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1.
Surface topography of used (in situ > 12 months) and unused CAPD catheters was studied by scanning electronmicroscopy (SEM) and confocal laser scanning microscopy (CLSM). Microbial biofilm was observed on all used catheters. Disruption and removal of the attached biofilm revealed extensive pitting of the catheter surface and scoring within the catheter pores. Similar, though less extensive, surface defects were present in unused catheters. Examination by CLSM, with software specific to the determination of surface topography, showed used catheters to have a surface microrugosity greater than that of unused catheters (p < 0.0005). Adherence studies with radiolabelled Staphylococcus epidermidis demonstrated increased adherence to used than to unused catheters (p < 0.0005) after 48 h. However, when catheters were pre-treated with spent dialysate there was a substantial reduction in bacterial adherence to either catheter and no significant difference in adherence to used and unused catheters. Surface microrugosity of CAPD catheters increases during use but is unlikely to be an important factor in bacterial adherence in vivo.  相似文献   

2.
Confocal laser scanning microscopy, in combination with fluorescent probes including fluorescence labelled antibodies, enables us to obtain optical sectioning images of fixed and living biological samples. It is a powerful method for studies of membrane transporter proteins in that it provides information on the spatial distribution of not only the transporter proteins themselves, but also the molecules and ions they transport. In the near future, it may also provide information on molecular interaction between and conformation changes of various proteins with the aid of new type of fluorescent probes which utilize the fluorescence resonance energy transfer phenomenon.  相似文献   

3.
JM White  GL Adams 《Canadian Metallurgical Quarterly》1996,10(2):329-36; discussion 337
Laser irradiation at and above parameters producing the modification threshold for dentin causes structural changes to the dentin surface. This study determined the microhardness of dentin before and after laser modification and acid treatment using a repeated-measures design. Seven dentin sections (4 mm in thickness) were cut from freshly extracted non-carious third molars using a diamond saw. The middle occlusal third was used as the test dentin surface. One section served as a control (C); three received laser modification (L) and then acid treatment (L + A); and three received acid (A) and then laser treatment (A + L). Laser modification was made using a pulsed (120 microseconds) fiber-optic-delivered (500 microns diameter) Nd:YAG (lambda = 1.06 microns) laser at the physical modification threshold of 207 J/cm2. Acid treatment consisted of 10% nitric acid applied for 45 seconds. Twenty Knoop indentation microhardness measurements (KHN) were obtained using 300 g force engaged for 15 seconds for each section before and after each treatment (n = 400). Knoop microhardness values recorded: C = 62 +/- 3; L = 149 +/- 35; A = 24 +/- 5; L + A = 40 +/- 16; and A + L = 33 +/- 5. Multifactor-repeated measures, with analysis of variance (ANOVA; p < or = 0.05), indicated significant differences between all treatment groups. Scanning electron microscopy analysis of dentin surfaces documented unique surface morphology for all treatment conditions. Laser modification of dentin before or after acid treatment increased dentin microhardness.  相似文献   

4.
Groups of photosensitive adult female blackheaded buntings were exposed to various ultrashort days photoperiodic regimes for 60 days in which a fixed 3 h photophase was coupled with dark phases in cycles of 22 to 32 hours duration. One group of buntings was kept in long days (15L:9D) as control. Significant increase in ovarian weight and circulating plasma estradiol concentration was marked in the cycles of 30 h (3L:27D), and 32 h (3L:29D) photoperiodic schedules as well as in control group (15L:9D), whereas there was no response in the cycles of 22 h (3L:19D) and 24 h (3L:21D). It seems that the response to ultrashort day cycles is due to a phase advance or delay in photosensitivity of the response system repeatedly shows coincidence of the external photophase (3 h) with the photoinducible phase of an endogenous circadian rhythm. Therefore, the present result appears to be consistent with Bünning hypothesis suggesting the involvement of an endogenous circadian component in the female blackheaded bunting.  相似文献   

5.
共焦激光扫描显微镜(CLSM)是普通光学显微镜与激光、计算机相结合的产物,具有比普通光学显微镜更高的分辨率,并且可以实现对样品的分层扫描,进而进行动态原位观察。利用CLSM可以直接观察金属的晶体长大过程,高温相变过程以及凝固过程中第二相粒子的各种行为。本文综述了CLSM系统的组成和原理以及其在冶金领域的应用,如夹杂物的碰撞、聚集、长大,在钢渣界面的扩散过程及在凝固前沿的捕捉/推进行为,析出物的形核析出过程等。  相似文献   

6.
In this paper we develop a compartmentalized, discrete simulation model for investigating the spatial distribution and dynamic properties of receptor crosslinking on the surface of a cell. Results generated by the model are compared with some of the major results of existing analytical models, and differences are discussed in relation to differences in the model assumptions. Finally, the model is used to evaluate the dynamic effects of a time-varying non-homogeneous ligand concentration.  相似文献   

