Transverse resonance island buckets for synchrotron-radiation based electron time-of-flight spectroscopy.

At the Metrology Light Source (MLS), the compact electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) with a circumference of 48 m, a specific operation mode with two stable closed orbits for stored electrons was realized by transverse resonance island buckets. One of these orbits is closing only after three turns. In combination with single-bunch operation, the new mode was applied for electron time-of-flight spectroscopy with an interval of the synchrotron radiation pulses which is three times the revolution period at the MLS of 160 ns. The achievement is of significant importance for PTB's future programs of angular-resolved electron spectroscopy with synchrotron radiation and similar projects at other compact electron storage rings. The scheme applied here for selecting the photons originating from a particular orbit by optical imaging has been used before in fs slicing applications and may be relevant for the BESSY VSR project of the Helmholtz-Zentrum Berlin.

Excretion of catecholamines in relatives of patients with familial neuroblastoma.

The urinary excretion of catecholamines in 13 close relatives of two distantly related patients with congenital neuroblastoma was investigated. One of these relatives was a child with already known ganglioneuroblastoma. The catecholamines noradrenaline and dopamine were determined. Vanilmandelic acid and homovanillic acid also were determined and numerous other catecholamine metabolites were measured. In contrast to some previous reports in the literature, no pathological excretion patterns were found in the healthy family members.

Exploring three-dimensional orbital imaging with energy-dependent photoemission tomography.

Recently, it has been shown that experimental data from angle-resolved photoemission spectroscopy on oriented molecular films can be utilized to retrieve real-space images of molecular orbitals in two dimensions. Here, we extend this orbital tomography technique by performing photoemission initial state scans as a function of photon energy on the example of the brickwall monolayer of 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) on Ag(110). The overall dependence of the photocurrent on the photon energy can be well accounted for by assuming a plane wave for the final state. However, the experimental data, both for the highest occupied and the lowest unoccupied molecular orbital of PTCDA, exhibits an additional modulation attributed to final state scattering effects. Nevertheless, as these effects beyond a plane wave final state are comparably small, we are able, with extrapolations beyond the attainable photon energy range, to reconstruct three-dimensional images for both orbitals in agreement with calculations for the adsorbed molecule.

Serum vanillylmandelic acid/homovanillic acid contributes to prognosis estimation in patients with localised but not with metastatic neuroblastoma.

In 211 patients with neuroblastoma, serum vanillylmandelic acid (VMA) and homovanillic acid (HVA) levels were determined and correlated to stage, histological differentiation, ferritin, neuron-specific enolase, lactate dehydrogenase (LDH) and outcome. Elevated serum VMA and/or HVA levels were found 16% less frequently than elevated urine levels. The incidence of the elevated serum levels increased with stage (stages I-III 58%, IV 78%, IVS 100%). Increased VMA/HVA ratios were not associated with a higher grade of tumour differentiation. Serum ferritin and neuron-specific enolase showed no correlation, and LDH a borderline non-random correlation with the serum catecholamine metabolites. Using age-related reference values a quotient of serum VMA/HVA (P = 0.061) < 0.7 indicated a poorer event-free survival (48 +/- 10%) than ratios > or = 0.7 (event-free survival 81 +/- 6%) for children with localised neuroblastoma (P = 0.0004). No correlation with prognosis was detected for patients with stage IV and stage IVS disease. We conclude that serum VMA and HVA determinations may be useful as tumour markers for 71% of neuroblastoma patients, and aid in estimating the prognosis in children with localised disease.

Renin and aldosterone secretion in pheochromocytoma. Effect of chronic alpha-adrenergic receptor blockade.

Patients suffering from pheochromocytoma characterized by an exclusive or almost exclusive excess of norepinephrine showed no (one patient) or only a moderate increase (two patients) in renin and aldosterone secretion. In those three patients with concomitant distinct hypersecretion of epinephrine, renin release (and aldosterone secretion except in one patient) was markedly enhanced. Similar results were obtained in a patient with excess norepinephrine and dopamine secretion. Renin release was markedly reduced in all patients during preoperative long-term alpha-adrenergic receptor blockade. With the exception of one patient, increased renin and aldosterone secretion was abolished. The results indicate that augmentation in renin release depends on the ratio of the different catecholamines secreted by the pheochromocytoma and their different effe-tiveness in stimulating beta-adrenergic receptors. Even in the presence of excess catecholamine secretion, there is evidence that renin secretion is predominantly mediated by beta receptors rather than by renal vascular alpha-adrenergic receptors. Normalization of catecholamine-induced enhanced renin release in patients with pheochromocytoma during chronic alpha-adrenergic receptor blockade supports the assumption that (alpha-) adrenergic blocking agents inhibit renin secretion distal to their blockade of specific adrenergic receptors. However, contrary to beta-adrenergic blockade, circadian rhythm of renin release seems to remain intact during alpha-adrenergic blockade.

