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At least 199 records · Page 11Linked to original sources

PubMed1998

Placement of a bladder neck purse-string cuff for the management of incontinence in children with myelodysplasia.

OBJECTIVES: Numerous surgical procedures have been developed in an attempt to increase bladder compliance and/or outlet resistance for the treatment of intractable incontinence in children with neurogenic lower urinary tract dysfunction. We report our experience with the development of a biocompatable purse-string cuff to increase outlet resistance by providing circumferential compression at the bladder neck. METHODS: A total of 12 children (6 boys, 6 girls) with myelodysplasia and persistent incontinence despite clean intermittent catheterization (CIC) and pharmacotherapy underwent urodynamic testing and cystoscopy that revealed neurogenic bladders with concomitant intrinsic sphincter deficiency. Through an anterior approach, the bladder neck was mobilized and wrapped with 5-mm polytetrafluoroethylene tubing. Five-millimeter woven polyester tape was then placed circumferentially within the polytetrafluoroethylene tubing lumen, purse-stringed under tension with a silicone tubing shod to appose the mucosa of the bladder neck, and secured under such tension with a surgical clip. Ten of the 12 patients underwent concomitant augmentation cystoplasty. RESULTS: Nine of 12 children (age range at time of operation 2.5 to 16 years) are continent on CIC in follow-up ranging from 6 months to 12 years. Four cuffs had to be surgically removed postoperatively. Two were removed secondary to inadvertent transvaginal placement. Two other cuffs were removed for infection. One child with persistent postoperative incontinence had the cuff retightened through a minor surgical procedure and has remained dry. Annual renal ultrasound examinations reveal stabilization of upper urinary tracts throughout the follow-up period in all but 1 patient. Postoperative urodynamic studies reveal increased bladder capacity, decreased intravesical pressures, and increased leak point pressures. CONCLUSIONS: The purse-string bladder neck cuff in combination with augmentation cystoplasty, when warranted, provides excellent, durable continence rates in children with myelodysplasia and neurogenic bladders. Attributes of the cuff are its relative low cost, ease of construction, unchanged angle of the bladder neck making catheterization easy, and potential adjustability in patients with persistent incontinence.

Adolescent↗

PubMed1999

Three-dimensional motion analysis of upper limb movement in the bowing arm of string-playing musicians.

OBJECTIVES: To explore the role of three-dimensional movement analysis in defining patterns of joint movement while bowing on different stringed instruments, and its potential for future use by the clinician in the study of musculoskeletal problems in musicians. DESIGN AND METHODS: A protocol was developed for analysis of bowing arm movements using the MacReflex 3-D analysis system- including definition of marker sites, positioning of the musician within the calibrated area and standardised bowing sequences. This protocol was then used to determine whether the system was sensitive to differences between instrument types and to variation in bowing style and technique between individual players. The ranges of movement in the shoulder, elbow and wrist were compared between instrument groups in a cohort of 39 asymptomatic string players. RESULTS: The system gave reproducible results on repeated testing, and demonstrated clear differences between instruments, as well as stylistic differences between players. Range of shoulder movement increased progressively towards the upper register of the cello, while decreasing on the violin. Maximum elevation of the shoulder was significantly greater on the cello (P<0.001), while elbow flexion, and therefore range, was consistently greater on the violin. CONCLUSIONS: Clear and reproducible differences in style and technique were demonstrated between individuals. The increased range of shoulder movement in the upper register of the 'cello may contribute to the greater prevalence of neck and shoulder symptoms among 'cellists. Further study is required to establish whether different musculoskeletal symptoms produce characteristic patterns which could help in diagnosis and development is required to make the system feasible for routine use. RELEVANCE: Musculoskeletal problems are common among musicians. Different instruments and playing positions make different demands on joints and may contribute to the variance in reported incidence of musculoskeletal symptoms among violinists and cellists. Three-dimensional analysis may prove helpful in the future for the diagnosis of different musculoskeletal syndromes in string players, or for identifying movement patterns which could exacerbate repetitive strain injuries. However, as this is the first application of the technique in this complex area, preliminary work was required to establish feasibility and to obtain data on normal players.

Arm↗

PubMed1999

Activation of human language processing brain regions after the presentation of random letter strings demonstrated with event-related functional magnetic resonance imaging.

This study addresses the question, to what extent the processing of meaningless random letter strings involves classical language related brain regions. Using event-related functional magnetic resonance imaging (fMRI), which allows random stimulus presentation, we could demonstrate activation in the left inferior frontal gyrus, the left superior temporal gyrus, left parietal and occipital regions after the presentation of random letter strings compared to real words. The activation in these classical language related brain areas reflects an intense lexical evaluation process of the meaningless stimuli. Real words contrasted with random letter strings activated the left angular gyrus, bilateral precuneus and the left posterior cingulate gyrus, which may reflect the access of higher semantic associations.

