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PubMed1980

[Present problems of addiction (author's transl)].

First the threatening increase of dependence on alcohol, medicines and illegal drugs is illustrated by reference to some statistics. After consideration of the causes of the increase of diseases of addiction, countermeasures are discussed. Possibilities for the practising doctor and possibilities for clinical treatment including juridical certification are put forward. In the treatment of misuse as a pre-form of addiction, the concept of an addiction group is presented in detail. This group is intended to enable the patient to find a definite place within his development of addiction by a combination of rational information and emotional learning.

Alcoholism↗

PubMed1995

A systematic approach to finding answers over the Internet.

New users often are surprised at how chaotic the Internet appears. They have heard so much about it and then find that it is a jumble of menus and resources. Even so, it is possible to find answers to reference questions on the Internet. This paper outlines a method for doing so. The method involves five steps: gather information and tools, learn the terminology, assemble a manual, write a strategy, and make bookmarks. The paper offers medical reference scenarios that illustrate how to search a database, find a program, find a document, and telnet to another site on the Internet.

Computer Communication Networks↗

PubMed1976

Photochemical inactivation of enzymes.

The mechanisms of enzyme inactivation by ultraviolet light and visible light in the presence of sensitizing dyes are reviewed. Recent flash photolysis studies on amino acids and enzymes are summarized in terms of proposed models relating the initial photochemical reactions to permanent chemical and biological damage. The generation and reactions of singlet oxygen are discussed in connection with photodynamic processes. The photochemical results are compared with ionizing radiations, particularly pulse radiolytic methods employing radical anions as selective probes. The interrelationships between the various modes of enzyme inactivation are discussed, as well as the new information to be learned about the structure and functions of the native enzymes from selective radiation-induced alterations.

Carboxypeptidases↗

PubMed1994

The neurosurgical intensive care unit in an era of health care reform.

Health care reform, public concern, and managed care will create an environment that demands highly creative strategies to deliver quality care while reducing costs. Patient satisfaction and outcomes will take on a high priority. To meet this challenge, the neurosurgical ICU of the future will be designed with a patient-focused theme wherein the physical environment embodies healing and humanism. Services will be brought to the patient rather than the patient accommodating the system. Patients and families will be the directors of their own care. Staff and families will have access to a highly sophisticated clinical information system, and learning for staff at all levels will be a part of everyday life in the ICU. Unit management will be within a framework of shared governance wherein the power base is with the direct care givers, and decision and policy making happens at the point closest to the patient. Patient outcomes will be a result of a highly organized collaborative model that includes primary nursing, critical paths, and case management. Partnerships between nurses and unit support staff will create skill-mix changes that allow the nurse to spend less time on nonclinical unit maintenance-type functions and more time with the patient and family. This will have a positive fiscal impact as well as enhance patient satisfaction and outcomes.

Cost-Benefit Analysis↗

PubMed1994

Primary structure and functional characterization of a Drosophila dopamine receptor with high homology to human D1/5 receptors.

Members of the superfamily of G-protein coupled receptors share significant similarities in sequence and transmembrane architecture. We have isolated a Drosophila homologue of the mammalian dopamine receptor family using a low stringency hybridization approach. The deduced amino acid sequence is approximately 70% homologous to the human D1/D5 receptors. When expressed in HEK 293 cells, the Drosophila receptor stimulates cAMP production in response to dopamine application. This effect was mimicked by SKF 38393, a specific D1 receptor agonist, but inhibited by dopaminergic antagonists such as butaclamol and flupentixol. In situ hybridization revealed that the Drosophila dopamine receptor is highly expressed in the somata of the optic lobes. This suggests that the receptor might be involved in the processing of visual information and/or visual learning in invertebrates.

Amino Acid Sequence↗

PubMed1994

[Levels of cognitive investigations in schizophrenia].

Attentional, information-processing and learning deficits can be evidenced in a significant number of schizophrenic patients. Nevertheless these deficits don't seem to characterize automatically a subgroup of negative patients; they can be as well encountered in positive form of schizophrenia or in non psychotic disorders. Often these deficits are preexisting to the development of the disease; they are considered by some authors as being inherited within the spectrum of schizophrenic disorders, schizotypic personality being part of it. Such cognitive disturbances are probably linked with multiple dysfunctions located in cortical and subcortical dopaminergic structures.

Attention↗

PubMed1993

Oncogenes and growth factors in human lung cancer.

