bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technical Aspects of Radiofrequency
Authors: Sluijter M. , Racz G. 
Published: March 2003

Abstract: Radiofrequency (RF) is an alternating electric field with an oscillating frequency of 500.000 Hz. If the resulting current flows through a percutaneously introduced electrode, heat will be produced around the electrode because the body tissue acts as a resistor. RF can, therefore, be used to ablate nervous tissue in the treatment of chronic pain. This method has gained acceptance for percutaneous cordotomy and for the treatment of trigeminal neuralgia. For spinal pain, the method had little success initially, but since the introduction of small diameter instrumentation, the results have markedly improved.he mechanism of action of RF has not been challenged until recently even though there was awareness that some observations were not consistent with the heat concept. The formation of heat is not the only occurrence during RF treatment, however. The tissue surrounding the electrode is also exposed to the RF electric field. This exposure has a biological effect as has been demonstrated both in cells in a cell culture and in the exposure to RF of dorsal root ganglia, resulting in transsynaptal induction of early gene expression in the dorsal horn. The mode of action of RF is, therefore, uncertain at the moment.The method of pulsed RF is based on the concept that the production of heat has been a by‐product of RF treatment and that the clinical effect is due to exposure to the electric field. In pulsed RF, the generator output is interrupted to allow for the elimination of heat in the silent period. The early results have been encouraging, but the results of controlled, prospective studies are not yet available.Since there are now 2 almost diametrically opposed views on the mode of action of RF, it is difficult to give recommendations for treatment. The decision is easy for indications for which heat RF has traditionally been contraindicated such as the treatment of peripheral nerves and trigger points. When the application of heat carries a potential risk, for instance if the dorsal root ganglion is the target structure, the use of pulsed RF is also recommended. As for the medial branch the situation is controversial. Since there are controlled studies available showing the effect of heat lesions, it is recommended that the technique should not be changed until further studies have been completed.Finally, the equipment for RF treatment is described and safety issues are discussed.
Risk of transmission of human immunodeficiency virus (HIV) by heat‐ treated factor VIII concentrates in patients with severe hemophilia A
Authors: Daenen S. , Hoogeveen Y. , Smit J.W. , van Imhoff G.W. , van der Meer J. , DeWolf J.T. , Sibinga C.T. , Halie R.M. 
Published: March 2003

Risk of transmission of human immunodeficiency virus (HIV) by heat‐ treated factor VIII concentrates in patients with severe hemophilia AAt the change from unheated to heat‐treated Factor VIII concentrates for the treatment of hemophilia A, 17 severe adult hemophiliacs (mean monthly dose, 4927 IU) were evaluated prospectively for signs of infection with human immunodeficiency virus (HIV). Viral serology and lymphocyte subpopulations (OKT3, OKT4, and OKT8‐positive cells) were examined monthly for 1 year. One patient seroconverted for HIV in the enzyme‐linked immunoabsorbent assay but was positive on the Western blot analysis from the outset. There was a slight but significant increase in OKT4+ cells and OKT4/OKT8 ratio. These data suggest that heat‐treated Factor VIII concentrates even when used in large amounts have a low risk of transmitting HIV.
Should autologous blood that tests positive for infectious diseases be used or discarded?
Authors: DZIK W. H. , DEVARAJAN S. 
Published: March 2003

ABSTRACTDecision analysis was applied to the question of whether to keep or discard autologous blood donations that test positive for viral markers. The decision is reached by analyzing a series of different events that lead to different outcomes. The probability of each event must be estimated and a value (“utility”) assigned to specific outcomes. The underlying assumptions of the analysis are reviewed. After assigning a probability to each event and a utility to each outcome, one can compute a probability (P*) that is compared to the likelihood that the autologous donor will need transfusion. If the probability of transfusion exceeds P*, then keeping the infectious unit is favored. Otherwise, discarding the infectious unit is preferred. The analysis argues against a single, uniform national policy regarding the disposition of infectious autologous units. The method outlined provides a rational basis for setting policy regarding a controversial issue in Transfusion Medicine.
Monitoring transfusionist practices: a strategy for improving transfusion safety
Authors: Shulman I.A. , Lohr K , Derdiarian AK , Picukaric JM 
Published: March 2003

