Transfusion-associated hyperkalemia in pediatric population: Prevalence, risk factors, survival, infusion rate, and RBC unit features.

BACKGROUND: Hyperkalemia is a rare life-threatening complication of red blood cell (RBC) transfusion. Stored RBCs leak intracellular potassium (K+) into the supernatant; irradiation potentiates the K+ leak. As the characteristics of patients and implicated RBCs have not been studied systematically, a multicenter study of transfusion-associated hyperkalemia (TAH) in the pediatric population was conducted through the AABB Pediatric Transfusion Medicine Subsection. STUDY DESIGN: The medical records of patients <18 years old were retrospectively queried for hyperkalemia occurrence during or ≤12 h after the completion of RBC transfusion in a 1-year period. Collected data included patient demographics, diagnosis, medical history, timing of hyperkalemia and transfusion, mortality, and RBC unit characteristics. RESULTS/FINDINGS: A total of 3777 patients received 19,649 RBC units during the study period in four facilities. TAH was found in 35 patients (0.93%) in 37 occurrences. The patient median age and weight were 1.28 years and 9.80 kg, respectively. All patients had multiple serious comorbidities. There were 79 RBC units transfused in the TAH events; 62% were irradiated, and the median age of the units was 10 days. The median total RBC volume transfused ≤12 h before TAH was 24% of patient estimated total blood volume, and the median infusion rate (IR) was19.6 ml/kg/h. Mortality rate within 1 day after the TAH event was 20%. CONCLUSIONS: The prevalence of TAH in children was low; however, the 1-day mortality rate was 20%. Patients with multiple comorbidities may be at higher risk for TAH. The IR was higher for patients who had TAH than the IR threshold for safe transfusion.

Superconducting properties of (Ba-K)Fe2As2 single crystals disordered with fast neutron irradiation.

Resistivity ρ(T), Hall coefficient RH(T), superconducting transition temperature Tc and slopes of the upper critical field dHc2/dT were studied in (Ba1-xKx)Fe2As2 (x = 0.218, 0.356, 0.531) single crystals irradiated with fast neutrons. It is found that dTc/dρSC-the rate of decreasing Tc as a function of the ρSC (ρSC is the resistivity at T = Tc)-linearly increases with concentration x. Slow changes in the Hall coefficient RH, as well as the quadratic electronic contribution to the resistivity, show that there are no substantial changes in the topology of the Fermi surface caused by irradiation. The slopes of the upper critical field dHc2/dT in ab and c directions as a function of ρSC determined by Hall measurements show a reasonable agreement with a model that suggests constancy of the band parameters.

Preparation, characterization and evaluation of adsorptive properties of orange peel based activated carbon via microwave induced K2CO3 activation.

This work explores the feasibility of orange peel, a citrus processing biomass as an alternative precursor for preparation of activated carbon (OPAC) via microwave assisted K(2)CO(3) activation. The operational parameters, chemical impregnation ratio, microwave power and irradiation time on the carbon yield and adsorption capability were investigated. The virgin characteristics of OPAC were examined by pore structural analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption isotherm, elemental analysis, surface acidity/basicity and zeta potential measurement. The optimum conditions resulted in OPAC with a monolayer adsorption capacity of 382.75 mg/g for methylene blue and carbon yield of 80.99%. The BET surface area, Langmuir surface area and total pore volume were identified to be 1104.45 m(2)/g, 1661.04 m(2)/g and 0.615 m(3)/g, respectively. Equilibrium data were simulated using the Langmuir, Freundlich, Dubinin-Radushkevich, Redlich-Peterson, and Toth isotherms, and kinetic data were fitted to the pseudo-first-order, pseudo-second-order and Elovich kinetic models.

Influence of irradiation on in vitro red-blood-cell (RBC) storage variables of leucoreduced RBCs in additive solution PAGGS-M.

