[Digital radiography: from storage phosphor plates to direct detector systems]

All three currently commercially available systems for digital radiography of the chest such as the selenium drum, storage phosphor plates and the flat panel direct detector systems provide an excellent image quality that is at least equivalent or superior to that of conventional film. Reasons for that are the continuously improved detective or dose efficiency of the detector systems and an improved image processing. The new direct detector systems have the largest potential for dose reduction while storage phosphor and selenium radiographs are usually obtained with a dose comparable to that of a 400 speed system. Improved image processing algorithms allow for the production of digital images that are adapted to the conventional image characteristics within the lung regions combined with an increased transparency of the high absorption areas such as the retrocardial and retrodiaphragmatic regions.

[The limping child. Differential radiologic diagnosis of acute gait disorder in childhood and adolescence]

Limping is a common and often challenging problem in children and adolescents. A limp is defined as asymetric deviation from a normal gait pattern. A systematic approach is necessary to determine the cause of the limp, so the radiologist should combine a thorough history, clinical information and pertinent radiologic testing. The possible differential diagnosis is extensive and includes many pathologies of the lower extremity and spine like trauma, infection, neoplasia, furthermore inflammatory, developmental and congenital disorders. In cases with knee or tight pain, an underlying hip condition should be considered. The childs age can narrow the possible differential diagnoses, because certain entities are age-related. Despite this wide bandwidth of entities, potential catastrophic causes like septic arthritis and malignant disease should be excluded first. Plain radiographs are often diagnostic. The choice of further imaging modalities like ultrasonography, magnetic resonance imaging, computed tomography and bone scan should be guided by the history and clinical findings.

Automated library generation using sequential microwave-assisted chemistry. Application toward the Biginelli multicomponent condensation

The concept of automated sequential microwave-assisted library synthesis is introduced. For this purpose a dedicated single-mode microwave reactor with a robotics interface including a liquid handler and gripper was employed. The liquid handler allows dispensing of reagents into the Teflon sealed reaction vials, while the gripper moves each sealed vial in and out of the microwave cavity after irradiation. This technology was employed for the Biginelli three-component cyclocondensation reaction. A diverse set of 17 CH-acidic-carbonyl compounds (1A-Q), 25 aldehydes (2a-y), and 8 urea/thioureas (3alpha-varphi) was used in the preparation of a dihydropyrimidine (DHPM) library. Out of the full set of 3400 possible DHPM derivatives, a representative subset of 48 analogues was prepared using automated addition of building blocks and subsequent sequential microwave irradiation of each process vial. For most building block combinations 10 min of microwave flash heating at 120 degrees C using AcOH/EtOH (3:1) and 10 mol % Yb(OTf)(3) as solvent/catalyst system proved to be successful, leading to an average isolated yield of 52% of DHPMs with >90% purity. For some building block combinations the general conditions were modified, for example, by changing the solvent, catalyst, reaction temperature, or irradiation time. This flexibility is a distinct advantage of sequential over parallel microwave-assisted processes where all reactions are exposed to the same irradiation conditions. When the unattended automation capabilities of the microwave synthesizer are used, a library of this size can be synthesized within 12 h.

Videofluoroscopy of swallowing in symptomatic patients who have undergone long-term intubation

OBJECTIVE

The aim of this study was to evaluate whether specific patterns of swallowing dysfunction occur in symptomatic patients after long-term intubation.

SUBJECTS AND METHODS

Twenty-one patients (16 men, five women; mean age, 66 years) who presented with clinical signs of aspiration after long-term intubation (mean duration, 24.6 days) underwent videofluoroscopy. They were analyzed for functional abnormalities of the tongue, soft palate, epiglottis, hyoid and larynx, pharynx, and the upper esophageal sphincter. We assessed the presence or absence of aspiration, the type of aspiration (pre-, intra-, and postdeglutitive), and a spectrum of other swallowing abnormalities.

RESULTS

There were 18 patients (86%) with radiologically proven aspiration. In another patient only laryngeal penetration occurred. There were 11 combinations of pre-, intra-, and postdeglutitive aspiration. Predeglutitive aspiration was predominant and present in 52% of our patients. We found functional abnormalities of the tongue in 48%, of the soft palate in 10%, of the epiglottis in 48%, of the pharynx in 71%, and of the upper esophageal sphincter in 24%.

