment of reliability in the evaluation of hand sensibility.

Evaluation of hand sensibility using measures of threshold and tactile discrimination are standard assessment methods following nerve injury. Many of the available sensory measures for the quantification of hand sensibility lack verification of intertester reliability. Intertester reliability of vibration threshold, cutaneous pressure threshold, two-point discrimination, object identification, and texture identification was established. The intraclass correlation coefficient ranged from 0.96 to 0.99 for all variables except texture identification (r = 0.77). Comparisons were made between the sensory measures and each functional measure. The strongest correlational relationship was between two-point identification and object identification. Based on the results of this study, evaluation of hand sensibility may be attained with measurement of vibration and cutaneous pressure threshold, two-point discrimination, and object identification.

Adult↗
PubMed2006

Quality control for digital mammography: part II. Recommendations from the ACRIN DMIST trial.

The Digital Mammography Imaging Screening Trial (DMIST), conducted under the auspices of the American College of Radiology Imaging Network (ACRIN), is a clinical trial designed to compare the accuracy of digital versus screen-film mammography in a screening population [E. Pisano et al., ACRIN 6652-Digital vs. Screen-Film Mammography, ACRIN (2001)]. Part I of this work described the Quality Control program developed to ensure consistency and optimal operation of the digital equipment. For many of the tests, there were no failures during the 24 months imaging was performed in DMIST. When systems failed, they generally did so suddenly rather than through gradual deterioration of performance. In this part, the utility and effectiveness of those tests are considered. This suggests that after verification of proper operation, routine extensive testing would be of minimal value. A recommended set of tests is presented including additional and improved tests, which we believe meet the intent and spirit of the Mammography Quality Standards Act regulations to ensure that full-field digital mammography systems are functioning correctly, and consistently producing mammograms of excellent image quality.

Breast↗
PubMed2006

Transcriptomic analysis of the cardiac left ventricle in a rodent model of diabetic cardiomyopathy: molecular snapshot of a severe myocardial disease.

Heart disease is the major cause of death in diabetes, a disorder characterized by chronic hyperglycemia and cardiovascular complications. Diabetic cardiomyopathy (DCM) is increasingly recognized as a major contributor to diastolic dysfunction and heart failure in diabetes, but its molecular basis has remained obscure, in part because of its multifactorial origins. Here we employed comparative transcriptomic methods with quantitative verification of selected transcripts by reverse transcriptase quantitative PCR to characterize the molecular basis of DCM in rats with streptozotocin-induced diabetes of 16-wk duration. Diabetes caused left ventricular disease that was accompanied by significant changes in the expression of 1,614 genes, 749 of which had functions assignable by Gene Ontology classification. Genes corresponding to proteins expressed in mitochondria accounted for a disproportionate number of those whose expression was significantly modified in DCM, consistent with the idea that the mitochondrion is a key target of the pathogenic processes that cause myocardial disease in diabetes. Diabetes also induced global perturbations in the expression of genes regulating cardiac fatty acid metabolism, whose dysfunction is likely to play a key role in the promotion of oxidative stress, thereby contributing to the pathogenesis of diabetic myocardial disease. In particular, these data point to impaired regulation of mitochondrial beta-oxidation as central in the mechanisms that generate DCM pathogenesis. This study provides a comprehensive molecular snapshot of the processes leading to myocardial disease in diabetes.

Animals↗
PubMed1998

DAF optimization using Taguchi methods and the effect of thermal cycling parameters on DNA amplification.

Taguchi methods, which are widely applied in industrial process design, were used to optimize DNA amplification finger-printing (DAF). Quadratic loss functions that penalize deviations from prediction values and L9 (3(4)) and L18 (3(8)) orthogonal arrays revealed effects and interactions of amplification reaction components and thermal cycling parameters. Analysis of variance (ANOVA) decomposed the contribution of individual factors to the experimental response (amplification yield and product number), while verification experiments established that optimum conditions were predictable, verifiable and reproducible. While several amplification components (primer, magnesium and enzyme) conditioned the amplification reaction, annealing temperature and time were the only important thermal cycling contributing factors. The Taguchi strategy defined a robust and transportable amplification protocol based on high annealing temperatures (typically 48 degrees C) and primer concentrations (typically 8 microM), which can be applied to the fingerprinting of a wide range of DNA templates of plant and fungal origin. The general strategy of robust experimental design holds potential as an optimization tool for other methods in molecular biology.

