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PubMed2004

Development of protamine hollow-fiber device for extracorporeal heparin removal.

Protamine was covalently coupled to a cellulose hollow fiber (cuprophan membrane) through epichlorohydrin-activated hydroxyl groups on the hollow fiber. An immobilization efficiency of as much as 15 mg protamine/g fiber could be achieved under optimal reacting conditions. Compared to a protamine hollow-fiber device produced using cyanogen bromide as an activator, the protamine hollow-fiber device using epichlorohydrin as an activator shows very high resistance to hydrolysis. Both in vitro and in vivo experiments showed that such a protamine hollow-fiber device had high heparin-removal capacity and efficiency, suggesting that this device may be suitable for various clinical applications in extracorporeal heparin removal.

Adsorption↗

PubMed2005

The association of pulmonary lymphangioleiomyomatosis with renal and hepatic angiomyolipomas in a prepubertal girl: a previously unreported entity.

Pulmonary lymphangioleiomyomatosis (PLAM) is a rare, diffuse progressive interstitial lung disease that affects females of childbearing age and is characterized by diffuse proliferation of abnormal smooth muscle fibers predominantly developing in the lung and leading to cystic destruction. A prepubertal 13-year-old girl with PLAM associated with renal and hepatic angiomyolipomas who was treated by nephroureterectomy and thoracoscopic pleurodesis is presented. To the best of our knowledge, this is the first reported case of PLAM associated with renal and hepatic angiomyolipomas at the prepubertal age. After evaluating the clinicopathologic features of this rare entity, the authors conclude that PLAM should be considered in the differential diagnosis of cystic pulmonary pathologies in children, particularly teenagers. The most important clinical aid is to bear this rare entity in mind when a child presents with renal and/or hepatic angiomyolipomas. Thoracoscopic pleurodesis is the most effective treatment modality for recurrent pneumothoraces.

Adolescent↗

PubMed1990

Image-guided stereotactic centered craniotomy and laser resection of solid intracranial lesions.

A technique in which solid intracranial lesions are removed using computerized image processing under stereotactic conditions is described. A specially developed carbon fiber ring holder compatible with most image studies is used as a reference system. Intraoperatively it affords freedom of patient positioning and unobstructed access to any site of the head. Four position alternatives of the aiming device allow the removal of lesions from any location. For superficial lesions located near eloquent areas, a 'centered' craniotomy is performed, usually under local anesthesia, and removal is performed using loupe magnification, bipolar coagulation ultrasonic aspiration of the Nd:YAG laser fiber in the contact or noncontact technique. In deep-seated lesions, a surgical 'corridor' is established and kept by means of retractors adapted for use with the stereotactic apparatus. Microsurgical techniques and the CO2 laser are used in solid lesions; in vascular lesions, bipolar coagulation or the ND:YAG laser can be used. Centered craniotomy allows the precise localization, enhancement, three-dimensional orientation and removal of lesions with minimal trauma to the surrounding brain. The technique has been applied in 78 cases where the extreme accuracy of the technique, benign postoperative course and short hospitalization have been impressive.

Angiography, Digital Subtraction↗

PubMed1996

Retinopetal projections in lampreys.

In the lamprey Lampetra fluviatilis the centrifugal visual system is well developed. Centrifugal fibers arise from cells of two tegmentomesencephalic nuclei-reticular mesencephalic area and nucleus M5 of Schober-as demonstrated by axonal tracing techniques and antidromic neuronal recordings after optic nerve stimulation. Amacrine and ganglion cells in the retina are targets of centrifugal innervation, as shown by electrophysiology and axonal tracing. Following postembedding immunogold labeling, 40% of centrifugal axon terminals in the retina express immunoreactivity to gamma-aminobutyric acid (GABA). About 65% of neurons in M5 and 15% of those in the reticular mesencephalic area have been observed to be immunoreactive for GABA. Combined horseradish peroxidase (HRP) labeling and double immunogold staining were used to investigate the central organization of the retinal feed-back loop. Some terminals of optic nerve fibers from the retina made direct synaptic contacts on dendrites of centrifugal cells of the reticular mesencephalic area and nucleus M5. Terminals of non-retinal origin, immunoreactive for GABA and glutamate, also made synapses on centrifugal neurons. Monosynaptic feed-back loops may be complemented by interneurons as well as by excitatory and inhibitory inputs of non-visual origin.

Animals↗

PubMed1994

Renal medullary captopril delivery lowers blood pressure in spontaneously hypertensive rats.