We are only beginning to understand the importance of lung cancer tumor biology in relation to prognosis and response to therapy. Many of the biologic and genetic changes we have described are preliminary observations and require further confirmation before clinical use. However, information concerning three oncogenes may soon prove to be helpful in the clinical arena: the myc genes in SCLC, and the ras genes and c-erbB-2 in NSCLC. In general their presence identifies poor patient response to therapy and poor survival. These markers are currently being used in a clinical setting at some research centers, but are not recommended for general diagnostic or prognostic use without further confirmation of their utility. Incorporation of this information with that learned by standard staging procedures may result in improved understanding of patient prognosis and challenge current concepts of lung cancer treatment. For example, surgically resected stage I NSCLC patients may benefit from adjuvant therapy if found to have these adverse biologic factors, and require more stringent follow-up after therapy. Finally the understanding of the pathogenesis of lung cancer may enable the development of novel therapy directed against these growth pathways. Our ultimate goal is to derive a therapeutic and prognostic paradigm involving both molecular-genetic and clinical factors to arrive at an optimal staging model and treatment plan.

Female↗

PubMed1993

International Foundation for Dermatology. A challenge to meet the dermatologic needs of developing countries.

The primary goal of the IFD, which serves under the aegis of the International Committee of Dermatology (the governing body of the International League of Dermatological Societies), is to improve dermatology and dermatologic care in rural areas and developing countries. The principal mission of the IFD is to create regional dermatology training centers in geographic areas of greatest need. The first such center, serving the 12 countries of the African Regional Health Community, is located in Moshi, Tanzania. After successfully completing a 2-year course, the emerging dermatology officers will return to their countries of origin to promulgate the information they have learned by teaching others. The second RDTC is located in Chimaltenango, Guatemala to serve 10 countries in the Caribbean basin by training auxiliary nurses to man health posts in rural areas in this region. All dermatologists in the developed world should view their responsibility to their profession and to those suffering from dermatologic diseases in developing countries as a challenge that can be met if we all labor together to ensure a better world for those who currently have minimal or no dermatologic care. Remember: Give a man a fish and you feed him for one day; teach a man to fish and you feed him for life!

Academic Medical Centers↗

PubMed1995

[Development of a practice-oriented curriculum. 9. Arthrology].

The background problem this article addresses is the need to reduce the quantity of medical information to a standard core of knowledge relative to the overwhelming amount of scientific information to be learned in the limited amount of time students have available. The article is part of a study the aim of which is to define a core students, independent of their further medical specialization. The design of this study is a survey of a representative sample of Swiss general practitioners who were asked to identify in the list of Nomina Anatomica the most prevalent anatomical entities (terms) occurring in their practice. To assure the representativeness of the sample the identified terms were compared to prevalent diagnoses of all Swiss general practitioners and to the incidence of cases in German hospitals. From the list of International Anatomical Nomenclature (IANC) 280 anatomical terms could be identified with respect to arthrology. Of these, 250 were judged uniformly by the physicians: 52 terms were considered relevant, while it was not though necessary for 198 terms to be relevant, while it is was not thought necessary for 198 terms to be learned, i.e. general practitioners agreed on 89.3% of the terms. Only 29.7% of the terms in the IANC list belong to anatomical core knowledge in arthrology. There is evidence for the representativeness of these findings when compared to the prevalence of diagnoses made by general practitioners and to the incidence of cases in German hospitals. The method of using criteria of prevalence in a survey to identify a core of knowledge in medicine is suited for the definition of learning content necessary for professional purposes.

Curriculum↗

PubMedDate not supplied

Anatomy of the auditory cortex.

Cortical auditory areas located in the superior temporal region (STR) in monkey and human. The primary auditory area (AI) occupies the cortex of the supratemporal plane (STP) and is surrounded by auditory association areas in circular sulcus and superior temporal gyrus (STG). Architectonic studies have parcellated auditory areas into a number of subregions. Beginning from the temporal polar proisocortex up to the parietal cortex, these areas shows progressive laminar differentiation, and are arranged into three parallel lines. The most medial line occupies the cortex of the circular sulcus. The regions of this line maintains limbic features and is termed as root line. Another line is located in STG. The regions of this line show progressive emphasis in the third and fourth layer neurons and is termed as belt line. Interposed between root and belt line is a core line located in STP. In this line there is greater accumulation of fourth layer neurons. Recent physiological studies have outlined several auditory representations surrounding AI. These auditory representations correspond to above mentioned architectonic subregions of STR. The subregions within each line have bidirectional connectional laminar specificity. The feedforward connections originate from the supragranular layer III and terminate in the around layer IV of the rostrally adjacent region. Feedback projections in contrast stem from the infragranular layers and terminate in layer I. The long association connections of auditory areas are with the prefrontal cortex (PFC), the multimodal areas and the limbic regions, and are derived from belt and root line areas of STR. These projections follow the rostro-caudal architectonic differentiation of STR. Thus the rostral STG areas are mainly connected with orbital and medial PFC areas whereas the caudal STG areas are connected with caudal PFC. The intermediate STG areas are preferentially related to the lateral PFC regions. It seems that STG-PFC connections are between the areas with similar level of architectonic differentiation. The thalamic connections of the subregions of STR also follow the architectonic organizations. The core line areas are preferentially related to ventral nucleus (MGv) of medial geniculate nucleus (MGN) whereas the root and belt line areas are connected respectively to magnocellular (MGmc) and dorsal (MGd) subdivisions of MGN. The root and belt areas share some connections and are also related to pulvinar, suprageniculate, dorsomedial and intralaminar nuclei. It seems therefore that progressive laminar and tripartrate organization of auditory regions of STR is reflected in intrinsic, association and thalamic connections. The feedforward connections may be engaged in analysis of external environmental cues whereas feedback connections may have a role in matching learned or stored information with incoming auditory signals. The preferential core line connectivity with MGv may be involved in spectral analysis of sound whereas the connections of the belt and root areas with MGmc, MGd, and pulvinar may have role in sound pattern recognition, auditory memory, the localization of sound in space as well as matching auditory information with other modalities.

