Evaluation of chest motion and volumetry during the breathing cycle by dynamic MRI in healthy subjects: comparison with pulmonary function tests

RATIONALE AND OBJECTIVES: To investigate diaphragm and chest wall motion during the whole breathing cycle using magnetic resonance imaging (MRI) and a volumetric model in correlation with spirometry. MATERIALS AND METHODS: Breathing cycles of 15 healthy volunteers were examined using a trueFISP sequence (5 slices in 3 planes, 3 images per second). Time-distance curves were calculated and correlated to spirometry. A model for vital capacity (VC), continuous time-dependent vital capacity (tVC), and investigating the influence of horizontal and vertical parameters on tVC was introduced. RESULTS: Time-distance curves of the breathing cycle using MRI correlated highly significant with spirometry (P < 0.0001). VC calculated by the model was similar to VC measured in spirometry (5.00 L vs. 5.15 L). tVC correlated highly significantly with spirometry (P < 0.0001). Vertical parameters had a more profound influence on tVC change than horizontal parameters. CONCLUSIONS: Dynamic MRI is a simple noninvasive method to evaluate local chest wall motion and respiratory mechanics. It widens the repertoire of tools for lung examination with a high temporal resolution.     

Dynamic magnetic resonance tomography and proton magnetic resonance spectroscopy of prostate cancers in rats treated by radiotherapy

RATIONALE AND OBJECTIVES: To establish an experimental setting for monitoring perfusion and metabolism in orthotopic prostate cancer at 1.5 T using dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and 1H-MR spectroscopy (MRS). METHODS: Dunning rat prostate cancer cells were injected into the prostate by open surgery. Twelve tumor-bearing rats (5 of these irradiated) and 6 healthy controls were followed up using gadolinium-diethylenetriaminepentaacetic acid -enhanced dynamic MRI and 1H-MRS. Amplitude and the exchange rate constant kep were calculated (2-compartment model). From 1H-MR spectra, ratios of choline (Cho) and creatine (tCr) were calculated. All tumors were examined histologically. RESULTS: On DCE MRI parameter maps, tumors showed increased vascularization. kep and microvessel density were correlated (r = 0.97). Tumors showed elevated Cho/tCr and an unexpected lipid fraction (2.0-2.2 parts per million). Irradiation slowed tumor growth significantly. Changes of perfusion and metabolism could be detected in all tumors during follow up. CONCLUSION: DCE MRI and 1H-MRS has potential to characterize orthotopic Dunning prostate cancer in rats, which is a promising model similar to human prostate carcinomas.     

Th2 cells shape the differentiation of developing T cell responses during interactions with dendritic cells in vivo

During priming, naive CD4(+) Th cells differentiate into cells that produce either IFN-gamma or IL-4. Even though the cascade of pathways that induces IL-4-producing Th2 cells has been determined in vitro, the signals promoting Th2 differentiation under physiological conditions remain enigmatic, especially the natural role of the single most important Th2-inducing signal,IL-4. Using Th2 and naive Th cells, each expressing a distinct transgenic TCR, here we show that Th2 cells migrate with the same dynamics as naive Th cells in draining lymph nodes and bind to the same DC, when driven by antigen in complete Freund's adjuvant (CFA). Th2-cell-derived IL-4 deviates CFA-induced Th1 development toward a Th2 phenotype, if both cell populations co-localize in the same T cell area, and are activated simultaneously. Thus, intranodal Th2 cells directly influence Th cell differentiation in vivo, but only under restricted conditions. These findings have implications for the design of cytokine-based therapies and explain the spreading of Th2 responses to multiple aeroallergens in allergic asthma, where naive Th and Th2 cells co-localize in lung-draining lymph nodes.     

Transcutaneous bilirubinometry in preterm infants

The aim of this study was to evaluate the accuracy and safety of transcutaneous bilirubinometry in preterm infants using the new bilirubin analyser BiliCheck^±. The study included 145 preterm children (23–36 wk gestation). Capillary blood sampling for determination of serum bilirubin (BS) was combined with transcutaneous bilirubin measurement (BTc) every morning until the sixth postnatal day and related to several clinical data (phototherapy (PT), infection signs, breathing disturbances, skin bleeding, etc.). Overall bilirubin concentration ranged from 17 to 371 μmol/l, and from 21 to 325 μmol/l for BS and BTc, respectively. Mean values obtained by BTc were significantly higher than BS values. The correlation coefficient between BS and BTc was r= 0.64 for the whole group, and r= 0.73 in infants without PT. As demonstrated by multiple regression analysis, BS‐BTc correlations were related only to gestational age (beta ‐0.32) and breathing disturbances (beta 0.29), indicating that the lower the gestational age and the more seriously ill the baby, the higher the incoherence between BS and BTc. Conclusion: BiliCheck^±provides a convenient, non‐invasive possibility for bilirubin estimation in preterm infants. However, there are limitations: the method gives reliable results only in newborns older than 30 wk gestation, without PT and artificial ventilation.     

Effect of thrombophilic factors on thromboembolism and other pregnancy complications

Pulmonary embolism and/or deep vein thrombosis are a major cause of maternal mortality. In a number of adverse pregnancy outcome including preeclampsia, recurrent spontaneous abortion, restricted fetal growth and fetal death a role for thrombophilia (acquired and hereditable) has been postulated. Monitoring of acquired factors such as antiphospholipid-antibodies and hereditable factors (factor V Leiden, prothrombin mutation) may help predict the occurrence of pregnancy complications. Low molecular weight heparins (LMWH), since their introduction well established during pregnancy, and the rate of adverse fetal outcomes are related to co-morbidity maternal conditions rather than to the treatment itself. The use of LMWH is recommended for all moderate risk and high-risk pregnant patients.     

