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PubMed2003

Acellular and glutaraldehyde-preserved tendon allografts for reconstruction of superficial digital flexor tendon in bovines: Part II--Gross, microscopic and scanning electron microscopic observations.

Sixteen tenorrhaphies were performed at mid-metatarsal region in eight buffalo calves. A 2-cm long gap was created in the superficial digital flexor (SDF) tendon in all animals. The gap was immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde-preserved tendon allografts in group II, and in group III the defect was repaired with autografts (control group). The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Gross observation revealed filling of host tendon-graft junction with fibrous connective tissue. Increased vascularity was seen in group I when compared with group II and III. Graft was resorbed in animals of group I and III, whereas partial absorption of graft was seen in group II. Histological observations on day 30 revealed restoration of cellularity in acellular graft and fragmentation and resorption of glutaraldehyde-preserved graft. Graft was replaced by newly formed fibrous connective tissue. Tissue reaction around polygalactin suture consisted of plasma cells, lymphocytes and macrophages. On day 90, most of the acellular graft was replaced by newly formed fibrous connective tissue. In group II the majority of graft portion remained at the site and was in a state of resorption. In the control group it was difficult to distinguish between the host tendon and the graft. Scanning electron microscopical observation showed densely packed neoformed tissue at host tendon-graft junction. Hydrolysis and invasion of connective tissue between polygalactin suture filaments, resorption of graft with cavity formation and dissolution of ground substance were observed.

Animals↗
PubMed1999

Cochlear nerve projections to the small cell shell of the cochlear nucleus: the neuroanatomy of extremely thin sensory axons.

Labeling cochlear nerve fibers in the inner ear of chinchillas with biotinylated dextran polyamine was used to trace the thin fibers (Type II), which likely innervate outer hair cells. These axons, 0. 1-0.5 microm in diameter, were distinguished from the thicker Type I, fibers innervating inner hair cells, and traced to small-cell clusters in the cochlear nucleus. This study provided two major new insights into the outer hair cell connections in the cochlear nucleus and the potential significance of very thin axons and synaptic nests, which are widespread in the CNS. 1) EM serial reconstructions of labeled and unlabeled material revealed that Type II axons rarely formed synapses with conventional features (vesicles gathered at junctions). Rather, their endings contained arrays of endoplasmic reticulum and small spherical vesicles without junctions. 2) Type II axons projected predominantly to synaptic nests, where they contacted other endings and dendrites of local interneurons (small stellate and mitt cells, but not granule cells). Synaptic nests lacked intrinsic glia and, presumably, their high-affinity amino acid transporters. As functional units, nests and their Type II inputs from outer hair cells may contribute to an analog processing mode, which is slower, more diffuse, longer-lasting, and potentially more plastic than the digital processors addressed by inner hair cells.

Animals↗
PubMedDate not supplied

An in vitro caries inhibition of photopolymerized glass ionomer liners.

Caries inhibition of traditional chemical cure glass ionomers has been established. The newer photopolymerized glass ionomers demonstrate a different composition that may impair the ability of providing prevention to secondary caries at restoration margins. The purpose of this study was to evaluate the caries inhibition of photopolymerized glass ionomers (Vitrebond-3M Dental Products, Photac Bond-ESPE/Premier Dental Products) compared to a photopolymerized composite resin (Pertac Universal Bond-ESPE/Premier) control. Two standardized Class V preparations were placed in thirty permanent molars, the gingival margin placed below the cementoenamel junction. Equal numbers of preparations were restored with Vitrebond, Photac Bond and Pertac Universal Bond, according to manufacturer's instructions. The teeth were coated with an acid resistant varnish to within 2 mm of the restoration margins. All teeth were subjected to an artificial caries challenge (pH 4.2) for five days, then axial sections of 100 microns were cut longitudinally through the restored margins and photographed under polarized light microscopy. The polarized micrographs were projected onto a digitizing pad, where demineralized areas adjacent to the restoration margins were quantitated. Results demonstrated the mean (+/- S.D.) area (microns2) demineralization 100 microns from the restoration gingival margin to be: Photac Bond 66.1 +/- 27.8; Vitrebond 47.2 +/- 37.2; Pertac Universal Bond 120.9 +/- 66.0. Duncan's multiple range test indicated there was no statistically significant difference in demineralization inhibition between the two photopolymerized glass ionomers Photac Bond and Vitrebond (p < 0.05), but both photopolymerized glass ionomers demonstrated significantly less demineralization than the Pertac Universal Bond composite resin control (p < 0.05).