CONCLUSION

Patients who are symptomatic after undergoing long-term intubation do not develop a specific type or pattern of swallowing dysfunction or aspiration, but show a large variety of aspiration types and associated swallowing disorders. Nevertheless, videofluoroscopy has the ability to reveal complex deglutition disorders and to aid precise planning of individualized functional swallowing therapy.

[Staging of breast carcinoma. Value of diagnostic imaging]

In women with breast cancer, staging of the tumor plays an important role and often is considered to be the most prognostic and therapeutic factor. The most widely used staging system is based on the pathologic TNM classification. In recent years conservative therapies such as preoperative chemo- or radiotherapy are used more often with limited tissue evaluation resulting in insufficient or even inaccurate staging data. Tumor size as well as nodal involvement is decisive in selecting a treatment method and assessing the response. Thus, more accurate preoperative in vivo staging is necessary. This article therefore gives an overview of the different imaging modalities (mammography, ultrasonography, magnetic resonance imaging, and nuclear medicine) used for breast cancer staging. Furthermore, results of these methods are compared critically with the pathohistologic staging.

Prenatal immune priming in onchocerciasis-onchocerca volvulus-specific cellular responsiveness and cytokine production in newborns from infected mothers

This study investigated the effect of maternal Onchocerca volvulus infection on humoral and cellular responsiveness in newborn children and their mothers. Onchocerca volvulus-specific IgG isotypes and IgE were significantly elevated in infected mothers and their infants. One year post partum, O. volvulus-specific IgG4 was strongly reduced in children of infected mothers, while IgG1 responses weakened only slightly. Umbilical cord mononuclear blood cells (UCBC) and peripheral blood cells (PBMC) from mothers proliferated in response to phytohaemagglutinin (PHA), concanavalin A (Con A), and the bacterial antigens streptolysin-O (SL-O) or purified protein derivative (PPD). UCBC from neonates born to O. volvulus-infected mothers responded lower (P < 0.01) to Con A (at 5 micrograms/ml), PPD (at 10 and 50 micrograms/ml) and O. volvulus-derived antigens (OvAg) (at 35 micrograms/ml), and in parallel, a diminished cellular reactivity (P < 0.01) by PBMC was observed to OvAg in mothers positive for O. volvulus. Several Th1-type (IL-2, IL-12, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha)) and Th2-type (IL-4, IL-5, IL-10, IL-13) cytokines were secreted by UCBC and PBMC in response to OvAg, bacterial SL-O and PHA. OvAg did not stimulate IL-2 and none of the mitogens or antigens induced production of IL-4 in neonates. In response to OvAg, substantially elevated (P < 0.01) amounts of IFN-gamma were produced by UCBC from newborns of O. volvulus-infected mothers. UCBC secreted low levels of IL-5 and IL-13, while higher amounts of IL-10 were found (P < 0. 01) in newborns from onchocerciasis-free mothers. In conclusion, maternal O. volvulus-infection will sensitize in utero parasite-specific cellular immune responsiveness in neonates and activate OvAg-specific production of several Th1- and Th2-type cytokines.

Regulatory effects of Th1-type (IFN-gamma, IL-12) and Th2-type cytokines (IL-10, IL-13) on parasite-specific cellular responsiveness in Onchocerca volvulus-infected humans and exposed endemic controls

