Measurement of the helicity asymmetry E for the reaction γ p → π 0 p : The CBELSA/TAPS Collaboration.

A measurement of the double-polarization observable E for the reaction γ p → π 0 p is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C 4 H 9 OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from E γ = 600 to 2310 MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses.

First measurement of the helicity asymmetry for γp → pπ0 in the resonance region.

The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300 MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed, which are traced to differences in the helicity amplitudes of well-known and established resonances. Precise values for the helicity amplitudes of several resonances are reported.

N(1520) 3/2(-) helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions.

New data on the polarization observables T, P, and H for the reaction γp→pπ(0) are reported. The results are extracted from azimuthal asymmetries when a transversely polarized butanol target and a linearly polarized photon beam are used. The data were taken at the Bonn electron stretcher accelerator ELSA using the CBELSA/TAPS detector. These and earlier data are used to perform a truncated energy-independent partial wave analysis in sliced-energy bins. This energy-independent analysis is compared to the results from energy-dependent partial wave analyses.

Well-established nucleon resonances revisited by double-polarization measurements.

The first measurement is reported of the double-polarization observable G in the photoproduction of neutral pions off protons, covering the photon energy range from 620 to 1120 MeV and the full solid angle. G describes the correlation between the photon polarization plane and the scattering plane for protons polarized along the direction of the incoming photon. The observable is highly sensitive to contributions from baryon resonances. The new results are compared to the predictions from SAID, MAID, and BnGa partial wave analyses. In spite of the long-lasting efforts to understand γp→pπ(0) as the simplest photoproduction reaction, surprisingly large differences between the new data and the latest predictions are observed which are traced to different contributions of the N(1535) resonance with spin parity J(P)=1/2(-) and N(1520) with J(P)=3/2(-). In the third resonance region, where N(1680) with J(P)=5/2(+) production dominates, the new data are reasonably close to the predictions.

Is the excretion of sebum regulated?

The kinetics of sebum excretion on the forehead of volunteers were measured over a period of at least 7 h. The transmission data obtained by the ground glass method were transformed into weight (sebum/cm2). The excretion time function can be described by the equation: w = A . (1 - B . e -C.t). This nonlinear function is typical for modes of excretion in the biological field. Regulation of sebum excretion is probable. Objections against such regulation by feedback were discussed.

Effects of skin extract on sebaceous gland function in the rat.

The subcutaneous injection of a rat skin extract inhibits sebum excretion. The mitotic rate in the sebaceous glands is reduced. Therefore, a chalone of the sebaceous gland seems to exist. The regulation of sebum excretion is discussed.

[Diagnostics and surgical therapy of enteric intussusception in adults illustrated by three cases]. / Dünndarminvagination beim Erwachsenen. Diagnostik und chirurgische Therapie anhand von 3 Fallbeispielen.

The diagnosis of enteric intussusception is rare in adults but not in children. The clinical picture often takes an insidious course. Acute abdomen may also be caused by enteric intussusception. We report on three patients with enteric intussusception and acute abdomen. In two cases, a CT led to the diagnosis of invagination of the small intestine. In one patient, invagination of the terminal ileum was detected during coloscopy. All patients were submitted to limited segment resection and end-to-end anastomosis. In all three cases, the invagination was caused by benign pathological changes. Enteric intussusception in adults always requires surgery. In more than 95% of the cases, pathological findings are obtained intraoperatively, which are benign in the small intestine in 85-95% of the cases.

[Management and outcome of vein of galen malformation in childhood]. / Management und Outcome der Vena-Galeni-Malformation im Kindesalter.

The vein of Galen malformation (VGM) is a rare congenital cerebral vascular malformation. In most cases it already has been diagnosed prenatally. The impact of heart failure due to the arteriovenous shunt is relevant for the prognosis.Prognosis of neonatal symptomatic VGM with early heart failure is severe. Therefore an interdisciplinary cooperation is necessary and it is important to treat patients in a clinic with a perinatal center and a neuroradiology and neurosurgery that is experienced in treating such patients. The genesis, the pathophysiology, the diagnostic agents, the therapeutic agents and the prognosis of VGM will be described.