We examined the contribution of renal medullary function to the maintenance of hypertension in spontaneously hypertensive rats by infusing captopril chronically into the renal medullary interstitial space of uninephrectomized rats. Changes in cortical and medullary blood flow were determined using a newly developed optical fiber implantation technique for laser-Doppler flowmetry. Renal medullary interstitial infusion of captopril (5 mg/kg per day) selectively increased medullary blood flow by 40% without altering renal cortical blood flow throughout the 5 days of captopril delivery. In association with the selective increase of medullary perfusion, a significant natriuresis was observed on the second day of the drug infusion, and urine osmolality was significantly reduced during the first 3 days of captopril infusion. Mean arterial pressure was significantly decreased by 20 mm Hg during 5 days of captopril infusion, and the chronic renal function curve was shifted to a lower level of arterial pressure compared with the control values when 0.9% sodium chloride saline vehicle was infused. Intravenously infused captopril at 5 mg/kg per day did not alter mean arterial pressure, excluding the possibility that the hypotensive effect of medullary captopril infusion was due to recirculation. In summary, chronic reduction of the elevated renal medullary vascular tone by medullary interstitial infusion of captopril reset the steady-state renal function curve and lowered arterial pressure in spontaneously hypertensive rats.

Animals↗

PubMed1989

Analysis of the characteristics of the flow velocity waveforms in left atrial small arteries and veins in the dog.

To clarify the characteristics of the phasic blood velocity pattern in small arteries and veins on the left atrial surface, we used our newly developed fiber-optic laser Doppler velocimeter. We intended particularly to examine the influence of atrial contraction and relaxation on velocity waveforms to obtain some insight into the nature of the mechanical force acting on the atrial intramyocardial vascular beds. In 14 anesthetized open-chest dogs, the left atrial appendage was gently displaced to expose small branches of the artery and vein. Vessels with an outer diameter of about 150-500 microns were chosen for the measurements because their walls are transparent to laser light. The fiber tip (velocity sensor) was fixed on the vessel surface with a drop of cyanoacrylate when good-quality Doppler signals were consistently observed. Additional experiments with three dogs were performed to observe the blood velocities in the atrial artery and vein during arrhythmia. The blood velocity waveform in the artery was similar to the pattern of aortic pressure during ventricular ejection (peak velocity, 18.8 +/- 7.8 cm/sec) but was characterized by a pronounced dip during atrial contraction. The temporal coincidence between the dip formation and atrial contraction was confirmed during atrial flutter with an atrioventricular block. After isoproterenol administration (2 micrograms i.v.), the acceleration rate of the forward flow velocity increased by 176% (p less than 0.05), and reverse flow appeared during atrial contraction in five cases out of eight (p = 0.013). The blood flow velocity in atrial small veins, on the other hand, was predominant during atrial contraction (peak velocity, 15.6 +/- 5.8 cm/sec). Isoproterenol increased the acceleration rate of this forward flow velocity by 121% (p less than 0.01). Nitroglycerin did not change the blood velocity waveform significantly in atrial arteries or in veins. The phase opposition between arterial inflow into and venous outflow from the atrial myocardium indicates that a large portion of the coronary inflow to the atrial myocardium may be stored due to the presence of atrial myocardial vascular capacitance. We conclude that atrial myocardial contraction impedes atrial inflow and promotes venous outflow from atrial capacitance vessels.

Animals↗

PubMed1985

Characterization of a monoclonal antibody (SBU-1) made to the thymic rudiment of sheep.

A monoclonal antibody (SBU-1) was raised to sheep thymic rudiment by fusion of NSI myeloma cells with spleen cells from BALB/c mice immunized with thymic rudiment isolated from fetal sheep between 25-30 days of gestation. By employing the indirect immunoperoxidase technique the antigen recognized by SBU-1 was found to be present in the epithelial reticular cells of the fetal sheep thymus. The intensity of staining decreased as gestation progressed. In the adult thymus the antigen was mainly restricted to Hassall's corpuscles and occasional epithelial cells in the medulla. In addition, the antigen was also shown to be present in epithelial cells of the small intestine, the bronchiole, the keratinized epithelium of the rumen, and the epithelial cells of the kidney tubules. By use of immunofluorescence the antigen was shown to be present in most of the cells of wool follicles and the cortex of developing wool fibers. Western blotting of SBU-1 against the low-sulfur alpha-keratin proteins of wool confirmed that the antigen recognized by SBU-1 belongs to a family of keratins. It was concluded that SBU-1 was raised against alpha-keratin expressed by the epithelial cells of the thymic rudiment and that the expression of this antigen on the reticular network of the thymus declined with advancement of pregnancy.