The present study investigated in vitro the regulatory effects of T helper 1 (Th1)-type (interferon-gamma, IFN-gamma; interleukin-12, IL-12) and Th2-type cytokines (IL-10, IL-13) on Onchocerca volvulus-specific cellular reactivity in onchocerciasis patients, and in exposed endemic control individuals presenting no clinical and parasitological signs of disease. In both patients and controls, addition of IL-10 dose-dependently depressed O. volvulus antigen (OvAg)-specific cellular proliferation, and peripheral blood mononuclear cells (PBMC) from patients who were more sensitive to the suppressive effect of IL-10 than those from endemic controls. However, neutralization of IL-10 by specific antibody did not reverse cellular hyporesponsiveness. In contrast to the inhibitory effects of IL-10, exogenous IL-12 and IL-13 augmented PBMC proliferative responses to OvAg both in patients and controls (P<0. 01) and neutralizing of IL-12 or IL-13 significantly decreased OvAg-specific proliferation in both groups. Exogenous IFN-gamma did not activate OvAg-specific proliferative responses in patients, but anti-IFN-gamma antibodies abolished cellular reactivity to OvAg. Antibody to IL-10 increased (P<0.05) OvAg-specific production of IL-5, IL-12 and IFN-gamma, and inversely, anti-IFN-gamma enhanced IL-10 (in patients only) and IL-5 and IL-13 in both patients and controls. Neutralization of IL-12 activated OvAg-specific production of IL-10, IL-2 and IFN-gamma. In conclusion, despite of an overproduction of IL-10, which suppressed cellular reactivity in patients and control individuals, OvAg-specific cellular responses were activated in vitro by exogenous supplementation with IL-12 and IL-13, and cytokine neutralization experiments confirmed that distinct type 1 and type 2 T helper cytokines cross-regulate expression and magnitude of O. volvulus-specific cellular responsiveness in humans.

Removal of non-transferrin-bound iron from blood with iron overload using a device with immobilized desferrioxamine

An extracorporeal hollow-fiber device with immobilized desferrioxamine (DFO) was developed for the removal of nontransferrin-bound iron (NTBI) from blood, without the toxicity of parenteral chelation. When blood circulates through the fibers having pores with 30 kD cut-off, non-transferrin-bound-iron (NTBI) crosses the fiber pores and is chelated by the immobilized desferrioxamine. Removal of circulating iron stimulates iron release from larger proteins and tissue stores, establishing continuous iron flow to the immobilized chelator. During in vitro circulation through a device, iron removed from blood of hemodialysis or sickle cell patients was proportional to, but always in less than 50% of the initial iron level. We attribute the inability to remove more serum iron to irreversible iron binding by transferrin. To investigate where removable and fixed iron was bound, iron binding proteins were analyzed in sera from six patients with genetic anemias and iron overload. Sera separated by sieving chromatography contained 1-14% of the iron in the < 30 kD protein pool, 26-48% was in the combined non-transferrin pools. Sera from hemochromatosis patients without iron overload did not contain NTBI. Circulation of hemochromatosis blood through the device removed one third of the iron, this came from all molecular weight fractions. Iron removal by the device from the < 30 kD pool appears to establish a disequilibrium, that stimulates continuous iron release from ligands with low iron affinity, renewing the pool in the < 30 kD range, which includes potentially toxic NTBI. Therapy with the chelator device having immobilized desferrioxamine should be beneficial for treatment of patients with iron overload.

Myocardial release of non-transferrin-bound iron during cardio-pulmonary bypass surgery

Myocardium reperfusion following coronary artery bypass grafting (CABG) may result in "reperfusion injury" by free radical generations. Since desferrioxamine administration attenuates this syndrome, non-transferrin-bound-iron (NTBI) released into the perfusing medium during CABG was implicated as a catalyst for oxygen radical formation. From 13 patients with "redo" CABG, specimens were collected from the coronary sinus (influx) and the aortic vent (efflux) after each distal coronary anastomosis. Specimens were subjected to sieving chromatography, and fractions were analyzed for total iron and NTBI using atomic absorption spectrometry (AAS). A statistically significant increase in NTBI was measured in influx (p = 0.002) and efflux samples (p = 0.023) collected after each graft. The combined amount of NTBI measured in these specimen was proportional to the CK-MB increase measured in the patients' sera on the day of surgery and the subsequent day. NTBI which accumulated in the circulatory bypass fluid during CABG may catalyze the generation of free radicals in the myocardium when body temperature is restored. This may aggravate myocardial damage as reflected by a post-surgical increase in CK-MB concentrations. Studies are in progress to develop new methods for the removal of NTBI during cardiac surgery. Tissue injury occurs with reperfusion during ischemia. This has been attributed to oxygen-derived free radicals that are generated by substances released from hypoxic areas (Kloner, Przyklenk et al., 1989; McCord, 1998). Reperfusion injury, i.e. the "reperfusion syndrome," occurs after coronary artery bypass grafting (CABG) when the ischemic myocardium is again provided with a supply of blood. Its most serious manifestations are arrhythmia and myocardial stunning (Ar"Rajab, Dawidson et al., 1996; Ferrari, Ceconi et al, 1996). The role of iron in reperfusion injury has been implicated by indirect evidence: during the reperfusion syndrome, the binding of iron with the chelator desferrioxamine (Ambrosio, Zweier et al., 1987; Bel, Martinod et al., 1996), or the administration of exogenous apo-transferrin, improved cardiac contractility and delayed manifestations of cardiac injury (Tiede, Sareen et al., 1990). Iron, as a transition metal, is able to catalyze free radical formation when released into the circulation from endogenous stores as non-transferrin-bound-iron (NTBI). This iron may be bound to small proteins or inorganic ligands (Halliwell and Gutteridge, 1984; Pollock and Campana, 1980; Zweier, 1992). A method for the measurement of NTBI was recently developed (Ambrus, Stadler et al., 1999). The purpose of this study was to explore whether a correlation exists among (a) the amount of NTBI released during CABG surgery, (b) the length of time of myocardial ischemia, and (c) the myocardial damage that occurs during cardiopulmonary bypass.

