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At least 253 records · Page 14Linked to original sources

PubMed2001

[Dissecting aneurysm of the anterior cerebral artery with persistent pearl & string sign on cerebral angiograms over a period of eight years].

We present a rare case of a dissecting aneurysm of the left anterior cerebral artery (ACA) with persistent pearl & string sign on cerebral angiograms over a period of 8 years. A 43-year-old woman with disturbance of consciousness and right sided hemiparesis was conservatively treated. Computed tomographic (CT) scan revealed a low-density area in the left frontal lobe. Initial angiography, which was performed at 6 months after the onset, showed a pearl & string sign at the A2 portion of the left ACA. After 8 years, repeat angiography again showed persistent pearl & string sign at the same portion of the left ACA. We discussed the changes in findings usually obtained in cerebral angiography concerning dissecting aneurysms in ACA.

Adult↗

PubMed2001

[Adaptation of Einthoven's string galvanometer for electrocardiography in the Netherlands].

After the Dutch physiologist Willem Einthoven (1860-1927) published the construction of his string galvanometer in 1901, the development of electrocardiography in the Netherlands was slow. During the next twenty years only a few string galvanometers were in use in the Netherlands, mostly in physiology laboratories. Publications concerning electrocardiographic tests on patients were scarce. In 1924, Einthoven was awarded the Nobel Prize for Physiology and Medicine for discovering the mechanism of the electrocardiogram. From that moment onwards, electrocardiography developed rapidly in the Netherlands and during the following 30 years particular use was made of the French string galvanometer designed by Boulitte.

Electrocardiography↗

PubMed1991

[Clinical effects and immune regulation of musk-moxa-string therapy in 39 patients with scrofula].

Immunological function and lymphocytic subsets of peripheral blood mononuclear cell (PBWC) from 39 patients with scrofula were investigated before and after treatment with musk-moxa-string therapy. The results showed that the percentage of CD3+, CD4+ cells and the ratio of CD4+/CD8+ cells were markedly decreased in the patients than normal control (P less than 0.001). On the contrary, the numbers of B lymphocytes and DR+ cells were increased. But the response of PBWC to phytohemagglutin in (PHA) stimulation markedly decreased in the patients than the normal control. After treatment with musk-moxa-string therapy, the percentage of CD3+, CD4+ cells and the ratio of CD4/CD8 were increased (P less than 0.001) and blastogenic response to mitogen stimulation with PHA recovered to normal. Meanwhile, the symptoms was improved and swell lymph node disappeared or was reduced markedly in size and the ulcer was healed completely. These findings suggest that the effect of musk-moxa-string therapy is caused by the enhancement of immunological capacity of the patients.

Adolescent↗

PubMed1994

Automated DNA sequencing using 4-color fluorescent detection of reactions primed with hexamer strings.

The use of strings of contiguous short primers rather than a single long primer has the potential to greatly diminish the cost, time and management efforts associated with sequencing by primer walking. For maximum impact, this chemistry must be adaptable to current fluorescent automated sequencers, which, while allowing automated acquisition of data, have reduced sensitivity when compared with radioactive-based sequencing. The ability to use hexamer strings on Applied Biosystems DNA sequencers has now been demonstrated for single-stranded templates. Procedures are described that allow sequence to be obtained up to 400 bases from the priming site. Signal strength is sufficient in this region to allow single base resolution and highly accurate automatic base calling to be performed by the sequencer. While these conditions can no doubt be further optimized, these results show the feasibility of inexpensive primer walking using hexamer string primers on currently available commercial DNA sequencers. This should have a wide range of applications from genome sequencing projects to the sequencing of cDNA clones without the necessity of creating nested deletions or the necessity of spending inordinate amounts of time and money on oligonucleotide synthesis.

Base Sequence↗

PubMed1993

Duodenal string test in typhoid fever.

