Mechanical damage of red blood cells by rotary blood pumps: selective destruction of aged red blood cells and subhemolytic trauma

In this study, mean cell volume (MCV), mean cell hemoglobin concentration (MCHC), and mean cell hemoglobin (MCH) were measured to quantify RBC damage by rotary blood pumps. Six-hour hemolysis tests were conducted with a Bio-pump BPX-80, a Sarns 15200 roller pump, and a prototype mag-lev centrifugal pump (MedTech Heart) using fresh porcine blood circulated at 5 L/min against a 100 mm Hg head pressure. The temperature of the test and noncirculated control blood was maintained at 37 degrees C. The normalized index of hemolysis (NIH) of each pump was determined by measuring the plasma-free hemoglobin level. The MCV was measured with a Coulter counter, and MCHC was derived from total hemoglobin and hematocrit. MCH was derived from MCV and MCHC. A multivariance statistical analysis (ANOVA) revealed statistically significant differences (n = 15, P < 0.05) in MCV, MCHC, and MCH between the blood sheared by the rotary blood pumps and the nonsheared control blood. Normalized to the control blood, the Bio-pump BPX-80 showed an MCV of 1.04 +/- 0.03, an MCHC of 0.95 +/- 0.04, and an MCH of 0.98 +/- 0.02; the mag-lev MedTech Heart had an MCV of 1.02 +/- 0.02, an MCHC of 0.97 +/- 0.02, and an MCH of 0.99 +/- 0.01; and the roller pump exhibited an MCV of 1.03 +/- 0.03, an MCHC of 0.96 +/- 0.03, and an MCH of 0.99 +/- 0.01. Per 0.01 increase in NIH, the BPX-80 showed a normalized MCV change of +10.1% and a normalized MCHC change of -14.0%; the MedTech Heart demonstrated a +6.9% MCV and -9.5% MCHC change; and the roller pump had a +0.5% MCV and -0.6% MCHC change. Due to shear in the pump circuits, the RBC increased while the MCHC decreased. The likely mechanism is that older RBCs with smaller size and higher hemoglobin concentration were destroyed fast by the shear, leaving younger RBCs with larger size and lower hemoglobin concentration. Subhemolytic trauma caused the intracellular hemoglobin to decrease due to gradual hemoglobin leakage through the micropores formed in the thinned membrane. In conclusion, the rate of change in MCV and MCHC with respect to NIH change provides useful information relating to selective destruction of RBCs, while the MCH level reflects subhemolytic damage.     

Photon-cell interactive Monte Carlo model based on the geometric optics theory for photon migration in blood by incorporating both extra- and intracellular pathways

A photon-cell interactive Monte Carlo (pciMC) that tracks photon migration in both the extra- and intracellular spaces is developed without using macroscopic scattering phase functions and anisotropy factors, as required for the conventional Monte Carlos (MCs). The interaction of photons at the plasma-cell boundary of randomly oriented 3-D biconcave red blood cells (RBCs) is modeled using the geometric optics. The pciMC incorporates different photon velocities from the extra- to intracellular space, whereas the conventional MC treats RBCs as points in the space with a constant velocity. In comparison to the experiments, the pciMC yielded the mean errors in photon migration time of 9.8±6.8 and 11.2±8.5% for suspensions of small and large RBCs (RBC(small), RBC(large)) averaged over the optically diffusing region from 2000 to 4000 μm, while the conventional random walk Monte Carlo simulation gave statistically higher mean errors of 19.0±5.8 (?p?相似文献   

Improvement of hemolysis performance in a hydrodynamically levitated centrifugal blood pump by optimizing a shroud size

Journal of Artificial Organs - We have developed a hydrodynamically levitated centrifugal blood pump. In the blood pump having hydrodynamic bearings, the narrow bearing gap has a potential for high...     

Effect of antihistamine eye drops on the conjunctival provocation test with Japanese cedar pollen allergen.

BACKGROUND: Approximately 16.2% of the Japanese population suffer from cedar pollinosis, with various manifestations such as ophthalmic, laryngo-pharyngeal and skin symptoms in addition to nasal symptoms. Thus, the annual pollen season is an agonizing period for patients. No study has reported symptoms and their clinical courses after conjunctival provocation with purified cedar pollen allergen Cry j1 as well as suppression of these allergen-induced ocular symptoms by antihistamine eye drops. METHODS: Nine patients with Japanese cedar pollinosis who had no nasal or ocular symptoms were included in the present study, after obtaining informed consent in writing. 1) Purified cedar pollen allergen Cry j1 was instilled in the left eye and phosphate-buffered saline (PBS) in the right eye as a control. 2) Levocabastine hydrochloride ophthalmic suspension and ketotifen fumarate ophthalmic solution were respectively instilled in the left and right eyes, which were then challenged with the allergen. Ocular symptoms after provocation with the allergen were recorded through the clinical course. RESULTS: Pollen allergen-induced ocular symptoms were itching and hyperemia of the palpebral conjunctiva, and itching lasted for more than 5 hours. Moreover, preadministration of antihistamine eye drops suppressed the increases in the ocular symptom scores, eliminating itching within 1 hour. Allergen provoked not only ocular symptoms but also nasal symptoms in 77.8% of patients. CONCLUSIONS: Preadministration of antihistamine eye drops suppressed the symptoms induced by the allergen, which suggests that this is an effective early therapy for Japanese cedar pollinosis, if it is started before the pollen season. However, self-protection by patients using a mask may not be effective enough to suppress nasal symptoms during the pollen season, requiring them to additionally wear glasses to avoid exposure to the allergen.     

Laboratory evaluation of the Sysmex NE-7000 flagging system; a tool for the recognition of abnormal cells in white cell differentials

Sysmex NE-7000 flagging system was evaluated for the recognition of abnormal cells in white cell differentials. Six flags that could mark blasts, immature granulocytes, left shift, nucleated red blood cells, atypical lymphocytes, and platelet clumps were selected for evaluation. 182 morphologic abnormal samples were screened from the Kobe University Hospital patients, by means of the 600 eye counts differentials. Blasts flag missed 8 of 28 cases, and immature granulocytes flag missed 25 of 56 cases. These missed cases contained either relatively few abnormal cells; less than 3% immature granulocytes, or absolutely few cells; less than 201 per micro liter blasts. Platelet clumps flag missed only 2 of 23 cases. But nucleated red blood cells and atypical lymphocytes flags missed all of 7 and 4 cases respectively. Left shift flag missed 36 of 64 cases, but it could help marking immature granulocytes or blasts. To use the NE-7000 as a screening tool, we compared the NE's all 35 flags versus abnormal cells or status based on the 100 eye counts. 1,153 cases were analyzed. Full agreement; 1047 (90.8%), partial agreement; 61 (5.2%), distributional false normal; 7 (1.6%), and morphological false normal; 4 (4.6%), were obtained. The more flags were used, the less abnormal cases were missed. But it accompanied the increase of the flag positive cases that must be confirmed by eye.     

Polymerization of styrene initiated by trichloroacetyl chloride and water

The polymerization of styrene initiated by trichloroacetyl chloride (TAC) and water was investigated. The reaction proceeded by an ionic mechanism and polymers of relatively low molecular weight were formed. From the analytical results of the polymer, it was suggested that the ionic decomposition of an intermediate complex formed by TAC and water yielded chloroformic acid which induced cationic polymerization of styrene.