Animals↗

PubMed2005

Breakdown of accommodation in nerve: a possible role for persistent sodium current.

BACKGROUND: Accommodation and breakdown of accommodation are important elements of information processing in nerve fibers, as they determine how nerve fibers react to natural slowly changing stimuli or electrical stimulation. The aim of the present study was to elucidate the biophysical mechanism of breakdown of accommodation, which at present is unknown. RESULTS: A model of a space-clamped motor nerve fiber was developed. It was found that this new model could reproduce breakdown of accommodation when it included a low-threshold, rapidly activating, persistent sodium current. However, the phenomenon was not reproduced when the persistent sodium current did not have fast activation kinetics or a low activation threshold. CONCLUSION: The present modeling study suggests that persistent, low-threshold, rapidly activating sodium currents have a key role in breakdown of accommodation, and that breakdown of accommodation can be used as a tool for studying persistent sodium current under normal and pathological conditions.

Animals↗

PubMed1989

Regulation of cytoskeletal protein organization and expression in human granulosa cells in response to gonadotropin treatment.

The organization and expression of the major cytoskeletal protein systems and of several cytoskeleton-associated proteins were analyzed in human granulosa cells obtained from preovulatory follicles in the course of an in vitro fertilization program. The cells were cultured in medium containing 5% fetal calf serum in the absence or presence of gonadotropins. Within several hours after the addition of hCG to cultured human granulosa cells, the cells acquired a rounded and aggregated morphology with numerous thin and long processes. Cells cultured without the gonadotropin had a flat and extended morphology on the substrate, with a well developed stress fiber system and numerous large vinculin-containing adhesion plaques. The [35S]methionine-labeled protein pattern of hCG-treated cells obtained by two-dimensional isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a 7- to 10-fold decrease in the synthesis of vinculin and the nonmuscle tropomyosin isoforms, and a 2- to 4-fold decrease in the synthesis of alpha-actinin and actin, without a comparable change in alpha- and beta-tubulin synthesis. In the absence of gonadotropins, human granulosa cells synthesized both the intermediate filament (IF) protein vimentin and cytokeratin-type IF proteins 8 and 18 and, to a lesser extent, cytokeratins 7 and 19. By immunofluorescence, both type of IF networks were detected in untreated cells, while hCG-treated cells synthesized and contained only vimentin-type IF networks. Thus, maintenance of the steroidogenic capacity in the presence of gonadotropins in human granulosa-luteal cells involves specific changes in cell shape and in both the organization and the expression of the microfilament and IF systems.

Actins↗

PubMed1990

Historical developments and perspectives in inorganic fiber toxicity in man.

The first patient known to have died from asbestosis (1900) began work in 1885, approximately 5 years after the industrial use of asbestos began in Britain. Mineral particles were found in his lungs. No special comment was made of their fibrous nature then nor when the first case was reported in 1924. The various neoplasms attributed to asbestos in the next decades posed an additional question: What influence did the fibrous shape of the particles have on carcinogenic potential? The cogency of the problem was amplified by the identification in humans of asbestos-like neoplasms with a fiber other than asbestos (erionite) and by the production of such neoplasms in experimental animals with a variety of man-made inorganic fibers, often used as substitutes for asbestos. The lessons learned about asbestos may help guide us in evaluating current fiber problems.

Air Pollutants, Occupational↗

PubMed2006

Particle-size and velocity measurements in flowing conditions using dynamic light scattering.

The noninvasive optical technique of dynamic light scattering (DLS) is routinely used to characterize dilute and transparent submicrometer particle dispersions in laboratory environments. A variety of industrial and biological applications would, however, greatly benefit from on-line monitoring of dispersions under flowing conditions. We present a model experiment to study flowing dispersions of polystyrene latex particles of varying sizes under varying flow conditions by using a newly developed fiber-optic DLS probe. A modified correlation function proposed in an earlier study is applied to the analysis of extracting the size and velocity of laminar flowing particulate dispersions. The complementary technique of laser Doppler velocimetry is also used to measure the speed of moving particles to confirm the DLS findings.

Journal Article↗

PubMed2005

Development of a multiwavelength Raman fiber laser based on phase-shifted fiber Bragg gratings for long-distance remote-sensing applications.