Adult↗

PubMed1999

Dynamic pattern of brain activation during sequencing of word strings evaluated by fMRI.

An impaired ability to recite highly automated word strings (e.g., the names of the months of the year) in reverse order concomitant with preserved production of the conventional sequence has been considered a salient sign of frontal lobe dysfunction. Using functional magnetic resonance imaging (fMRI), the spatial and temporal pattern of brain activation during covert performance of these tasks was evaluated in healthy subjects. As compared to the response obtained during forward recitation, re-sequencing of the word string yielded additional activation of the bilateral middle and inferior frontal gyri, the posterior parietal cortex and the left anterior cingulate gyrus. The prefrontal responses are in accordance with the clinical findings referred to. However, the set of activated areas, as a whole, presumably reflects contribution of the various components of the working memory system to the sequencing of word strings. During successive periods of task administration, subjects showed a linear increase of production speed. Analysis of corresponding dynamic changes of regional hemodynamic responses revealed a significant increase at the level of the left inferior parietal cortex and a decrease within the mesial aspect of the left superior frontal gyrus. Presumably, the former finding reflects increasing demands on the phonological short-term memory store, due to faster updating of its content under increased word production rate. Decreasing activation within the superior frontal gyrus might indicate contribution of this area to the initiation of the cognitive processes subserving the sequencing of verbal items. These findings demonstrate the capability of fMRI as a powerful tool for the analysis of dynamic brain activation.

Adult↗

PubMed1999

Color flow scan diagnosis of the carotid string may prevent unnecessary surgery.

Can the color flow scanner assist in the diagnosis and management of patients with preocclusive lesions of the carotid bifurcation (so-called 'string sign')? Twenty-three patients were identified as having a 'string' by duplex criteria. Seventeen patients underwent angiography, which confirmed the duplex findings in 14 patients. In three, the angiogram was originally misread as showing an occluded internal carotid Artery. Six patients were managed solely on the basis of the duplex findings. Based on arteriography and/or duplex criteria, 12 involved internal carotid arteries were not explored. One artery went on to occlude asymptomatically. The remaining 11 have remained patent and asymptomatic (follow-up 6-72 months). Five arteries were predicted operable and underwent successful endarterectomy. Six were predicted inoperable yet underwent exploration. All were ultimately treated by ligation +/- external carotid endarterectomy without subsequent neurological deficit. Duplex scans can identify internal carotid artery string signs, determine operability and may predict the functionally occluded artery that can be safely observed.

Arteriosclerosis↗

PubMed2003

Reversal of radial artery 'string sign' at 6 months follow-up.

The clinical importance of radial artery string sign is still debated. We present a case of reversal of radial artery string sign in 6 months with concomitant involution of competitive flow arising from an important collateral coronary circulation to an occluded right coronary artery. The hypothesis that the string sign is an extreme form of autoregulation of the radial artery is confirmed, and the flow reserve of this conduit is emphasized.

Coronary Angiography↗

PubMed2004

SeeDNA: a visualization tool for K-string content of long DNA sequences and their randomized counterparts.

An interactive tool to visualize the K-string composition of long DNA sequences including bacterial complete genomes is described. It is especially useful for exploring short palindromic structures in the sequences. The SeeDNA program runs on Red Hat Linux with GTK+ support. It displays two-dimensional (2D) or one-dimensional (1D) histograms of the K-string distribution of a given sequence and/or its randomized counterpart. It is also capable of showing the difference of K-string distributions between two sequences. The C source code using the GTK+ package is freely available.

Algorithms↗

PubMed2000

Bit-string methods for selective compound acquisition

Selective compound acquisition programs need to ensure that the compounds that are chosen do not contain undesirable functionality. This is easy to achieve if a supplier is prepared to provide unambiguous structure representations for the compounds that they have available: this paper discusses selection techniques that can be used when a supplier is prepared to make available only fragment bit-string representations for the compounds in their catalog. Experiments with three databases and three types of bit-string show that a simple k-nearest-neighbor searching method provides a surprisingly effective, although far from perfect, way of selecting compounds when only bit-string representations are available. A second approach, based on the use of a fragment weighting scheme analogous to those used in substructural analysis studies, proved to be noticeably less effective in operation.

Journal Article↗

PubMed2002

Complete closure by purse-string suture after Mohs micrographic surgery on thin, sun-damaged skin.

BACKGROUND: The purse-string suture technique is useful for partial closure of surgical defects. OBJECTIVE: We demonstrated that 100% closure can often be obtained on surgical defects of the thin skin on the upper extremities. METHODS: Standard purse-string suture techniques were used to close surgical defects on the upper extremities. RESULTS: 100% closure of surgical defects on upper extremities was demonstrated. CONCLUSIONS: Purse-string suture technique is useful for repairs of surgical defects on the upper extremities when the skin is very thin but not recommended when the skin is thick.