7.
OBJECTIVES: To assess the relationship between haematocrit and risk of stroke. DESIGN: Prospective study of a cohort of men followed up for 9.5 years. SETTING: General practices in 24 towns in England, Scotland and Wales (British Regional Heart Study). SUBJECTS: A total of 7735 men aged 40-59 years at screening, selected at random from one general practice in each of 24 towns. MAIN OUTCOME MEASURES: Fatal and non-fatal strokes. RESULTS: During a follow-up period of 9.5 years for all men there were 123 stroke events (33 fatal) in the 7346 men in whom the haematocrit level had been determined. In the cohort as a whole, risk of stroke was significantly raised at haematocrit levels > or = 51% (relative risk [RR] = 2.5; 95% confidence intervals [CI] 1.2-5.0) after adjustment for age, social class, smoking, body mass index, physical activity, presence of diabetes and pre-existing ischaemic heart disease. Further adjustment for systolic blood pressure did not attenuate this association (RR = 2.4; 95% CI 1.2-4.9). A raised haematocrit was associated with an increase of stroke only in men with hypertension (systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 90 mmHg or on regular antihypertensive treatment). No increased risk of stroke was seen at the higher haematocrit level (> or = 51%) in normotensive men. At haematocrit levels below 51%, hypertension was associated with a three-fold increase in risk of stroke compared with normotension (RR = 3.4, 95% CI 2.3, 5.1). At haematocrit levels > or = 51%, hypertension was associated with a nine-fold increase in risk of stroke compared with normotension (RR = 9.3; 95% CI 4.2, 21.0). Exclusion of men receiving regular antihypertensive therapy did not alter the strong associations seen. CONCLUSION: The data suggest that an elevated haematocrit is an independent risk factor for stroke and that it interacts synergistically with elevated blood pressure.  相似文献   

8.
PURPOSE: Determination of excised cornea viability is of interest for transplant-storage evaluation, but also for in vitro diffusion-study design and ocular-toxicity assessment. By using simultaneous vital staining by calcein AM (CAM) and ethidium homodimer-1 (EH-1), as "live" and "dead" probes, respectively, we developed a confocal laser scanning microscopy (CLSM) assay to determine epithelial and endothelial viability and estimate cornea thickness. METHODS: New Zealand White rabbit corneas were stored in phosphate-buffered saline (PBS) or Optisol at 4 degrees C or at room temperature. At various times, corneas were stained with an EH-1/CAM solution and observed, without further treatment, by CLSM. Storage effects on the cornea were also assessed by using an MTT assay. RESULTS: Stromal swelling, shedding of the upper epithelial layers, and severe endothelial damage were observed after 4 h in PBS at room temperature. After 8 h, lower epithelial cell death was observed, along with loss of endothelial structure. Corneas stored in similar conditions in Optisol were indistinguishable from controls. Storage in Optisol at 4 degrees C affected the superficial layers of the corneal epithelium similarly at both 7 and 14 days. Extensive epithelial shedding and wing-cell death were observed at 25 days, but the basal layer remained approximately 50% healthy. Significant endothelial cell loss was observed at 25 days. MTT results were consistent with CLSM data in the medium-term storage study only. CONCLUSIONS: This CAM/EH-1 CLSM fluorescence assay is a sensitive index of viability in cornea, and thus may prove useful in investigations in which maintenance of vital functions in different cell layers is critical.  相似文献   

9.
Dentine rods measuring approx. 0.7 x 0.7 x 5.0mm were prepared from the crowns of extracted human third molars. The specimens were demineralized in 0.5 M EDTA (pH 7.0) for 3 days and their volume measured with a digital micrometer under a dissecting microscope. The specimens were randomly assigned to experimental groups and were chemically dehydrated in acetone. Next they were dried using either hexamethyldisilazane, Peldri II, or critical-point drying techniques. The dimensions of the specimens were measured again after each step and the changes in volume were expressed as a percentage of the original demineralized volume. The effects of fixing the specimens in 10% buffered formalin before dehydration with acetone were also investigated for every drying procedure. Dehydration in acetone caused a small but significant reduction in the volume of demineralized formalin-fixed specimens but unfixed specimens did not change significantly. In general, all three drying procedures caused some shrinkage in demineralized dentine specimens. Unfixed specimens exhibited a volumetric shrinkage of approx. 15-20% after drying with any of the methods. Fixed specimens shrank more than unfixed specimens after drying (25-35%). Regardless of the drying technique, the specimens shrank a further 10-20% when measured in the vacuum chamber of the scanning electron microscope. Among the three drying techniques employed, hexamethyldisilazane seems to be a very useful alternative to critical-point drying for the preparation of dentine specimens for scanning electron microscopy.  相似文献   

