Single Sheath Research Articles

P-396 Single sheath lead extraction — As effective as laser?

P-396 Single sheath lead extraction — As effective as laser?

Extracellular matrix of different composition supports the various splenic compartments of guinea fowl ( Numida meleagris).

The extracellular matrix (ECM) of the spleen of the guinea fowl has been studied by immunohistochemistry. Each splenic compartment contains a different composition of ECM. Reticular-fiber-specific collagen III is expressed by the red pulp and thymus-dependent periarterial lymphatic sheath, but silver impregnation reveals a reticular-fiber-like structure in the periellipsoidal white pulp (PWP) where collagen III is absent. The penicillar capillaries of one central artery are enveloped by a single branching sheath or sleeve: the ellipsoid or Schweigger-Seidel sheath. The shape of the sleeve shows more resemblance to a deer antler than to an ellipsoid; it emerges at the beginning of the penicillar capillaries and ends at the edge of the PWP. It is wrapped by a novel discontinuous basement-membrane-like structure that expresses tenascin and that is named the capsule of the Schweigger-Seidel sheath (CSS). The cuboidal-shaped inner cell layer of the ellipsoid can be identified by a novel monoclonal antibody: BID3. BID3-positive stellate-shaped cells also occur in the PWP, suggesting that this cell population has migratory capability. Monoclonal antibody KIF8 recognizes an ECM component in the ellipsoid not only of guinea fowl, but also of chicken and quail, and may thus identify an ellipsoid-specific antigen. Collagen I is associated with both the basement membrane of the penicillar capillary and the CSS, whereas collagen III is present only in the CSS. Laminin is expressed in the red pulp, but its staining pattern does not indicate the presence of the "ring fibers", which suggests the absence of sinuses. Fibronectin is the only ECM molecule studied that occurs in every splenic compartment, indicating extensive intrasplenic cell migration.

P1541 Single sheath lead extraction

P1541 Single sheath lead extraction

Technical success rate of uterine artery embolisation for treatment of uterine leiomyomas at the University of the Free State

The technical success rate of uterine artery embolisations at the Department of Diagnostic Radiology, University of the Free State (UFS) is reported. From November 1998 to July 2001, 67 women, aged 35 - 75 years, received uterine artery embolisation. The procedure was usually performed through a single 4-French sheath set which was introduced into the right femoral artery using a 4- French catheter and injecting PVC particles (150 - 550 micron). Embolisation was performed successfully in 85.5% of the women. The mean total fluoroscopy time was 16.8 minutes, ranging from 4.8 minutes to 47.3 minutes.

Observation of vortex patterns and movement in Y-123 and Bi-2212 samples by means of the Bitter technique

We have examined vortex patterns and vortex movement in single crystal Y-123 and Y-123 quench-melt growth (QMG) samples, and also in single crystal Bi-2212 and Bi-2223 silver sheath material, by means of the Bitter technique. The observation temperature ( T d) and the strength of an external magnetic field (Hex) were varied. We observed movement of the vortices in single crystal Y-123 at higher temperatures ( T d>0.7 T c) with Hex=100 Gauss. The distance moved depended on T d. However, the movement also depended on the external dc magnetic field. It became clear that the vortex moved even at low temperature in a small magnetic field. We observed the vortex pattern of a Y-123 QMG sample. The vortices existed locally around Y-211 precipitate particles. It was also found from the observation of vortices in single crystal Bi-2212 that the vortices actively moved when the vortex interval was larger than two λ. The vortex movement of Bi-2223 silver sheath material was different compared to that of single crystal Bi-2212.

Continuous regional analgesia: can we afford not to use it?

Continuous regional analgesia: can we afford not to use it?

The division of the sciatic nerve in the popliteal fossa: anatomical implications for popliteal nerve blockade.

The sciatic nerve (SN) originates from the L4-S3 roots in the form of two nerve trunks: the tibial nerve (TN) and the common peroneal nerve (CPN). The TN and CPN are encompassed by a single epineural sheath and eventually separate (divide) in the popliteal fossa. This division of the SN occurs at a variable level above the knee and may account for frequent failures reported with the popliteal block. We studied the level of division of the SN in the popliteal fossa and its relationship to the common epineural sheath of the SN. The level of division of the SN sheath into TN and CPN above the knee was measured in 28 cadaver leg specimens. The SN was invariably formed of independent trunks (TN and CPN) encompassed in one common epineural sheath. The SN divided at a mean distance of 60.5 +/- 27.0 mm (range 0 to 115 mm) above the popliteal fossa crease. We conclude that the TN and CPN leave the common SN sheath at variable distances from the popliteal crease. This finding and the relationship of the TN and CPN sheaths may have significant implications for popliteal block. When performing popliteal block, insertion of the needle at 100 mm above the popliteal crease is more likely to result in placement of the needle proximal to the division of the sciatic nerve than placement at 50 or 70 mm, according to the classical teaching.

