Fagositik aktivasyon yoluyla lökosit işaretlemede Tc-99m poli (l-laktik) asit mikrokürelerinin kullanımı

Amaç: Bu çalışmanın amacı Tc-99m poli (l-laktik) asit (PLA) mikrokürelerini lökositleri fagositik yolla işaretleyebilmek için hazırlamak ve gerekli optimum şartları belirlemektir. Yöntem: PLA polimerlerinden (MA:52.000 D) çözücü buharlaştırma yöntemi ile PLA mikroküreleri (1-5 µm) hazırlandı. Daha sonra pH 3’te kalay klorürle Tc-99m ile işaretlendi, işaretleme verimi % 95’in ve stabilitesi ise 24 saat içinde % 70’in üzerinde bulundu. 50 ml heparinli kan gönüllü sağlıklı erişkin insanlardan alınarak oda sıcaklığında sedimantasyona bırakıldı ve lökositten zengin plazma elde edildi. 1 mL’de hazırlanan 50 mCi Tc-99m-PLA mikroküresi lökosit çökeleğine ilave edilip rotator bir mekanik sallayıcıda 37oC’de 1. saat inkubasyona bırakıldı. Tc-99m PLA ile işaretlenen lökositler santrifüj ile süspansiyondan ayrıldı, yıkandı ve trombositten fakir plazma ile süspansiyon yapıldı. Bulgular: Lökositlerin işaretlenme verimi yaklaşık % 70 bulundu. Monositlerin PLA mikrokürelerini fagosite ettiği elektron mikroskobunda gösterildi. Lökositlerin kemotaktik indeksi 2’nin üzerinde bulundu. Lökositlerin canlılığı Tripan mavisi ile değerlendirildi ve % 90’ın üzerinde bulundu. Sonuç: Tc-99m-PLA mikroküreleri ile lökosit işaretlemenin potansiyel değeri olduğu görülmektedir. Monositlerin daha belirgin işaretlenmesi nedeniyle özellikle kronik inflamasyonda kullanılabilir.

Phagocyting labeling of leukocytes with Tc-99m PLA (poly l-lactic acid) microspheres

Objective: The aim of this study was to prepare Tc-99m poly (l-lactic) acid (PLA) particles for phagocyting engulfment by leucocytes and determine optimization conditions. Methods: PLA microspheres (1-5 µm) were prepared from PLA polymeres (MW=52.000) by solvent evaporation from methylene chloride. Then, they were labeled with Tc-99m by stannous chloride reduction at pH 3 with an efficiency of >95% and a stability of >70% at 24 hours. 50 mL heparinized blood was obtained from normal adult volunteers. The precipitate was removed and the sediment was washed with 0.9 NaCl and then centrifuged at 600 rpm for 5 minutes. 50 mCi Tc-99m-PLA particles in 1 mL was added to precipitated leukocytes and rotated in mechanical shaker in incubation at 37oC for 1 hour. Tc-99m-PLA labeled leukocytes were separated by centrifugation, washed and suspended in platelet poor plasma. Results: Leukocytes were labeled with an efficiency of about 70%. The engulfment of PLA particles by monocytes and the integrity of cell membrane afterwards were demonstrated by electron microscopy. Chemotactic index was >2. The viability of leukocytes was >90%, determined with trypan blue. Conclusion: Our results indicated the potential value of leukocyte labeling with Tc-99m PLA microspheres. This may be especially useful in demonstrating chronic infection, because of the preference of monocytes in labeling.

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