Dental Caries↗
PubMed2003

Esophagogastric junction opening during relaxation distinguishes nonhernia reflux patients, hernia patients, and normal subjects.

BACKGROUND AND AIMS: Flow across the esophagogastric junction (EGJ) is strongly related to opening dimensions. This study aimed to determine whether opening of the relaxed EGJ was altered in patients with gastroesophageal reflux disease (GERD). METHODS: Seven normal subjects (NL), 9 GERD patients without hiatus hernia (NHH), and 7 with hiatus hernia (HH) were studied. Cross-sectional area (CSA) of the relaxed EGJ was measured during low-pressure distention using a modified barostat technique that resulted in filling a compliant bag straddling the EGJ with renograffin to the set pressure. Swallows were imaged fluoroscopically at distensive pressures of 2-12 mm Hg. The diameter of the narrowest point of the EGJ in PA and lateral projections was measured from digitized images. CSA was determined as a function of intrabag pressure. RESULTS: The minimal EGJ opening aperture occurred at the diaphragmatic hiatus in all subjects. At pressures </=0 mm Hg, EGJ opening was observed only in HH patients, making it plausible for these patients to reflux during deglutitive relaxation. At pressures >0 mm Hg, there were significant increases in EGJ CSA both for HH and NHH compared with NL (P < 0.001) and for HH compared with NHH (P < 0.005). This difference may explain the diminished air/water discrimination seen during transient lower esophageal sphincter (LES) relaxation-associated reflux in GERD patients. CONCLUSIONS: Anatomic degradation of the EGJ distinguishes GERD patients from normal subjects, and these changes may impact on both the observed mechanisms of reflux and the constituents of reflux during transient LES relaxation. Therapy focused on EGJ compliance may benefit GERD patients.

Adult↗
PubMedDate not supplied

Delayed reconfiguration of a Guglielmi detachable coil mass associated with late occlusion of an adjacent aneurysm and parent vessel.

We present a case of asymptomatic, progressive, late occlusion of the left superior cerebellar artery (SCA) and an aneurysm arising from the junction of the SCA and basilar artery after embolization of an adjacent aneurysm arising between the left posterior cerebral artery and the left SCA. The delayed occlusion was associated with reconfiguration of the Guglielmi detachable coils at the neck of the treated aneurysm.

Angiography, Digital Subtraction↗
PubMed1997

Lead uptake in brain capillary endothelial cells: activation by calcium store depletion.

The mechanism by which lead crosses the blood-brain barrier is not known. Brain capillary endothelial cells, which form tight junctions with each other, are an important component of the blood-brain barrier. Lead must traverse these cells to reach the brain. In the present study, uptake of lead was followed in primary cultures of bovine brain capillary endothelial cells. Lead uptake into cells was measured by monitoring the fluorescence of cells loaded with indo-1 at a wavelength where indo-1 fluorescence is independent of calcium but quenched by binding of lead. Lead uptake was visualized with digital images recorded with a fluorescence microscope. Lead added to the extracellular medium caused fluorescence quench over time which was reversed upon addition of a membrane permeant heavy metal chelator. Lead uptake by cells in suspension, measured by fluorescence spectroscopy, exhibited time and concentration dependence. Lead uptake was enhanced following depletion of intracellular Ca2+ stores by the addition of thapsigargin, cyclopiazonic acid, or tert-butylhydroquinone, inhibitors of the sarco/endoplasmic reticulum calcium ATPase. SK&F 96365, which blocks store-operated calcium channels, inhibited the stimulation of lead uptake by thapsigargin. These results indicate that indo-1 fluorescence quench is a useful method for investigation of lead uptake in brain capillary endothelial cells. Furthermore, entry of lead into these cells is activated by the depletion of intracellular Ca2+ stores and may occur via store-operated cation channels.

