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PubMed1987

Enrichment of blood units with young red cells (neocytes) with the IBM 2991 cell washer.

The transfusion of young red blood cells (neocytes) is a complementary approach to the present treatment of thalassaemia major patients. Fresh neocytes were harvested from 34 volunteers with the IBM 2991 cell washer (CW). The upper part of 24 units was separated into 6 aliquots (T1-T6) of 15 ml each and the residue homogenized. Four biological criteria were used to evaluate young red cell quality, the erythrocyte pyruvate kinase activity, the mean corpuscular volume, the reticulocyte count and ektacytometry; each sample (T1-T6) showed an enrichment with neocytes as compared with the standard unit. A real efficiency of this technique with the IBM 2991 CW was obtained with the first third of the unit, corresponding to the T1-T4 fractions. The estimation of the theoretical mean life span of T1-T2 was 270 days. The last 10 units were separated into two halves: the enrichment of the first half was worse than in the first third of the previous technique. We concluded that the transfusional program of thalassaemia patients could profit by the use of the most enriched part of a standard blood unit with the IBM 2991 CW.

Blood Specimen Collection↗
PubMed1992

The effect of early and late cord-clamping on blood viscosity and other hemorheological parameters in full-term neonates.

This study was done to compare postnatal alterations in blood viscosity (capillary viscometer) and its determinants: hematocrit, plasma viscosity (capillary viscometer), red cell aggregation (Myrenne aggregometer) and red cell deformability (rheoscope) in the first five days of postnatal life in full-term neonates with early (< 10 s) and late (3 min) cord-clamping. The fetal blood volume of the placenta ("residual placental blood volume") decreased from 52 +/- 8 ml/kg of neonatal body weight after early cord-clamping to 15 +/- 4 ml/kg after later cord-clamping. Neonatal blood volume, calculated as the difference between an assumed total feto-placental blood volume of 115 ml/kg and the measured fetal blood volume of the placenta, was 50% higher in the late cord-clamped infants than in the early cord-clamped infants. Both groups showed similar viscosity, hematocrit and other rheological parameters in cord blood. In the infants with early cord-clamping, the hematocrit decreased from 0.48 +/- 0.04 l/l at birth to 0.43 +/- 0.6 l/l after 24 h (p < 0.05). Whole blood viscosity did not change significantly with age. After late cord-clamping, the hematocrit rose from 0.50 +/- 0.04% at birth to 0.63 +/- 0.05 l/l at 2 h of age (p < 0.005) and dropped to 0.59 +/- 0.5 l/l (p < 0.05) at 24 h. Blood viscosity increased by 40% (p < 0.001) within the first 2 h, but did not change significantly during the following five days. In both groups, plasma viscosity and red cell aggregation increased significantly (p < 0.05) on day 5 due to significant increases in total plasma protein and fibrinogen concentrations (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Proteins↗
PubMed2005

Neonatal screening for congenital hypothyroidism in West Black Sea area, Turkey.

The aim of this study was to investigate the incidence of congenital hypothyroidism (CH) in the West Black Sea Area, a mild-to-moderate iodine deficient area in Turkey. Neonatal screening for CH was performed using blood specimens collected onto filter paper. Thyrotropin [thyroid-stimulating hormone (TSH)] was measured by radioimmunoassay, and a value >20 microU/ml was considered as cut-off point for re-examining. Venous serum was obtained to measure TSH, thyroxin (T4), free T4 (FT4) and thyroglobulin (TG). To determine the iodine status of the study area, median urinary iodine was measured in 212 randomly selected neonates and their mothers. A total of 18606 neonates were screened from three cities (Bolu, Düzce, and Zonguldak) between 2000 and 2002. With a cut-off point of TSH value >20 microU/ml, the recall rate was found 1.6%. Eight cases of CH were diagnosed (incidence 1/2326). There were three cases of transient hypothyroidism, with an incidence of 1/6202. Twenty-six percent of the TSH values was greater than 5 microU/ml. Median urinary iodine concentrations in neonates and their mothers were 85 microg/l and 40 microg/l, respectively. The incidences of CH, transient hypothyroidism and the recall rate were higher in our study area than many countries in Europe. The study area has been affected by mild-to-moderate iodine deficiency. Neonatal screening for CH should be introduced in Turkey without delay. A national comprehensive infantile hypothyroidism and iodine prophylaxis policies should be developed.

Child, Preschool↗
PubMedDate not supplied

Conventional blood sampling versus On-Line Clearance Monitoring.

On-line Clearance Monitoring (OCM) calculates the Kt/V during a dialysis session using a module incorporated into the Fresenius 4008 H/S haemodialysis machine (1). The method is based on repeated increments in dialysate sodium concentrations followed by measuring the change of dialysate sodium concentration after the dialysate has passed through the kidney. OCM is a patient friendly, non-invasive and easy method for measuring Kt/V. Kt/V calculated on single-pool urea kinetics according to Daugirdas was compared to Kt/V measured by OCM in thirty stable patients on chronic haemodialysis. Patients were dialysed using a dialyser with either a high-flux polysulfone or a haemophane membrane. In four patients OCM was measured in ten consecutive sessions to assess the intra-individual variation in OCM. The calculated Kt/V was compared to Kt/Vocm in three patients at five consecutive dialysis sessions to measure the intra-individual correlation. A linear correlation was present between Kt/Vocal and Kt/Vac for both the polysulfone and haemophane membrane. Intra-individual Kt/Vocm showed very stable values with an average variation of less than 5%. Intra-individual correlation between calculated Kt/V and Kt/Vocm was high.

