Pontine veins. MRI cross-sectional anatomy

Summary The pons is covered by a rich venous network offering numerous vascular landmarks in MRI and during surgery. We present an original study of the veins as they appear on MR multiplanar scans after gadolinium IV injection. This prospective study is based on 40 consecutive patients with normal posterior fossa structures. One of the major venous collectors follows the pons: the superior petrosal v. was identified on MRI in 95% of our cases. Its hooklike extremity drains into the superior petrosal sinus. The inferior petrosal v. was never identifiable. The superficial pontine venous network are identified in 72.5% of cases in the axial plane and were organised in longitudinal and transverse collectors, whose MR aspects are presented here.

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Les veines du pont. Anatomie sectionnelle en IRM

Résumé Le pont, enveloppé des citernes subarachnoïdiennes, est parcouru à sa surface par de nombreux vaisseaux qui constituent autant de points de repère topographiques en IRM que de rapports chirurgicaux. Nous présentons une étude de l'anatomie veineuse en coupe telle que l'IRM la révèle après injection de Gadolinium. Cette étude prospective comporte 40 patients indemmes de lésion de la fosse crânienne postérieure. Le pont est longé par un des collecteurs majeurs du tronc cérébral : la v. pétreuse supérieure, identifiée dans 95 % des cas. Elle se jette par un crochet caractéristique dans le sinus pétreux supérieur. La v. pétreuse inférieure n'a jamais été reconnue. Les vv. pontiques forment un réseau maillé visible dans 72,5 % des cas en coupes axiales et comportant des axes transversaux et longitudinaux dont les critères d'identification sont présentés selon le plan de coupe.

     

Interleukin 1 inhibitory activity secreted by a human myelomonocytic cell line (M20)

Culture supernatants from a myelomonocytic cell line (M20) were found to inhibit interleukin 1 (IL 1) activity in vitro. The factor, isolated from these supernatants, inhibited augmentation of phytohemagglutinin response of mouse thymus cells induced by IL 1 derived from several established cell lines. Various IL 1-dependent activities such as lymphocyte and fibroblast proliferation in vitro were also inhibited by the factor. The factor did not inhibit IL 2-induced or other proliferative responses not related to IL 1. Preliminary biochemical characterization of the factor indicated that the activity resides in a protein with a molecular mass of 52 kDa.     

Wertigkeit moderner Verfahren zur Lokalisation von Phäochromocytomen

Zusammenfassung Bei sechs Patienten mit adrenalem Phäochromocytom erfolgte die Lokalisationsdiagnostik durch Ultraschalluntersuchung, Phlebographie der Nebennieren und selektiver Katecholaminbestimmung im Blut der Vena cava sowie der Nebennierenvenen. Durch die selektive Katecholaminbestimmung konnten alle Phäochromocytome lokalisiert werden, durch die Ultraschalluntersuchung fünf, durch die Phlebographie vier. Ein Phäochromocytom von 1,5 g Gewicht, das nur durch die selektive Katecholaminbe-stimmung, nicht aber durch Ultraschall oder Phlebographie lokalisiert wurde, konnte computertomographisch dargestellt werden.Um Fehldiagnosen bei der selektiven Katecholaminbestimmung zu vermeiden, darf vor der Blutentnahme aus den Nebennierenvenen kein Röntgenkontrastmittel injiziert werden, da dies zu einer erheblichen Adrenalin- oder Noradrenalinfreisetzung aus dem Nebennierenmark führen kann.     

Multilocus haplotype analyses reveal association between 5 novel IL-15 polymorphisms and asthma

BACKGROUND: IL-15 is a T(H)1-related cytokine that is involved in the inflammatory response in various infectious and autoimmune diseases. IL-15 has recently been shown to be upregulated in T-cell-mediated inflammatory disorders. The observations suggest a potential role for this cytokine in a variety of pathologic conditions, including T(H)1-mediated and T(H)2-mediated inflammatory diseases. OBJECTIVE: In this study, we searched for single nucleotide polymorphisms in the whole IL-15 gene and investigated their association with inflammatory and/or atopic phenotypes. METHODS: The screening for single nucleotide polymorphisms was performed by single-strand conformation polymorphism analysis. Genotyping of the identified polymorphisms was performed by restriction fragment length polymorphism. Genotypic association analysis used the Armitage trend test. Haplotype frequency estimation and subsequent testing for differences between cases and controls were performed by using the programs FASTEHPLUS and FAMHAP. RESULTS: We identified 5 novel noncoding nucleotide sequence variants, all of which were typed in our asthmatic, our atopic, and our control population. According to the Armitage trend test, none of the 5 polymorphisms is associated with the phenotype bronchial asthma or atopy. However, multilocus haplotype analysis based on simulations to find out whether the haplotype frequencies differed between cases and controls by using the program FAMHAP yielded a P value of 6.1 x 10(-5) in the asthmatic versus the control population, which is highly significant. Furthermore, we obtained a nominally significant result of P=.0232 for the atopic versus the control population by using FAMHAP. CONCLUSION: These results strongly underscore previous findings that suggest a potential role of this cytokine in allergic diseases.     