BACKGROUND: Data from New York State indicate that about 1 of every 33,000 red cell units transfused is ABO‐incompatible with the recipient. National application of these data suggests that as many as 360 ABO‐incompatible whole blood and red cell transfusions might occur annually in the United States. Phlebotomy and blood bank laboratory errors cause some of these ABO‐incompatible transfusions, but the greatest number result either partially or solely from the failure of transfusionists to identify properly either a patient or the blood component a patient receives.STUDY DESIGN AND METHODS: A quality assessment/quality improvement (QA/QI), process is described that allowed for the direct oversight (monitoring) of transfusionists' practices and for the assessment of institutional policies for blood administration.RESULTS: At the beginning of the QA/QI process, monitoring of blood administration practices revealed that a variance from institutional blood administration policy occurred during 50 percent of blood and component transfusions. As a result of the QA/QI process, the percentage of transfusions with an associated variance from institutional policy dropped to nearly zero.CONCLUSION: The QA/QI process described in this report, or one similar to it, could improve transfusion safety and serve as a model for increased involvement by transfusion service medical directors in the oversight of transfusionists' practices.
Validation of use of the Nageotte hemocytometer to count low levels of white cells in white cell‐reduced platelet components
Authors: Moroff G. , Eich J. , Dabay M. 
Published: March 2003

BACKGROUND: Determination of the white cell (WBC) count in WBC‐reduced platelet components requires methods that have a detection limit in the range of approximately 5.0 × 10(2) to 5.0 × 10(4) per mL.STUDY DESIGN AND METHODS: With a 50‐microL Nageotte hemocytometer and bright‐field microscopy (200x magnification), studies were conducted to develop and validate a method that could be used routinely with filtered and apheresis‐harvested platelets. A 1‐in‐5 dilution of sample with a commercially available blood‐diluting fluid was used because, with a lower (1‐in‐2) dilution, the observed number of WBCs was substantially less than the number expected at relatively high platelet counts (> 1.9 × 10(9)/mL).RESULTS: The observed and expected WBC counts in WBC‐ reduced platelet samples correlated well at levels between approximately 5 and 1100 WBCs per counting area (5.0 × 10(2)‐1.1 × 10(5)/mL). At levels of more than 300 to 400 WBCs per counting area, accurate counts were obtained when 10 of the 40 rectangles were counted.CONCLUSION: These studies provide data to confirm that the 50‐ microL Nageotte hemocytometer can be used to accurately count low levels of WBCs in platelet components.
What can we learn about the need for transfusion from patients who refuse blood? The experience with Jehovah's Witnesses
Authors: Viele M.K. , Weiskopf R.B. 
Published: March 2003

BACKGROUND: A transfusion threshold of 7 g per dL (70 g/L) of hemoglobin has been proposed for patients, although scant human data are available to support this recommendation.STUDY DESIGN AND METHODS: The medical community's experience with Jehovah's Witnesses was examined, in order to assess the lowest tolerable hemoglobin concentration and the lower transfusion threshold of 7 g per dL (70 g/L) of hemoglobin. A MEDLINE search was conducted to capture medical and surgical reports involving Jehovah's Witnesses from 1970 through early 1993.RESULTS: Sixty‐one reports of untransfused Jehovah's Witnesses with hemoglobin concentrations < or = 8 g per dL (80 g/L) or hematocrits < or = 24 percent (0.24) were identified. Of 50 reported deaths, 23, as stated in the original reports, were primarily due to anemia. Except for three patients who died after cardiac surgery, all patients whose deaths were attributed to anemia died with hemoglobin concentrations < or = 5 g per dL (50 g/L). Twenty‐five survivors were reported with hemoglobin < or = 5 g per dL (50 g/L).CONCLUSION: These data have significant limitations but suggest that survival, without transfusion, is possible at low hemoglobin concentrations, while mortality with an unknown incidence is encountered at hemoglobin concentrations below 5 g per dL (50 g/L).
Blood use in patients undergoing repeat coronary artery bypass graft procedures: multivariate analysis
Authors: Bracey A.W. , Radovancevic R. , Radovancevic B. , McAllister H.A. , Vaughn W.K. , Cooley D.A. 
Published: March 2003