The diverse expression of immunity in humans at distinct states of Onchocerca volvulus infection

This study examined the development and persistence of immunity in humans presenting defined states of Onchocerca volvulus infection, i.e. in exposed endemic control individuals without microfilaridermia and clinical disease, in patients with patent or post-patent onchocerciasis, and in patients concurrently infected with Mansonella perstans. Onchocerca volvulus antigen (OvAg)-specific cellular reactivity was significantly diminished in microfilariae (mf)-positive patients, while the highest reactivity was measured in exposed but mf-negative endemic controls, those being free of any clinical signs of onchocercal disease. In patients who became post-patent, responses to OvAg were significantly augmented, but did not approach entirely the magnitude observed in endemic controls. In onchocerciasis patients with concurrent mansonelliasis, cellular unresponsiveness to OvAg persisted, even when mf of O. volvulus were eliminated permanently by repeated ivermectin therapy. Cells from mf-positive onchocerciasis patients produced significantly less interferon-gamma (IFN-gamma) (P < 0.01) and interleukin-5 (IL-5) (P < 0.05) in response to OvAg than those taken from endemic controls or post-patent individuals in whom IFN-gamma and IL-5 production was similarly high. In contrast, both OvAg-driven as well as spontaneous IL-10 secretion was higher in mf-positive patients than in endemic controls or post-patent cases. In all individuals examined, serological recognition of OvAg by immunoglobulins was dominated by IgG4; in mf-positive patients OvAg of 205,000-12,000 molecular weight (MW) were strongly bound. In post-patent individuals, and similarly in endemic controls. OvAg recognition by IgG4 varied from intense (with numerous antigens being recognized) to weak or absent antigen binding. Significantly elevated OvAg-specific IgG isotypes were measured in mf-positive onchocerciasis patients in comparison with endemic controls or post-patent individuals (with the exception of IgG3). IgG1, IgG2 and IgE were higher, but IgG4 was lower in endemic controls compared with post-patent onchocerciasis patients. The ratios of IgG4/IgG1 differed (P < 0.001) between endemic controls and mf-positive or post-patent onchocerciasis patients, with IgG4/IgG1 ratios of R < 3.0 being characteristic for endemic controls and post-patent O. volvulus infection. In conclusion, this cross-sectional immunoepidemiological investigation showed that distinct states of O. volvulus infection correlate with a particular cellular and humoral immune response. The mf-free condition appeared to be associated with a vigorous parasite-specific cellular reactivity and a particular cytokine production profile, while concurrent M. perstans infection depressed OvAg-specific cellular responsiveness. Antibody responses, in all likelihood, reflected the intensity and state of infection, and not the degree of acquired immunity protective against parasite aggregation.

Salmonella enteritidis colonization in turkey poults

An experimental trial on the colonization of two Salmonella enteritidis strains (phage types 4 and 8) originating from meat turkey flocks, were carried out. Three-day old poults were inoculated orally with approximately 10(6) cfu/bird (one group with PT8 and the other with PT4). clinical signs were not observed in any of the groups. The total reisolation rates from cloacal swabs in birds inoculated with PT4 was higher than from birds inoculated with PT8. The inoculated strains could also be detected in contact birds. Examination of internal organs 21 days p.i. revealed higher isolation rates in the group infected with PT4 than with PT8. The results indicate that both phage types of S. enteritidis were able to colonize the intestinal tract and the internal organs of turkey poults. However, the colonization and duration of shedding differed between the two phage types. This may be due to the fact that PT8 strain used was free from the S. e. virulence plasmid 37 MDa.