Twenty five children between 4-12 years of age hospitalized with a clinical diagnosis of enteric fever were studied for evaluating the practicality and sensitivity of duodenal string-capsule culture (DSCC) and compared with conventional cultures from blood (BC), urine (UC) and stool (SC). Duodenal string capsule (DSCC) was successfully inserted in 18 patients (72%). Insertion of DSCC failed in 7 patients (28%) and all of them were below 6 years of age. Salmonella typhi was isolated from DSCC and/or BC in 13 cases (72.2%). DSCC was positive in 11 out of 13 confirmed cases of typhoid fever (84.6%). BC was positive in 8 cases (61.5%). DSCC was successful in isolating the organism in about 30% more cases than BC. Duodenal string test was a simple, non-invasive and a reliable test which when used in combination with BC could identify almost all cases of enteric fever irrespective of duration of fever and prior use of antibiotics.

Bile↗

PubMed1983

Evaluation of the string test in intestinal bacterial overgrowth.

To determine the efficacy in assessing bacterial overgrowth, the string test (EnteroTest-Pediatric) and duodenal aspiration were compared in 18 children with chronic diarrhea. Isolation and significance of organisms in the small intestine were identical with both methods in all patients. These data suggested that the string test is an accurate, simple, and safe method for assessment of small-intestinal microflora.

Adolescent↗

PubMed2005

Temperature-dependent and friction-controlled electrochemically induced shuttling along molecular strings associated with electrodes.

The temperature and solvent composition dependence of the electrochemically stimulated rate of shuttling of the redox-active cyclophane, cyclobis(paraquat-p-phenylene), on a molecular string has been studied. The molecular string includes a pi-donor diiminebenzene-site that is associated on one side with an electrode, and stoppered on the other side with an adamantane unit. The cyclophane rests on the pi-donor site, owing to stabilizing pi-donor-acceptor interactions. Electrochemical reduction of the cyclophane units, to the bis-radical cation cyclophane, results in the shuttling of the reduced cyclophane towards the electrode, a process that is driven by the removal of the stabilizing donor-acceptor interactions, and the electrostatic attraction of the reduced product by the electrode. The latter process is energetically downhill, and is temperature-independent. Upon oxidation of the reduced cyclophane that is associated with the electrode, the energetically uphill shuttling of the oxidized cyclophane to the pi-donor site proceeds. The rate of this translocation process has been found to be temperature-dependent, and controlled by the solvent composition. The experimental results have been theoretically analyzed in terms of Kramers' molecular friction model. The theoretical fitting of the experimental results, using solutions of variable composition, reveals that the rate-constants for the uphill reaction in a pure aqueous solution follow the temperature-dependence of the viscosity of water. The results demonstrate the significance of friction phenomena in shuttling processes within molecular machines.

Journal Article↗

PubMed2004

Reaction pathways and projection operators: application to string methods.

The reaction path is an important concept of theoretical chemistry. We discuss the definition with the help of diverse projection operators for the intrinsic reaction coordinate (IRC), for the following of the reduced gradient (RGF) or Newton trajectory (NT), and for the Gradient Extremal (GE). We describe different numerical schemes for the definitions in the context of string methods. It comes out that Newton trajectories are the best ansatz for a string method.

Journal Article↗

PubMed1999

Polycations. 5. Inducement of psi-DNA circular dichroism signals for duplex deoxyribonucleotide homopolymers by polycationic strings.

Atypical circular dichroism intensity enhancements previously associated with Psi-DNA condensates are reported for poly(dG-dC):poly(dG-dC) and poly(dA-dT):poly(dA-dT) upon addition to them of a polycationic string salt. Polycationic strings are organic species incorporating several cationic sites in a linear array through the molecule. The effect observed herein with a small molecule model system holds promise for elucidation of the structural details associated with Psi-DNA condensate formation.

Cations↗

PubMed1995

Cysteine-string proteins as templates for membrane fusion: models of synaptic vesicle exocytosis.

Cysteine-string proteins are relatively small, cysteine-rich components of synaptic vesicle membranes. Recent investigations demonstrated that at least 11 of the 13 cysteine residues of the Torpedo cysteine-string protein are fatty acylated. This exceptional level of fatty acylation occurs along a short stretch (less than 25 residues) of amino acids which are flanked on either side by very polar amino and carboxy termini. This amphipathic structure may have unique capabilities to catalyze events at membrane interfaces. We propose two distinct pathways to explain how these capabilities might subserve membrane fusion and exocytosis.