Bias↗
PubMed1967

Concurrent isolation from patient of two arboviruses, Chikungunya and dengue type 2.

Chikungunya virus and dengue type 2 virus were isolated from a single blood specimen taken from a patient in the acute phase of a dengue-like illness seen at Christian Medical College Hospital, Vellore, South India, in October 1964. In serial blood specimens collected from this patient there was an increase in antibody to these same two viruses. The technique for unmasking an agent (such as dengue) with a long incubation period in mice in the presence of an agent with a short incubation period is described.

Animals↗
PubMed1988

Pharmacokinetics and antiviral activity in simian varicella virus-infected monkeys of (R,S)-9-[4-hydroxy-2-(hydroxymethyl) butyl]guanine, an anti-varicella-zoster virus drug.

The acyclic guanosine analog (R,S)-9-[4-hydroxy-2-(hydroxymethyl)butyl]guanine, (+/-)2HM-HBG, is an effective inhibitor of herpes simplex virus and varicella-zoster virus infections in vitro. This report is concerned with the pharmacokinetic evaluation of the drug in rats and monkeys and its antiviral activity in African green monkeys infected with simian varicella virus (SVV), a virus closely related to varicella-zoster virus that is also susceptible to inhibition by (+/-)2HM-HBG. Elimination half-lives in plasma following intravenous administration to monkeys (100 mumol/kg of body weight) ranged from 1.8 to 2.2 h, and total body clearance was 9.0 +/- 0.4 ml/min per kg (mean +/- standard error). After oral administration, levels in plasma were low, with a maximum concentration of the drug of only 3.1 +/- 0.8 microM, a time to reach maximum concentration of drug of 2.7 +/- 0.4 h, and an oral bioavailability of 10.6 +/- 1.4%. Because of the low oral bioavailability, SVV-infected monkeys were treated intramuscularly with (+/-)2HM-HBG. (+/-)2HM-HBG at a dosage of 10 mg/kg of body weight per day allowed moderate viremia, whereas a dosage of 30 mg/kg of body weight per day strongly suppressed viremia with minimal numbers of virus plaques from blood specimens collected at days 3, 5, and 7 postinfection and complete clearance at day 9 postinfection. Titers of antibody to SVV were also low. Treatment three times daily was somewhat more efficacious than treatment twice daily. Thus, (+/-)2HM-HBG is an effective inhibitor of SVV replication in vivo, despite the fact that leves of (+/-)2HM-HBG in plasma were low at extended periods of time and below the concentration of drug giving 50% inhibition of plaque formation obtained in vitro.

Administration, Oral↗
PubMed1993

Reproducibility of lysis-centrifugation cultures for quantification of Mycobacterium avium complex bacteremia.

While quantitative mycobacterial blood cultures have been accepted as the standard for evaluating response to various Mycobacterium avium complex (MAC) treatment regimens, variability in this methodology has not been evaluated in a rigorous fashion. We thus studied the reproducibility of quantitative MAC cultures by a lysis-centrifugation culture system within and among five institutions. To measure the intralaboratory variation in mycobacterial colony counts, colony counts from duplicate blood specimens collected from 52 AIDS patients with MAC bacteremia were determined. Colony counts ranged from 0 to 50,000 CFU/ml. Nonparametric analyses revealed there was no significant difference in colony counts between the 52 duplicate specimens. The agreement between the intralaboratory paired specimens, as measured by the intraclass correlation coefficient, was 0.997. To measure the interlaboratory variation, multiple 10-ml aliquots from 12 patients were distributed to five institutions and processed within 24 to 32 h by lysis-centrifugation. For the 12 specimens distributed to the five laboratories, two-way analysis of variance for repeated measures revealed no significant difference in an individual patient's colony counts between laboratories (P > 0.2). We conclude that quantitation of mycobacterial colony counts by the lysis-centrifugation system is reproducible within and between institutions. Clinical trials evaluating response to therapeutic interventions for MAC can use multiple laboratories for quantitation of mycobacteremia. Furthermore, a 24- to 32-h delay in processing appeared to have no impact on reproducibility.

AIDS-Related Opportunistic Infections↗
PubMed1993

Growth and survival of Serratia marcescens under aerobic and anaerobic conditions in the presence of materials from blood bags.