Slow and fast inhibition and an H-current interact to create a theta rhythm in a model of CA1 interneuron network.

The oriens-lacunosum moleculare (O-LM) subtype of interneuron is a key component in the formation of the theta rhythm (8-12 Hz) in the hippocampus. It is known that the CA1 region of the hippocampus can produce theta rhythms in vitro with all ionotropic excitation blocked, but the mechanisms by which this rhythmicity happens were previously unknown. Here we present a model suggesting that individual O-LM cells, by themselves, are capable of producing a single-cell theta-frequency firing, but coupled O-LM cells are not capable of producing a coherent population theta. By including in the model fast-spiking (FS) interneurons, which give rise to IPSPs that decay faster than those of the O-LM cells, coherent theta rhythms are produced. The inhibition to O-LM cells from the FS cells synchronizes the O-LM cells, but only when the FS cells themselves fire at a theta frequency. Reciprocal connections from the O-LM cells to the FS cells serve to parse the FS cell firing into theta bursts, which can then synchronize the O-LM cells. A component of the model O-LM cell critical to the synchronization mechanism is the hyperpolarization-activated h-current. The model can robustly reproduce relative phases of theta frequency activity in O-LM and FS cells.

Comedo formation in acne.

Comedones contain a considerable quantity of water. In some cases a water content of more than 40% can be detected. The comedo consists of two parts, an inner nucleus built up to unorganized materials and a capsule with concentrically arranged shells. The material of the nucleus contains small scales produced by normal keratinization. The materials of the capsule consists of larger scales, which result from hyperkeratosis. The nucleus of the comedo seems to be identical with the early comedo. A similar structure can be formed in vitro by adding water to sebum. Microorganisms have optimal growth conditions in the early comedo.

[Kinetics of refatting of human hair (author's transl)]. / Bestimmung der Rückfettungskinetik der Haare

The sensitivity of the ground glass method for measurement of lipids can be considerably increased by a more sensitive polish of the glass plates. Therefore lipid measurements are possible in areas with only few sebaceous glands and even on scalp hairs. The hair lipids are continuously measureable without disturbance by sebum from the skin of the head and without extracting the hair of the test person; the time needed for measurement is only short. The curve for the refatting of the hair can be quantitatively recorded. Beside the measurement of the dynamics of hair fatting, we now have a method to prove the cosmetical treatment of hair which also allows experiments to be carried out on a larger scale.

[Evaluation of syncope in children with tilt table test]. / Synkopenabklärung bei Kindern mittels Kipptischuntersuchung.

Tilt table testing is a well approached examination for differentiating unexplained syncope and control trial after therapy. It is evaluated at children and is fast and reliable in spite of high personality effort. We present the indication of examination, course of examination, additional procedures like transcranial doppler sonography, reaction models during the tilt table examination and treatment features for neurocardiogenic syncope.

[Value of transcranial Doppler sonography during tilt table test in children]. / Wertigkeit der transkraniellen Dopplersonographie in der Kipptischuntersuchung bei Kindern.

AIM: Transcranial Doppler sonography was used to asses time relation and characteristically changes in middle cerebral artery blood flow velocity before syncope during tilt table test in children. METHOD: We performed tilt table tests in 40 pediatric patients with a medical history for syncope after exclusion of neurologic and cardiologic diseases. Examination was done in a 70 degrees postural position under control of electrocardiogram, blood pressure measurement and measurements of blood flow velocity of middle cerebral artery by transcranial Doppler with 3-MHz probe. RESULTS: In 13 children syncope occurred after 5 to 45 min (average 23.3). 10 of them were neurocardiogenic syncopes. With it diastolic and medium blood flow velocity of middle cerebral artery initial ever increased while resistance and pulsatility index decreased. Just before syncope the diastolic blood flow velocity decreased dramatically thus no diastolic blood flow could be measured, respectively. Almost we could measure no diastolic blood flow just before syncope occurred. CONCLUSION: Patients with neurocardiogenic syncope do have characteristically blood flow velocity changes of middle cerebral artery just before loosing consciousness. Transcranial Doppler is a usefully examination during tilt table. Clear transcranial Doppler results can help to prevent children from the impending syncope.