Single-equation models for the tear film in a blink cycle: realistic lid motion.

We consider model problems for the tear film over multiple blink cycles that utilize a single equation for the tear film; the single non-linear partial differential equation that governs the film thickness arises from lubrication theory. The two models that we consider arise from considering the absence of naturally occurring surfactant and the case when the surfactant is strongly affecting the surface tension. The film is considered on a time-varying domain length with specified film thickness and volume flux at each end; only one end of the domain is moving, which is analogous to the upper eyelid moving with each blink. Realistic lid motion from observed blinks is included in the model with end fluxes specified to more closely match the blink cycle than those previously reported. Numerical computations show quantitative agreement with in vivo tear film thickness measurements under partial blink conditions. A transition between periodic and non-periodic solutions has been estimated as a function of closure fraction and this may be a criterion for what is effectively a full blink according to fluid dynamics.     

Syntheses and ESR spectra of radicals produced in the thermal decomposition of tetraarylsuccinonitriles

Tetraarylsuccinonitriles 2a – e were synthesized via oxidative dimerization of diarylacetonitriles 1a – e in basic media. The thermal decomposition of 2 results in two identical cyanodiarylmethyl radicals 3 . Both ¹H and ¹³C NMR analyses of 1a – e and 2a – e and ESR spectra of 3a – e are presented and discussed. The results of ESR measurements provide a plausible explanation for the different reactivity of cyanodiarylmethyl radicals 3a – e in free radical polymerization.     

Facilitation at the frog neuromuscular junction during and after repetitive stimulation

Summary 1. E.p.p.s and min.e.p.p.s were recorded intracellularly from Mg-blocked nerve muscle preparations (M. sartorius and M. cutaneous pectoris) of summer and winter frogs in vitro.2. Prolonged repetitive stimulation at frequencies above 5/sec induced synaptic facilitation (measured as e.p.p. increase) which continued to increase throughout the longest periods of stimulation tested (40 sec at 20/sec). For a given number of stimuli the facilitation was the greater the higher the frequency of stimulation.3. Increasing the release of ACh per impulse by reducing the Mg-concentration of the bathing solution caused a levelling off and even a depression of the e.p.p.s in the course of tetanic stimulation, i.e. the pattern of the e.p.p. response shifted towards that found in curarized preparations.4. After stimulation the e.p.p.s remained enlarged for periods from 100 to several hundreds of msec, depending on the number and frequency of the conditioning volleys. At frequencies below 100/sec the frequency of stimulation significantly influenced the amount and duration of the e.p.p. facilitation whereas at frequencies above 100/sec the duration of the e.p.p. facilitation was mainly determined by the number of conditioning volleys.5. After stimulation the frequency of the spontaneous min.e.p.p.s was increased. This increase decayed to the control level with a time course similar to that of the e.p.p. facilitation. The possibility is discussed that these parallel changes of e.p.p. amplitude and min.e.p.p. frequency are probably due to a mobilization of transmitter from its presynaptic stores to the release sites.

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Zusammenfassung 1. An Mg-blockierten Nerv-Muskel-Präparaten in vitro (M. sartorius und M. cutaneous pectoris) von Sommer- und Winterfröschen wurden intracellulär e.p.p. und min.e.p.p. gemessen.2. Lange tetanische Reizung mit Frequenzen von mehr als 5 Hz verursacht synaptische Bahnung (gemessen als e.p.p.-Vergrößerung). Diese Bahnung nimmt auch am Ende des längsten untersuchten Tetanus (40 sec bei 20 Hz) noch zu. Für eine gegebene Zahl von Reizen steigt die Bahnung mit der Reizfrequenz.3. Bei Vergrößerung der pro Impuls freigesetzten Menge ACh durch eine Reduktion der Mg-Konzentration der Badelösung erreicht die e.p.p. Amplitude im Verlauf des Tetanus ein Plateau oder beginnt sogar abzunehmen, d.h. die e.p.p. verhalten sich mehr wie in curarisierten Präparaten.4. Nach Reizung bleibt das e.p.p. gebahnt. Je nach Anzahl und Frequenz der Reize dauert die Bahnung hundert bis einige hundert Millisekunden an. Bei Reizfrequenzen von weniger als 100 Hz beeinflußt die Frequenz sowohl die Dauer als auch das Ausmaß der Potenzierung beträchtlich, während bei Frequenzen von mehr als 100 Hz die Dauer hauptsächlich durch die Zahl der Reize bestimmt wird.5. Nach Reizung ist die Frequenz der spontanen min.e.p.p. erhöht. Mit einem Zeitverlauf ähnlich dem der e.p.p.-Potenzierung kehrt die Frequenz der min.e.p.p. wieder zum Ausgangswert zurück. Diese parallelen Veränderungen der e.p.p. Amplitude und der min.e.p.p. Häufigkeit sind wahrscheinlich durch eine vermehrte Bereitstellung (Mobilisation) von Überträgersubstanz am synaptischen Spalt aus den präsynaptischen Speichern verursacht.