Forebrain white matter in spontaneously hypertensive rats: a quantitative image analysis study

The volume and the morphology of brain white matter as well as the number and the size of glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes were investigated in 6-month-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar–Kyoto (WKY) rats. The volume of frontal and occipital cortex and of hippocampus was decreased in SHR in comparison with normotensive rats, whereas the volume of neostriatum was unchanged. A remarkable decrease of the volume of internal capsule and striosomes, a moderate reduction of that of corpus callosum and no changes of the volume of external capsule and of white matter of hippocampus were also observed in SHR. In SHR the number of astrocytes was higher in the frontal and occipital cortex and in the white matter of the CA 1 and CA 3 subfields of the hippocampus, but not in the corpus callosum or in the grey matter of the CA 1 and CA 3 subfields. Staining for myelin did not reveal alterations in single fibre sheath morphology. These findings indicate the occurrence of changes of forebrain white matter in SHR, consisting in the reduction of it without qualitative modifications of myelinated fibres. The development of gliosis apparently not related with changes of volume of white matter was also found.

Advances in abdominal interventional radiology

Advances in abdominal interventional radiology

The feasibility of magnetic field reduction by phase relationship optimization in cable systems

This paper investigates the feasibility of magnetic fields reduction by optimization of phase relationships in a multi-circuit underground power cable system, carrying unbalanced loads. A novel algorithm was developed for fast calculation of the multi-circuit power cable system-generated magnetic field. The unbalanced load was modeled by random selection of phase current values. A computer code was written to calculate the statistical distribution of the magnetic field above the cables on the ground level. The program calculates the maximum magnetic field for different phase relationships and selects the optimum phase relationship. Several multi-circuit power cable systems used by electric utilities have been analyzed. The results show that the optimization of phase relationships effectively reduces the magnetic field for power cable systems with both single and multi-point grounded sheaths in spite of the load unbalance.

Comparison of a consistent theory of radio frequency sheaths with step models

In order to find analytically tractable models for the electrode sheath of a capacitively coupled rf discharge, step models are used in the literature, describing the electron density by a step function oscillating with the radio frequency ω (ωpi≪ω≪ωpe). Comparison of the results of these step models with the results of numerical calculations shows similar current–voltage characteristics for symmetric discharges. On the other hand, distinct deviations in the spatial behavior of field and potential for a single sheath are observed. We discuss the deviations of the step models and show that they arise from systematic errors in the boundary conditions which are due to misinterpretations of the asymptotic two scale formalism. On the basis of a systematic two scale theory, we develop an improved step model with correct boundary conditions.

Simultaneous delivery of two patent arterial duct coils via one venous sheath.

A female child, 10 months of age, weighing 7.2 kg, was catheterised for closure of a patent arterial duct. Aortography was performed in the lateral projection and the minimum diameter...

Morphology of oligodendrocytes during demyelination in optic nerves of mice infected with Semliki Forest virus.

Multiple sclerosis (MS) is a demyelinating disease which affects oligodendrocytes, the myelinating cells of the CNS. Demyelination is known to occur in the optic nerves of Balb/c mice infected with the avirulent A7(74) strain of Semliki Forest virus (SFV), and many of the changes are similar to those of patients with MS. The aim of the present study was to determine how demyelination proceeds in individual oligodendrocytes in SFV infection, to help in understanding the pathology of demyelination and remyelination in MS. The whole-cell morphology of individual oligodendrocyte units (defined as the oligodendrocyte, its processes and the internodal myelin segments of the axons it ensheaths) was characterized using intracellular dye injection in isolated intact optic nerves. In untreated control mice, oligodendrocytes had a relatively uniform morphology and each cell on average provided 20 or so nearby axons with single myelin sheaths with internodal lengths of approximately equal to 150 microns. In SFV infected mice, during the peak of demyelination at post-inoculation days 14-21, 55% of oligodendrocytes displayed a range of morphological abnormalities, which most likely represented sequential changes in oligodendrocytes during demyelination. Thus, at the earliest stage of demyelination oligodendrocytes developed swellings or vacuolations along their internodal myelin sheaths, which became gradually attenuated and were completely lost in extreme cases. The results show that whole oligodendrocyte units were affected during SFV-induced demyelination and this is the basis of the focal nature of lesions in this viral model of MS. Individual oligodendrocyte units which had lost their full complement of myelin sheaths had the appearance of immature oligodendrocytes, suggesting they had undergone dedifferentiation. We concluded that these cells may not be destroyed during demyelination and it is possible they are capable of remyelination which is a feature of SFV infection in mice and MS in humans.