Analysis of Variance↗
PubMed2005

In vivo application of RNA interference: from functional genomics to therapeutics.

RNAi has rapidly become a powerful tool for drug target discovery and validation in cell culture, and now has largely displaced efforts with antisense and ribozymes. Consequently, interest is rapidly growing for extension of its application to in vivo systems, such as animal disease models and human therapeutics. Studies on RNAi have resulted in two basic methods for its use for gene selective inhibition: 1) cytoplasmic delivery of short dsRNA oligonucleotides (siRNA), which mimics an active intermediate of an endogenous RNAi mechanism and 2) nuclear delivery of gene expression cassettes that express a short hairpin RNA (shRNA), which mimics the micro interfering RNA (miRNA) active intermediate of a different endogenous RNAi mechanism. Non-viral gene delivery systems are a diverse collection of technologies that are applicable to both of these forms of RNAi. Importantly, unlike antisense and ribozyme systems, a remarkable trait of siRNA is a lack of dependence on chemical modifications blocking enzymatic degradation, although chemical protection methods developed for the earlier systems are being incorporated into siRNA and are generally compatible with non-viral delivery systems. The use of siRNA is emerging more rapidly than for shRNA, in part due to the increased effort required to construct shRNA expression systems before selection of active sequences and verification of biological activity are obtained. In contrast, screens of many siRNA sequences can be accomplished rapidly using synthetic oligos. It is not surprising that the use of siRNA in vivo is also emerging first. Initial in vivo studies have been reported for both viral and non-viral delivery but viral delivery is limited to shRNA. This review describes the emerging in vivo application of non-viral delivery systems for RNAi for functional genomics, which will provide a foundation for further development of RNAi therapeutics. Of interest is the rapid adaptation of ligand-targeted plasmid-based nanoparticles for RNAi agents. These systems are growing in capabilities and beginning to pose a serious rival to viral vector based gene delivery. The activity of siRNA in the cytoplasm may lower the hurdle and thereby accelerate the successful development of therapeutics based on targeted non-viral delivery systems.

Animals↗
PubMed2006

Aberrant intestinal expression and allelic variants of mucin genes associated with inflammatory bowel disease.

Loss of intestinal mucosa integrity is an important factor in the pathogenesis of inflammatory bowel disease (IBD). The aim of this study was to characterize expression changes and allelic variants of genes related to intestinal epithelial barrier function in this disease. Therefore, ileal and colonic mucosal biopsies from nonaffected regions of patients with ulcerative colitis (UC) and Crohn's disease (CD), as well as non-IBD probands, were subjected to Affymetrix DNA-microarray analysis. Real-time reverse transcription polymerase chain reaction was used for verification in larger IBD sample numbers. Disturbed mRNA expression was identified for several mucin genes in both disease groups and tissues. A significant downregulation in the colon was obtained for MUC2 in CD and MUC12 in CD and UC. Expression analysis of all dysregulated mucins in a broad human tissue panel revealed dominant epithelial tissue-specific transcription. In silico analysis of the regulatory regions of these mucins indicated nuclear factor kappaB (NFkappaB) binding sites in each promoter. Furthermore, NFkappaB was overrepresented in mucin promoters and a component of a specific combination of transcription factors (composite module). In vivo stimulation experiments in the adenocarcinoma cell line LS174T showed inducible mucin expression by the cytokines tumor necrosis factor-alpha and transforming growth factor-beta, which could be blocked by NFkappaB signaling inhibitors. Allelic discrimination screening obtained statistically significant associations for the MUC2-V116M (P = 0.003) polymorphism with CD and for MUC4-A585S (P = 0.025), as well as MUC13-R502S (P = 0.0003) with UC. These data suggest that the disturbed expression of mucin genes and the connection to the NFkappaB pathway may influence the integrity of the intestine and therefore contribute to the pathophysiology of IBD.