Animals↗
PubMed2002

Transmyometrial embryo transfer and junctional zone contractions.

BACKGROUND: Embryo transfer is a crucial step in IVF-embryo transfer cycles. Several studies have explored transmyometrial embryo transfer, but although this procedure has several favourable characteristics, its role in assisted reproduction has not yet been established. Junctional zone (JZ) contractions during embryo transfer are associated with a negative outcome and factors which increase JZ contractions should be avoided. METHODS: In this study, we have investigated the effect of transmyometrial embryo transfer on JZ contractions. Ten patients with a previously difficult embryo transfer, or a difficult mock embryo transfer, underwent transmyometrial embryo transfer. Before and after this procedure a transvaginal ultrasound scan was performed and this was recorded on videotape for 5 min. The recordings were digitized and then analysed for JZ contractions. RESULTS: Transmyometrial embryo transfer causes a significant increase in JZ contractions. CONCLUSION: The increase in JZ contractions after transmyometrial embryo transfer forms a theoretical objection to this procedure. However, its alternative, a difficult transcervical embryo transfer, is also associated with an increase in JZ contractions. We therefore suggest a large prospective study to investigate the most effective method of embryo transfer in cases where a difficult transcervical embryo transfer is anticipated due to cervical factors.

Adult↗
PubMed1996

Effect of cuspid positioning in the cleft at the time of secondary alveolar bone grafting on eventual graft success.

This investigation was to determine the relationship between the success of secondary alveolar bone grafting and the position of the permanent cuspid relative to the cleft at the time of grafting. In this retrospective study utilizing periapical radiographs take on cleft patients to evaluate bone grafting results, the subjects were patients treated at the Lancaster Cleft Palate Clinic, a private institution specializing in the care of cleft patients. Sixty-seven patients (20 BCLP; 47 UCLP) were selected for this study based on availability of quality radiographs and a minimum of 6-month post-surgical follow-up. All patients underwent alveolar bone grafting (mean age, 10 years 7 months). Presurgical radiographs were taken within 3 months of the operation. Post-surgical radiographs were taken to evaluate the outcome of grafting (mean follow-up, 2 years 10 months). Radiographs were traced and digitized on a total of 86 cleft sites. Presurgically, a ratio was used to determine the amount of cuspid crown emerged through the alveolus into the cleft site relative to the anatomic cuspid-crown length. Post-surgically, ratios of bone support for the teeth mesial and distal to the cleft were established by dividing the amount of root covered by bone by the anatomic root length. Ratios expressing the height of alveolar crest relative to the cementoenamel junction (CEJ) of adjacent teeth and amount of alveolar notching relative to the mesial tooth root length were also evaluated. Linear regressions of each of the five ratios of graft outcome on the cuspid-eruption ratio were done. No significant correlations could be found between final graft success and the amount of cuspid crown exposed in the cleft at the time of grafting. Cuspid position could not be shown to be a significant factor in determining graft success.

Alveolar Process↗
PubMed1998

Platelet-derived growth factor, intimal hyperplasia, and ischemic complications in giant cell arteritis.

OBJECTIVE: To explore whether vasoocclusion in giant cell (temporal) arteritis (GCA) is related to intimal hyperplasia and in situ production of platelet-derived growth factor (PDGF). METHODS: Temporal artery biopsy specimens from patients with GCA were analyzed for the presence of intimal hyperplasia. Expression of PDGF-A and PDGF-B was assessed by immunohistochemistry and digitized image analysis. RESULTS: PDGF-A and PDGF-B were widely expressed in inflamed arteries. CD68+ macrophages, smooth muscle cells, and multinucleated giant cells produced PDGF, whereas hyperplastic intimal tissue did not. Arteries with marked luminal narrowing and those with no or minimal luminal narrowing differed in the extent and distribution of PDGF expression. Concentric intimal hyperplasia was associated with the accumulation of PDGF-A- and PDGF-B-producing CD68+ macrophages at the media-intima junction. PDGF+,CD68+ macrophages in close proximity to the internal elastic lamina frequently coproduced matrix metalloproteinase 2. Intimal hyperplasia of the temporal artery correlated with ischemic complications of GCA, such as ocular involvement, jaw claudication, and aortic arch syndrome. CONCLUSION: Production of PDGF has a role in arterial occlusion in GCA. The excessive fibroproliferative response leading to luminal narrowing can be distinguished from the stenosing process in atherosclerosis and postangioplasty restenosis, suggesting that there are different response patterns to arterial injury. In GCA, macrophages at the media-intima border are the dominant source of PDGF. Since vasoocclusion is associated with a number of serious complications in GCA, inhibition of intimal proliferation should be a major goal of treatment.