We propose a simple and flexible multiwavelength Raman fiber laser based on phase-shifted fiber Bragg gratings (FBGs) and a tunable chirped FBG. Using a simple multiwavelength Raman laser configuration with a single phase-shifted FBG and a tunable chirped FBG, we readily achieved simultaneous two-channel sensing probes with a high extinction ratio of more than 50 dB over a 50-km distance. The multiwavelength output was stable and the peak fluctuation was less than 0.5 dB. The temperature and strain sensitivities are estimated to be 10.1 pm/degrees C and 7.5 pm/microstrain, respectively.

Environmental Monitoring↗

PubMed2006

Fiber-Bragg-grating-assisted surface plasmon-polariton sensor.

A theoretical scheme for a new surface plasmon-polariton (SPP) fiber sensor with a fiber Bragg grating imprinted into the fiber core for SPP excitation is presented for the first time to our knowledge. In our scheme the energy in the fiber core mode can be transferred to a SPP with high efficiency by means of a properly designed short-period fiber Bragg grating (SPG). Developed for the cylindrical (fiber) geometry, our scheme without loss of generality can be applied to a planar geometry. Our simulations are based on the coupled-mode method and are performed at telecommunications wavelengths.

Journal Article↗

PubMed2006

Sugarcane borer (Lepidoptera: Crambidae) management threshold assessment on four sugarcane cultivars.

This research assesses the potential for using different economic injury thresholds in management of a key insect pest on susceptible and resistant commercially produced cultivars of sugarcane (Saccharum spp. hybrids). In a 2-yr sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), study involving four commercially produced sugarcane cultivars and four insecticide treatment thresholds, 'LCP 85-384' and 'HoCP 91-555' were the most susceptible based on percentage of bored internodes compared with the more resistant 'HoCP 85-845' and 'CP 70-321'. In 2001, the 10% infested stalks threshold was not as effective as the 5% early season-10% late season and 5% full season for HoCP 91-555. Based on D. saccharalis injury under natural infestation conditions, susceptible cultivars seem to require a lower infestation threshold than the more resistant cultivars to achieve adequate injury reduction. Among yield components, only the theoretical recoverable sugar per stalk was significantly increased by applying insecticides. With the resistant HoCP 85-845, differences were not detected for percentage of bored internodes among treated versus untreated management regimes. The resistant HoCP 85-845 had higher levels of fiber in our study; however, no clear pattern on resistance mechanisms was established, because the resistant cultivar CP 70-321 had comparatively low levels of fiber. The development of cultivar-specific thresholds is expected to lower the amount of insecticide used for D. saccharalis management in the sugarcane industry, reduce selection pressure, and delay the development of insecticide resistance.

Agriculture↗

PubMed2026

Transcriptomic Changes Associated with Electroacupuncture in a DMCAO Model of Delayed Cognitive Impairment.

INTRODUCTION: Delayed Cognitive Impairment (DCIS) occurs in approximately 31% to 77% of individuals following stroke. Clinical findings have indicated that electroacupuncture may alleviate post-stroke DCIS. However, insights derived from animal models remain limited. The present study utilized a Distal Middle Cerebral Artery Occlusion (DMCAO) mouse model to investigate the potential mechanisms of electroacupuncture through hippocampal transcriptomic analysis. MATERIALS AND METHODS: Adult male BALB/c mice were subjected to DMCAO and received electroacupuncture treatment. High-throughput RNA sequencing of hippocampal tissue was performed to identify Differentially Expressed Genes (DEGs). Enrichment analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, hierarchical clustering, and Protein-Protein Interaction (PPI) network analysis, were performed to elucidate potential biological mechanisms. RESULTS: The DMCAO model exhibited features consistent with DCIS. Electroacupuncture treatment was associated with improved cognitive performance and enhanced hippocampal neuroplasticity. A total of 116 DEGs were identified in the DMCAO group compared with the sham group, while 69 DEGs were identified in the DMCAO + electroacupuncture group compared with the untreated DMCAO group. DISCUSSION: GO enrichment analysis indicated that electroacupuncture modulated biological processes related to nerve fibers, axonal development, neuronal regulation, cellular processes, and cardiovascular protection. KEGG pathway analysis indicated involvement in pathways associated with neuronal recovery and axonal function. The PPI network comprised 28 nodes and 33 interactions, with hub genes such as Gna13, Hipk2, and Stambp playing key roles. Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) results were consistent with RNA sequencing findings. CONCLUSION: Electroacupuncture improved DCIS in the DMCAO mouse model. Transcriptomic analysis of the hippocampus provided preliminary evidence of the potential mechanisms underlying the therapeutic effects of electroacupuncture treatment following ischemic stroke.