BACKGROUND: The effect of gamma irradiation on leucoreduced red-blood-cells (RBCs) stored in an additive solution (AS) containing phosphate, adenine, glucose, guanosine, saline and mannitol (PAGGS-M) has not yet been studied, and there are different recommendations about storage time of leucoreduced RBCs after irradiation. STUDY DESIGN AND METHODS: We studied 63 leucoreduced RBC units. All RBCs were stored in AS PAGGS-M and leucoreduced on the collection day. Twenty-one components were irradiated on Day +14 with 30 Gy and 22 served as non-irradiated controls. Samples were drawn and analysed from these 43 units on Day +7, +14, +21, +28, +35, +42 and +49 from the collection day. From 20 units, no samples were taken earlier than on Day +49. Of these, 10 components had been irradiated on Day +14 with 30 Gy and 10 served as non-irradiated controls. RESULTS: Gamma irradiation induced an enhanced in vitro haemolysis rate in the irradiated components. One of the irradiated units showed a haemolysis rate over the recommended limit of 0·8% on Day +42 and four on Day +49. The leakage of potassium ions from irradiated RBCs started to increase faster than that of unirradiated RBCs from the day of irradiation. Lactate dehydrogenase levels increased faster in irradiated units 3 weeks after irradiation. We showed that taking samples weekly does not affect the final result. CONCLUSIONS: Our findings show that the European recommendations should not be changed in regard to the limitation of the storageability after irradiation of leucoreduced RBCs. The damage after irradiation and storage cannot be prevented by using the high-quality AS PAGGS-M.

Effect of same-dose single or dual field irradiation on damage to miniature pig parotid glands.

AIM: To evaluate the effect of single or dual field irradiation (IR) with the same dose on damage to miniature pig parotid glands. METHODOLOGY: Sixteen miniature pigs were divided into two IR groups (n=6) and a control group (n=4). The irradiation groups were subjected to 20 Gy X-radiation to one parotid gland using single-field or dual-field modality by linear accelerator. The dose-volume distributions between two IR groups were compared. Saliva from parotid glands and blood were collected at 0, 4, 8 and 16 weeks after irradiation. Parotid glands were removed at 16 weeks to evaluate tissue morphology. RESULTS: The irradiation dose volume distributions were significantly different between single and dual field irradiation groups (t=4.177, P=0.002), although dose volume histogramin (DVH) indicated the equal maximal dose in parotid glands. Saliva flow rates from IR side decreased dramatically at all time points in IR groups, especially in dual field irradiation group. The radiation caused changes of white blood cell count in blood, lactate dehydrogenase and amylase in serum, calcium, potassium and amylase in saliva. Morphologically, more severe radiation damage was found in irradiated parotid glands from dual field irradiation group than that from single field irradiation group. CONCLUSION: Data from this large animal model demonstrated that the radiation damage from the dual field irradiation was more severe than that of the single field irradiation at the same dose, suggesting that dose-volume distribution is an important factor in evaluation of the radiobiology of parotid glands.

Effects of radiation and alpha-tocopherol on saliva flow rate, amylase activity, total protein and electrolyte levels in oral cavity cancer.

OBJECTIVE: The objective of the present study was to evaluate early and late effects of radiation and a-tocopherol on the secretion rate of saliva and on selected saliva salivary parameters in oral cavity cancer patients. PATIENTS & METHODS: Eighty-nine histologically confirmed oral cavity cancer patients (OCC) were enrolled in the study. Resting whole saliva was collected before, during and at the end of the radiation therapy (RT) and simultaneous supplementation with alpha - tocopherol to the radiation treated patients (RT + AT). RESULTS: Salivary flow rate, pH, amylase activity, total protein, sodium and potassium were analyzed. Increased pH, potassium and decreased flow rate, amylase activity, protein content and sodium were observed in 6 weeks of radiation treated patients when compared to OCC patients. A significant improvement of those parameters was observed on alpha - tocopherol supplementation in RT + AT patients. CONCLUSION: Supplementation with alpha - tocopherol improves the salivary flow rate thereby, maintains salivary parameters.