Animals↗

PubMed1997

Predicting developmental shifts in perceptual weighting schemes.

Recent models of developmental changes in speech perception suggest that the weights assigned to acoustic properties change as children gain experience with a native language. Empirical evidence supports this position, but few suggestions have been offered as to what guides this shift. These three experiments were designed to improve our ability to predict how perceptual weighting schemes change with development. The specific hypothesis explored was twofold: (1) the weight assigned by adults to any one acoustic property differs across phonetic environments according to how informative that property is in each environment; and (2) the weight assigned by children to any one acoustic property differs less across phonetic environments because children have not fully learned the patterns of covariation between phonetic informativeness and environment for each property. Experiment 1 replicated previous findings of age-related differences in the weights assigned to noise spectra and formant transitions in labeling of syllable-initial fricatives (/s/ or /[symbol: see text]/). In experiment 2 the variation in F3-onset frequency associated with place of fricative constriction was eliminated. This property differs more (i.e., is more informative) in /u/ than in /a/. Accordingly adults' transition effect was reduced more for /u/ than for /a/ from experiment 1. Children's transition effect was similarly reduced across vowel environments. In experiment 3, F3-onset frequency was appropriately manipulated for both vowels, and adults transition effect increased more for /u/ than for /a/ from experiment 2. The increase in children's transition effect was more similar across vowels. We conclude that the children had not fully learned how information provided by F3 transitions varies across /a/ and /u/ environments, and suggest that developmental weighting shifts may be guided by children learning the relation between phonetic informativeness and environment.

Adult↗

PubMed2001

Prototype formation in autism.

Individuals with autism have difficulty integrating information and generalizing previously learned concepts to new situations. It was hypothesized that these problems result from an underlying impairment in category formation. Persons with autism may not abstract a summary representation (a prototype) during category learning and, instead, may form categories by memorizing a list of rules. Children with autism, Down syndrome, and normal development participated in one set of category learning tasks that could be solved using a rule-based approach and a second set of tasks in which there was no rule that defined category membership (prototype tasks). In the rule-based tasks, all groups were successful at using a rule to learn a new category. In the prototype tasks, only the typically developing children were able to learn a new category. Neither the persons with autism nor the persons with Down syndrome appeared to develop a prototype during category learning. These data suggest that persons with autism and Down syndrome have difficulty categorizing new information by forming prototypes and, instead, tend to rely on a rule-based approach to learning.

Adolescent↗

PubMed2005

Neural coding of distinct statistical properties of reward information in humans.

Brain processing of reward information is essential for complex functions such as learning and motivation. Recent primate electrophysiological studies using concepts from information, economic and learning theories indicate that the midbrain may code two statistical parameters of reward information: a transient reward error prediction signal that varies linearly with reward probability and a sustained signal that varies highly non-linearly with reward probability and that is highest with maximal reward uncertainty (reward probability = 0.5). Here, using event-related functional magnetic resonance imaging, we disentangled these two signals in humans using a novel paradigm that systematically varied monetary reward probability, magnitude and expected reward value. The midbrain was activated both transiently with the error prediction signal and in a sustained fashion with reward uncertainty. Moreover, distinct activity dynamics were observed in post-synaptic midbrain projection sites: the prefrontal cortex responded to the transient error prediction signal while the ventral striatum covaried with the sustained reward uncertainty signal. These data suggest that the prefrontal cortex may generate the reward prediction while the ventral striatum may be involved in motivational processes that are useful when an organism needs to obtain more information about its environment. Our results indicate that distinct functional brain networks code different aspects of the statistical properties of reward information in humans.

