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G Schüler

Publications and source records attributed to G Schüler.

At least 19 recordsLinked to original sources
PubMed2002

Latent inhibition and schizophrenia: Pavlovian conditioning of autonomic responses.

Latent inhibition (LI) is an important model for understanding cognitive deficits in schizophrenia. Disruption of LI is thought to result from an inability to ignore irrelevant stimuli. The study investigated LI in schizophrenic patients by using Pavlovian conditioning of electrodermal responses in a complete within-subject design. Thirty-two schizophrenic patients (16 acute, unmedicated and 16 medicated patients) and 16 healthy control subjects (matched with respect to age and gender) participated in the study. The experiment consisted of two stages: preexposure and conditioning. During preexposure two visual stimuli were presented. one of which served as the to-be-conditioned stimulus (CSp + ) and the other one was the not-to-be-conditioned stimulus (CSp - ) during the following conditioning ( = acquisition). During acquisition, two novel visual stimuli(CSn + and CSn - ) were introduced. A reaction time task was used as the unconditioned stimulus (US). LI was defined as the difference in response differentiation observed between preexposed and non-preexposed sets of CS + and CS - . During preexposure, the schizophrenic patients did not differ in electrodermal responding from the control subjects, neither concerning the extent of orienting nor the course of habituation. The exposure to novel stimuli at the beginning of the acquisition elicited reduced orienting responses in unmedicated patients compared to medicated patients and control subjects. LI was observed in medicated schizophrenic patients and healthy controls, but not in acute unmedicated patients. Furthermore LI was found to be correlated with the duration of illness: it was attenuated in patients who had suffered their first psychotic episode.

Adolescent↗
PubMed2001

Ion channel-forming alamethicin is a potent elicitor of volatile biosynthesis and tendril coiling. Cross talk between jasmonate and salicylate signaling in lima bean.

Alamethicin (ALA), a voltage-gated, ion channel-forming peptide mixture from Trichoderma viride, is a potent elicitor of the biosynthesis of volatile compounds in lima bean (Phaseolus lunatus). Unlike elicitation with jasmonic acid or herbivore damage, the blend of substances emitted comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. Inhibition of octadecanoid signaling by aristolochic acid and phenidone as well as mass spectrometric analysis of endogenous jasmonate demonstrate that ALA induces the biosynthesis of volatile compounds principally via the octadecanoid-signaling pathway (20-fold increase of jasmonic acid). ALA also up-regulates salicylate biosynthesis, and the time course of the production of endogenous salicylate correlates well with the appearance of the methyl ester in the gas phase. The massive up-regulation of the SA-pathway (90-fold) interferes with steps in the biosynthetic pathway downstream of 12-oxophytodienoic acid and thereby reduces the pattern of emitted volatiles to compounds previously shown to be induced by early octadecanoids. ALA also induces tendril coiling in various species like Pisum, Lathyrus, and Bryonia, but the response appears to be independent from octadecanoid biosynthesis, because inhibitors of lipoxygenase and phospholipase A(2) do not prevent the coiling reaction.

Alamethicin↗
PubMed1999

[From epidemiology of melanoma to prevention--facts and references].

Melanoma incidence rates in Switzerland are very high for European standards. Incidence is increasing like in other white populations; melanoma mortality has stopped its secular increase and is decreasing in people under the age of 65. The reasons for the high melanoma rates in Switzerland can only be guessed: Switzerland is a rich country (melanoma is more prevalent among the rich); the Swiss are known to spend their vacations in Southern countries, exposing themselves to the sun. The paradox of increasing incidence and decreasing mortality rates is discussed, also from the view of the histopathologist. Melanoma patients are at increased risk for subsequent skin carcinoma (basalioma/spinalioma) and vice versa. This may be explained by the common risk factor: sun exposure. The importance of primary prevention is stressed; the Swiss Cancer League is organising annual education campaigns among youngsters. Secondary prevention should focus on high risk groups: families prone to melanoma; older men.