Colocalization of cholinergic, adrenergic and peptidergic receptors on astrocytes.

By means of combined immunohistochemical and auto-radiographic techniques we have studied the colocalization of cholinergic, adrenergic and peptidergic binding sites on astrocytes in explant cultures of rat spinal cord, brain stem and cerebellum. Many astrocytes which were immunostained by the monoclonal muscarinic receptor antibody M 35 were also intensely labelled by 3H-noradrenaline, the beta-adrenergic antagonist 3H-dihydroalprenolol and the peptides 125I-angiotensin II, 125I-neuropeptide Y and 3H-bradykinin. Electrophysiological studies demonstrating that muscarine, the adrenergic agonists noradrenaline and isoprenaline as well as angiotensin II, neuropeptide Y and bradykinin affect the membrane potential of the same astrocytes provide further evidence for the coexistence of cholinergic, adrenergic and peptidergic receptors on astrocytes.

Electrophysiological evidence for the presence of receptors for cholecystokinin and bombesin on cultured astrocytes of rat central nervous system.

The action of cholecystokinin (CCK) and bombesin (Bom) was studied on the membrane potential of astrocytes in explant cultures of rat cortex, cerebellum, brain stem and spinal cord. Both peptides (10(-8) and 10(-7) M) caused a hyperpolarization of most astrocytes studied. The hyperpolarization by CCK was markedly reduced or blocked by the CCKB-antagonist L-365,260 whereas addition of the Bom-antagonist [D-Phe12,Leu14]-Bom antagonized the effects of Bom, suggesting a specific action of these peptides. When CCK and Bom were tested on the same cell, both peptides were effective, indicating a colocalization of receptors for CCK and Bom on the glial membrane. Our electrophysiological investigations provide strong evidence for the existence of functional CCK and Bom receptors on astrocytes.

A synchrotron-radiation-based variable angle ellipsometer for the visible to vacuum ultraviolet spectral range.

A rotating analyzer spectroscopic polarimeter and ellipsometer with a wide-range θ-2θ goniometer installed at the Insertion Device Beamline of the Metrology Light Source in Berlin is presented. With a combination of transmission- and reflection-based polarizing elements and the inherent degree of polarization of the undulator radiation, this ellipsometer is able to cover photon energies from about 2 eV up to 40 eV. Additionally, a new compensator design based on a CaF2 Fresnel rhomb is presented. This compensator allows ellipsometric measurements with circular polarization in the vacuum ultraviolet spectral range and thus, for example, the characterization of depolarizing samples. The new instrument was initially used for the characterization of the polarization of the beamline. The technical capabilities of the ellipsometer are demonstrated by a cohesive wide-range measurement of the dielectric function of epitaxially grown ZnO.

[Radiology of suprarenal glands (author's transl)]. / Die Radiologie der Nebennieren

Hypertension in endocrine disorders (Cushing's syndrome, Conn's syndrome, Pheochromocytoma) is frequently accompanied by a confusing clinical symptomatology. The underlying pathology is a cortical hyperplasia or a tumor of the adrenal cortex or medulla. The differentiation from other causes of hypertension is primarily based upon laboratory findings (plasma and urinary concentration of cortico-steroids, Renin, Angiotensin and catecholamines as well as their derivates). The preoperative tumor localization by urography, arteriography and adrenal venography as well as the visualization of glandular hypertrophy by adrenal venography is of fundamental importance with regard to treatment of these disorders.

Acoustical changes of loudly spoken speech and their effects on speech recognition in hearing-impaired listeners.

