Biomedical subjects

K Janatpour

Publications and source records attributed to K Janatpour.

4 recordsLinked to original sources

PubMed2005

Comparison of X-ray vs. gamma irradiation of CPDA-1 red cells.

BACKGROUND AND OBJECTIVES: Transfusion-associated graft-versus-host disease (TA-GVHD) is a serious, potential complication of blood transfusion that is essentially prevented by blood product irradiation. Blood product irradiation is currently performed using gamma irradiation. X-ray irradiation is an alternative that has certain advantages: an X-ray irradiator is less expensive and does not have a radioactive source. However, the biochemical effects of X-ray irradiation on red blood cells (RBCs) have not been well characterized. The primary purpose of our study was to compare the effects of X-ray irradiation with gamma irradiation on RBC membrane permeability. A secondary purpose was to verify that X-ray irradiation has the same effect on lymphocytes as gamma irradiation. MATERIALS AND METHODS: Ten RBC units were split into two portions; five units of each were then irradiated with either gamma or X-ray at a dose of 35 Gy or 25 Gy, respectively. Free plasma haemoglobin and extracellular potassium levels were measured in each unit over time. Another unit was divided into three parts for lymphocyte studies; one part was not irradiated as a control and the other two received 25 Gy of irradiation via X-ray or gamma irradiation, respectively. RESULTS: Minimally increased free plasma haemoglobin was found only in X-ray-irradiated units after 25 Gy compared to gamma-irradiated units. However, extracellular potassium levels were not significantly different in these groups. Extracellular potassium levels were slightly higher only in gamma irradiated units at 35 Gy. X-ray and gamma irradiation were equivalent in affecting lymphocyte function. CONCLUSIONS: Small differences in RBC membrane permeability are found between gamma-irradiated and X-ray-irradiated units. However, these differences are not likely to be clinically important.

Adenine↗

PubMed2004

Platelet function abnormalities in qualified whole-blood donors: effects of medication and recent food intake.

BACKGROUND AND OBJECTIVES: Platelet function abnormalities have been reported in blood donors who have not consumed aspirin. Our objective was to identify factors other than aspirin that may contribute to impaired platelet function in qualified volunteer blood donors. MATERIALS AND METHODS: Blood samples were obtained from 24 donors following routine blood donation. Donors completed a study questionnaire that included questions about recent food consumption, medication and medical history. Platelet activation was measured using monoclonal antibodies and flow cytometry. CD62P expression and PAC-1 binding on platelets were used as indicators of platelet activation. Platelet function was measured on a platelet function analyser (PFA-100) using both collagen/epinephrine (cEPI) and collagen/ADP (cADP) cartridges. RESULTS: Fifty-four per cent of donors (13 of 24) had normal platelet function. Thirty-eight per cent (nine of 24) had prolonged cEPI closure times, of whom four (17%) had no cEPI closure (> 300 seconds). No closure was associated with aspirin use (two donors) or chocolate consumption (two donors) before donation. Two donors (8%) had either a shortened cEPI or cADP closure time. CONCLUSIONS: Platelet dysfunction in qualified blood donors is underestimated. Platelet function screening can identify donors with diet-related platelet dysfunction or with poor recollection of aspirin use.

Adult↗

PubMed2002

Interpretation of atypical patterns encountered when using a flow cytometry-based method to detect residual leukocytes in leukoreduced red blood cell components.

BACKGROUND: Universal leukoreduction of blood components is becoming the standard of care. Flow cytometry methods are being used for quality control of the leukoreduction process. METHODS: We provide an atlas of atypical flow cytograms generated by a commercial LeucoCOUNT assay that was used to enumerate residual leukocytes in leukoreduced red blood cell components. Numeric results are derived from a flow cytogram generated by the assay. RESULTS: Three types of atypical flow cytogram patterns were observed during process validation or routine quality control of leukoreduced red blood cell components. (a) Fixation artifact: Fixation of control or test samples can alter the staining intensity compared with fresh cells. (b) "Rain" pattern: Flow cytometry methods count slightly damaged leukocytes not removed during leukoreduction. Slightly damaged leukocytes appear on a flow cytogram like "rain" falling from a well-defined "cloud" of intact residual leukocytes. Discrepancies between automated flow cytometry results and subjective manual counting methods can occur. (c) Autofluorescence-debris pattern: Cell debris and age-related changes in the sample can cause shifts in the fluorescence staining pattern, resulting in erroneous test results. CONCLUSION: Review of flow cytograms is essential for accurate reporting of flow cytometry-based methods for enumerating residual leukocytes in leukoreduced blood components.

Artifacts↗

PubMed2001

Blood support for pediatric surgery.

Increasingly complicated surgeries are being performed on neonatal and pediatric patients. Provision of a safe and adequate blood supply is essential for the success of many of these surgeries. Depending on the clinical situation, autologous and/or allogeneic blood may be used. However, in all cases, every attempt should be made to minimize the number of donor exposures to reduce the risk of transfusion transmitted infections. Transfusion of neonatal and pediatric patients requires additional considerations too, such as the risk of graft vs host disease, cytomegalovirus infection, the effects of various preservative anticoagulant solutions, electrolyte levels during blood storage, and wheather or not leukoreduced components are indicated.

Blood Donors↗