Worldline approach to Sudakov-type form factors in non-Abelian gauge theories

We calculate Sudakov-type form factors for isolated spin-1/2 particles (fermions) entering non-Abelian gauge-field systems. We consider both the on- and the off-mass-shell case using a methodology which rests on a worldline casting of field theories. The simplicity and utility of our approach derives from the fact that we are in a position to make, a priori, a more transparent separation (factorization), with respect to a given scale, between short- and long-distance physics than diagramatic methods.Comment: 18 pages. RevTex is used. No figure

Deeply virtual electroproduction of photons and mesons on the nucleon : leading order amplitudes and power corrections

We estimate the leading order amplitudes for exclusive photon and meson electroproduction reactions at large Q^2 in the valence region in terms of skewed quark distributions. As experimental investigations can currently only be envisaged at moderate values of Q^2, we estimate power corrections due to the intrinsic transverse momentum of the partons in the meson wavefunction and in the nucleon. To this aim the skewed parton distribution formalism is generalized so as to include the parton intrinsic transverse momentum dependence. Furthermore, for the meson electroproduction reactions, we calculate the soft overlap type contributions and compare with the leading order amplitudes. We give first estimates for these different power corrections in kinematics which are relevant for experiments in the near future.Comment: 59 pages, 21 figure

Short and long-term effects of neuroleptics in relation to their cellular mechanism of action

1. 1. Some mechanisms of action of neuroleptics at cellular level are reviewed, mainly the effects on synaptic transmission and the effects on chromatin. 2. 2. As regard to the effects at synaptic level, a brief review is presented on the available evidence in support of the currently prevailing dopamine hypothesis. 3. 3. Studies carried out on the mechanisms and sites of action of neuroleptics on chromatin show that: 3.1. a. Behavioral changes caused by psychotropic drugs in experimental animals are associated with chromatin alterations and induced macromolecular syntheses. 3.2. b. Parkinsonian and possibly drug-induced extrapyramidal symptoms are associated with aberrations in protein synthesis. 3.3. c. Destabilization under "stress" of the heterochromatin in schizophrenics seems to be due to histone modifications and is partly prevented by neuroleptic treatment. © 1979

Changes in the prevalence of symptoms of depression and depression across Greece

This paper reports on the regional prevalence of symptoms of depression and clinical depression (current major depressive episodes) in Greence in the years 1978 and 1984. Prevalence rates were estimated from two extensive, nationwide cross-sectional home surveys on psychosocial issues and health, carried out in four geographical areas: the Greater Athens area, the Greater Thessaloniki area, the rest of the urban areas and rural areas. The methodology used, the sampling procedure and the screening instrument (The Center for Epidemiologic Studies-Depression Scale) were the same in both surveys. Within the 6-year period a substantial increase in the prevalence of symptoms of depression in all geographic areas was observed, with the Athenian respondents expressing a higher number of symptoms of depression than their counterparts from the other areas. The prevalence of current major depressive episodes, according to specific criteria matched with criteria from the DSM III R, was increased in 1984 in Athens and in the rural areas only. We suggest that economic instability between 1978 and 1984 probably contributed to the changes in the rates of depressive disorders. © 1992 Springer-Verlag

Aberrant mRNA in parkinsonism: Support for hypothesis from studies with Chloramphenicol

THE observations that the normally high concentration of dopamine in the substantia nigra is reduced in Parkinsonism1, that reserpine, which depletes catecholamines, can produce a Parkinsonian syndrome2 and that both anticholinergic drugs and L-dopa partially relieve the symptoms of the disease3,4, have led to the implication of an imbalance between dopaminergic and cholinergic activity in Parkinsonism. Our recent results, however, support previous reports that, apart from a neuro-transmitter deficiency, a dysfunction of protein synthesis might be involved. According to this hypothesis, an unknown agent interferes with the normal function of the glial genome. It stimulates the synthesis of new messenger RNA (mRNA) which specifies proteins for growth and division. The normal inverse metabolic coupling between neurone and glia is disturbed during proliferation, and as a result similar changes to those in the proliferating glia may occur in the neurone, leading to its biochemical and functional de-differentiation. The neurone may no longer be capable of synthesizing certain functional proteins, including those needed for neurotransmitter synthesis, transport and storage. As a result, though not degenerate, it would fail to act as a signalling device. Our data in support of this hypothesis are (a) that reserpine, which induces a Parkinsonism-like syndrome in man2, induces increased synthesis of DNA, RNA and proteins in animals, and intense glial proliferation5; (b) that an increase in RNA, inversely related to melanin content, occurs in the nigral neurones of Parkinsonian patients who died during the early stages of the disease (M. I., submitted for publication); (c) that an abnormal electrophoretic pattern of blood cell proteins was found in Parkinsonian patients (H. Pataryas and C. N. S., manuscript in preparation). © 1970 Nature Publishing Group

