Carboxy-terminal extension stabilizes the topological stereoisomers of guanylin

The peptide hormone guanylin constitutes two topological stereoisomers, which are connected through an equilibrium of interconversion. To investigate the importance of amino acid residues in the central region between the inner cysteines and at the carboxy terminus for this isomerism, synthetic derivatives of guanylin were compared by HPLC, 2D ¹H NMR spectroscopy and by their guanylyl cyclase-C (GC-C)-activating potency. An increase in the central sterical bulk by introduction of diiodo-Tyr⁹ had virtually no effect on the isomerization kinetics. Compared to guanylin, carboxy-terminal amidation did not affect the equilibrium between the two isoforms either. In contrast, two significantly stabilized isomers were obtained by extending the carboxy terminus of guanylin with one additional leucine resembling the characteristic of human uroguanylin isomers. This effect was intensified by a further Lys-Lys extension, thus revealing that the conformational exchange between the guanylin isomers is dependent on the extent of the sterical hindrance in the carboxyterminal region of this peptide. Demonstrated by 2D NMR spectroscopy, the separated isomers of the carboxy-terminally extended derivatives of guanylin exhibit unambiguously closely related structures as found originally for guanylin isomers, which are only detectable as a mixture. Because only one of the stabilized guanylin isomers activates guanylyl cyclase-C, the three-dimensional structure of the GC-C-activating guanylin isomer is now defined. The stabilized isoforms of guanylin described in this study represent suitable tools for the separate functional investigation of the GC-C-agonistic isomer of guanylin as well as of its isomeric counterpart.     

Spontaneous awakening from sleep in infants

Spontaneous awakenings from sleep were studied in a group of 20 infants whose sleep-waking patterns were recorded polygraphically for 24 h. While 10 infants were orally fed the other 10 underwent continuous feeding for various gastrointestinal diseases. Spontaneous awakening from sleep was analysed with regard to the prior sleep state, age and feeding condition. Infants awoke preferentially out of REM sleep and less often out of non-REM sleep. The feeding condition had no significant influence on the distribution of awakenings. The propensity for REM awakenings was significantly greater than would have been expected according to the REM sleep amount. This tendency was more pronounced for younger (less than or equal to 3 months) than for older (greater than or equal to 4 months) infants. REM sleep episodes which were interrupted by awakenings were significantly shorter than uninterrupted ones, since awakenings occurred predominantly shortly after REM sleep onset. It is proposed that the specific pattern of brain activity during REM sleep facilitates the transition from sleep into the waking state, particularly in the youngest infants.     

Untersuchungen über die Dupuytrensche Kontraktur bei Bierfahrern

Ohne ZusammenfassungMit 1 TextabbildungHerrn Prof. Dr. Holstein zum 60. Geburtstag gewidmet.     

Messung des Verlaufs der Aufmerksamkeit bei intoxizierten Patienten

The level and course of attention was measured hourly in 9 drug intoxicated patients after a suicide attempt over periods which varied between 12 and 72 hrs. Attention was measured by the use of two additive 5 step scales for susceptibility to stimulation and reactivity, which were developed by the authors in earlier investigations and proven to be very reliable. Although, the original data set of attention measures was different among the patients, some common features could be elaborated: 1. The level of attention varies very little within 1 hr. Differences greater than one step on the scales were rarely observed between two measurements. 2. The mean course of recovery from attention deficit is linear throughout the scales while the variance is substantial at each step of the scales. For quantification of attention deficit a measure was defined which gives the relation between the actual deficit and full attention. Since the correlation between both scales is high over the whole observation period, it was concluded that the intoxication alters the level but not the structure of attention.     

Ventricular enlargement in teenage patients with schizophrenia spectrum disorder

Recent research has demonstrated statistically significant differences between the ventricular-brain ratios (VBRs) of schizophrenic patients and control subjects. In this study the VBRs of teenage schizophrenic/schizophreniform patients (N = 15) and borderline patients (N = 8) were measured and compared with those of controls of similar ages (N = 18). The schizophrenic group had significantly larger ventricles than the other two groups (p less than .0001). These findings support the hypothesis of previous investigators that ventricular enlargement is present early in the course of schizophrenia.     

109. Transjuguläre Leberdiagnostik: Cholangiographie,Biopsie, Portographie

Zusammenfassung Seit 3 Jahren befindet sich ein Festkörpersuchgerät (Fa. Siemens, Erlangen) zur intraoperativen Steinlokalisation sowie zur Lokalisation von Glassplittern und Metallteilen in Wunden im Handel. Das Gerät wandelt die bei der Berührung von Konkrementen, etc. mit Sonden entstehenden mechanischen Schwingungen in elektrische Spannungsimpulse um und setzt diese in hörbare akustische Signale um/ Bei Choledochusrevisionen ist das Gerät empfehlenswert, ein Verzicht auf die intraoperative Röntgenkontrolle oder zusätzliche Choledochoskopie ist dadurch nicht möglich.