Surveillance on Salmonella in turkey flocks and processing plants

The present investigation was carried out to investigate the occurrence and distribution of Salmonella infection on all stages of turkey production. Therefore, samples from turkey parent flocks, hatchery, meat turkey flocks, turkey feed and finally from the surveillanced flocks at different steps in processing plant were examined. Salmonella was isolated from 4 out of 6 turkey parent flocks (66.7%), but none of the examined 485 samples from the hatchery revealed positive Salmonella results. Eight out of 24 monitored meat turkey flocks were free from Salmonella during the entire rearing period (33.3%); seven flocks (29.2%) appeared to be infected with only one serovar and in another 9 flocks (37.5%) two or more different serovars were isolated during the rearing period, in some cases at the same time. In 20 out of 506 examined feed samples Salmonella was isolated (3.95%). During processing, bacteriological investigations on the presence of Salmonella were carried out on the monitored flocks at different processing steps. Cross contamination seems to be very common during processing and even in several flocks contamination appeared to have started already during transport.

Treatment of aluminum overload using a cartridge with immobilized desferrioxamine

Intravenous desferrioxamine (DFO) is the method commonly used to treat aluminum toxicity. This laboratory has developed a hollow fiber device with immobilized DFO, an "Aluminum DFO-HP" (DFO-HP), for the purpose of removing aluminum without the chelator (DFO) entering the blood. With Food and Drug Administration approval, a polysulfone DFO-HP, placed in the extracorporeal circuit in series with the patient's customary dialyzer, was tested for its safety and ability to remove aluminum in patients with ESRD who had aluminum overload. During treatment with this device, no toxic reactions, side effects, or hematologic or clinical laboratory changes were seen other than those associated with dialysis. Average aluminum clearance with the DFO-HP device was 25.3 mL/min with a range of 7.2 to 52.4 mL/min, whereas aluminum clearance with the F-60 polysulfone high-flux dialyzer was 8.4 mL/min. Aluminum clearance of the cuprophane dialyzers in series with the DFO-HP was negligible. The amount of aluminum removed over a 2-h treatment with DFO-HP ranged from 94 to 628 micrograms, which corresponded to 32 to 199% of the initial aluminum in the circulation before that particular treatment. The excess 99% was provided from aluminum released from tissue sites into the circulation throughout the duration of the treatment. It is expected that, because of the efficiency and safety of the DFO-HP device, the time presently needed for aluminum depletion using intravenous DFO will be greatly shortened and the potential toxicity of intravenous DFO will be eliminated.

Mechanical fragility of erythrocyte membrane in neonates and adults

The shortened life span of neonatal red blood cells (RBC) is associated with accelerated membrane loss. The present study was designed to measure the critical shear force that causes membrane failure and the rate of membrane failure for neonatal and adult RBC. A micropipette technique was used to determine the membrane extensional (shear) elastic modulus (i.e. resistance of the membrane to extensional elastic deformation), the rate of extensional membrane deformation (i.e. surface viscosity), and the tension for local membrane fragmentation. A flow channel system was used to determine the critical shear force of plastic membrane deformation (i.e. beginning of membrane tether formation), the rate of plastic deformation, and the plastic shear viscosity coefficient. The extensional elastic modulus of neonatal RBC was 18% smaller and the rate of elastic deformation was 25% longer compared with adult cells (p less than 0.05). Membrane surface viscosity was similar for both cell types. The tension for local membrane fragmentation in the micropipette was 23% lower in neonates than in adults. However, the strain (i.e. extent of membrane deformation calculated as ratio of the stress resultant and the elastic modulus) at which membrane rupture in the micropipette occurred was similar for neonatal and adult RBC. This indicates that the smaller critical tension for neonatal RBC membrane failure was due to increased membrane elastic deformability.(ABSTRACT TRUNCATED AT 250 WORDS)