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101.
Geometric, osmotic, and membrane mechanical properties of density- separated human red cells 总被引:7,自引:0,他引:7
Although there is evidence that the deformability of the entire red blood cell (RBC) decreases during aging, reports on changes in relevant specific properties associated with the aging process are limited and not in total agreement. The purpose of this study was to evaluate some of the factors that might contribute to this decreased deformability. Geometric, osmotic, and membrane mechanical properties of unfractionated, top ("young") and bottom ("old") RBC from 5 healthy adult donors were measured using micropipette techniques. Surface area, volume, and diameter of RBC were measured at osmolalities of 297, 254, 202, and 153 mosm/kg. Two membrane mechanical properties, surface shear modulus of elasticity (mu) and time constant (tc) of viscoelastic recovery, were studied only in isotonic media. At each of the osmolalities, volume and surface area of the bottom cells were about 25% lower than those of the top cells. Bottom cells showed smaller increases in volume with decreasing osmolality than top cells; the surface area remained constant with changing osmolality for all three groups. The surface area-to-volume ratio and the minimum cylindrical diameter of the bottom cells were essentially identical to the top cells. However, both the surface area index (actual are of RBC divided by area of a sphere of same volume) and the swelling index (maximal volume divided by actual volume) of the bottom cells were significantly lower than top RBC. The shear modules of elasticity (mu) was about 0.006 dyne/cm in all 3 RBC populations, indicating that the forces necessary to deform a portion of the membrane did not change with RBC aging. The viscoelastic time constant (tc) was 0.148 +/- 0.020 (SD) sec for the bottom RBC and 0.099 +/- 0.017 sec for the top cells. This difference indicates that shape recovery following membrane deformation is delayed in old RBC. The membrane surface viscosity (eta), calculated as the product of tc times mu was 0.95 +/- 0.22 x 10(-3) dyne-sec/cm for the bottom cells and 0.54 +/- 0.15 x 10(-3) for the top RBC. These data indicate that the relative deficit in membrane surface area and the increased membrane viscosity of old RBC may be important determinants for their decreased deformability and their eventual removal from the circulation. 相似文献
102.
AIM: To demonstrate the range of applying laser angioplasty after unsuccessful recanalization of the superficial femoral artery (SFA) with conventional interventional techniques. MATERIALS AND METHODS: In a prospective trial in 94 cases with occlusion of the SFA and formerly unsuccessful conventional percutaneous transluminal angioplasty, laser angioplasty for recanalization was applied. The average length of the SFA was 17.5 cm (range 4–36 cm). The recanalization attempt was made using the crossover technique in 78 patients, in eight patients with the antegrade technique and in another eight patients using the transpopliteal technique. The primary recanalization attempt was performed with Terumo wires (curved and straight) as well as different catheters (Multipurpose/Vertebralis/Cobra). the unsuccessful recanalization attempt the laser catheter was applied. RESULTS: The application of laser angioplasty demonstrated a successful recanalization of the SFA in 76/94 patients (80.9%). In 18 patients (19.1%) the recanalization was not possible even with percutaneous transluminal laser angioplasty (PTLA). The reason for the unsuccessful PTLA was in 10 cases due to obstructing calcified material, which was resistant to PTLA application. In four cases obstructing calcifications caused the laser catheter to be positioned in subintimal tissue, resulting in perforation occlusion of the SFA. In another four patients there was an aberrant anatomy of the SFA which resulted in a direct vessel injury after advancing the laser catheter. After a follow-up period of 12 months primary, primary-assisted and secondary patency rates were 50.0%, 65.8% and 73.7%, respectively. DISCUSSION: In primarily unsuccessful recanalization of the SFA, PTLA allows in After 80% of cases a successful recanalization of the SFA. The technical success rate and the patency rate support the application of PTLA. (Int J Cardiovasc 2000; 3: 153–160) 相似文献
103.