Using X-ray absorption spectra to monitor specific radiation damage to anomalously scattering atoms in macromolecular crystallography.

Radiation damage in macromolecular crystals is not suppressed even at 90 K. This is particularly true for covalent bonds involving an anomalous scatterer (such as bromine) at the 'peak wavelength'. It is shown that a series of absorption spectra recorded on a brominated RNA faithfully monitor the extent of cleavage. The continuous spectral changes during irradiation preserve an 'isosbestic point', each spectrum being a linear combination of 'zero' and 'infinite' dose spectra. This easily yields a good estimate of the partial occupancy of bromine at any intermediate dose. The considerable effect on the near-edge features in the spectra of the crystal orientation versus the beam polarization has also been examined and found to be in good agreement with a previous study. Any significant influence of the (C-Br bond/beam polarization) angle on the cleavage kinetics of bromine was also searched for, but was not detected. These results will be useful for standard SAD/MAD experiments and for the emerging 'radiation-damage-induced phasing' method exploiting both the anomalous signal of an anomalous scatterer and the 'isomorphous' signal resulting from its cleavage.

Photocatalytic degradation of pathogenic bacteria with AgI/TiO2 under visible light irradiation.

The photocatalytic disinfection of pathogenic bacteria in water was investigated systematically with AgI/TiO2 under visible light (lambda > 420 nm) irradiation. The catalyst was found to be highly effective in killing Escherichia coli and Staphylococcus aureus. The adsorbed *OH and hVB+ on the surface of the catalyst were proposed to be the main active oxygen species by study of electron spin resonance and the effect of radical scavengers. The process of destruction of the cell wall and the cell membrane was verified by TEM, potassium ion leakage, lipid peroxidation, and FT-IR measurements. Some products from photocatalytic degradation of bacteria such as aldehydes, ketones, and carboxylic acids were identified by FT-IR spectroscopy. These results suggested that the photocatalytic degradation of the cell structure caused the cell death. The electrostatic force interaction of the bacteria-catalyst significantly affected the efficiency of disinfection on the basis of the E. coli inactivation under different conditions.

Kinetic study of the thermoluminescence of KMgF3:LaF3 compounds employing the general one trap model.

The parameters characterising the trap centres involved in the thermoluminescence of KMgF3:LaF3 compounds have been found by deconvolving the glow curve with the General One Trap model (GOT). For the fitting procedure the Levenberg-Marquardt method has been employed. Tm-T(stop) measurements along with initial rise measurements were performed in order to estimate the number of peaks the glow curve is made up of, and the corresponding activation energies. Instead of the Runge-Kutta method, a novel algorithm has been employed to integrate the differential equation of the GOT model, which reduces the computational time nearly 30 times with respect to the former when the glow curve is recorded with a lineal heating rate profile. The strong computational time reduction makes feasible a large number of runs with different guess values. An interesting result is that the concentration of disconnected deep traps is much less than the concentration of trap centres.

The effect of oscillating low intensity magnetic field on the Na+, K+, Ca++, and Mg++ concentrations in the maternal and fetal circulation of the dually perfused human placental cotyledon.

Dual-sided perfusions of the human placental cotyledon in vitro were used to study effects of low intensity magnetic fields (MFs) of 2 mT, 50 Hz (E1, 10 perfusions) and 5 mT, 50 Hz (E2, 10 perfusions). In the control group C (10 experiments) no field was used. Perfusions lasted 180 min each. Increased release of calcium ions from the placental cotyledon was found in the fetal circulation during perfusion when the 2 mT, 50 Hz MF was used. No changes in the release of sodium and magnesium ions were observed compared to the control group. The 5 mT, 50 Hz oscillating MF intensified the release of sodium ions from the perfused cotyledon both to the fetal and maternal circulation up to the 150th min of the experiment. Increased release of magnesium ions was observed only to the fetal circulation between 120 and 180 min and of calcium ions to the fetal circulation between 60 and 180 min. No significant differences in K concentrations were found between the control and MF exposed cotyledons under conditions of these experiments.