10.
OBJECTIVE: p53 Protein plays an important role in cellular growth control. This study investigated p53 protein expression in cell smears of endometrial carcinomas supplemented by confocal laser scanning microscopy (CLSM). STUDY DESIGN: Imprints from surgical specimens of 20 endometrial carcinomas were used. p53 Protein expression was investigated immunocytochemically using the monoclonal antibody pAb1801. Using CLSM, three-dimensional morphology was studied. RESULTS: Of the 20 cases of endometrial carcinoma, 8 stained positively for p53 protein. p53 Showed heterogeneous intranuclear localization, which appeared to be associated with chromatin structure. CONCLUSION: Immunocytochemical detection of p53 overexpression in cell samples is practical, and CLSM has vast potentials in studying the intranuclear arrangement of chromatin.  相似文献   

11.
Local delivery of pharmacologic or genetic agents with a porous balloon catheter offers a potential therapeutic approach to reducing restenosis and atherosclerosis and minimizing undesirable systemic toxicity. However, the delivery efficiency and intramural retention of liquid agents is low. The local intramural delivery and prolonged retention of 5 microns microparticles (MP) has been described previously. The current study was designed to evaluate the distribution of locally delivered MPs and to determine the effects of MP size and infusion pressure on intramural delivery efficiency. A 1% suspension of fluorescent, latex MPs (1 or 4.5 microns in diameter) was infused at either 3 or 6 atm into atherosclerotic rabbit femoral arteries (n = 32) immediately after angioplasty. Four groups of arteries were evaluated: 1) 1 micron MPs infused at 3 atm; 2) 1 micron MPs at 6 atm; 3) 4.5 microns MPs at 3 atm; and 4) 4.5 microns MP at 6 atm. The location of MPs was evaluated by fluorescent and light microscopy and confocal laser scanning microscopy. The tissue was dissolved and the delivered MPs quantified. All groups manifested numerous MPs within the vasa vasorum and periadventitial microvasculature, with a substantially lesser number within the neointimal and medial layers. The intramural deposition of the MPs was associated with dissection within the intima or media caused by the antecedent angioplasty or local delivery, indicating that an intact vessel wall is an anatomic barrier to MP delivery. The median values of fractional intramural delivery, defined as the percentage of infused MPs retained within the arterial wall, were 0.059%, 0.071%, 0.047%, and 0.062% for the groups 1 through 4, respectively (p not significant [NS]). The values of intramural particle concentration, expressed as the total number of MPs per weight of arterial tissue, were 55, 65, 1.5, and 1.2 x 10(4) MPs/mg for groups 1 through 4, respectively (p < 0.001 for 1 micron vs 4.5 microns MPs). Although more 1 microM MPs were delivered than 4.5 microns MPs, the fractional intramural delivery was unaffected by particle size or infusion pressure. The local delivery of MPs at atherosclerotic sites after angioplasty is characterized by fractional intramural delivery values similar to values of nonparticulate agents, with few MPs deposited into intima or media in the absence of a dissection caused by the antecedent angioplasty or the delivery procedure itself.  相似文献   

12.
Three 4-hour bus rounds were organized as part of an international palliative care congress, to promote patient-based education both at home and in acute care hospitals. Patient cases were presented and discussed en route to and from each visit. A total of 23 medical specialists visited 16 patients (10 in three different hospitals and 6 at home). A mean of 5.3 cases were presented during each round. A total of nine journal club articles were presented, a mean of three (2-4) articles per round. A questionnaire was filled out anonymously by all 23 participants. On a scale of 1 (worst) to 5 (best) they gave the rounds an overall rating of 5 (range 4-5). These findings suggest bus rounds provide an opportunity for intensive exposure to patient-based learning, both in acute care hospitals and at home.  相似文献   

13.
Continuity of care beyond the walls of the acute hospital setting has always been a major emphasis in nursing. There is concern that the care needs of older adults at the time of discharge have been increased by shortened hospital stays. Yet little is known about the specific and changing health care needs of older adults during the early days at home following discharge from acute care, particularly those who are discharged without community referrals. To learn more about the experiences of this population, the College of Nursing at the University of Southern Maine, in collaboration with the Nursing Service Department at Maine Medical Center, conducted a demonstration project. This project involved follow-up home visits to older adults who were discharged to their homes from an acute care setting.  相似文献   