Adult↗
PubMed1994

The combinatorial synthesis and chemical and biological evaluation of a 1,4-benzodiazepine library.

A library of 192 structurally diverse 1,4-benzodiazepine derivatives containing a variety of chemical functionalities including amides, carboxylic acids, amines, phenols, and indoles was constructed from three components, 2-aminobenzophenones, amino acids, and alkylating agents, by employing Geysen's pin apparatus [Geysen, H. M., Rodda, S. J., Mason, T. J., Tribbick, G. & Schoofs, P. G. (1987) J. Immunol. Methods 102, 259-274]. Rigorous analytical verification of the chemical integrity and yield of a representative collection of the diverse derivatives was carried out. In addition, the library of derivatives was evaluated for binding to the cholecystokinin A receptor by employing a competitive radio-ligand binding assay. This provided detailed structure versus activity relationships that were confirmed by independent large-scale synthesis and evaluation of several of the 1,4-benzodiazepine derivatives.

Amino Acid Sequence↗
PubMed2005

A system-on-chip digital pH meter for use in a wireless diagnostic capsule.

This paper describes the design and implementation of a system-on-chip digital pH meter, for use in a wireless capsule application. The system is organized around an 8-bit microcontroller, designed to be functionally identical to the Motorola 6805. The analog subsystem contains a floating-electrode ISFET, which is fully compatible with a commercial CMOS process. On-chip programmable voltage references and multiplexors permit flexibility with the minimum of external connections. The chip is designed in a modular fashion to facilitate verification and component re-use. The single-chip pH meter can be directly connected to a personal computer, and gives a response of 37 bits/pH, within an operating range of 7 pH units.

Algorithms↗
PubMed1985

Proximity and hierarchy: orthogonal dimensions of family interconnectedness.

The purpose of this research was to develop logical and empirically valid conceptual tools for investigating relationships between family patterns of interconnectedness and psychosocial functioning of children in the family. The family systems concept of boundary was analyzed into two component concepts: Proximity (interpersonal boundaries) and generational Hierarchy (subsystem boundaries). These concepts were operationalized as dimensions, and eight families were assessed by means of interaction coding, interview, and Kinetic Family Drawing to yield empirical verification of these dimensions. Findings indicated that Proximity and Hierarchy are reliable, valid, and independent dimensions of family interconnectedness. Weak generational Hierarchy was associated with increased levels of psychological dysfunction for both identified patients and their siblings. High Proximity was similarly associated with psychological dysfunction, but only for identified patients. The hypothesis that enmeshment is a composite pattern of high Proximity and weak Hierarchy was disconfirmed. Suggestions for future research include systemic analysis of deviation-counteracting and -amplifying relationships between patterns of Proximity and Hierarchy, on the one hand, and psychosocial dysfunction, on the other.

Child↗
PubMed1979

[Biomedical technique in physiology (author's transl)].

On the basis of two examples of projects being realized in the department of physiology in Graz the use of engineering methods in physiological research is demonstrated. The first example presents a survey of the use of system-theoretical methods for the investigation of overall regulation of circulation under working conditions. Using two test-signals (impulse input, random input) for experimental identification, the impulse response of heart-rate to changes in work load was obtained. The impulse responses of the volunteers were then characterized by a set of three parameters, allowing statistical evaluation, classification for diagnostic means and verification of hypotheses. The second example deals with an investigation of the signal structure of ultrasound-CW-Doppler-systems. Basing on the general Doppler-principle, which is already in use in angiology it was tried to quantify the determinants of the audio-signal, describing it by statistical functions and by experiments on simple models (tube-models). The goal of the experiments is a quantitative assessment of volume-flow and an enhancement of information about the scattering medium (rheological properties of blood).

Doppler Effect↗
PubMed1995

[A transference from somewhere else: reevaluation of the controversies between Melanie Klein and Anna Freud (of noise and silence)].