Brain Ischemia↗
PubMed1986

Use of bioprosthetic tendon in digital pulley reconstruction--an experimental study.

The potential clinical application of Glutaraldehyde treated bioprosthetic material in the hand as implants to substitute for damaged pulley, tendon or ligament has not been fully explored. This study tries to evaluate the efficacy and safety of the proposed bioprosthetic pulley in an experimental model. One of the digital flexor pulleys of the rabbit's foot was excised and replaced by a bioprosthetic pulley using a standardized technique. Autogenous tendon graft was used as the control on the opposite foot. Altogether twenty rabbits (40 feet) were included in the study and they were sacrificed at different time intervals up to one year. The retrievals were analysed for flexor tendon adhesions and rupture of the pulley macroscopically. Histological and Electron Microscopy study of the 'pulley' and 'pulley-bone' junction were also carried out. Results show consistently the progressive creeping substitution of the bioprosthetic material by the rabbit's own tissue without significant inflammatory reactions. Neither adhesions nor breakage of the pulley were detected, the results comparing favourably with the control group using autografts except for the longer time taken for the substitution process.

Animals↗
PubMed2006

[Tridimensional ultrasound of the prostate].

OBJECTIVES: To present the examination technique of grayscale tridimensional transrectal prostatic ultrasound and its clinical viability. To define the ultrasonographic patterns and to report the clinical experience of our group. METHODS: We analyze selected exams from a database of more than 600 digitally stored tridimensional transrectal prostatic ultrasounds performed with a robotic probe. We collect the opinion and observations of the examiners, all of them experts on prostatic ultrasound. Each case has been completed with pathologic and clinical data. RESULTS: The time spent for each test was less than three minutes, achieving good quality, reproducible exams. The analysis of the front view offers the greatest contribution in comparison to the conventional technique, allowing a more clear detection of structures such as the junction with the seminal vesicles, the capsular contour, and urethra. CONCLUSIONS: Tridimensional transrectal prostatic ultrasound is an imaging test applicable in the clinical practice which offers quality images and may provide great benefits for the diagnosis and local staging of prostate cancer, by means of the analysis of the front view.

Humans↗
PubMed1999

RhoA inactivation enhances endothelial barrier function.

The modulation of endothelial barrier function is thought to be a function of contractile tension mediated by the cell cytoskeleton, which consists of actomyosin stress fibers (SF) linked to focal adhesions (FA). We tested this hypothesis by dissociating SF/FA with Clostridium botulinum exoenzyme C3 transferase (C3), an inhibitor of the small GTP-binding protein RhoA. Bovine pulmonary artery endothelial cell (EC) monolayers given C3, C3 + thrombin, thrombin, or no treatment were examined using a size-selective permeability assay and quantitative digital imaging measurements of SF/FA. C3 treatment disassembled SF/FA, stimulated diffuse myosin II immunostaining, and reduced the phosphotyrosine (PY) content of paxillin and 130- to 140-kDa proteins that included p125(FAK). C3-treated monolayers displayed a 60-85% decline in F-actin content and a 170-300% increase in EC surface area with enhanced endothelial barrier function. This activity correlated with reorganization of F-actin and PY protein(s) to beta-catenin-containing cell-cell junctions. Because C3 prevented the thrombin-induced formation of myosin ribbons, SF/FA, and the increased PY content of proteins, these characteristics were Rho dependent. Our data show that C3 inhibition of Rho proteins leads to cAMP-like characteristics of reduced SF/FA and enhanced endothelial barrier function.

ADP Ribose Transferases↗
PubMed2003

[The application of intravascular ultrasound imaging in identifying the visceral artery in aortic dissection].