Adult↗
PubMed1998

The topography of non-linear cortical dynamics at rest, in mental calculation and moving shape perception.

Differential cortical activation by cognitive processing was studied using dimensional complexity, a measure derived from nonlinear dynamics that indicates the degrees of freedom (complexity) of a dynamic system. We examined the EEG of 32 healthy subjects at rest, during a visually presented calculation task, and during a moving shape perception task. As a nonlinear measure of connectivity, the mutual dimension of selected electrode pairs was used. The first Lyapunov coefficient was also calculated. Data were tested for non-linearity using a surrogate data method and compared to spectral EEG measures (power, coherence). Surrogate data testing confirmed the presence of nonlinear structure in the data. Cognitive activation led to a highly significant rise in dimensional complexity. While both tasks activated central, parietal and temporal areas, mental arithmetic showed frontal activation and an activity maximum at T3, while the moving shape task led to occipital activation and a right parietal activity maximum. Analysis of mutual dimension showed activation of a bilateral temporal-right frontal network in calculation. The Lyapunov coefficient showed clear topographic variation, but was not significantly changed by mental tasks (p<.09). While dimensional complexity was almost unrelated to power values, nonlinear (mutual dimension) and linear (coherence) measures of connectivity shared up to 37% of variance. Data are interpreted in terms of increased cortical complexity as a result of recruitment of asynchronously active, distributed neuronal assemblies in cognition. The topography of nonlinear dynamics are related to neuropsychological and neuroimaging findings on mental calculation and moving shape perception.

Adult↗
PubMed1996

Exploration of interactions between prognostic factors of stage I malignant melanoma.

While many studies have sought prognostic factors of malignant melanoma using multivariate survival models, the interaction between predictors has been much less studied. We have studied data from 1,560 patients with stage I melanoma collected at the Cancer Registry of the Canton of Zurich over the period 1980-1990 and explored interactions between predictors by identifying two separate multivariate Cox models for men and women and investigating two-way interactions between predictors in each model. Considerable differences between models for man and women were observed. In particular, in women a pronounced interaction between 'histology' and 'Clark level' was identified. Without this interaction 'histology' and 'Clark level' are not significant but when the interaction term was included both predictors become significant. Thus, omission of an interaction term may preclude the recognition of main effects ('masking'). For female patients with nodular tumours prognosis is essentially independent of Clark level. In contrast, for female patients with non-nodular tumours, prognosis was found to be strongly dependent on Clark level. In the case of Clark level 2 prognosis was extremely good: no patient was observed to die from melanoma. We conclude that it may be worth considering interaction terms. With large enough sample sizes it may be preferable to stratify patients into subgroups and to identify separate models for each stratum instead of having to cope with interactions of higher order.

Adult↗
PubMed1995

[Penis carcinoma in a young chimney sweep. Case report 200 years following the description of the first occupational disease].

We report on a 32-year-old patient who, following exposure to soot over a total of 78 weeks as a professional chimney sweep, developed squamous cell carcinoma of the penis. Since the epoch-making description of occupational cancer of the scrotum by Percivall Pott in 1775, soot-related cancer of the scrotum and penis has become anecdotal. As our patient presented with inguinal lymph node metastases, a wide circumcision was performed, followed by preoperative chemotherapy and bilaterial lymphadenectomy. The patient has been free of disease for over 9 years with no functional loss.

Adult↗
PubMed1994

Estimating the incidence of cancers in Switzerland: 1983-1987.

Estimates have recently been made of the incidence of cancers in the countries of the European Community. Similar estimates are given for Switzerland, based on data from the six Swiss cantonal cancer registries, all of which have been operating for at least 12 years. These registries cover Basel, Geneva, Neuchatel, St Gall and Appenzell, Vaud and Zurich, which account for about 50% of the Swiss population as a whole. Two different methods were used to extrapolate from the incidences observed in the regions covered by cancer registration to the entire country. The first method is based solely on the distribution of populations according to the country's main linguistic groups, whereas the second relies on mortality data. Estimates obtained by the second approach are presented and their reliability is discussed. Comparison of the age incidence curve with that of Denmark tends to confirm the validity of the estimations. Estimated standardised rates (world population) for all sites except nonmelanomatous skin cancer are 294.3 for males and 214.2 for females. Comparisons with other European countries show that in males, lung cancer is relatively less common in Switzerland, whereas in females, breast cancer is relatively more frequent.