Adult↗

PubMed1998

Recall of old and recent information.

A neural network model for 'forgetting upon learning' is developed in such a way that old information can also be evoked. A new synaptic clipping scheme coupled with selective reinforcement of information is introduced that mimics the learning and memory functions of the 'limbic system' in the brain. The model thus enables both long-term (old) and short-term (recent) memories to exist concurrently, without one affecting the other, as one expects in a realistic situation.

Humans↗

PubMed2003

Castration in rats impairs performance during acquisition of a working memory task and exacerbates deficits in working memory produced by scopolamine and mecamylamine.

RATIONALE: Although much research has focused on the effects of ovarian hormones on learning and memory in females, less information is available regarding the effects of testicular hormones on learning and memory in males. Additionally, despite evidence of an interaction of testicular hormones and the cholinergic system in areas of the brain implicated in learning and memory, no information is available regarding the behavioral consequences of that interaction. OBJECTIVES: We assessed the effect of castration in male rats on working memory during acquisition of a radial maze. We also assessed the interactive effects of castration and scopolamine, a muscarinic receptor antagonist, as well as mecamylamine, a nicotinic receptor antagonist, on behavior. METHODS: Young adult male rats were castrated or underwent sham surgeries. Beginning 10 days after surgeries, performance on a task of working memory was assessed across 24 days of acquisition in an eight-arm radial maze. Following acquisition, scopolamine and mecamylamine dose-effect curves were established. RESULTS: Castration of male rats significantly decreased arm-choice accuracy during acquisition. Castration significantly exacerbated impairments in arm-choice accuracy produced by scopolamine as well as mecamylamine, without altering the disruptive effects of the drugs on the rate at which rats entered the arms of the maze. CONCLUSIONS: These results indicate that castration in male rats impairs working memory during acquisition of a spatial maze task. Additionally, these results suggest that the absence of testicular hormones increases the sensitivity of male rats to the impairing effects of scopolamine as well as mecamylamine on working memory.

Animals↗

PubMed1993

Segmentation of medical images through competitive learning.

In image analysis applications, segmentation of gray-level images into meaningful regions is an important low-level processing step. Various approaches to segmentation investigated in the literature, in general, use either local information of gray-level values of pixels (region growing based methods, for example) or the global information (histogram thresholding based methods, for example). Application of these approaches for segmenting medical images often does not provide satisfactory results. Medical images are usually characterized by low local contrast and noisy or faded features causing unacceptable performance of local information based segmentation methods. In addition, because of a large amount of structural information found in medical images, global information based segmentation methods yield inadequate results in region extraction. We present a novel approach to image segmentation that combines local contrast as well as global gray-level distribution information. The presented method adaptively learns useful features and regions through the use of a normalized contrast function as a measure of local information and a competitive learning based method to update region segmentation incorporating global information about the gray-level distribution of the image. In this paper, we present the framework of such a self organizing feature map, and show the results on simulated as well as real medical images.

Algorithms↗

PubMed1994

Early object labels: the case for a developmental lexical principles framework.

Universally, object names make up the largest proportion of any word type found in children's early lexicons. Here we present and critically evaluate a set of six lexical principles (some previously proposed and some new) for making object label learning a manageable task. Overall, the principles have the effect of reducing the amount of information that language-learning children must consider for what a new word might mean. These principles are constructed by children in a two-tiered developmental sequence, as a function of their sensitivity to linguistic input, contextual information, and social-interactional cues. Thus, the process of lexical acquisition changes as a result of the particular principles a given child has at his or her disposal. For children who have only the principles of the first tier (reference, extendibility, and object scope), word learning has a deliberate and laborious look. The principles of the second tier (categorical scope, novel name-nameless category' or N3C, and conventionality) enable the child to acquire many new labels rapidly. The present unified account is argued to have a number of advantages over treating such principles separately and non-developmentally. Further, the explicit recognition that the acquisition and operation of these principles is influenced by the child's interpretation of both linguistic and non-linguistic input is seen as an advance.

Child Language↗

PubMed2002

The use of information and communication technology in veterinary education.

The internet provides new opportunities to deliver distance and e-learning to the veterinary profession both at undergraduate and postgraduate levels. There are now numerous examples of successful computer-based educational projects in UK higher education, which provide useful models for veterinary science. This will present challenges for academics who will need to adapt their teaching methodologies and students who will have to develop new ways of learning. The future of Information and Communication Technologies (ICT) in the veterinary sector is difficult to predict but it is likely to have far reaching effects on the profession.

Computer-Assisted Instruction↗