Animals↗

PubMed2000

[Woody plant and gravity].

In this review, we attempted to summarize the effect of gravity on growth of woody plants, broad leaved trees, on earth. It is well known that in tilted broad leaved trees, tension wood formed in the secondary xylem causes negative gravitropism. Gibberellin has been shown to induce tension wood in weeping branch, causing its upright growth. Recent study has shown that seedling of Japanese cherry tree grown on three dimensional clinostat, a device that simulates microgravity, grew at random angles, and that the formation of secondary xylem, as supporting tissue for upright growth, decreased. In the decreased xylem formation, the inhibition of the differentiation and development of fiber cell was clearly observed. These results suggest that in attitude control and morphogenesis of stem in woody plant, secondary xylem formation seriously relates to gravity on earth. In woody plant, the mechanism of gravity perception and the following signal transduction have not yet been elucidated, although the recent study reported the possibility that endodermal starch sheath cells and plant hormones may play some role in the mechanism. Space experiment for woody plant is expected to study these problem.

Biomechanical Phenomena↗

PubMed1988

The reaction of peri-implant tissues to titanium alloy and apatite-coated implants during the healing phase.

Oral implantation has been a controversial dental therapeutic procedure. Many implant materials and designs are presently in progress of study to evaluate the long term response of peri-implant tissues, together with anticipated loading considerations. The purpose of this examination was to make clear whether a fibrous layer would form between bone and Titanium alloy and apatite-coated Titanium implants under stressed and unstressed conditions, during the healing phase after implantation. The in vivo evaluation of 10 implants were made on two dogs. The upper 2nd and 3rd and lower 3rd and 4th premolar teeth were extracted and the sockets allowed to heal for 3 months. The implants in the unstressed condition were completely submerged, and in the stressed condition they were left with their top 2 mm above the surface of the bone, so that after suturing the top of the implant was exposed to the oral environment. After the postoperative healing phase of 3 months, the animals were killed and the specimens were prepared for histological, SEM examinations and EDX analysis of the interface zone between bone and the implants. Histological examination showed a direct contact between the apatite-coated implant and new bone, so that the implant became anchored to bone without an intervening soft tissue layer and a similar result was obtained between the Titanium implant and bone in the unstressed condition. However the high magnification electron micrographs showed a thin connective tissue between the bead-blasted surface of the Titanium implant and bone, and this peri-implant tissue could be detached from the implant. In the stressed condition, a thin layer of fibrous tissue was interposed between the Titanium implant and bone. The high magnification electromicroscopical views of the interface zone between the bone and these implants showed coarse fiber bundles developed perpendicular to the Titanium surface and their terminal ends were confluent with the rugged Titanium surface presumably as a result of micro-movement during the 3 months healing phase. In this study, an adequate space for a development of fibro-anchorage was about 20-200 microns in width. If occlusal stresses were within permissible range in healing period, the relative motion of the implant and bone was then optimal for the formation of a fibro-anchorage. It could be suggested that an ideal stress transfer from the Titanium implant to bone might be achieved by this fibro-anchorage.

Animals↗

PubMed1984

Investigations on lens transparency and its disturbances by microdensitometric analyses of Scheimpflug photographs.

During the aging process, the lens is subjected to changes of its pertinent properties which condition the transmission of light of different wavelengths. Between the second and the third decade, for instance, wavelengths below 400 nm are almost completely absorbed. The increase in lens thickness, effected by the appositional growth during life, might be considered responsible for this phenomenon, if the newly developing lens fibers in the outer periphery would synthesize proteins which, with respect to light transmission, differ from those formed during the embryonic phase. For such a phenomenon, however, no indication was found either by clinical observations or biochemical research. -Microdensitometric analysis of Scheimpflug-photographs of the anterior eye segment allows measurements of lens transparency in the single lens which directly depend on the respective wavelengths used in the photographic procedure. Investigations performed with this method on a normal age-grouped population, show that the changes in light transmission are most evident in two of the lens segments. The lens nucleus shows a continuous increase in light scatter during aging. Also the anterior cortex - particularly in the deeper layers - shows changes in light transmission. With advancing age (beginning between 30 and 40 years of age), increased lens fluorescence is found in the region of the deeper anterior cortex, which can be excited by UV wavelengths of 330-380 nm. This phenomenon is not found in the lens nucleus. The localization of the changes within the lens clearly shows that they are due to age-related modifications of the protein properties earlier designated as posttranslational or postsynthetic molecular modifications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