Multiply myelinated axons in the optic nerve of mice deficient for the myelin-associated glycoprotein.

We recently reported that some retinal ganglion cell axons in mice deficient for the myelin-associated glycoprotein are concentrically surrounded by more than one myelin sheath. In the present study, we demonstrate that myelin sheaths displaced from the axon reveal a normal ultrastructure of compact myelin, with the only exception that multiple myelination of axons frequently correlates with the presence of unfused regions of major dense lines. Supernumerary sheaths terminated on other sheaths or on astrocyte cell surfaces in a pattern closely resembling the morphology of a true paranode. The thickness of compact myelin of multiply myelinated axons was significantly increased when compared with axons of similar caliber surrounded by a single myelin sheath. Our observations demonstrate that maintenance of compact myelin and paranodal regions is not dependent on direct axonal contact and that the presence of more than one concentric myelin sheath around an axon results in dysregulation of the axon-to-fiber ratio.

Percutaneous Retrieval of Two Wallstent Endoprostheses from the Heart through a Single Jugular Sheath

O SCVIR, 1995 The rapidly expanding use of endovascular devices has necessitated new techniques to remove misplaced or migrated devices. Percutaneous removal of a single Wallstent with use of a combined femoral and jugular vein approach has been described previously (1). The present case demonstrates successful percutaneous retrieval of two Wallstents, one from the right atrium and one from the tricuspid valve, via a single preexisting sheath in the internal jugular vein (IJV).

980-83 Advantages of Sealing Arterial Puncture Sites After PTCA with a Single Collagen Plug: A Randomized, Prospective Trial

Only little data exist comparing collagen plugging of arterial puncture sites at identical conditions with conventional sheath pulling. Furthermore it has not been investigated whether one single plug is also effective after PTCA. Therefore we randomized 150 pats to either one single collagen plug or conventional sheath (8F) pulling. Both groups did not differ in age, gender, BSA, BP or APTT. single collagen plug control Compression time (min) 3 ± 3 16 ± 7 * normal local findings 87% 77% little local swelling 8% 21% * severe local swelling 5% 2% hematoma ≤ 7 cm 20% 29% hematoma > 7 cm 5% 4% patient comfort index 8.3 3.5 * * p < 0,05 Collagen plugging of arterial puncture sites after PTCA is as effective as conventional sheath pulling and significantly reduces time to hemostasis. Patient comfort is markedly increased. Since one single plug is very effective, costs may be cut in half.

Diastematomyelia: diagnosis by prenatal sonography.

Diastematomyelia is a form of spinal dysraphia involving a sagittal cleft in the spinal cord with splaying of the posterior spinal elements. This may be an isolated abnormality or in association with more serious dysraphic conditions. In isolated diastematomyelia, the skin is intact and the prognosis excellent. This study aimed to determine the usefulness of prenatal sonography in diagnosing diastematomyelia and in predicting the isolated form. The usefulness of the sonographic findings of an extra posterior echogenic focus between the fetal spinal laminae and splaying of the posterior elements for the prenatal sonographic diagnosis of diastematomyelia was assessed in five cases prospectively and in one case retrospectively. The posterior echogenic focus was first seen on prenatal sonograms at a mean age of 19 weeks' gestation (range, 18-20 weeks). The final diagnosis of diastematomyelia was made at autopsy in two cases (one with an associated meningocele), at postmortem radiography in one, at surgery in one, and at CT myelography in two. Postnatal spinal sonograms were obtained in each case. The ability to detect fetal spinal widening on prenatal sonograms was compared with the postnatal radiologic appearance on spinal plain film radiographs. Diastematomyelia was confirmed in all five cases where the extra posterior echogenic focus was seen at prenatal sonography. The double spinal cord was within a single dural sheath in three cases, with no bony bar present. A double dural sheath with a bony bar was noted in a fourth case. In the fifth case, a bony bar was seen on a postmortem spinal X-ray, but a double dural sheath could not be confirmed because an autopsy was not performed. In the case where diastematomyelia was not suspected on prenatal sonograms, the dural sheath was single and no bony bar was present. Splaying of the posterior elements was seen on postnatal radiographs in all cases but was suspected in only four on prenatal sonograms. Prenatal sonography accurately predicted isolated diastematomyelia in four cases and complicated diastematomyelia in one case. The one case missed prenatally was of isolated diastematomyelia. A diagnosis of diastematomyelia can be made if an extra posterior echogenic focus is seen on prenatal sonography. Splaying of the posterior elements of the fetal spine is frequently present. The pregnancy should be managed differently depending on whether the diastematomyelia is isolated, with the skin intact, or is in association with more serious neural tube defects. This distinction is possible prenatally.