Several patients receiving blood transfusions during the summer of 1991 developed bacteremia after the transfusion. In all cases, the infection was caused by Serratia marcescens. The same strain of Serratia marcescens was isolated from the patients and from the outer surface of unfilled blood bags. The transport containers for the blood bags were made anoxic by using a catalyst in order to prevent microbial growth. The survival and growth of S. marcescens K202, which was isolated from the blood bags, was studied at different oxygen concentrations in deionized water containing materials derived from the blood bags. The rate of survival and growth of S. marcescens was highest under anaerobic conditions, in which growth occurred with all materials and even in deionized water alone. In contrast, S. marcescens did not survive in control cultures under semi-anaerobic and aerobic conditions. Growth was observed, however, under both aerobic and semi-anaerobic conditions in the presence of each of the tested blood bag materials. These findings indicate that the conditions in the transport containers for the blood bags were favorable for the survival and growth of S. marcescens.

Aerobiosis↗
PubMed1997

Detection of Mycobacterium tuberculosis in BACTEC 12B broth cultures by the Roche Amplicor PCR assay.

To evaluate the ability of the Amplicor MTB Assay to detect Mycobacterium tuberculosis complex (MTBC) organisms in BACTEC 12B broth cultures, 249 cultures with a growth index (GI) of > or = 20 from 160 patients were tested retrospectively. Specimens were processed by standard methods, and then BACTEC 12B vials and Middlebrook 7H11/7H115 plates were inoculated, incubated, and interpreted in accordance with the manufacturer's instructions and laboratory protocol. From 12B vials with a GI of > or = 20, and aliquot of broth was removed and frozen at -20 degrees C until assayed by PCR. PCR results were compared to those obtained by the usual laboratory protocol, whereby MTBC organisms were identified by a DNA probe assay performed on broth from 12B vials with a GI or > or = 300 or on colonies from solid medium. Of the 249 broth cultures evaluated, 142 contained mycobacteria, including 44 that contained MTBC organisms. Of these 44 cultures, 41 were PCR positive; the 3 that were PCR negative were blood specimens collected in an Isolator tube. All 98 cultures with nontuberculous mycobacteria and the 107 that did not contain mycobacteria were PCR negative. Thus, the sensitivity and specificity of PCR were 93 and 100%, respectively. For those culture sin which MTBC organisms were identified by both the DNA probe and PCR assays, the mean time from specimen inoculation to detection and identification of MTBC organisms was 16 (range, 4 to 26) days for the PCR and 28 (range, 13 to 43) days for the DNA probe assay (P < 0.0001). In summary, PCR is a rapid, reliable method for detection of MTBC organisms in BACTEC 12B broth cultures with a GI of > or = 20.

Bacterial Typing Techniques↗
PubMed2000

Comparison of the CMV brite turbo assay and the digene hybrid capture CMV DNA (Version 2.0) assay for quantitation of cytomegalovirus in renal transplant recipients.

We compared the CMV Brite Turbo Kit (BT) and the Digene Hybrid Capture CMV DNA (version 2.0) assay (HC2) in the quantitation of pp65 antigenemia and cytomegalovirus (CMV) DNA levels in immunosuppressed renal transplant recipients. Of 123 blood specimens collected from 24 renal transplant recipients, BT and HC2 assays detected 35 and 39 positive samples, respectively. The overall concordance rate between the two assays was 90%. Discordant results were observed at low levels of viremia, so that 8 samples were HC2 positive but BT negative and another 4 were BT positive but HC2 negative. There was good correlation (R(2) = 0.766; P<0.01) between the levels of CMV DNA and pp65 antigenemia in the 31 concordant positive samples. Correlation between results obtained with the two assays was confirmed by longitudinal studies for a patient who developed clinical CMV disease. HC2 may be more sensitive at low viremia levels and allow earlier detection of impending CMV disease. The BT assay offered the advantage of a rapid (2-h) turnaround time. We conclude that BT and HC2 assays have similar sensitivity and efficacy in the diagnosis and monitoring of CMV infection and disease in renal transplant recipients. While the HC2 assay would be appropriate for centers that handle a large number of samples, the BT test may be more suitable for small sample numbers or when results are needed urgently.

Antigens, Viral↗
PubMed2004

Cost effective use of satellite packs in neonates: importance of birth weight.

BACKGROUND: Blood banks split an adult packed red cell bag (usually 250 ml) into 30 ml bags, making a total of eight neonatal "satellite" packs per donor. These packs are then "allocated"/"committed" to be used to serially transfuse a newborn. AIM: To study transfusion requirements of premature infants in relation to their birth weight and thereby attempt to rationalise the method of dispensing satellite blood packs. METHOD: Data on the distribution of neonatal transfusions with respect to weight were obtained retrospectively from unit A (51 infants, 168 transfusions) and unit B (46 infants, 151 transfusions). These data were used to model the effect of different policies on donor exposure and number of unused packs. RESULTS: Infants weighing less than 1000 g at birth have significantly higher transfusion requirements than those weighing 1000 g or more (p = 0.001 (unit A), p = 0.004 (unit B)). Our model predicted a significant reduction in donor exposure if eight packs/infant were allocated to those weighing < 1000 g, and a significant cut in the number of unused packs if four satellite packs/infant were allocated to those weighing > or = 1000 g. CONCLUSIONS: It would be safer and cost effective to allocate eight packs/infant to those with birth weights < 1000 g and four packs/infant to those with birth weights > or = 1000 g.

Birth Weight↗