OBJECTIVE: To study the role of intravascular ultrasound (IVUS) imaging in identifying the visceral artery in aortic dissection. METHODS: Twenty-two patients with aortic dissection were studied by IVUS via a femoral approach. The relationship between the visceral artery origin and the true and false lumens were differentiated by IVUS. The detection rate of visceral artery by IVUS was compared with those of CT and digital subtraction angiography (DSA). The cause of visceral ischemia was determined by the relationship between the intimal flap and the visceral artery origin in IVUS findings, and compared with routine examinations. RESULTS: The outer wall of the true lumen had a three layer structure while that of the false lumen had only one layer structure in IVUS imaging. There was an acute angle between the outer wall of the false lumen and the intimal flap at the true and false lumen junction. The thrombosis in the false lumen could be detected by IVUS. These features can assist in the differentiation of the true and false lumen. The relationship between the visceral artery origin and the true and false lumen could be determined in 81 out of 84 arteries, among which 54 were originated from the true lumen, and 27 from the false lumen. The detecting rate of visceral arteries by IVUS was 96.4%, higher than CT (70.2%) and DSA (84.5%), chi(2) = 20.74 and 6.91, P < 0.01. Static narrowing in 6 arteries and dynamic narrowing in 1 artery were visualized by IVUS, while only 2 static narrowings could be detected by CT. CONCLUSIONS: IVUS has an advantage over routine examinations at detecting visceral artery origin and clarifying the mechanism of visceral ischemia.

Adult↗
PubMed2005

Comparison of posterior capsule opacification rates between hydrophilic and hydrophobic single-piece acrylic intraocular lenses.

PURPOSE: To determine the effect of intraocular lens (IOL) material on the development of posterior capsule opacification (PCO) at 1 year. SETTING: Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. METHODS: One hundred six eyes of 53 patients with bilateral cataract and no other ocular comorbidity were prospectively randomized to receive a hydrophobic acrylic or hydrophilic acrylic single-piece IOL in the first eye to have surgery. The alternate IOL was implanted in the fellow eye 4 to 6 weeks later. All surgery was performed by a single surgeon. Postoperative follow-up was 1 day, 1 and 6 months, and 1 year. At each visit, the best corrected high- and low-contrast visual acuities were assessed and a high-intensity digital retroillumination photograph was taken. Posterior capsule opacification was assessed from the digital images by a single operator using a dedicated software program and calculated as the percentage area of opacified capsule. RESULTS: One year postoperatively, the median percentage area of PCO was 50.3% in the hydrophilic IOL group and 4.9% in the hydrophobic IOL group (P<.001). The difference in PCO was not accounted for by loss of contact between the capsulorhexis and IOL surface. Further analysis showed that lens epithelial cells tended to invade the posterior capsule at the haptic-optic junction. This was more marked in the hydrophilic IOL group. CONCLUSIONS: The rate of PCO was significantly higher with the hydrophilic IOL. However, the results cannot be attributed to the IOL material alone as they show the importance of both IOL material and design.

Acrylic Resins↗
PubMed1994

A role for Ca(2+)-conducting ion channels in mechanically-induced signal transduction of airway epithelial cells.

Mechanical stimulation of a single cell in a cultured monolayer of airway epithelial cells initiates an intercellularly communicated increase in intracellular Ca2+ concentration ([Ca2+]i) that propagates radically through adjacent cells via gap junctions, forming an intercellular Ca2+ wave. Mechanically-induced intercellular Ca2+ waves also occur in the absence of extracellular Ca2+. However, in Ca(2+)-free medium an increase in [Ca2+]i of the stimulated cell does not occur. Thus, mechanically-induced [Ca2+]i changes in the stimulated cell are influenced by the extracellular Ca2+ concentration. To investigate if a channel-mediated Ca2+ flux across the plasma membrane contributes to the elevation of [Ca2+]i in the stimulated cell we used digital image microscopy to measure mechanically-induced [Ca2+]i changes in the presence of Ca2+ channel blockers. In Ca(2+)-free medium containing Gd3+ (20 microM) mechanical stimulation resulted in an [Ca2+]i increase in the stimulated cell. The delay time between mechanical stimulation and increase in [Ca2+]i of the stimulated cell was dependent on extracellular [Gd3+], with a half-maximal effective concentration of approximately 40 microM. Mechanical stimulation in Ca(2+)-free medium containing La3+ (10 microM) or Ni2+ (100 microM) gave similar results. Mechanical stimulation in Ca(2+)-free medium containing the dihydropyridine Ca2+ channel blockers nifedipine (10 microM) and nimodipine (10 microM) also resulted in an increase of [Ca2+]i of the stimulated cell. Mechanical stimulation of cells treated with thapsigargin to deplete intracellular Ca2+ stores, in the presence of 1.3 mM extracellular Ca2+, results in an increase in [Ca2+]i of the stimulated cell without the propagation of an intercellular Ca2+ wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Determination of sensitivity to metocurine in exercised horses.