Animals↗

PubMed2000

Special factors in biological strings.

Biological macromolecules such as DNA, RNA, and proteins can be regarded as finite sequences of symbols (or words) over a finite alphabet. In this paper, we refer to DNA (RNA) sequences which are words on a four-letter alphabet. A comparison is made between some "genes", or fragments of them, with random sequences or random reshuffled sequences on the same alphabet and having the same length. Some combinatorial techniques of analysis of finite words are developed. A crucial role in the comparison is played by the so-called special factors of a given word. In all the analysed DNA (RNA) fragments the distribution on the length of the number of right (left) special factors differs, in a very typical way, from the corresponding distribution in a string on the same alphabet and having the same length generated by a random source or obtained by making a random alteration (=shuffling) of the original string. This kind of change is irrespective of the length in the range that we have considered <2650 bp and of the phylogenetic origin of the fragment.

Animals↗

PubMed1978

Higher order structure in metaphase chromosomes. II. The relationship between the 250 A fiber, superbeads and beads-on-a-string.

The morphology of metaphase chromosome-derived chromatin fibers released from cells by non-ionic detergent cell lysis in the presence of divalent cations has been studied by electron microscopy. In these preparations the euchromatic arms appear as a series of loops, 200-300 A in diameter, which are composed of closely-apposed nucleosome arrays. The higher order fiber in chromosomes derived from detergent-lysed cells appears to be less stable than chromatin fibers obtained by mechanical cell lysis. The fiber breaks down into a series of non-uniform nucleosome aggregates (superbeads) and finally to chromatin in a beads-on-a-string morphology upon incubation at 31 degrees for 20 min. These observations allow us to suggest a relationship between uniform thick fibers, superbead-containing fibers, and beads-on-a-string chromatin within metaphase chromosomes.

Animals↗

PubMed1994

Posterior cruciate ligament (PCL) reconstruction--an in vitro study of isometry. Part I. Tests using a string linkage model.

In six intact cadaver knees, we measured how the distance between six selected points in and around the femoral and tibial attachment area of the posterior cruciate ligament (PCL) changed with knee flexion. After complete removal of the PCL, 2-mm drill holes were made at the selected points. Each femoral point was measured against each tibial point using a heavy string that was passed through the drill holes. The distal end of the string was attached to a measuring unit. The changes in femorotibial distance were noted during flexion from 0 degrees to 110 degrees in 10 degree steps. The tibial drill hole locations had only a minor effect on the changes in femorotibial distance. The most isometric point was located in the centre of the posterior intercondylar area. The femoral locations of the drill holes were the primary determinant of whether the distance increased, decreased or remained nearly constant. According to our results, the most isometric femoral point is located at the posterosuperior margin of the anatomical PCL attachment. Using the tibial isometric point as a reference, the femoral points positioned anterior or posterior to the isometric point produced considerable changes in the femorotibial distance upon knee flexion. The anterior point led to an increase of about 7-8 mm at 110 degrees of flexion, the posterior point to a decrease of the same extent. Much smaller changes in femorotibial distance resulted from the points located superior or inferior to the femoral isometric point.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1988

Swivel purse-string instrument for low anterior resection.

A purse-string instrument was modified to facilitate stapler anastomosis in rectal surgery. The instrument jaw was modified to permit rotation on its axis. The technique described is used to minimize the difficulty related to purse-string placement during low anterior resection of the rectum, especially in males with a narrow pelvis and in obese female patients.

Anastomosis, Surgical↗

PubMed2003

In situ growth of the novel SM1 euryarchaeon from a string-of-pearls-like microbial community in its cold biotope, its physical separation and insights into its structure and physiology.