Fluid flow electrophoresis model.

Molecular delivery via electroporation is typically done via molecular diffusion and tissue perfusion. The inherent variability in those distribution methods limits the efficacy of this medical and laboratory technique. Electrophoresis has been shown to improve the distribution and placement of the molecule [Gene Therapy 9 (2002) 1286]. This paper presents a fluid flow model for electrophoresis in tissues. Parallel plate and four-needle needle array electrodes are the electrodes modeled as the delivery devices. The parallel plate electrode produces a homogeneous distribution of the analyte but the needle array electrode creates a peak where the electric field effects diminish.

[The neuromediator modulation of the ionic composition of the brain cells in rats irradiated at nonlethal doses]. / Neiromediatornaia moduliatsiia ionnogo sostava kletok golovnogo mozga krys pri obluchenii v neletal'nykh dozakh.

It had been found that both the single prolonged irradiation and chronic (fractionated) one with doses of 25 and 50 cGy (1.75 mGy/min) caused essential modification of the biphase modulative effects of acetylcholine and gamma-aminobutyric acid upon K+ level in rat brain cortex slices to be compared to the acute lethal irradiation influence. The results of model experiments showed saturated fatty acids to be significant for the changes in regulative functions of nerve cell membranes after exposure to low dose-rate radiation.

Extremely low frequency magnetic fields can either increase or decrease analgaesia in the land snail depending on field and light conditions.

Results of prior investigations with opioid peptide mediated antinociception or analgaesia have suggested that these extremely low frequency (ELF) magnetic field effects are described by a resonance mechanism rather than mechanisms based on either induced currents or magnetite. Here we show that ELF magnetic fields (141-414 microT peak) can, in a manner consistent with the predictions of Lednev's parametric resonance model (PRM) for the calcium ion, either (i) reduce, (ii) have no effect on, or (iii) increase endogenous opioid mediated analgaesia in the land snail, Cepaea nemoralis. When the magnetic fields were set to parameters for the predictions of the PRM for the potassium ion, opioid-peptide mediated analgaesia increased and there was evidence of antagonism by the K(+) channel blocker, glibenclamide. Furthermore, these effects were dependent on the presence of light; the effects were absent in the absence of light. These observed increases and decreases in opioid analgaesia are largely consistent with the predictions of Lednev's PRM.

Effects on Rb(+)(K+) uptake of HeLa cells in a high K(+) medium of exposure to a switched 1.7 Tesla magnetic field.

Effects of a switched, time-varying 1.7 T magnetic field on Rb(+)(K+) uptake by HeLa S3 cells incubated in an isosmotic high K(+) medium were examined. The magnetic flux density was varied intermittently from 0.07-1.7 T at an interval of 3 s. K(+) uptake was activated by replacement of normal medium by high K(+) medium. A membrane-permeable Ca(2+) chelating agent (BAPTA-AM) and Ca(2+)-dependent K(+) channel inhibitors (quinine, charibdotoxin, and iberiotoxin) were found to reduce the Rb(+)(K+) uptake by about 30-40%. Uptake of K(+) that is sensitive to these drugs is possibly mediated by Ca(2+)-dependent K(+) channels. The intermittent magnetic field partly suppress ed the drug-sensitive K(+) uptake by about 30-40% (P < 0.05). To test the mechanism of inhibition by the magnetic fields, intracellular Ca(2+) concentration ([Ca(2+)]c) was measured using Fura 2-AM. When cells were placed in the high K(+) medium, [Ca(2+)]c increased to about 1.4 times the original level, but exposure to the magnetic fields completely suppressed the increase (P < 0.01). Addition of a Ca(2+) ionophore (ionomycin) to the high K(+) medium increased [Ca(2+)]c to the level of control cells, regardless of exposure to the magnetic field. But the inhibition of K(+) uptake by the magnetic fields was not restored by addition of ionomycin. Based on our previous results on magnetic field-induced changes in properties of the cell membrane, these results indicate that exposure to the magnetic fields partly suppresses K(+) influx, which may be mediated by Ca(2+)-dependent K(+) channels. The suppress ion of K(+) fluxes could relate to a change in electric properties of cell surface and an inhibition of Ca(2+) influx mediated by Ca(2+) channels of either the cell plasma membrane or the inner vesicular membrane of intracellular Ca(2+) stores.