Adolescent↗
PubMed1993

[Switzerland: a country with high skin cancer rate].

On an European scale, Swiss melanoma incidence and skin cancer mortality rates are exceedingly high, in contrast to the neighbouring countries. Incidence rates of melanoma and nonmelanoma skin cancers are on the increase. From 1921 up to the present, melanoma death rates have been increasing; the excess of male over female mortality has developed since 1950 only. Since the mid-1970s, melanoma mortality under the age of 65 fluctuates without increasing. In the older age-groups increase continues, especially in older men, in whom the melanoma is often localized on the trunk. Compared to other European sources spinalioma and basaloma are rather frequent. Kaposi's sarcoma is rare but increasing. The annual number of new skin malignancies in Switzerland is estimated to be approximately 5000 for men and 4000 for women.

Basal Cell Carcinoma↗
PubMed1991

[Prognosis in ankylosing spondylitis].

Based on the literature we describe the prognosis and natural history of ankylosing spondylitis. The data on mortality are controversial and it seems that only a small group of patient show a decreased survival. It is a chronic disease with most prominent features of pain and increasing stiffness during the first decade. After a course of 40 years 90% of patients have none or only mild disability. Generally quality of life is slightly reduced. Most patients remain engaged in full-time employment, but job adaptations are often unavoidable and vocational counseling seems to be worthwhile.

Activities of Daily Living↗
PubMed1991

Trends in mortality from coronary heart and cerebrovascular disease in Switzerland, 1969-87.

Trends in age-specific and age-standardized death certification rates from all ischaemic heart disease and cerebrovascular disease in Switzerland have been analysed for the period 1969-87, i.e. since the introduction of the Eighth Revision of the International Classification of Diseases for coding causes of death. For coronary heart disease, overall age-standardized rates of males in the mid-late 1980's were similar to those in the late 1960's, although some upward trend was evident up to the mid 1970's (with a peak rate of 120.4/100,000, World standard, in 1978) followed by steady declines in more recent years (103.8/100,000 in 1987). These falls were larger in truncated (35 to 64 years) rates. For females, overall age-standardized rates were stable around a value of 40/100,000, while truncated rates tended to decrease, particularly over most recent years, with an overall decline of over 25%. Examination of age-specific trends showed that in both sexes declines at younger ages were already evident in the earlier calendar period, while above age 50 some fall became evident only in most recent years. Thus, in a formal log-linear age/period/cohort model, both a period and a cohort component emerged. In relation to cerebrovascular diseases, the overall declines were around 40% in males (from 67.4 to 41.2/100,000, World standard) and 45% for females (from 56.6 to 31.7/100,000), and were proportionally comparable across subsequent age groups above age 45. The estimates for the age/period/cohort model were thus downwards both for the period and the cohort component although, in such a situation, it is difficult to disentangle the major underlying component.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Low dose ionising radiation and cancer: findings and methods. Report of a meeting and consequences for Switzerland].