Who needs treatment? A nationwide psychiatric case identification study

'Case' identification has been considered a major issue in cross-sectional psychiatric epidemiologic surveys. The question is: what is a 'case' and how reliable and valid can criteria be selected? This paper deals with this issue with respect to our experience obtained from a cross-sectional home survey on psychosocial issues and mental health carried out in Greece, with a nationwide probability sample of 4,292 respondents. Mental health status was assessed by use of the CES-D and Langner scales. A high proportion (29%) of respondents was characterized by a degree of mental impairment scoring above the cut-off points in both scales. In order to identify the true psychiatric 'cases', a total of 9 clinical and help-seeking criteria were selected after examining their discriminant power. Finally, a much lower proportion of the sample was identified as probable (7.2%) and definite (8.0%) psychiatric cases in need of care

Enzyme activity of G-6-PD, γ-GT and lysozyme in white cells of schizophrenics

In a controlled study the activity of glucose-6-phosphate dehydrogenase (G-6-PD) in red and white blood cells, γ-glutamyl transpeptidase (γ-GT) and lysozyme in serum and white blood cells was studied in 22 drug-free schizophrenic patients and 17 healthy volunteers. The activities of the above enzymes were found to be reduced in the white cells of schizophrenics compared with controls. The differences in activity of G-6-PD in red cells and of γ-GT and lysozyme in serum between the two groups were not revealed as significant. The observed low enzyme activities might provide a further basis for interpreting the reported functional deficiency in neutrophils of schizophrenics. Possible mechanisms in relation to biological abnormalities in schizophrenia are discussed

Local shaping of function in the motor cortex: Motor contrast, directional tuning

In this review we bring together three different lines of evidence to bear on the issue of local shaping of function in the motor cortex. The first line of evidence comes from the description by Cajal (1904) of the recurrent collaterals of pyramidal cell axons in the precentral gyrus. The second line of evidence comes from the electrophysiological study of the functional effects of these collaterals [Stefanis, C., Jasper, H. 1964a. Intracellular microelectrode studies of antidromic responses in cortical pyramidal tract neurons. J. Neurophysiol. 27, 828-854.; Stefanis, C., Jasper, H. 1964b. Recurrent collateral inhibition in pyramidal tract neurons. J. Neurophysiol. 27, 855-877.] and associated interneurons [Stefanis, C. 1969. Interneuronal mechanisms in the cortex. In: The Interneuron, Brazier, M.A.B. (ed.), Berkeley, CA: University of California Press, pp. 497-526.] using intracellular recordings. And third came the discovery of directional tuning in the motor cortex [Georgopoulos, A.P., Kalaska, J.F., Caminiti, R., Massey, J.T. 1982. On the relations between the direction of two-dimensional arm movements and cell discharge in primate motor cortex. J. Neurosci. 2, 1527-1537.] in the behaving monkey. We hazard the hypothesis that the bell-shaped directional tuning curve is the outcome of orderly, local neuronal interactions in the motor cortex in which the recurrent pyramidal cell collaterals play a crucial role. Specifically, we propose that these collaterals and the intercalated interneurons they impinge upon serve to spatially sharpen the motor cortical activation to a locus corresponding to the direction of the intended movement. Thus, the originally proposed role of the pyramidal cell collaterals in enhancing "motor contrast" [Stefanis, C. 1969. Interneuronal mechanisms in the cortex. In: The Interneuron, Brazier, M.A.B. (ed.), Berkeley, CA: University of California Press, pp. 497-526.] would translate to creating a "directional tuning field" on the motor cortical surface, where the enhanced motor contrast would correspond to high activity at the center of directional field, and the suppression of the fringe would correspond to lower activity at the periphery of the field, resulting, together in spatial tuning

Moclobemide (Ro 11‐1163) in long‐term treatment

Patients requiring long‐term treatment of depression (at least 60 days) were followed up at monthly intervals under treatment with moclobemide. A total of 102 patients completed 1 year of treatment; the mean dose at the start of treatment was 340 mg daily, decreasing to 300 mg after a year. Three quarters of these patients were suffering from endogenous depression. The investigator's overall assessment of efficacy was good or very good for 96% of patients; efficacy judged together with tolerance was good or very good for 85% of patients. There were no noteworthy changes in safety parameters throughout the study, and adverse events were mainly minor and of short duration. The result of this analysis suggests that moclobemide is effective, safe and well tolerated in long‐term administration. Copyright © 1990, Wiley Blackwell. All rights reserve