On the basis of results in dogs, conditioning exercise may increase sensitivity to nondepolarizing muscle relaxants. Five Thoroughbreds were exercised/conditioned 3 times weekly on a treadmill for 8 months. Increasing maximal rate of O2 consumption verified that the horses were responding to exercise conditioning. Six nonexercised Thoroughbreds served as the control group. Studies were done with horses under general anesthesia by use of halothane during partial paralysis by a brief constant-rate infusion with the muscle relaxant, metocurine iodide. Quantification of degree of paralysis of the hoof twitch (eg, digital extensor) occurred with simultaneous quantification of blood values of metocurine. Pharmacokinetic and pharmacodynamic analyses of the data were done by a nonlinear regression program, using the Hill equation. There were no differences in findings between exercised and nonexercised horses. The mean blood concentration for the 50% paralyzing dose of metocurine was 0.44 +/- 0.11 (SD) microgram/ml in exercised horses, and 0.58 +/- 0.22 microgram/ml in nonexercised horses. Despite evidence for a response to conditioning, a significant change in the sensitivity of the neuromuscular junction to metocurine was not found.

Animals↗
PubMed1985

Detection of synchrony in the discharge of a population of neurons. II. Implementation and sensitivity of a synchronization index.

This report describes the use of a synchronization index (Is; Hamm et al., 1985a) and its sensitivity to various forms and degrees of synchrony between spike trains. The dependence of the Is on signal-to-noise ratio, the number of synchronized spike trains and their degree of synchrony is shown in analog and digital simulations. These simulations and a comparison with peristimulus time histograms under conditions of induced synchrony reveal that the Is is a sensitive measure of synchronization in a population of spike trains.

Afferent Pathways↗
PubMed2000

[Detection of the venous system of the skull base using three-dimensional CT angiography (3D-CTA): utility of the subtemporal approach].

Three-dimensional computed tomography angiography (3D-CTA) was compared with digital subtraction angiography (DSA) for the delineation of the skull base venous system in presurgical planning of the subtemporal approach in 201 sides of 109 patients. The axial stereoscopic images and multi-projection images were used in 3D-CTA, and the anteroposterior views and lateral views were used in DSA. DSA showed that the vein of Labbe (VL) was the most common venous flow on the lateral or basal surface of the temporal lobe, whereas 3D-CTA demonstrated that the involvement of the temporo-basal vein (TBV) was equal to that of VL in frequency. 3D-CTA showed that the VL flowed into the transverse sinus (TS) on 132 sides, the sigmoid sinus-TS junction on 29 sides, and the lateral tentorial sinus (LTS) on 40 sides. DSA showed that the VL flowed into the TS on 157 sides and into the LTS only on 5 sides. DSA showed that the TBV flowed into the TS on 37 sides but axial 3D-CTA showed that the TBV flowed into the LTS on 48 sides. This inconsistency reflects the difficulty in confirming and identifying these veins on the anteroposterior view of DSA, due to the overlapping of veins and poor delineation. Axial stereo and multi-projection images of 3D-CTA provided practical images of the deep veins of the skull base venous system and showed the relative anatomical relationships of the arteries and bony structures. This information can specify the venous inflow point, and help to determine the direction of approach and working space, and also help to identify intraoperative landmarks for the subtemporal approach. Presurgical examination of the deep venous system with 3D-CTA may help to minimize unexpected injury to veins and venous infarction.

Angiography, Digital Subtraction↗