The level of speech is usually increased in conversations with unaided hearing-impaired listeners. However, the speaker may talk at conversational levels to aided hearing-impaired persons. In this case, the level of speech is electronically increased by the hearing aid. In the present study, the acoustical changes of loudly spoken speech and their effects on speech recognition were investigated in 20 patients with sensorineural hearing loss. Eight test words of the German Speech Intelligibility Test ('Freiburger Sprachtest') were recorded at original levels of 60 and 75 dB SPL by a male speaker. Both recordings were presented to hearing-impaired subjects at a playback level of 75 dB SPL. Thus, the level of the 60 dB SPL recording was increased electronically by 15 dB. For the 75 dB SPL recording, playback and recording levels were identical. The average whole-word score was 49% for the 60 dB SPL recording and 39% for the 75 dB SPL recording. This difference was statistically significant (0.002 less than P less than 0.005). The results of the speech recognition ability tests could be explained by the acoustical changes of the loudly spoken speech. In the 75 dB SPL recording, the levels of voiceless fricatives, nasals and plosives were significantly lower than in the 60 dB SPL recording. Spectrally, the fundamental frequency was increased and the configuration of the first formant was altered in the 75 dB SPL recording. The significance of the findings for clinical speech audiometry and hearing aid evaluation is discussed.

The role of surgery, radio- and chemotherapy in the treatment of neuroblastoma and ganglioneuroblastoma.

Personal experiences with biochemical assessments of the urinary catecholamine metabolite excretion in 460 patients with neuroblastoma and 55 patients with ganglioneuroblastoma, as well as prognostic factors and selected data characterizing the role of surgery, radio- and chemotherapy in the treatment of neuroblastoma are reviewed. Recommendations regarding optimal combinations of the 3 treatment modalities are made, taking into account age and stage.

[Therapy and follow-up in pheochromocytoma]. / Zur Therapie und verlaufskontrolle beim Phäochromozytom.

Following a brief presentation of signs and symptoms in 13 patients with pheochromocytoma, the modern procedures for correct diagnosis and tumor localization are outlined. The importance of adequate preoperative treatment with alpha- and, if necessary, beta-adrenergic receptor blocking agents is stressed. The authors also show how the sudden life-threatening blood pressure changes which used to occur frequently during surgical manipulation of the tumor can now be reliably avoided. Pheochromocytoma may arise multifocally; moreover, because the coincidence of pheochromocytoma and associated tumors such as medullary carcinoma of the thyroid gland, adenoma of the parathyroid gland, mucosal neuroma, neurofibroma and chemodectoma is considerably higher amongst these patients and their relatives, it is essential to follow up not only patients with pheochromocytoma but also their relatives, in order to detect recurrences or other neoplasms in time.

Dopamine-beta-hydroxylase in patients with cystic fibrosis.

The enzymatic activity of plasma dopamine-beta-hydroxylase (DBH) was determined in 92 children/adolescents with cystic fibrosis, in 25 parents (heterozygotes) of these patients and in 68 healthy controls. Statistically significant (P less than 0.01) lower DBH levels were found in cystic fibrosis patients (17.9 +/- 1.4 mumol/min per 1, SEM) compared to the controls (25.5 +/- 2.1 mumol/min per 1). In 37 patients plasma norepinephrine and dopamine levels were compared to the enzymatic activity, no significant correlation between these variables being shown (r = -0.134 for norepinephrine; r = 0.159 for dopamine). However, due to the large variability of DBH within the groups and due to the lack of relationship of this enzymatic activity to plasma catecholamines, it is concluded that these differences may neither account for the observed elevation of plasma dopamine in cystic fibrosis patients (0.94-6.73 nmol/l vs. 0.01-0.986 nmol/l for controls) nor for their putative autonomic dysfunction.

Different effects of selective and nonselective beta adrenoceptor blockade on urinary catecholamine and creatinine excretion in stress.

We tested the hypothesis that (1) beta 1-selective and nonselective beta adrenoceptor blockades have a different influence on stress-induced catecholamine overshoot, and (2) beta 1-selective blockade shifts the epinephrine/norepinephrine ratio in favor of norepinephrine. Seven violinists were investigated; each performed four times in public after ingesting different beta blockers. A significantly greater urinary norepinephrine/creatinine excretion was found with selective beta blockade than with nonselective. In addition during selective beta blockade creatinine excretion decreased significantly in comparison with nonselective blockade. This might be due to a higher concentration of circulating norepinephrine, stimulating alpha receptors in the renal vasculature.

Uncommon Gm phenotypes in sera from neuroblastoma patients.

Gm phenotypes and IgG subclass levels were determined in the sera of 68 patients with neuroblastoma. The frequency of the uncommon phenotypes Gm(a+,f+,g-,b+) and Gm(a+,f+,g+,b-) was found to be significantly higher in the neuroblastoma group than in normal blood donors (p less than 0.001). IgG subclass concentrations in the nine sera with uncommon Gm phenotypes and in the sera of neuroblastoma patients were inconspicuous.