Starting from The Freud-Klein Controversies, the author explores the historical reality of these controversies and their transformations into myth which give them the appearance of titanic fights. The verification of the different periods, the description of the variations in themes and style of intervention of the principal actors of these debates show aspects of the way a psychoanalytic institute works and of the theoretical elaboration in psychoanalysis: these appear very different from what the myth suggests. The major function of myth is, as Freud noted and Strachey reminds us, to hide very trite, even shameful realities. History and myth, theoritical effort and institutional life are all organized from and around transference, a major axis of psychoanalytic thought. When we organize our psychoanalytic lives in societies, we have the pride or the vanity of participating in a great historical movement. This goes back to the work of transference in institutional life that involves primal objects in the crudeness of their sexuality. Such is the constraining strength of transference. Being fully conscious of it, like Stratchey or Balint show us, enables to alleviate its violence and stimulate creativity.

Creativity↗
PubMed2000

Probiotic Therapy and Functional Foods for Prevention of Urinary Tract Infections: State of the Art and Science.

In the past year, interest has heightened in the potential for probiotics to prevent urinary tract infection (UTI). Mainly, this has been due to concerns about antibiotic resistance and recognition of the scientific efficacy of probiotics. The critical factors in any successful application of probiotics to patient care are the scientific basis for selecting probiotic strains and clinical verification that they are effective against the recurrence of UTI. Three strains--Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum B-54 and RC-14--have been shown to colonize the vagina and act as a barrier to the ascension of uropathogens into the bladder. Their ability to produce growth and adhesion antagonists against urogenital pathogens is clinically important, because these appear to be important mechanisms of action. Probiotic therapy has been shown to be safe, but too few reliable products are on the market, and none are yet available for use against UTI. Given the right strains and delivery system, probiotic therapy could provide the first new UTI-prevention system in 40 years, and may help in the management of recurrent UTI.

Journal Article↗
PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗
PubMed1987

Oxytocin-like immunoreactive nerves are associated with insulin-containing cells in pancreatic islets of anglerfish (Lophius americanus).

Recent reports indicate that oxytocin exerts direct effects on the release of insulin and glucagon from the endocrine pancreas of the rat. The purpose of this study was to determine whether oxytocin-like immunoreactivity is present in the anglerfish islet, and if it is associated with subsets of hormone-producing cells. Antisera against oxytocin, insulin, glucagon, somatostatin, neuropeptide Y, and the 200-kd neurofilament polypeptide were applied to serial 5 micrometers sections of pancreatic islets. The antiserum to the 200-kd neurofilament polypeptide labeled nerve bundles and axons, some of which were also stained with the oxytocin antiserum. Oxytocin immunoreactivity was observed in large nerves that branched into varicose fibers. These fibers were consistently associated only with clusters of insulin-producing cells. Successive application of oxytocin and insulin antisera to the same section provided additional verification of this relationship. Oxytocin-labeled nerves were not associated with cells immunoreactive to glucagon, somatostatin, or neuropeptide Y (anglerfish peptide Yg). The results demonstrate that oxytocin or an oxytocin-like peptide is located in fibers that surround only insulin-producing cells in the anglerfish islet. Although the functional significance of this observation remains to be determined, the results imply that oxytocin, or an oxytocin-like peptide, may affect the synthesis or release of insulin from anglerfish islets.

Animals↗
PubMed2004

QSPR treatment of rat blood:air, saline:air and olive oil:air partition coefficients using theoretical molecular descriptors.

A QSPR treatment has been applied to a data set that consists of 100 diverse organic compounds to relate the logarithmic function of rat blood:air, saline:air and olive oil:air partition coefficients (denoted by log K(b:a), log K(s:a), and log K(o:a), respectively), with theoretical molecular and fragment descriptors. Three QSPR models with squared correlation coefficients of 0.881, 0.926, and 0.922, respectively, were obtained. The verification of the predictive power of these models on a test set of 33 organic chemicals that were not included in the training set gave satisfactory squared correlation coefficients: 0.791 for rat blood:air, 0.794 for saline:air and 0.846 for olive oil:air.

Animals↗
PubMed2005

Recording of ECG signals on a portable MiniDisc recorder for time and frequency domain heart rate variability analysis.