Stimulation of lung maturity: investigation of ambroxol in various animal models.

The surfactant or phospholipid lining of the alveolar surface is essential for lung function and airway stability. In premature neonates, the idiopathic respiratory distress syndrome (IRDS) is usually due to a prenatal deficiency in pulmonary surfactant. Experimental and clinical investigations with corticosteroids and other drugs were conducted to study various aspects of lung maturation. The present study of Ambroxol, a new compound with surfactant stimulating properties, was carried out on adult and foetal animals. In adult experimental animals an increase in the activity of Type II pneumocytes was shown by measuring various biochemical parameters. In models of premature animals comparable to clinical IRDS conditions, the antenatal treatment of foetal lambs and rabbits with Ambroxol enhanced lung maturation.

Modulation of A10 dopamine neurons by gamma-aminobutyric acid agonists.

Microinjection of the gamma-aminobutyric acidA agonist, muscimol, into the A10 region of the rat produced a dose-dependent increase in motor activity. This effect was antagonized by intra-A10 administration of the gamma-aminobutyric acidA antagonist, bicuculline, and by peripheral administration of haloperidol, and was associated with an increase in extracellular levels of dopamine metabolites in the nucleus accumbens. Although microinjection of the gamma-aminobutyric acidB agonist, baclofen, into the A10 region did not alter motor activity, it abolished the capacity of intra-A10 injection of mu opioid agonist, Tyr-D-Ala-Gly-MePhe-Gly(ol), or muscimol to increase motor activity. Baclofen also prevented the motor stimulant response to peripheral injection of cocaine or amphetamine, but was ineffective in blocking caffeine-induced behavioral activity. Pretreatment with baclofen prevented the capacity of a mu opioid agonist to elevate dopamine metabolite levels in the nucleus accumbens and prefrontal cortex in postmortem tissue. Baclofen also prevented the elevation of extracellular dopamine content in the nucleus accumbens produced by injection of a mu opioid agonist into the A10 region, as measured in the conscious rat with in vivo dialysis. Finally, when dopamine metabolite levels were elevated in the prefrontal cortex by mild footshock, it was shown that pretreatment with baclofen in the A10 region abolished this response. These data support electrophysiological studies suggesting that activation of gamma-aminobutyric acidB receptors on dopamine perikarya inhibits dopaminergic activity, while activation of gamma-aminobutyric acidA receptors results in an indirect disinhibition of dopaminergic function.

[An occurrence of a neurogenic sarcoma in an irradiated field following the combined surgical-radiologic treatment of a childhood adenosarcoma of the kidney]. / Zum Auftreten eines neurogenen Sarkoms im Bestrahlungsgebiet nach kombinierter operativ-radiologischer Behandlung eines kindlichen Adenosarkoms der Niere.

Malignant neoplasias in childhood generally are an increased risk for the patient to fall ill with a second tumor. Second tumors in former irradiation field are seldom, but are acknowledged radiogenically if histology is different to that of the first tumor and a sufficiently long period is between the two tumors. A patient is represented who had been operated and irradiated because of an adenosarcoma of the kidney at the age of seven and who has fallen ill with a neurogenic sarcoma in irradiation area more than 30 years later. The same patient had to suffer from radiogenic retardation during differentiation of lumbar apparatus of attitude and locomotion and on the other hand he became father of a healthy daughter at the age of 32.

[Effect of smoking on pulmonary glycoprotein metabolism and phospholipid content]. / Einfluss des Rauchens auf den pulmonalen Glykoprotein-Stoffwechsel und Phospholipid-Gehalt.

We investigated the influence of smoking on the cell count, proteins and phospholipids in the bronchoalveolar lavage fluid in 371 patients. In the case of smokers, the cell count and the content of N-acetylglucosaminidase-an enzyme involved in glycoprotein metabolism were elevated. In contrast, the concentrations of protein, alpha amylase and phospholipids were lower than in the nonsmokers. The figures for ex-smokers were, for the most part, similar to those of the non-smokers.