BACKGROUND: The prevailing clinical opinion is that patients undergoing repeat coronary artery bypass graft (CABG) operation require more blood transfusions than do patients undergoing primary CABG operation. To determine the extent of this increased demand and the variables responsible for it, the cases of 196 patients who had undergone primary procedures and 65 patients who had had repeat procedures at the same institution were reviewed.STUDY DESIGN AND METHODS: To analyze the differences in transfusion requirements for these two groups, the following data were obtained: number of transfusions given between the time of surgery and the time of hospital discharge; preoperative hemoglobin (Hb), hematocrit (Hct), prothrombin time, and platelet count; Hb and Hct at hospital discharge; time the patient was on cardiopulmonary bypass; number and type of grafts; estimates of intraoperative blood loss; and chest‐tube blood shed during the first 48 hours after surgery.RESULTS: The groups were comparable with respect to age, body weight, preoperative Hb and Hct, number of grafts, and aspirin exposure. Patients in the repeat group had 35‐percent greater blood loss and required 75‐percent more blood components than did the patients undergoing primary procedures. The mean number of blood components transfused per patient was as follows: red cells, 3.8 +/− 0.5 units in repeat patients and 2.2 +/− 0.2 units in primary patients (p = 0.002); platelets, 2.9 +/− 0.9 vs. 1.1 +/− 0.2 (p = 0.043); fresh‐frozen plasma, 1.6 +/− 0.4 vs. 0.8 +/− 0.1 (p = 0.044). Analysis of variables by regression method for repeat patients showed a predictive effect of blood loss (p < 0.0001), prolonged time on cardiopulmonary bypass (p < 0.0001), preoperative Hb (p = 0.0003), and aspirin exposure (p = 0.0094) on red cell transfusion rate in repeat patients (R‐square = 0.7778, Prob > f = 0.0001).CONCLUSION: Repeat CABG patients have higher transfusion rates. These findings may be attributed to the increased microvascular bleeding, prolonged time on cardiopulmonary bypass, lower preoperative Hb, and the use of preoperative antiplatelet medications.
Albumin batches and B19 parvovirus DNA
Authors: Lefrère J. J. , Mariotti M. , de la Croix I. , Lerable J. , Thauvin M. , Burnouf T. , Folléa G. 
Published: March 2003

BACKGROUND: B19 parvovirus (B19) may be transmitted iatrogenically by blood, and its prevalence in blood donations is estimated at 1 in 3,300 to 1 in 50,000. As a large number of blood donations make up the plasma pools used to produce plasma derivatives, even a virus as rare as B19 in a population of blood donors may result in the frequent contamination of plasma batches. The percentage of albumin batches containing B19 DNA has never been determined.STUDY DESIGN AND METHODS: The presence of B19 DNA was investigated by a polymerase chain reaction assay (with a primer pair in the VP1 region) in a total of 12 and 17 batches of 4‐ and 20‐percent albumin, respectively, from two different manufacturers.RESULTS: No B19 DNA was detected in the batches tested.CONCLUSION: The current fractionation process used to obtain these albumin preparations is seen to allow the efficient degradation and/or elimination of B19.
Reliability of the third‐generation recombinant immunoblot assay for hepatitis C virus
Authors: Damen M. , Zaaijer H.L. , Cuypers H.T. , Vrielink H. , van der Poel C.L. , Reesink H.W. , Lelie P.N. 
Published: March 2003

BACKGROUND: In a confirmatory laboratory, the second‐generation recombinant immunoblot assay (RIBA‐2) was replaced by the third‐ generation RIBA (RIBA‐3) in March 1993. The aim of this validation study was to compare the sensitivity and specificity of RIBA‐2 and RIBA‐ 3 in a routine setting, by using a validated hepatitis C virus (HCV) RNA polymerase chain reaction to establish plasma viremia.STUDY DESIGN AND METHODS: RIBA‐2 testing was performed (March 1991‐March 1993) in 593 HCV RNA‐positive and 1498 HCV RNA‐negative subjects. RIBA‐3 testing was performed (March 1993‐May 1994) in 220 HCV RNA‐positive and 530 HCV RNA‐negative subjects. All samples reacted for anti‐HCV in enzyme‐ linked immunosorbent assay.RESULTS: In HCV RNA‐positive individuals, the sensitivity of RIBA‐3 was significantly higher than that of RIBA‐2 (99.5% vs. 93.3%, p = 0.0005). This was not caused by inclusion of the NS5 antigen, but by a higher sensitivity of the antigens c33 and c100 (RIBA‐2: 94.3% and 62.6%; RIBA‐3: 99.5% and 88.6%). Replacement of the c22 and c100 recombinant proteins by synthetic peptides significantly reduced nonspecific reactivity against these antigens (p < 0.0001). Unfortunately, increased nonspecific reactivity against the modified c33 antigen and the new NS5 antigen canceled out this effect. Two‐band reactivity occurred more often in nonviremic persons than in viremic persons (32.7% vs. 8.2%, p < 0.0001). Risk factors for HCV infection were less frequently observed in 11 blood donors with two‐band reactivity than in 6 blood donors with other positive RIBA‐3 patterns (18% vs. 83%, p = 0.03).CONCLUSION: The higher sensitivity of RIBA‐3 significantly reduced the number of indeterminate test results in HCV RNA‐positive persons. Confirmatory laboratories must be aware of the frequent occurrence of nonspecific, isolated reactivity and even nonspecific, two‐band reactivity in anti‐HCV enzyme‐linked immunosorbent assay‐reactive blood donors.
Rejuvenation of irradiated AS‐1 red cells
Authors: Samuel L.H. , Anderson G. , Mintz P.D. 
Published: March 2003

