Role of primate basal ganglia and frontal cortex in the internal generation of movements

In order to more comprehensively assess the role of the basal ganglia in the internal generation of movements, we studied the activity of neurons in the head of the caudate and in the rostral putamen in relation to the execution of movements. Monkeys performed self-initiated and stimulus-triggered arm reaching movements in separate blocks of trials. With stimulus-triggered movements, 217 striatal neurons increased their activity after the trigger stimulus (127 in caudate, 90 in putamen). Of these, 68 neurons showed time-locked responses to the trigger stimulus, with a median latency of 60 ms, that were independent of visual or auditory stimulus modalities. Three quarters of responses were conditional on a movement being performed. These responses may participate in neuronal processes through which the reception of a stimulus is translated into the execution of a behavioral reaction. Further, 44 neurons increased their activity before the earliest muscle activity without being clearly time-locked to the stimulus (148-324 ms before movement onset), 55 neurons were activated later before the movement, and 50 neurons were activated after movement onset. With self-initiated movements, 106 striatal neurons showed movement-related activity beginning up to 460 ms before movement onset (52 in caudate, 54 in putamen). Comparisons between the two types of movement were made on 53 neurons with premovement activity beginning more than 500 ms before self-initiated movements. Only one fifth of them also showed movement-related activity with stimulus-triggered movements, including trigger responses. Comparisons among 39 neurons with movement-related activity during self-initiated arm movements showed that about half of them also showed movement-related activity with stimulus-triggered movements. These data demonstrate a considerably segregated population of striatal neurons engaged in the internal generation of movements, whereas processes underlying the execution of movements appear to involve overlapping neuronal populations.     

Vorwort

Ohne Zusammenfassung     

Monosomy 7p in meningiomas: a rare constituent of tumor progression

We present karyotypes of 15 meningiomas with structural aberrations of chromosome 7, which were taken from a consecutive series of 400 cytogenetically characterized meningiomas. Twelve of these tumors (80%) displayed partial or complete monosomy 7p with a consensus deleted region of 7p12 approximately pter, in 6 of 15 cases arising from an unbalanced whole-arm t(1;7)(q11;p11), and in 4 of 15 cases from a whole-arm translocation involving other chromosomes. Other types of partial aneusomy 7 (3/15 cases) or balanced aberrations of chromosome 7 (2/15 cases) were relatively rare. In most cases (11/15), the centromeric region of chromosome 7 was involved in the rearrangements. We conclude that in meningiomas, the near-centromeric region of chromosome 7 is particularly prone to structural rearrangements most frequently resulting in monosomy 7p. The investigation of the histopathologic features of this rare cytogenetic subgroup of meningiomas showed no clear genotype/phenotype correlation. As 7 of 11 of the meningiomas with monosomy 7p belonged to World Health Organization grades II or III, which usually comprise less than 20% of all meningiomas, partial loss of 7p appears to be involved in tumor progression in meningiomas. Because monosomy 7p is typically associated with the strongly progression-associated monosomy 1p, however, monosomy 7p represents a cofactor more than a stand-alone feature of meningioma progression.     

A Direct Comparison of the Skin Conductance and Skin Resistance Methods

The purpose of the present study was a direct comparison between simultaneous recordings of skin conductance and skin resistance. Sixty male students received a series of 30 white noise stimuli, while measures were taken continuously from four sites on the palmar surfaces of the fingers. Evaluations were made for response amplitudes, recovery, and for an approximate area measure. Magnitude of reactions and reliabilities were compared using ANOVA procedures. Behavioral concordances were estimated as correlations with the subjects' ratings of stimulus intensities. Conductance and resistance measures do not differ in amplitude, in area, or in strength of their reliabilities and behavioral concordances. No differences in any respect are found between sites. Skin conductance yields significantly (p < .01) shorter recovery times than skin resistance, which is discussed in terms of membrane permeability change.     

Die pH-Aktivitätsspektren der sauren proteolytischen Enzymaktivitäten von Harn und Serum

Zusammenfassung 1. Die p_H-Abhängigkeit der sauren proteolytischen Enzymaktivitäten von Harn und Serum wurde mit Hämoglobin und Casein als Substraten mittels zweier unabhängiger analytischer Methoden im Bereich von p_H 0,9–4,4 untersucht. Die p_H-Aktivitätskurven von Harn und Serum wiesen hinsichtlich der Form, der Lage und der Ausprägung von Aktivitäts-Maxima deutliche Unterschiede auf. Die mittlere Aktivität der Seren betrug etwa ein Drittel der mittleren proteolytischen Aktivität der Harne.2. Die saure proteolytische Enzymaktivität des Harnes wurde durch Zusatz einer Heparin-Präparation gehemmt. Das Maximum der Hemmung lag zwischen p_H 2,2 und 3,0.3. Die saure proteolytische Enzymaktivität des Harnes zeigte sich bei p_h 3,50 alkalistabiler als diejenige bei p_H 2,15.4. Die Befunde werden im Hinblick auf die Theorie einer exogen-endogenen Partition der Enzyme des Gastrointestinaltraktes und die Heterogenität der sauren gastrointestinalen Proteasen diskutiert. Es wird geschlossen, daß die Bestimmung einer renalen Protease-Clearance wegen fehlender Zuordnungsmöglichkeit der proteolytischen Enzymaktivitäten von Harn und Serum zu bestimmten Enzymen bzw. Proenzymen noch nicht möglich ist.     