Weak extremely-low-frequency magnetic field-induced regeneration anomalies in the planarian Dugesia tigrina.

We recently reported that cephalic regeneration in the planarian Dugesia tigrina was significantly delayed in populations exposed continuously to combined parallel DC and AC magnetic fields. This effect was consistent with hypotheses suggesting an underlying resonance phenomenon. We report here, in a parallel series of investigations on the same model system, that the incidence of regeneration anomalies presenting as tumor-like protuberances also increases significantly (P < .001) in association with exposure to weak 60 Hz magnetic fields, with peak intensities ranging between 1.0 and 80.0 microT. These anomalies often culminate in the complete disaggregation of the organism. Similar to regeneration rate effects, the incidence of regeneration anomalies is specifically dependent upon the planaria possessing a fixed orientation with respect to the applied magnetic field vectors. However, unlike the regeneration rate effects, the AC magnetic field alone, in the absence of any measurable DC field, is capable of producing these anomalies. Moreover, the incidence of regeneration anomalies follows a clear dose-response relationship as a function of AC magnetic field intensity, with the threshold for induced electric field intensity estimated at 5 microV/m. The addition of either 51.1 or 78.4 microT DC magnetic fields, applied in parallel combination with the AC field, enhances the appearance of anomalies relative to the 60 Hz AC field alone, but only at certain AC field intensities. Thus, whereas our previous study of regeneration rate effects appeared to involve exclusively resonance interactions, the regeneration anomalies reported here appear to result primarily from Faraday induction coupling. These results together with those reported previously point to two distinct physiological effects produced in regenerating planaria by exposure to weak extremely-low-frequency (ELF) magnetic fields. They further suggest that the planarian, which has recently been identified elsewhere as an excellent system for use in teratogenic investigations involving chemical teratogens, might be used similarly in teratogenic investigations involving ELF magnetic fields.

[The postradiation effect of noradrenaline, serotonin and dopamine on the activity of the Na-K pump in rat brain slices]. / Postradiatsionnyi éffekt noradrenalina, serotonina i dofamina na aktivnost' Na,K-nasosa srezov mozga krys.

Whole-body X irradiation with doses of 0.155 and 0.310 C/kg was shown to modify in different ways the activating effects of noradrenaline and serotonin, as well as a biphase effect of dopamine (5.10(-8)--1.5.10(-3) M) on Na,K-pump of neuronal membranes. The resulting effect was a function of a combination of radiation doses and neurotransmitter concentrations and thus showed different modes of interaction between neurotransmitter and ion-transport systems of brain cells in radiation sickness. The authors discuss possible molecular mechanisms of radiation modification of the functional interaction between the neurotransmitter and the active ion-transport systems in nerve cells.

[The postradiation effect of acetylcholine and GABA on the active potassium uptake by slices of rat cerebral cortex]. / Postradiatsionnyi éffekt atsetilkholina i GAMK na aktivnyi zakhvat kaliia srezami kory golovnogo mozga krys.

Whole-body X irradiation (0.155 and 0.310 C/kg) was shown to modify the biphase effect of acetylcholine and GABA on antigradient K+ uptake by rat brain sections. Radiation made the effects of neuromediators on active K+ transport be differently directed: acetylcholine enhanced the inhibitory effect of radiation and GABA restored the Na-K-pump function.

Dosimetric properties of europium-doped potassium bromide thermoluminescent crystals.