BACKGROUND: Gamma irradiation of blood components is used to prevent transfusion‐associated graft‐versus‐host disease. The demand for irradiated blood components is increasing because of the increase in directed donation by family members. Irradiated units currently have a recommended maximum storage life of 28 days. Since in vivo recovery is related to red cell ATP levels, rejuvenation of stored irradiated units using a pyruvate‐inosine phosphate‐adenine additive was explored.STUDY DESIGN AND METHODS: Units of AS‐1 red cells from 16 volunteer donors were divided into two equal volumes and one split unit from each was irradiated with 25 Gy. Ten units were irradiated on Day 5, 6, or 7 of 4°C storage and 6 units were irradiated on Day 1 of 4°C storage. All units were rejuvenated for 1 hour at 37°C using a pyruvate‐inosine‐phosphate‐adenine additive on Day 42 of 4°C storage. Units were assayed for ATP, 2, 3 DPG and supernatant sodium, potassium, and glucose.RESULTS: ATP and 2, 3 DPG levels were restored equally well in irradiated and non‐irradiated units. The previously reported irradiation‐induced red cell potassium‐sodium shift was demonstrated. Supernatant potassium and sodium levels did not reverse 1 hour after rejuvenation was completed. There was no significant difference in results between units irradiated on Day 1 or Day 5, 6, or 7.CONCLUSION: Red cell ATP and 2, 3 DPG levels were restored in irradiated AS‐1 units stored at 4°C for 42 days using a pyruvate‐inosine‐phosphate‐adenine rejuvenation additive.
Rapid identification of bacterially contaminated platelets using reagent strips: glucose and pH analysis as markers of bacterial metabolism
Authors: Burstain J.M. , Brecher M.E. , Workman K. , Foster M. , Faber G.H. , Mair D. 
Published: March 2003

BACKGROUND: One in every 1000 units of platelets is bacterially contaminated, which puts patients at risk for transfusion‐associated sepsis and death. However, there is currently no screening test in place to detect contaminated units. The use of commercially available multiple‐reagent urine dipsticks for this purpose was evaluated.STUDY DESIGN AND METHODS: Platelet concentrates were inoculated with either sterile saline or suspensions of Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Klebsiella pneumoniae, or Serratia marcescens to a final concentration of 50 colony‐forming units (CFU) per mL. The platelets were analyzed daily by the use of multiple‐reagent strips, quantitative culture, and glucometry.RESULTS: B. cereus grew rapidly, reaching 107 CFU per mL 1 day after inoculation, while S. epidermidis grew slowly, achieving similar concentrations 4 to 6 days after inoculation. Two of 10 dipstick reagents, glucose and pH, proved useful in detecting bacteria. Both were lower in bacterially contaminated units than in controls. Glucose data obtained from automated analyzers validated the dipstick data. All organisms were detected at concentrations ≥107 CFU per mL, and S. aureus and K. pneumoniae were detected in the range of 103 to 105 CFU per mL.CONCLUSION: The multiple‐reagent test used had a sensitivity and specificity of 95 percent (≥107 CFU/mL) and 98 to 100 percent, respectively. These data indicate that urine dipsticks can be used to rapidly and inexpensively detect bacterial contamination in platelet concentrates, which potentially will reduce morbidity and mortality at minimal cost.
At least three hepatitis C virus strains implicated in Swedish and Danish patients with intravenous immunoglobulin‐associated hepatitis C
Authors: Widell A , Zhang Y.‐Y. , Andersson‐Gäre B. , Hammarström L. 
Published: March 2003