Necrotizing enterocolitis in a married couple due to a staphylococcal toxin

A married couple affected by necrotizing enterocolitis is described. Both had the same toxin-producing Staphylococcus aureus which was considered to be responsible for the necrotizing enterocolitis.     

A mathematical model for the description of oxygen-diffusion in the intervillous space of the human placenta (author's transl)

The oxygen consumption has a central place in the complicated interaction between diminished oxygen supply and degenerative trophoblastic tissue change. In the present investigation, that serves as a mathematical model, the problem of the diffusion equation for the constant state is discussed and solved. It is shown that the diminishing of length of the radius of the maternal blood compartment has the same meaning as the decrease in the flow velocity. The influence of the mass transfer coefficient h on the oxygen partial pressure and on the oxygen transfer is investigated. The influence of parameter variations on the placental alterations during toxemia is discussed and their clinical importance is obvious. Our theoretical model elusidates the value of an early therapeutical approach in the case of toxemia.     

Radical scavenger activity of phenylethanoid glycosides in FMLP stimulated human polymorphonuclear leukocytes: structure-activity relationships

Radical scavenger activities of 21 phenylethanoid glycosides, including 15 ester derivatives of caffeic, ferulic, vanillic and syringic acid as well as 6 deacyl derivatives were determined by quantifying their effects on the production of reactive oxygen species (ROS) in a luminol-enhanced chemiluminescence assay with formyl-methionyl-leucyl-phenylalanine (FMLP) stimulated human polymorphonuclear neutrophils (PMNs). All phenylethanoids acylated with phenolic acids showed strong antioxidant activity whereas the deacyl derivatives were more than 30-fold less active. Therefore, the antioxidant activity is mainly related to the number of aromatic methoxy and hydroxy groups and the structure of the acyl moiety (C6-C1 or C6-C3). In contrast, modification of the sugar chain or replacement of hydroxy groups by methoxy groups in the acyl or the phenylethanoid moiety is of minor importance. The position of the acyl moiety is without significance. Free caffeic, ferulic, vanillic and syringic acid are less active compared to the phenylethanoid derivatives. This points to the importance of dissociation and lipophilicity of these acids in a cellular test system.     

Retention of hyaluronic acid in alginate beads: aspects for in vitro cartilage engineering.

Alginate has been used successfully for three-dimensional chondrocyte cultures and may be important for cartilage transplant formation. However, alginate is not a natural component of the cartilage matrix. The aim of this study was (a) to supplement alginate with the extracellular matrix component hyaluronic acid; and (b) to analyze the hyaluronic acid retention in different alginate gels. Hyaluronan is assumed to improve proteoglycan retention and may be important for in vitro matrix formation, tissue turgor, and biomechanical quality. Alginate and hyaluronan were mixed with chondrocytes and polymerized as were alginate, hyaluronan, and fibrinogen. [3H]hyaluronan was used to quantitate the leakage of hyaluronan from the gel beads. After 28 days in culture, 1.2% alginate beads supplemented with 0.26% hyaluronan contained only 9% of the initial amount of hyaluronan whereas 2.4% alginate beads still contained about 55% of the initial 0.22% hyaluronan. Release of hyaluronan from the beads was significantly lower if the beads additionally contained fibrin. Alginate beads supplemented with hyaluronan or fibrin showed increased chondrocyte proliferation compared to controls. Supplemented hyaluronan greatly diffuses out of alginate gels of lower densities. It must be assumed also that most of the hyaluronan newly synthesized by chondrocytes in these cells diffuses into the surrounding culture medium. The in vitro development of a sufficiently hygroscopic cartilage ground substance therefore may be very limited. Sufficient hyaluronic acid retention can be achieved in alginate gels with concentrations above 1.2% or by addition of fibrin.     

Intragastric formation of ammonia in Campylobacter pylori associated gastritis. Diagnostic and pathogenetic significance

The diagnostic relevance of measurement of ammonia (NH3) in not stimulated gastric juice in patients with campylobacter pylori associated gastritis (CPAG) is in discussion. The role of CP-urease induced NH3 in pathogenesis of active gastritis is unclear. In answering to this questions we evaluated the sensitivity and specifity of NH3-test and CLO-test in cases of CPAG (n = 50), non CPAG (n = 16) and normal gastric mucosa (n = 20). We found a 88% sensitivity and a 86% specifity for NH3-test, a sensitivity for CLO-test of 80% and a specifity rate of 87%. NH3-test correlated well with CLO-test (n = 51, p less than 0.01) and semiquantitative histological identification of CP (p less than 0.01, n = 22). On the other hand we tried to correlate the amount of NH3 in the gastric juice and the histological degree of gastritis activity (infiltration of leucocytes of the lamia propria) in CPAG (n = 78) and Non-CPAG (n = 32) and before and after therapy in CPAG (n = 9) with bismuthsubnitrate (2 g/d, 14 d). There was no correlation between the amount of NH3 and the degree of active chronic gastritis in patients with CPAG (with or without therapy) and patients with non CPAG. It seems that NH3 has a diagnostic but no pathogenetic role in the process of inflammatory activity of CPAG.