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With 6 Figures in the Text

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This work was supported by the Deutsche Forschungsgemeinschaft.     

Flame Retardant Mechanisms of Red Phosphorus and Magnesium Hydroxide in High Impact Polystyrene

Summary: The flame retardant mechanisms of red phosphorus, magnesium hydroxide and red phosphorus combined with magnesium hydroxide were studied in high impact polystyrene by means of comprehensive decomposition studies and combustion tests. The study is intended to illuminate prerequisites and the potential of red phosphorus as a fire retardant for hydrocarbon polymers in the condensed phase and in the gas phase. Thermal and thermo‐oxidative decomposition, decomposition kinetics and the product gases evolved were characterized using thermogravimetry coupled with Fourier transform infrared spectroscopy and mass spectroscopy, respectively. Fire behaviour was investigated with a cone calorimeter using different external heat fluxes, whereas the flammability was determined by limited oxygen indices. The combustion residues were analysed using XPS. Red phosphorus reduced the heat release in HIPS due to radical trapping in the gas phase. Magnesium hydroxide influenced fire behaviour by heat sink mechanisms, release of water and the formation of a magnesia layer acting as a barrier. The combination of both flame retardants in HIPS nearly resulted in a superposition. A slight synergy in barrier characteristics was due to the formation of magnesium phosphate, whereas a slight anti‐synergism occurred in flammability and in the gas phase action. The latter effect is controlled by a decreased fuel rate due to the barrier layer rather than by an initiation of red phosphorus oxidation in the condensed phase.

Heat release rate and total heat release at various external heat fluxes for HIPS (dotted = 70 kW · m^?2, dashed = 50 kW · m^?2, solid = 30 kW · m^?2).     

Chronic exposure to superantigen induces regulatory CD4(+) T cells with IL-10-mediated suppressive activity

The repeated injection of bacterial superantigens (SAg), such as staphylococcus enterotoxin (SE) A or B, has been shown in mice to induce a state of unresponsiveness characterized by the lack of secretion of Th1 lymphokines, such as IL-2 and IFN-gamma, following subsequent SAg challenge. We made the observation, in vivo as well as in vitro, that unresponsiveness to SAg could be transferred from SEA- to SEB-reactive T cells (and reversibly from SEB- to SEA-specific T cells) in C57BL/6 mice but not in BALB/c mice. Since C57BL/6 mice, unlike BALB/c mice, possess TCR V(beta)3+ and V(beta)11+ T cells able to react with both SEA and SEB, we hypothesized that SAg-unresponsive V(beta)3(+) and V(beta)11+ T cells could mediate linked suppression of other SAg-reactive T cells. To analyze further this possibility, spleen cells from BALB/c mice made unresponsive to SEB were tested for their capacity to suppress the response of normal BALB/c cells to SEB. The production of both IFN-gamma and IL-2 following SEB stimulation was greatly impaired in co-cultures containing CD4(+) T cells, but not CD8(+) T cells, isolated from unresponsive animals. In vivo, the production of both IFN-gamma and IL-2 responses to SEB was dramatically reduced in animals adoptively transferred with unresponsive spleen cells. This suppression was abrogated in recipients injected with neutralizing anti-IL-10 antibodies. Moreover, in animals made unresponsive to SEB, SAg-reactive CD4(+) T cells were found to express high levels of CTLA-4, a molecule recently described to play an essential role in the suppressive function of regulatory T cells. Taken together these results demonstrate that the repetitive injection of SAg induces the differentiation of regulatory CD4(+) T cells capable of suppressing SAg-reactive naive T cells.     

Adjunct effect of loratadine in the treatment of acute sinusitis in patients with allergic rhinitis

H₁-blockers are often added to the standard treatment of acute sinusitis, but this is not supported by a controlled study. A multicentric, randomized, double-blind, placebo-controlled, parallel-group study was done in 139 allergic patients (15–65 years) to assess the adjunct efficacy of loratadine in acute exacerbation of rhinosinusitis. Sinusitis was diagnosed by symptoms and confirmed by rhinoscopy and sinus radiograph. Allergy was characterized by skin tests, RAST, and history. Patients were treated with antibiotics (14 days), oral corticosteroids (10 days), and loratadine (10 mg OD) or placebo (28 days). Treatment efficacy was assessed over 28 days by symptom scores quoted daily by patients. Physicians also rated total symptom scores at entry and at day 28. At entry, both groups had similar symptoms. Placebo-treated patients improved significantly, but patients who received loratadine had a significantly greater improvement in sneezing ( P =0.003) after 14 days, and in nasal obstruction ( P =0.002) after 28 days. Physicians found that patients receiving loratadine were significantly improved compared to placebo patients ( P =0. 0125). Loratadine in addition to standard therapy was found to improve the control of some symptoms of sinusitis.