BACKGROUND: Three reported Swedish cases of hepatitis C in patients receiving an intravenous immunoglobulin (Gammagard, Baxter Healthcare, Deerfield, IL) were among the first to bring to light a worldwide outbreak of hepatitis C associated with non‐solvent/detergent (SD)‐treated Gammagard. In February 1994, all implicated batches of Gammagard were recalled and exposed patients traced.STUDY DESIGN AND METHODS: Sera from all identified and hepatitis C‐viremic Swedish and Danish patients (n = 14) exposed to the implicated batches underwent hepatitis C virus genotyping and sequencing of the core region and hypervariable region 1 of E2. Genomic amplification was also done on 15 non‐SD‐treated batches of Gammagard.RESULTS: Twelve patients were infected with subtype 1a and surprisingly, two with subtype 2b. Analysis of the core region showed identical sequences in four patients and the only consistently positive batch. Five patients shared another sequence, whereas three other subtype 1a patients each manifested unique sequences. The two subtype 2b isolates were identical. Genomic fingerprinting of the hypervariable region confirmed identity within each group with great stringency. Amplification with iso‐late‐specific primers showed mixed infection in one patient whose exposure was confined to a single batch.CONCLUSION: The few batches implicated presumably were contaminated with several strains.
No‐fault compensation for transfusion‐associated hepatitis B virus, hepatitis C virus, and HIV infection: Italian law and the Tuscan experience
Authors: Fineschi V. , Cateni C. , Fanetti P. L. , Turillazzi E. 
Published: March 2003

BACKGROUND: On February 25, 1992, in Italy, a law (Number 210; referred to as 210/1992) was promulgated providing economic indemnity for persons infected with hepatitis B virus, hepatitis C virus, and HIV via transfusion or the administration of hemoderivatives.STUDY DESIGN AND METHODS: The requests for compensation presented in the central Italian region of Tuscany from the time of the law's promulgation through December 31, 1996, were analyzed. These requests are surveyed by medical commissions in the regional military hospitals, which must compile a report of the completed assessments, formulate a decision concerning verified illnesses, and express an opinion on the existence of a relationship of causality between the damaging event and the impairment or death of the subjects.RESULTS: Out of 428 requests for indemnity, 372 have been granted and 56 denied. Posttransfusion infections (286 cases) were clearly more prevalent than those due to hemoderivatives (141 cases). Cases of hepatitis, particularly type C, constitute the great majority of the infections for which indemnity was sought, while cases of HIV infection are scarce and in sharp decrease in the data from 1995 and 1996.CONCLUSIONS: Italian Law 210/1992 has been recognized as providing a benefit to persons infected medically, but its efficiency is greatly obstructed by a lack of documentation regarding transfusions performed in the past.
Exposure to GB virus type C or hepatitis G virus in selected Australian adult and children populations
Authors: Hyland C. A. , Mison L. , Solomon N. , Cockerill J. , Wang L. , Hunt J. , Selvey L. A. , Faoagali J. , Cooksley W. G. E. , Young I. F. , Trowbridge R. , Borthwick I. , Gowans E. J. 
Published: March 2003

BACKGROUND: The epidemiology and disease association for the GB virus type C (GBV‐C) or hepatitis G virus (HGV) are poorly understood.STUDY DESIGN AND METHODS: This study describes the exposure rates to GBV‐ C/HGV in diverse Australian population groups by testing for current infection and evidence of past infection with a reverse transcriptase polymerase chain reaction and an anti‐E2 enzyme‐linked immunosorbent assay, respectively. Subjects included volunteer blood donors, hepatitis C antibody (anti‐HCV)‐positive donors, children, hemodialysis patients, pregnant women attending a prenatal clinic, injecting drug users (IVDUs), and adult hemophiliacs.RESULTS: Combined GBV‐C RNA and E2 antibody prevalence was 6.5 percent (6/93) in children, 13.3 percent (75/565) in blood donors, 14 percent (14/99) in pregnant women, 22.5 percent (18/80) in hemodialysis patients, 80 percent (56/70) in anti‐ HCV‐positive donors, 88.6 percent (31/35) in IVDUs, and 85.7 percent (54/63) in adult hemophiliacs. Children had the lowest antibody rate, 1.1 percent, whereas the rate was 10.8 percent for blood donors and rose to 45.7 percent for IVDUs, 57.1 percent for anti‐HCV‐positive donors, and 74.6 percent for hemophiliacs. In contrast, current infection rates were comparable for children, blood donors, and pregnant women (5.4, 2.6, and 6%, respectively), rising to 11.1 percent for hemophiliacs, 24.3 percent for anti‐HCV‐positive donors, and 48.6 percent for IVDUs. Ten of 12 blood donors had persistent viremia, while 2 had recent infections, 1 with apparent resolution.CONCLUSION: Exposure to GBV‐C can commence at an early age, although ongoing exposure may also occur among adults with no apparent risk factors. GBV‐ C RNA positivity was not associated with abnormal plasma alanine aminotransferase levels among blood donors.