Today's society is concerned about the dangers of ionising radiation, especially in the aftermath of Chernobyl. On the other hand, there exists a widespread lack of understanding radiation biology and radioepidemiology--the very sciences which provide the data from which today's risk estimates have been derived. The papers in this issue of the Journal were presented at a workshop on "Low level radiation and cancer: data and methods" held on 10th-11th December in Feuisberg, near Zurich. The meeting was organised by the Institute of Social and Preventive Medicine of the University of Zurich under the auspices of the Swiss Federal Office of Public Health. Its aims were threefold. First, to give an introduction to some basic facts and methodological issues in radiation physics, biology and epidemiology. Secondly, to give an overview of the availability of data for radioepidemiological research in Switzerland and, thirdly, to evaluate possible research strategies in this country. A list of some notions and units commonly used in the radiation sciences serves an an introduction to the field (G. Schüler et al.). In using units and notions it is important to distinguish the description of biological experiments and epidemiological observations from definitions and risk projections proposed by international reports and consensus bodies for radioprotection purposes. The next papers deal more specifically with selected aspects of the basic sciences. Dosimetry means quantifying the physical effects of ionizing radiation in human tissue; this is not a straight-forward procedure (I. Cordt). The foundations of general radiation biology are succinctly summarised by C. Michel. An account of our present knowledge and theories of radiation carcinogenesis is provided by W. Burkart. W Lutz compares dose-response models of chemical carcinogenesis with those used in radiation carcinogenesis. During the last decade the epidemiological foundations of radioprotection have changed considerably. Longer follow-up studies have become available from the atomic bomb survivors and fro other cohorts. A new dosimetry system (DS 86) has been introduced for Hiroshima and Nagasaki. Exposure to domestic radon has become a major focus of interest. Not only the data, but also the methods of analysis and modeling of risks have evolved, as shown by the recent reports of national and international scientific committees.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1991

Too little concern for breast cancer risk in radiation protection estimates?

Risk estimates of radiogenic breast cancer from recent consensus reports are found to depend as much on the models used as on the data. Some features of the models of BEIR V and the ICRP 1990 Recommendations are hardly supported in the literature and tend to underrate breast cancer risk in radioprotection.

Breast Neoplasms↗
PubMed1989

[Melanoma mortality in switzerland 1970-1986].

Time trends of mortality from malignant melanoma in Switzerland are presented. The death rates are based on the death certificates routinely collected by the Federal Office of Statistics and are age-adjusted (standard Europe). Mortality rates in Switzerland are the highest of any country in central Europe. Time trends in mortality show a significant increase in the elderly (aged over 64 years), whereas in the younger age group (30-64 years), the trend remains constant (no significant increase). For all age groups there is a significant increase in mortality (26% for men and 20% for women). Risk factors are presented. A higher risk of mortality from malignant melanoma among upper socioeconomic strata also applies to Switzerland. In view of the reported time trend in mortality, it is suggested that elderly people be addressed more specifically in future melanoma education campaigns.

Adult↗
PubMed1988

[Malignant lymphomas in HIV-infected patients].

Eleven patients with non-Hodgkin's lymphoma and three patients with Hodgkin's disease were observed among 876 anti-HIV-positive subjects attending the AIDS clinic at the University Hospital, Zurich, Switzerland. Compared to the general population this represents a 50-fold (95% confidence limits: 25-90) increased risk of non-Hodgkin's lymphoma and an 11.4-fold (2.3-33) increased risk for Hodgkin's disease in anti-HIV-positive men. High malignancy, advanced stage of disease at the time of diagnosis, and extranodal localization are characteristic of non-Hodgkin's lymphoma in AIDS patients, which carries a poor prognosis. However, remissions and prolonged disease-free survival are possible in individual cases. Only one opportunistic infection was observed during 92 months of treatment and observation using a mild chemotherapeutic regimen (m-BACOD). Less myelosuppressive chemotherapeutic schedules appear to be more beneficial than aggressive regimens in anti-HIV-positive patients due to the lower incidence of opportunistic infections.

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Trends in and distribution of lung cancer in Switzerland].

Recent trends in lung cancer mortality in Switzerland and the distribution of this cancer by districts, linguistic regions, and occupations are described. In 1985 7.5% of male deaths were due to the disease; female lung cancer is increasing (male-female ratio of deaths 1985: 5.9;in the age-class 35-44: 1.5). From 1970 to 1980, lung cancer became more frequent in the French-speaking area than in the rest of Switzerland. The geographic distribution shows a correlation with population density (chiefly in the over 65 age group) and there were high rates in agglomerations such as Basle and in some peripheral regions. The impact of smoking and occupational/environmental factors on the distribution of lung cancer by regions and occupations is discussed.

Adult↗