14.
Confocal microscopy was used to study the tight junctional permeability in living rat parotid and submandibular glands. The interstitial space of the tissue was perfused with medium containing fluorescent tracers Lucifer Yellow (anionic: MW 457), Propidium Iodide (cationic: MW 668) and dextrans labeled with FITC or RITC (anionic and neutral: MW 3K, 10K, 40K, 70 K and 500 K) to monitor whether or not these tracers permeate into the lumen across the junction. In the acini of normal glands, fluorescence was detected in the basolateral space but not in the luminal space up to 30 min. However, when secretion was induced by isoproterenol or carbachol, fluorescence appeared in the luminal space within 2 to 5 min. This did not involve the disruptive changes in tight junction ultrastructure, nor was it irreversible; the luminal fluorescence disappeared again when the secretagogues were removed. Tracers up to MW 40 K for isoproterenol and MW 10 K for carbachol revealed the luminal fluorescence in parotid acini, with little indications of the charge preference characteristics. The luminal fluorescence also appeared by anoxia, enzymatic cell dissociation and the cytochalasin D treatment. It was suggested that the tight junctions in salivary acini dynamically alter their permeability and modulate the passage of large molecules through the paracellular pathway. Oxygen supply, extracellular matrices and cytoskeletons were suggested to influence these regulations.  相似文献   

15.
16.
Osteoclasts are multinuclear bone-resorbing cells which contain abundant mitochondria. Morphological studies have suggested that a correlation may exist between mitochondrial concentration and bone resorption by osteoclasts. However, investigation of mitochondrial transmembrane potential (delta psi) and volume has been hampered by the difficulty in obtaining a sufficient number of osteoclasts for assessing these characteristics by flow cytometric analysis. In this study, we have used confocal laser scanning microscopy after loading the cells with Rhodamine 123 and 10-nonyl Acridine Orange to record mitochondrial delta psi and volume, respectively, in isolated rat osteoclasts cultured on bovine bone slices. Optimal staining conditions were found to be 10 micrograms ml-1 for 40 min for Rhodamine, and 1 microM for 10 min for the 10-nonyl Acridine Orange derivative. Two osteoclast populations, whose shape seemed to reflect bone resorption and migratory functions, were identified depending on their shape and on the distribution of the two dye probes. 'Round-shaped' osteoclasts had significantly higher mitochondrial delta psi and volume in the apical regions than in the basolateral portions (p < 0.00001). In contrast, mitochondrial delta psi and volume in 'irregular-shaped' osteoclasts were rather evenly distributed in both these regions (p > 0.05). Our results indicate that there is an apical polarization of mitochondria in osteoclasts corresponding to the energy demands associated with bone resorption.  相似文献   

17.
Despite the reducing exposure to allogeneic blood in cardiac surgery, most of patients with anemia still require allogeneic blood. In this study, we have attempted to harvest the blood from cardiac patients with baseline hemoglobin levels below 11.0 g/dl using recombinant human erythropoietin (rHuEPO). 29 anemic patients undergoing cardiac surgery at our hospital between January 1994 and March 1997 were divided into two groups: 3 weeks' treatment with recombinant human erythropoietin (rHuEPO) and blood donation (group 1, n = 15) and iron supplementation alone (group 2, n = 14). There were no statistically significant differences among the two groups in patients characteristic and surgical data. No serious adverse events after phlebotomy were apparent in patients donating autologous blood. Patients in group 1 had significantly higher hemoglobin levels than patients in group 2 at 7 days before operation. The number of reticulocytes were increased at just before operation in group 1, whereas group 2 showed no significant increase. The estimated hemoglobin increase in group 1 were higher at 7 days and just before operation. In 75% of group 1, allogeneic blood transfusion could be avoided, while all patients in group 2 received allogeneic blood transfusion. This study suggests that the combination of rHuEPO administration and autologous blood donation would be beneficial for anemic patients in elective cardiac surgery. The use of rHuEPO should not be restricted to anemic patients.  相似文献   

18.
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20.
Stones with different compositions respond differently to shock wave lithofragmentation. Likewise, the various lithotrity systems used may have different effects on the stones. To determine the relationships between stone composition and their fragmentation patterns, we conducted an in vitro study using endoscopy, magnifying glass, light microscope and scanning electron microscope on fragments obtained after lithotrity of 60 pure stone with different compositions: calcium oxalate monohydrate and dihydrate (OXMH and OXDH), phosphocarbonate (PC), ammonium magnesium phosphate (AMF) and uric acid (UA). Fragmentation was carried out with 4 different lithofragmenting sources (electrohydraulic, piezoelectric, ultrasound and pulse laser). No morphologic differences in the fractures induced by the various lithofragmenting sources were demonstrated. OXMH and UA stones basically break up by intercrystalline fracture and splitting of their concentric plates. OXDH breaks up mainly by intercrystalline fractures aided by the fibrillar organic material and phosphocarbonates found in the intercrystalline spaces. Fragmentation in infective stones (AMF and PC) occurs across the intercrystalline surfaces and by intracrystalline fracture. Ammonium urate fragments break up by intracrystalline fractures that run across the equatorial plane of its characteristic acicular microspheres.  相似文献   

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