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Biomedical subjects

A Heinz

Publications and source records attributed to A Heinz.

At least 37 records · Page 2Linked to original sources
PubMed2004

Precise mass measurement of 68Se, a waiting-point nuclide along the rp process.

Mass measurements of 68Ge, 68As, and 68Se have been obtained with the Canadian Penning Trap mass spectrometer. The results determine the mass excess of 68Se as -54 232(19) keV, the first measurement with a precision and reliability sufficient to address the light-curve and energy output of x-ray bursts as well as the abundances of the elements synthesized. Under typical conditions used for modeling x-ray bursts, 68Se is found to cause a significant delay in the rp process nucleosynthesis.

Journal Article↗
PubMed2004

Is the nuclear spin-orbit interaction changing with neutron excess?

The difference in the energies of the lowest states corresponding to the two nodeless single-particle orbitals outside the Z=50 closed proton shell, h(11/2) and g(7/2), increases with neutron excess. We have measured the Sn(alpha,t) reaction for all seven stable even Sn isotopes and found that the spectroscopic factors are constant for these two states, confirming their characterization as single-particle states. The trend in energies is consistent with a decrease in the nuclear spin-orbit interaction. A similar trend, also suggesting a decreasing spin-orbit splitting, is seen in the energies of the neutron single-particle states outside the N=82 core, i(13/2) and h(9/2).

Journal Article↗
PubMed2004

Depletion and restoration of endogenous monoamines affects beta-CIT binding to serotonin but not dopamine transporters in non-human primates.

The radioligand [123I]beta-CIT binds to dopamine transporters in striatum and to serotonin transporters in brainstem. Endogenous dopamine or serotonin may compete with radioligand binding at monoamine transporters. We used alpha-methyl-p-tyrosine (AMPT) to block dopamine production and measured [123I]beta-CIT binding before and after endogenous dopamine was restored by IV administration of the dopamine precursor L-dihydroxyphenylalanine (L-DOPA) in rhesus monkeys. P-chlorophenylalanine (pCPA) was used to inhibit serotonin production, and [123I]beta-CIT binding was assessed before and after IV administration of the serotonin precursor 5-hydroxy-L-tryptophan (L-5-HTP) restored endogenous serotonin. Pretreatment with benserazide blocked peripheral decarboxylization in both paradigms. Serotonin restoration measurably displaced [123I]beta-CIT binding to brainstem serotonin transporters but not to striatal dopamine transporters. Restoration of dopamine apparently did not affect [123I] beta-CIT binding to striatal dopamine transporters. However, dopamine restoration reduced radioligand binding to brainstem serotonin transporters, most likely due to dopamine release from serotonin neurons following L-DOPA administration. The higher striatal density of dopamine transporters relative to dopamine concentrations may explain why [123I] beta-CIT displacement by endogenous dopamine was not observed. This study indicates that [123I]beta-CIT binding in brainstem (raphe area) is affected by endogenous serotonin release in vivo and that L-DOPA treatment may cause serotonin neurons in the brainstem to corelease dopamine.

5-Hydroxytryptophan↗
PubMed2004

Analysis of the interaction of a hybrid system consisting of bovine adrenodoxin reductase and flavodoxin from the cyanobacterium Anabaena PCC 7119.

The mitochondrial steroid-hydroxylating system in vertebrates and the NADPH producing electron transfer chain in photosynthetic organisms contain structurally and functionally similar components. Examination of a potential hybrid reconstitution of the electron transfer chain between different components of both systems could help to improve our knowledge on protein-protein interaction and subsequent electron transfer. Here we analyzed the interaction between bovine adrenodoxin reductase and flavodoxin from the cyanobacterium Anabaena PCC 7119. Optical biosensor as well as steady state and fast kinetic experiments showed their ability to form distinct productive complexes. Compared with the corresponding physiological systems the electron transfer is rather slow, probably due to the lack of specificity at the interaction surface.

Animals↗
PubMed2004

[AWMF-guideline: cocaine-, amphetamine-, ecstasy- and hallucinogen-related disorders].

Actually, guidelines for treatment of substance-related disorders were written under the overall control of the DG-Sucht e. V. and the DGPPN e. V. This appears within the framework of the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaft (AWMF). The leading objective of these guidelines is the description of the current scientifically proven and evidence-based medicine in addiction to derive recommendations to therapy. In this context, the guideline for treatment of cocaine-, amphetamine-, ecstasy-, and halluzinogen-related disorders is introduced.