The dosimetric thermoluminescent properties of potassium bromide crystals doped with europium have been investigated. Nominal concentrations of europium ions varied between 0.01% and 1%. The crystals were annealed prior to irradiation following different thermal treatments. We report the glow curve and dose-response characteristics to 60Co gamma rays. After a particular annealing, the crystals showed a strong thermoluminescent peak near 100 degrees C and a linear response for doses between 0.03 cGy and 10 cGy. The sensitivity is approximately 10 times that of lithium fluoride (TLD-100).

SO.(4-)-induced oxidation of 1,3,6-trimethyluracil and 1,3,5-trimethyluracil (1,3-dimethylthymine) by potassium peroxodisulphate in aqueous solution: an interesting contrast.

In order to mimic the direct effect of ionizing radiation on DNA, deoxygenated aqueous solutions of potassium peroxodisulphate, tert-butanol and 1,3,6-trimethyluracil (1,3,6-Me3 U) or 1,3-dimethylthymine (1,3-Me2 T) were irradiated with 60Co gamma rays; the sulphate radical formed by the reaction of the solvated electron with peroxodisulphate oxidizes these pyrimidines. In the case of 1,3,6-Me3 U, a chain reaction results in the formation of sulphuric acid, the glycols (two thirds) and 1,3,6-trimethylisobarbituric acid (one third). Typically, at 5 x 10(-4) mol dm-3 1,3,6-Me3 U, 4 x 10(-2) mol dm-3 S2O8(2-) and 10(-2) mol dm-3 tert-BuOH with a dose-rate of 2.2 x 10(-3) Gy s-1, G(H+) is 220 x 10(-7) mol J-1. We believe that the sulphate radical adds to the 1,3,6-Me3 U and the adduct rapidly loses the sulphate dianion, giving rise to the 1,3,6-Me3 U radical cation. This reacts with water, yielding a proton and the reducing 1,3,6-Me3U C(5)-OH,C(6)-yl radical, which reacts with peroxodisulphate and so propagates the chain. In this oxidation process a carbocation is formed which can either react with water yielding the glycols, or deprotonate yielding the 1,3,6-trimethylisobarbituric acid. The 1,3-Me2 T system behaves differently. No chain reaction of any significance is induced. In the presence of oxygen an allyl-type radical can be trapped, as shown by the subsequent formation of 1,3-dimethyl-5-formyluracil (G = 2.1 x 10(-7) mol J-1) and 1,3-dimethyl-5-hydroxymethyluracil (G = 0.2 x 10(-7) mol J-1). As the corresponding products are not observed in the 1,3,6-Me3 U system, it is concluded that in contrast to the 1,3,6-Me3 U radical cation, the 1,3-Me2 T radical cation efficiently deprotonates (at C5-methyl), apart from also being able to react with water. In basic solution, OH- adds to the 1,3-Me2 T radical cation, thereby suppressing the formation of the allyl-type radical. Quantum-chemical model calculations on uracil, thymine and 6-methyluracil show why 1,3-Me2 T and 1,3,6-Me3 U should differ in their behaviour.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of ultraviolet irradiation on calcium, sodium and potassium levels in albino rats]. / Vliianie ul'trafioletovogo oblucheniia na soderzhanie kal'tsiia, natriia i kaliia v organizme belykh krys.

Data presented by the authors testifies to the fact that neither 2 weeks, nor one month after the 10-day course of ultraviolet irradiation (UVR) with an intensity from 1/4 up to 2 biodoses daily changes in calcium, sodium and potassium content in blood serum of laboratory animals (white rats) were detected. At the same time, 2 weeks following the cessation of UVR course a tendency towards calcium accumulation in the whole organism of laboratory animals was observed, which was most noticeable+ after daily 10-day exposure to UVR with an intensity from 1/2 up to 1 biodose. The tendency was still present one month following the termination of UVR course. The total sodium and potassium store in the whole organism of laboratory animals did not practically change either immediately, or 2 weeks, or 1 month after the termination of 10-day UVR course with the intensity from 1/4 to 2 biodoses daily.