Recently, a unique archaeal/bacterial community that grows in a macroscopically visible string-of-pearls-like structure in cold (~10 degrees C), sulfurous marsh water was discovered. Here, a new technique is described that allows the fast and reliable growth of these string-of-pearls-like microbial communities in larger quantities on polyethylene nets in nature. The microbial net population, estimated to consist of about 10,000 single pearls, can be harvested once a week and the archaeal cells selectively separated by density gradient centrifugation. As in native pearls, the archaeal cell fraction obtained consisted of a single type of coccoid cells only, 0.6 micro m in diameter. This novel type of euryarchaea has been tentatively named SM1 euryarchaeon. Electron microscopy and immuno-fluorescence in situ hybridization (immuno-FISH) revealed that about 100 pili-like fibers, up to 3 micro m in length, emanate radially from the surface of each cell. The SM1 euryarchaeal cells exhibited a viability of about 90%. The optimal conditions for viability were temperatures between -2 degrees C and 20 degrees C, pH 5-9, and low salt conditions; cell viability was independent of oxygen partial pressures. The cultures stained gram-positive, the cell wall was sensitive to SDS, EDTA and Proteinase K treatment. The cells did not exhibit the typical fluorescence for methanogens and did not contain coenzyme F(420). The G+C-content was 34.5 mol%.

Archaea↗

PubMedDate not supplied

Neoumbilicoplasty through a purse-string suture of three defatted flaps.

A wide range of techniques have been described to reconstruct a nonexistent umbilicus; nevertheless, a perfect result is difficult to obtain. We provide another alternative to reconstruct the umbilicus using a purse-string suture of three defatted flaps. Good results were obtained by creating a rounded umbilicus with a sufficient depth, which will have long-term effects. Widening, stenosis, or external scars did not occur. The purse-string suture as a complementary technique of neoumbilicoplasty allows us to obtain and keep the shape of a cylinder which is the umbilicus and avoid its widening. It can also be done in an abdomen with thick or thin adipose panniculus, thus helping to improve and influence the final result.

Abdomen↗

PubMed2002

Impairment of central pattern generation in Drosophila cysteine string protein mutants.

The cysteine string proteins are integral synaptic vesicle proteins, critical for fast, Ca2+ -regulated exocytosis. Drosophila larvae with null mutations for the cysteine string protein (csp) gene have temperature-sensitive impairments of neurotransmission and presynaptic calcium removal at the neuromuscular junction. Using the larval Drosophila preparation to examine central pattern generation, we characterized the temperature sensitivity of locomotor patterns in wildtype and csp mutant larvae. Intraburst frequency of motoneuronal activity reached 100 Hz and was sufficiently high to rescue the temperature-sensitive synaptic failure in the mutant. Nevertheless, we show that deletion of the csp gene resulted in a severe deficiency in the generation of coordinated larval motor rhythms. Csp mutants that could generate patterned motor activity had slower, poorly coordinated rhythms with altered temperature sensitivity. We conclude that the temperature-sensitive paralysis characteristic of csp mutants is not a direct result of synaptic failure at neuromuscular junctions, as might be expected, but is the result of a failure of locomotor circuit operation at a higher integrative level.

Action Potentials↗

PubMed1998

Wide distribution of the cysteine string proteins in Drosophila tissues revealed by targeted mutagenesis.

The "cysteine string protein" (CSP) genes of higher eukaryotes code for a novel family of proteins characterized by a "J" domain and an unusual cysteine-rich region. Previous studies had localized the proteins in neuropil and synaptic terminals of larval and adult Drosophila and linked the temperature-sensitive paralysis of the mutants described here to conditional failure of synaptic transmission. We now use the null mutants as negative controls in order to reliably detect even low concentrations of CSPs by immunohistochemistry, employing three monoclonal antibodies. In wild-type flies high levels of cysteine string proteins are found not only in apparently all synaptic terminals of the embryonic, larval, and adult nervous systems, but also in the "tall cells" of the cardia, in the follicle cells of the ovary, in specific structures of the female spermatheca, and in the male testis and ejaculatory bulb. In addition, low levels of CSPs appear to be present in all tissues examined, including neuronal perikarya, axons, muscles, Malpighian tubules, and salivary glands. Western blots of isolated tissues demonstrate that of the four isoforms expressed in heads only the largest is found in non-neural organs. The wide expression of CSPs suggests that at least some of the various phenotypes of the null mutants observed at permissive temperatures, such as delayed development, short adult lifespan, modified electroretinogram, and optomotor behavior, may be caused by the lack of CSPs outside synaptic terminals.

Age Factors↗