Adult↗
PubMed2003

Determination of the 8B neutrino spectrum.

We have measured the total energy of the alpha particles following the beta decay of 8B by implanting 8B into a planar silicon surface barrier detector. Calibration was performed using alpha particles following the beta decay of 20Na, similarly implanted. The alpha spectrum is used to infer the 8B neutrino spectrum which is an important input in the interpretation of experiments that detect energetic neutrinos from the Sun. The alpha spectrum reported here is in disagreement with the previous best measurement which used two detectors in coincidence.

Journal Article↗
PubMed2003

[Outpatient alcohol detoxification].

Increasing significance is being attributed to outpatient detoxification treatment of alcohol-dependent patients. Many patients want to undergo outpatient detoxification or even carry it out without professional supervision. In some Scandinavian countries and in the USA, outpatient detoxification under medical supervision has increased substantially. In these countries,numerous studies describe outpatient alcohol detoxification as a safe and cost-reducing method. These studies vary in many aspects, especially regarding the nature and dose of the withdrawal medication, but also concerning the inclusion criteria of patients. Medications to treat or prevent alcohol withdrawal symptoms are rather heterogeneous. Besides well-known standard medication established in inpatient treatment (e.g.,benzodiazepines and carbamazepine), interesting studies report the application of rather uncommon substances such as physostigmine and psychotropic analgesic nitrous oxide (PAN) for alcohol detoxification. This article provides an overview on outpatient alcohol detoxification and discusses its transfer to practical application.

Alcohol Deterrents↗
PubMed2003

[Different explanatory models for addictive behavior in Turkish and German youths in Germany: significance for prevention and treatment].

Due to cultural and social barriers, immigrants seldom frequent centers for information, counseling, and treatment of addictive disorders. We examine cultural differences in the explanatory models of addictive behavior among Turkish and German youths in Germany with statistical devices that map the concepts associated with problems of addiction. Relevant differences were found between the disorder concepts of Turkish and German youth. German but not Turkish youths classified eating disorders among severe addictive disorders and associated them with embarrassment and shame. Concerning substance abuse, German but not Turkish youths clearly differentiated between illegal drug abuse and the abuse of alcohol and nicotine. Nearly half of all Turkish youths rejected central medical concepts such as "physical dependence" or "reduced control of substance intake" as completely inadequate to characterize problems of addictive behavior. Preventive information programs must consider these differences and use concepts that are accepted and clearly associated with addictive behavior by immigrant populations.

Adolescent↗
PubMed2003

Serotonin transporter availability correlates with alcohol intake in non-human primates.

A low level of alcohol intoxication upon initial exposure and impulsive aggressiveness predispose humans to alcoholism. In non-human primates, central serotonin transporter availability and turnover rate were associated with aggressive behavior and a low response to initial alcohol exposure. We assessed the respective effects of these factors on alcohol intake in a free choice paradigm. Serotonin transporter availability in the raphe area, the origin of central serotonergic projections, was measured with single-photon emission computed tomography and the radioligand [(123)I]beta-CIT in 11 rhesus monkeys with low and high central serotonin turnover. The amount of alcohol intake in the 3-month observation period was positively correlated with serotonin transporter availability (R=0.76, P=0.006), but not with aggressiveness (R=0.19, P=0.6) or alcohol response upon first exposure (R=-0.48, P=0.2). In a linear multiple regression analysis with serotonin transporter availability, alcohol response, and aggressiveness as independent variables, 82% of the variance of alcohol intake was explained and serotonin transporter availability emerged as the only statistically significant factor (beta=7.81, P=0.006). These observations indicate that there may be a direct relationship between serotonin transporter availability and alcohol intake after controlling for aggression and alcohol response on first exposure.

Aggression↗
PubMed2003

Molecular brain imaging and the neurobiology and genetics of schizophrenia.

It has been hypothesized that schizophrenia is related to dysfunction in temporolimbic-prefrontal neuronal networks, which is acquired early in an individual's development. After puberty, relatively reduced prefrontal control of striatal dopaminergic neurotransmission may lead to unmodulated striatal dopamine (DA) activity, and the positive symptoms of acute psychosis. Brain imaging studies support the notion of prefrontal dysfunction in schizophrenia and correlated upregulation of presynaptic striatal DA activity. Recent molecular brain imaging studies have combined genetic assessments with a multimodal neuroimaging approach to further refine our understanding of the pathophysiologic architecture of the disorder. We review the literature on functional brain imaging in schizophrenia and discuss genotype effects on core psychotic symptoms. A promising research strategy is the identification of genetic and environmental factors that contribute to intermediate phenotypes such as working memory deficits in schizophrenia. Molecular brain imaging can help to unravel the complex interactions between genes and environment and its association with neuronal network dysfunction in schizophrenia.