Humans↗

PubMed2003

Revisiting the purse-string closure: some new methods and modifications.

BACKGROUND: Surgical wounds resulting from the extirpation of cutaneous malignancies can be repaired in a number of ways. One alternative, which has been used extensively in our practice, is the purse-string closure. This method of closure offers distinct advantages in the proper setting over traditional methods of closure. OBJECTIVE: Over the years, our approach to this procedure has evolved, and we have integrated a number of new modifications that are presented later here. METHODS: A report of three illustrative cases is given. RESULTS: Three cases are presented that illustrate some new modifications to the purse-string closure. CONCLUSION: The purse-string closure, which uses circumferential tissue advancement, can be used to close a wide range of surgical wounds. This method also frequently offers the advantage of an excellent cosmetic outcome.

Aged↗

PubMedDate not supplied

Three purse-string sutures allow immediate start of peritoneal dialysis with a low incidence of leakage.

Peritoneal dialysis (PD) depends to a great extent on a well-functioning dialysis catheter. The number of patients choosing PD also depends on the possibility of starting dialysis with this technique without needing to use hemodialysis (HD) intermediate or in the beginning of the procedure. This review describes various insertion techniques focusing on a surgical insertion technique using purse-string sutures to fix the peritoneum around the catheter with the inner cuff of a Tenckhoff catheter invaginated between purse-string sutures of the peritoneal membrane and the inner rectus muscle fascia. A third purse-string suture is used to fix the catheter and to tighten the hole in the external rectus fascia. This technique enables immediate start of PD with only a limited risk for early and late leakage. Similar fixation sutures could be considered when inserting catheters, using other insertion modes, to tighten the hole and the position of the cuff and the catheter.

Catheters, Indwelling↗

PubMed2004

First-principles string molecular dynamics: an efficient approach for finding chemical reaction pathways.

A recently proposed approach, called "string method," allows us to find minimum energy pathways connecting two metastable states of a system [W. E et al., Phys. Rev. B 66, 052301 (2002)]. So far this approach has been only used with empirical force field parametrizations of the atomic potential energy surface or in the context of macroscopic continuum models. Here we show that the string method can be efficiently combined with first-principles molecular dynamics to provide an accurate description of chemical reaction pathways and barriers. We illustrate the first-principles string molecular dynamics by applying it to the study of a surface chemical reaction, for which extensive experimental and theoretical works are available, namely, the adsorption of H(2) on the reconstructed Si(100) surface.

Journal Article↗

PubMed1998

Vesicles on strings: morphological evidence for processive transport within the Golgi stack.

Cis-Golgi cisternae have a higher freeze-fracture particle density than trans-cisternae. Transport vesicles neighboring cis or trans positions of the Golgi stack have a particle concentration comparable to that of the adjacent cisterna and the buds emerging from it. This implies that transport vesicles remain locally within the stack during their lifetime, near their origin, favoring a processive pattern of transport in which vesicle transfers occur preferentially between adjacent cisternae in the stack. A "string theory" is proposed to account for processive transport, in which a carpet of fibrous attachment proteins located at the surface of cisternae (the strings) prevent budded vesicles from diffusing away but still allow them to diffuse laterally, effectively limiting transfers to adjoining cisternae in the stack. Fibrous elements that multivalently connect otherwise free COPI-coated vesicles and uncoated transport vesicles to one or two cisternae simultaneously are discerned readily by electron microscopy. It is suggested that long, coiled coil, motif-rich, Golgi-specific proteins including p115, GM130, and possibly giantin, among others, function as the proposed strings.

Adenosine Triphosphate↗

PubMed1990

Electromyographic analysis of bow string release in highly skilled archers.

A predominant archery coaching tenet holds that the most effective means of releasing the bow string is by relaxation of the finger flexor muscles without activation of finger extensors. To evaluate the validity of this view, EMG patterns of the flexor digitorum superficialis and extensor digitorum muscles of the draw arm were examined using surface EMG electrodes in 15 highly skilled archers as each performed six shots. Each archer displayed consistent EMG patterns from shot-to-shot and two distinct flexor-extensor patterns were exhibited by the sample. The first, characterized by eight of the archers, supported the relaxation principle. For these archers, both flexor and extensor digitorum activity decreased markedly immediately prior to or at arrow release. The second pattern, characteristic of the remaining seven archers, contradicted the coaching tenet. While the flexor digitorum pattern was essentially the same as that described for the first pattern, the extensor digitorum displayed a marked increase in activity just prior to release, indicating that string release was facilitated by an active extension of the fingers. It was concluded that highly skilled archers do not predominantly reflect a release consistent with the coaching canon and that factors other than the string release mechanism discriminate the performances of skilled archers.