Litomosoides carinii microfilarial sheaths: Partial amino-acid sequences of several major polypeptide constituents

Isolated sheaths from Litomosoides carinii microfilariae were disintegrated by reduction with dithiothreitol and were 14C-carboxymethylated. Five major sheath proteins thus solubilized were purified by size exclusion chromatography and reversed-phase HPLC (rpHPLC). Proteolytic fragments of complete sheaths and of the single sheath proteins were isolated by rpHPLC and were N-terminally sequenced. A library of 27 partial sheath polypeptide sequences was thus established, 21 of which could be assigned to three L. carinii sheath structural genes ( shp1,2, and 3/3a) isolated on the basis of this and of previous amino acid sequence information. The remaining peptides document the presence of at least one additional major sheath constituent.

Prediction of Ion Energy and Angular Distributions in Single and Dual Frequency Plasmas

We present a model to predict the energy and angular distributions of ions which impact the substrate in low (100–450 kHz), high (13.56 MHz), and dual frequency plasmas. The model combines a single and dual frequency plasma sheath model with Monte Carlo simulations of ion transport. The sheath model for single and dual frequency parallel plate plasma systems provides the time dependent sheath thickness and the time and spatially dependent electric field in the sheath, which are necessary for the Monte Carlo simulations. Monte Carlo simulations are used to track the ion motion and to generate the energy and angular distributions. Both charge transfer and hard sphere elastic collisions are included in the Monte Carlo simulations. The model predictions of the ion energy and angular distributions agree well with experimental data for argon plasmas and with the predictions of other analytical models and Monte Carlo simulations in the low (100 kHz) and high (13.56 MHz) frequency limits. Model predictions show that the shapes of the ion angular and energy distributions and the resultant average ion energy and angle become independent of pressure and frequency above 10 Torr. Below 10 Torr, changing the frequency mix from 100% high frequency to 100% low frequency lowers the average ion energy, increases the maximum ion energy, and increases the directionality of the ions.

Infrageneric phenetic relations in new world Panicum (Poaceae: Panicoideae: Paniceae): a numerical analysis

Numerical studies based on 64 characters placed 188 American species of the genus Panicum L. in 23 sections clustered in five major groups. The same major groups were obtained when the five characters that define the subgenera were excluded from the analyses. Groups 1 and 2 included C4 species. Species with an outer parenchymatous sheath in group 1 corresponded to subg. Panicum, whereas species with a single mestome sheath in group 2 corresponded to subg. Agrostoides. Group 3 included the intermediate C3–C4 species belonging to subg. Steinchisma. C3 sections were clustered together but arranged in a different way than previous classifications. Group 4 included sections from subg. Phanopyrum with basic chromosome number x = 10, whereas group 5 included the other sections of Phanopyrum with x = 9 together with sections from subg. Dichanthelium also with x = 9. The two subgroups of subg. Phanopyrum are not only different in chromosome number but also in inflorescence type and upper anthecium ornamentation. On the other hand the x = 9 sections of Phanopyrum remain in the same cluster with sections from subg. Dichanthelium in numerical analyses where basic chromosome number is removed. These results suggest the possibility of sinking Dichanthelium into Phanopyrum and then split the latter when more cytological data become available. Kranz syndrome and basic chromosome number were the characters with the highest contribution to the delimitation of the major groups. On the basis of these results different existing hypotheses on the classification of the genus Panicum are discussed. Key words: Panicum, numerical taxonomy.