Animals↗
PubMed2003

Anhedonia, self-experience in schizophrenia, and implications for treatment.

Anhedonia - the inability to experience pleasure - is a symptom of several psychiatric disorders such as depression, drug and alcohol dependence, but also schizophrenia. The concept of anhedonia played a major role in psychiatric and psychoanalytic explanations of psychotic behavior. The relationship between notions of anhedonia and of mental evolution and regression (in the work of Myerson and Bleuler) is discussed. The non-evolutionist views of Rado and Meehl are described. Then the concept of anhedonia is discussed in relationship to the phenomenological approach of Sass and Parnas, who view anhedonia as one manifestation of a self-disturbance or self-disorder that is fundamental in schizophrenia. Concerning treatment of anhedonia, it was often hypothesized that anhedonia is associated with a dysfunction of the mesolimbic dopaminergic reward system. However, studies in humans and non-human animal models indicate that dysfunction of central dopaminergic neurotransmission interferes with the process of motivation rather than with the ability to experience pleasure; the latter may be more mediated by the opioidergic and serotonergic neurotransmission. Understanding the neurobiological correlates of motivation and pleasure may provide new options to treat anhedonia in patients with schizophrenia.

Animals↗
PubMed2003

The influence of gender and emotional valence of visual cues on FMRI activation in humans.

Emotional neuroscience maps neurocircuits associated with the processing of affective stimuli. To assess gender differences in brain activation elicited by affective stimuli, we used pictures from the International Affective Picture System in a functional magnetic resonance imaging (fMRI) study. Ten male and ten female age-matched healthy volunteers were included and viewed affectively negative versus positive pictures, which were presented in an event related design. There was a significant interaction between valence of emotional stimuli and gender in the sublenticular extended amygdala (SLEA) and the rostral anterior cingulate. fMRI activation in these regions was stronger for negative compared to positive cues in women. In men fMRI activation was independent of stimulus valence. These results suggest to take gender differences into account when emotional paradigms are tested in functional brain imaging.

Adult↗
PubMed2003

Neurotransmitter changes by interferon-alpha and therapeutic implications.

Interferon alpha (IFN-alpha) is a cytokine that is widely used for the treatment of chronic viral infection or malignant disorders. During treatment with IFN-alpha, severe neuropsychiatric syndromes may occur such as depression with suicidal ideation, paranoid psychoses or confusional states. The neurobiological correlates of these side effects are widely unknown. Besides induction of other cytokines and hormonal changes, IFN-alpha has been shown to modulate the opioid, serotonin, dopamine and glutamate neurotransmitter system. Positive therapeutic effects of antidepressants such as selective serotonin-reuptake-inhibitors (SSRI) or of opioid receptor antagonists support the hypothesis that neurotransmitter changes play an important role in the development of IFN-alpha associated neuropsychiatric side effects. We review recent research about IFN-associated neurotransmitter changes in the central nervous system and discuss treatment strategies.

Animals↗
PubMed2003

Neurobiological correlates of the disposition and maintenance of alcoholism.

The last decade witnessed a rapid increase in the knowledge of the etiopathology and treatment of alcoholism. The current disease concept includes psychosocial and neurobiological foundations and consequences of alcoholism. Neurobiological research points to dispositional factors such as a low level of response to alcohol, which is partly heritable and seems to be associated with monoaminergic dysfunction and reduced GABAergic alcohol effects. Chronic alcohol intake stimulates counteradaptive neuroadaptation in central GABAergic and glutamatergic neurotransmission, which increases alcohol tolerance. Neuroadaptation to chronic alcohol effects is not immediately reversed during detoxification and can cause clinical withdrawal once alcohol intake is terminated. Sensitization of the dopaminergic and opioidergic reward system may contribute to alcohol craving and reduced control of alcohol intake. New treatment options include pharmacological approaches and indicate that behavior or motivational therapy and the attendance of patient groups may equally reduce the relapse risk.

Acute Disease↗