Serotonin transporter binding in Tourette Syndrome

Recent studies provided evidence for an involvement of the dopaminergic system in the pathophysiology of Tourette Syndrome (TS). However, little is known about possible impairment of other neurotransmitter systems. In obsessive-compulsive disorder (OCD), a common comorbidity in TS, it is suggested that the serotonergic system plays a major role in the pathogenesis. We, therefore, used [I-123]2[beta]-carbomethoxy-3[beta]-(4-iodophenyl)tropane ([123I]beta-CIT) and single photon emission computed tomography (SPECT) to investigate serotonin transporter (SERT) binding capacity in 12 patients with TS with various degrees of associated obsessive compulsive behaviour (OCB) and 16 age-matched healthy controls. Binding ratios in TS patients not receiving serotonin reuptake inhibitors (SSRI) (n=8) were significantly reduced compared to age-adjusted ratios from normal controls (2.8 versus 3.2, p=0.003). Treatment with SSRI resulted in a significant reduction of SERT availability. Performing linear regression analysis for this small group, SSRI-free patients indicated trends for a negative correlation between [123I]beta-CIT binding on SERT and OCB (r=-0.78, p=0.023) as well as complex motor tics (r=-0.68, p=0.064). In healthy controls, but not in the TS group, we found an age-related decline in SERT binding capacity (0.28% decrease per year, p=0.038). Our data are in agreement with previous results suggesting an impairment of the serotonergic system in TS. It can be speculated that the reduction in SERT binding capacity is associated with the degree of comorbid OCB.     

OH Radical-induced chemical reactions of polynucleotide complexes

Poly(A + U), the 1:1 complex of poly(riboadenylic acid), poly A, and poly(ribouridylic acid), poly U, at pH 8 and self-complexed poly A at pH 4 exist as double helices in dilute aqueous solution. These complexes exhibit a similar behavior as native calf thymus DNA upon irradiation with 16 MeV electron pulses. Thus time resolved Rayleight light scattering measurements showed that crosslinking and double strand breakage can be clearly separated, the former proceeding faster than the latter. The extent to which the two processes occur depends on the ionic strength of the solution. At ionic strenghts exceeding 10 ^?1 mol/l crosslinking is the dominant process indicating that h_crit, the critical length between two single strand breaks for the accomplishment of double strand breaks, is strongly reduced. The investigation of complexes of poly A and Mg²⁺ ions revealed that the destruction of salt bridges is the rate determining process for the decrease of the light scattering intensity due to mainchain scission. This implies that life-times of salt bridges can be determined.     

Beeinflußt das geschlecht die zuweisung zur stationären psychiatrischen behandlung?

Zusammenfassung In Mannheim wurde im Jahre 1968 mit dem schrittweisen Aufbau eines gemeindenahen psychiatrischen Versorgungssystems begonnen. Bestandteil dieses Versorgungskonzepts sind Absprachen zwischen den beteiligten stationären Einrichtungen, die die Zuweisung der Patienten zur stationären Behandlung regeln. Eine modellgestützte, multivariate Analyse von Inanspruchnahmedaten einer Kohorte von 126 schizophrenen Patienten weist nach, daß die Ungleichverteilung der Geschlechter auf die Institutionen das Ergebnis dieser Absprache ist; dabei sind Krankheitsdauer und die Art der Zuweisung von entscheidender Bedeutung.Die vorliegende Arbeit entstand im Rahmen eines von der Deutschen Forschungsgemeinschaft geförderten Projekts im Sonderforschungsbereich 116 Psychiatrische Epidemiologie der Universität Heidelberg (Sprecher: Prof. Dr. Dr. M. Schmidt)     

Some dietary fibers reduce the absorption of carotenoids in women

Dietary fiber may be partly responsible for the lower bioavailability of carotenoids from food than from purified supplements. Due to the lack of detailed information available, we investigated the effects of different kinds of dietary fiber on the absorption of carotenoids and alpha-tocopherol. Six healthy young women received an antioxidant mixture consisting of beta-carotene, lycopene, lutein, canthaxanthin and alpha-tocopherol together with a standard meal. The meal did not contain additional dietary fiber or was enriched with pectin, guar, alginate, cellulose or wheat bran (0. 15 g. kg body weight(-1)). The increases in plasma carotenoid and alpha-tocopherol concentrations were followed over 24 h, and the areas-under-curves (AUC(24h)) were calculated. The mean AUC(24h) of beta-carotene was significantly (P < 0.05) reduced by the water-soluble fibers pectin, guar and alginate with a mean decrease of 33-43%. All tested fibers significantly reduced the AUC(24h) of lycopene and lutein by 40-74% (P < 0.05). The dietary fiber effect on the AUC(24h) of canthaxanthin was almost significant (P = 0.059) and there was no effect on the AUC(24h) of alpha-tocopherol. We conclude that the bioavailability of beta-carotene, lycopene and lutein given within a mixed supplement is markedly reduced by different kinds of dietary fiber.