Adult↗

PubMed2001

Separating effects of orthographic similarity and contour summation in the identification of masked letter strings.

We separated effects of contour summation and orthographic similarity under masking conditions, by comparing identification with simultaneous and sequentially presented letter strings, which either did or did not overlap spatially. With overlapping simultaneous stimuli, performance was better for strings with similar contours than for strings with the same letters (the orthographic similarity condition). This suggests that contour summation effects were strongest in the condition where stimuli had similar contours. With sequential presentations, performance in the similar contour and the orthographically similar conditions was equated when the stimuli were overlapping. However, effects of contour summation decreased when prime and target letters were spatially displaced, whereas performance in the orthographically similar condition was maintained. We conclude that effects of orthographic similarity can be distinguished from effects of contour summation, under masking conditions.

Female↗

PubMed1993

A novel cytoskeletal structure involved in purse string wound closure and cell polarity maintenance.

The process of wound repair in monolayers of the intestinal epithelial cell line, Caco-2BBe, was analyzed by a combination of time-lapse differential interference contrast (DIC) video and immunofluorescence microscopy, and laser scanning confocal immunofluorescence microscopy (LSCIM). DIC video analysis revealed that stab wounds made in Caco-2BBe monolayers healed by two distinct processes: (a) Extension of lamellipodia into the wounds; and (b) Purse string closure of the wound by distinct arcs or rings formed by cells bordering the wound. The arcs and rings which effected purse string closure appeared sharp and sheer in DIC, spanned between two and eight individual cells along the wound border, and contracted in a concerted fashion. Immunofluorescence analysis of the wounds demonstrated that the arcs and rings contained striking accumulations of actin filaments, myosin-II, villin, and tropomyosin. In contrast, arcs and rings contained no apparent enrichment of microtubules, brush border myosin-I immunogens, or myosin-V. LSCIM analysis confirmed the localization of actin filaments, myosin-II, villin, and tropomyosin in arcs and rings at wound borders. ZO-1 (a tight junction protein), also accumulated in arcs and rings around wounds, despite the fact that cell-cell contacts are absent at wound borders. Sucrase-isomaltase, an apically-localized integral membrane protein, maintained an apical localization in cells where arcs or rings were formed, but was found in lamellipodia extending into wounds in cells where arcs failed to form. Time-course, LSCIM quantification of actin, myosin II, and ZO-1 revealed that accumulation of these proteins within arcs and rings at the wound edge began within 5 minutes and peaked within 30-60 minutes of wounding. Actin filaments, myosin-II, and ZO-1 achieved 10-, 3-, and 4-fold enrichments, respectively, relative to cell edges which did not border wounds. The results demonstrate that wounded Caco-2BBe monolayers assemble a novel cytoskeletal structure at the borders of wounds. The results further suggest that this structure plays at least two roles in wound repair; first, mediation of concerted, purse string movement of cells into the area of the wound and second, maintenance of apical/basolateral polarity in cells which border the wound.

Actins↗

PubMed1996

A tissue-specific repressor in the sea urchin embryo of Lytechinus pictus binds the distal G-string element in the LpS1-beta promoter.

LpS1 RNA transcripts and proteins are expressed exclusively in the aboral ectoderm of the embryo in the sea urchin Lytechinus pictus. We have characterized the LpS1-beta promoter to identify the cis-acting elements that may be involved in the aboral ectoderm-specific expression of the LpS1-beta gene. The distal G-string site, composed of six contiguous guanine deoxynucleotides located at -721 to -726, was analyzed. A mutation at the distal G-string caused over a two-fold increase in reporter chloramphenicol acetyltransferase gene activity and inappropriate expression of reporter green fluorescent protein in nonaboral ectoderm cells in L. pictus embryos. These results suggest that the proteins that bind the distal G-string act as a spatial repressor in the nonaboral ectoderm cells of the developing embryo.

Animals↗

PubMed2003

Finding subtle motifs by branching from sample strings.

UNLABELLED: Many motif finding algorithms apply local search techniques to a set of seeds. For example, GibbsDNA (Lawrence et al. 1993, Science, 262, 208-214) applies Gibbs sampling to random seeds, and MEME (Bailey and Elkan, 1994, Proceedings of the Second International Conference on Intelligent Systems for Molecular Biology (ISMB-94), 28-36) applies the EM algorithm to selected sample strings, i.e. substrings of the sample. In the case of subtle motifs, recent benchmarking efforts show that both random seeds and selected sample strings may never get close to the globally optimal motif. We propose a new approach which searches motif space by branching from sample strings, and implement this idea in both pattern-based and profile-based settings. Our PatternBranching and ProfileBranching algorithms achieve favorable results relative to other motif finding algorithms. AVAILABILITY: http://www-cse.ucsd.edu/groups/bioinformatics/software.html

Algorithms↗