Analysis of heart rate variability (HRV) is a non-invasive technique useful for investigating autonomic function in both humans and animals. It has been used for research into both behaviour and physiology. Commercial systems for human HRV analysis are expensive and may not have sufficient flexibility for appropriate analysis in animals. Some heart rate monitors have the facility to provide inter-beat interval (IBI), but verification following collection is not possible as only IBIs are recorded, and not the raw electrocardiogram (ECG) signal. Computer-based data acquisition and analysis systems such as Po-Ne-Mah and Biopac offer greater flexibility and control but have limited portability. Many laboratories and veterinary surgeons have access to ECG machines but do not have equipment to record ECG signals for further analysis. The aim of the present study was to determine whether suitable HRV data could be obtained from ECG signals recorded onto a MiniDisc (MD) and subsequently digitised and analysed using a commercial data acquisition and analysis package. ECG signals were obtained from six Thoroughbred horses by telemetry. A split BNC connecter was used to allow simultaneous digitisation of analogue output from the ECG receiver unit by a computerised data acquisition system (Po-Ne-Mah) and MiniDisc player (MZ-N710, Sony). Following recording, data were played back from the MiniDisc into the same input channel of the data acquisition system as previously used to record the direct ECG. All data were digitised at a sampling rate of 500 Hz. IBI data were analysed in both time and frequency domains and comparisons between direct recorded and MiniDisc data were made using Bland-Altman analysis. Despite some changes in ECG morphology due to loss of low frequency content (primarily below 5 Hz) following MiniDisc recording, there was minimal difference in IBI or time or frequency domain analysis between the two recording methods. The MiniDisc offers a cost-effective approach to intermediate recording of ECG signals for subsequent HRV analysis and also provides greater flexibility than use of human Holter systems.

Algorithms↗
PubMed1999

Three-dimensional localisation based on projectional and tomographic image correlation: an application for digital tomosynthesis.

Accurate three-dimensional tumor localisation in Radiotherapy, is critical to the treatment outcome, particularly when high dose gradients are present. A number of techniques have been proposed for the localisation of anatomical structures or markers. The present study proposes an approach to a concurrent maximisation of localisation accuracy and efficiency by correlation of tomographic and projectional images. The method introduces an element of direct verification and interactive optimisation of the process. Tomographic images are used for the identification of a point of interest. Its position is computed within the treatment co-ordinate system and verification of this position is achieved by obtaining the beam's eye view of the identified point on two projection radiographs. The key element of the approach is that all images used should be part of one single image data set. The implementation of this localisation method, as part of the functionality of a Digital Tomosynthesis prototype, has provided an integrated facility for localisation, of optimised accuracy and precision, while easy and efficient to use. The considerations are general and apply in principle to any imaging system that can augment tomographic images with projections.

Algorithms↗
PubMed2002

An empirical model for independent dose verification of the Gamma Knife treatment planning.

A formalism for an independent dose verification of the Gamma Knife treatment planning is developed. It is based on the approximation that isodose distribution for a single shot is in the shape of an ellipsoid in three-dimensional space. The dose profiles for a phantom along each of the three major axes are fitted to a function which contains the terms that represent the contributions from a point source, an extrafocal scattering, and a flat background. The fitting parameters are extracted for all four helmet collimators, at various shot locations, and with different skull shapes. The 33 parameters of a patient's skull shape obtained from the Skull Scaling Instrument measurements are modeled for individual patients. The relative doses for a treatment volume in the form of 31 x 31 x 31 matrix of points are extracted from the treatment planning system, the Leksell Gamma-Plan (LGP). Our model evaluates the relative doses using the same input parameters as in the LGP, which are skull measurement data, shot location, weight, gamma-angle of the head frame, and helmet collimator size. For 29 single-shot cases, the discrepancy of dose at the focus point between the calculation and the LGP is found to be within -1% to 2%. For multi-shot cases, the value and the coordinate of the maximum dose point from the calculation agree within +/-7% and +/-3 mm with the LGP results. In general, the calculated doses agree with the LGP calculations within +/-10% for the off-center locations. Results of calculation with this method for the dimension and location of the 50% isodose line are in good agreement with results from Leksell GammaPlan. Therefore, this method can be served as a useful tool for secondary quality assurance of Gamma Knife treatment plans.

Computer Simulation↗