Cor HJ Lamers Stefan Sleijfer Sabine van Steenbergen Pascal van Elzakker Brigitte van Krimpen Corrien Groot Arnold Vulto Michael den Bakker Egbert Oosterwijk Reno Debets Jan W Gratama 《Molecular therapy》2013,21(4):904-912
Autologous T cells genetically modified to express a chimeric antibody receptor
(CAR) against carboxy-anhydrase-IX (CAIX) were administered to 12 patients with
CAIX-expressing metastatic renal cell carcinoma (RCC). Patients were treated in
three cohorts with a maximum of 10 infusions of a total of 0.2 to 2.1 ×
109 CAR T cells. CTC grade 2–4 liver enzyme disturbances
occurred at the lowest CAR T cell doses, necessitating cessation of treatment in
four out of eight patients in cohorts 1 and 2. Examination of liver biopsies
revealed CAIX expression on bile duct epithelium with infiltration of T cells,
including CAR T cells. Subsequently four patients were pre-treated with CAIX
monoclonal antibody (mAb) G250 to prevent CAR-specific toxicity and showed no
liver toxicities and indications for enhanced peripheral T cell persistence. No
clinical responses were recorded. This report shows that CAIX-targeting CAR T
cells exerted antigen-specific effects in vivo and induced liver
toxicity at the lowest dose of 0.2 × 109 T cells applied,
illustrating the potency of receptor-modified T cells. We provide in-patient
proof that the observed “on-target” toxicity is antigen-directed and
can be prevented by blocking antigenic sites in off-tumor organs and allowing
higher T cell doses. 相似文献
104.
Purpose: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). Method: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. Results: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. Conclusions: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological?-?biomechanical assessment of spasticity during active, functional movement. 相似文献
105.
106.
107.
C Ziebold R von Kries A Siedler HJ Schmitt 《Acta paediatrica (Oslo, Norway : 1992)》2000,89(S435):17-21
Recently published and as yet unpublished data allow a reasonable estimate of the annual burden of pneumococcal disease in Germany. At least 277000 episodes of otitis media and at least 2000 episodes of sinusitis occur in children under the age of 5 y. Pneumococcal meningitis was found in 200 children under the age of 16 y; the estimate for all age groups ranges from 450 to 1100 cases. Of approximately 150000 cases of ambulatory pneumococcal pneumonia, at least 63 000–105000 patients are hospitalized each year.
Conclusion: Further studies of pneumococcal epidemiology in Germany are needed, and continued surveillance will be necessary for a better understanding of the overall burden of pneumococcal disease in children as well as adults. 相似文献
Conclusion: Further studies of pneumococcal epidemiology in Germany are needed, and continued surveillance will be necessary for a better understanding of the overall burden of pneumococcal disease in children as well as adults. 相似文献
108.
Biliary stricture dilatation: multicenter review of clinical management in 73 patients 总被引:7,自引:0,他引:7
Mueller PR; vanSonnenberg E; Ferrucci JT Jr; Weyman PJ; Butch RJ; Malt RA; Burhenne HJ 《Radiology》1986,160(1):17-22
Eighty-nine biliary strictures in 73 patients who had undergone percutaneous balloon dilatation were reviewed to determine long-term patency rates and clinical management problems. The majority of dilatations were performed in patients with anastomotic strictures (n = 44), iatrogenic strictures (n = 28), and strictures associated with sclerosing cholangitis (n = 17). Patency rates after 36 months or more were 67%, 76%, and 42%, respectively. Complications, mostly minor, occurred in less than 7% of patients. Of patients with significant biliary obstruction, 15% had little or no intrahepatic biliary duct dilatation demonstrated by cross-sectional imaging and/or direct cholangiography. No definite conclusions could be drawn about the utility of long-term internal/external stenting. 相似文献
109.
110.
W Oh DK Stevenson JE Tyson BH Morris CE Ahlfors G Jesse Bender RJ Wong R Perritt BR Vohr KP Van Meurs HJ Vreman A Das DL Phelps T Michael O’Shea RD Higgins 《Acta paediatrica (Oslo, Norway : 1992)》2010,99(5):673-678
Objectives: To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18–22 months corrected age in extremely low birth weight infants. Method: Total plasma bilirubin and unbound bilirubin were measured in 1101 extremely low birth weight infants at 5 ± 1 days of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18–22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow‐up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors. Results: Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow‐up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow‐up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. Conclusions: In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma bilirubin and death or adverse neurodevelopmental outcomes at 18–22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants. 相似文献