Biomedical subjects

Fritz Henn

Publications and source records attributed to Fritz Henn.

5 recordsLinked to original sources

PubMed2004

Rats with congenital learned helplessness respond less to sucrose but show no deficits in activity or learning.

Inbred rat strains for congenital learned helplessness (cLH) and for congenital resistance to learned helplessness (cNLH) were investigated as a model to study genetic predisposition to major depression. Congenitally helpless rats respond less to sucrose under a progressive ratio schedule. This is not confounded by locomotor hypoactivity: in contrast, cLH rats show a slight hyperactivity during the first 5 min of an open field test. cLH rats acquire operant responding to sucrose as readily as cNLH rats and exhibit normal memory acquisition and retrieval in the Morris water maze, thus ruling out general learning deficits as the cause of the decreased response to sucrose. Reduced total responses and reduced breaking points for sucrose in the cLH strain argue for anhedonia, which is an analogue to loss of pleasure essential for the diagnosis of major depressive episodes, and thus confirm the validity of congenitally learned helpless rats as a model of major depression.

Animals↗

PubMed2003

Reduced cell proliferation in the dentate gyrus is not correlated with the development of learned helplessness.

BACKGROUND: A plethora of indirect findings suggests that mood disorders may be caused by or result in structural changes in the brain, namely decreased hippocampal cell proliferation. METHODS: To test for these hypotheses, we used a rat model of depression, learned helplessness. Moderate unpredictable and inescapable foot shocks induced learned helplessness only in a portion of the rats. Rats that showed helpless behavior were compared to those behaving normally after inescapable shock. Proliferating cells in the dentate gyrus were labeled with BrdU (bromodeoxyuridine). RESULTS: Helpless behavior appeared before the decrease of dentate gyrus cell proliferation was maximal. Cell proliferation was decreased to the same extent in animals that developed helplessness as those that were not helpless. Furthermore, immobilization stress, which reduced the rate of cell proliferation, did not induce learned helplessness. CONCLUSION: These results are in line with reports that the rate of dentate gyrus cell proliferation is acutely down-regulated by stress, but the development of helpless behavior does not correlate with this process. Further studies will have to clarify if during learned helpless behavior neurogenesis is impaired by altered differentiation or survival of cells.

Analysis of Variance↗

PubMed2002

Alcoholism and somatic comorbidity among homeless people in Mannheim, Germany.

AIMS: To assess the prevalence of alcoholism and somatic codisorders of homeless people. DESIGN: Epidemiological cross-sectional field study in a sample of the homeless in the area. SETTING: The study was conducted from 1997 to 1999 in the inner-city area of Mannheim, Germany (approximately 320 000 inhabitants). PARTICIPANTS: One hundred and two single homeless people (15-16% of the estimated total population of single homeless people in the city). MEASUREMENT: Alcoholism, substance abuse and mental disorders were diagnosed with the SCID. Medical examinations were performed by an experienced physician. Blood samples were taken and urine samples collected. Further assessments were conducted for factors potentially correlating with mental or physical state. FINDINGS: Of the study probands, 63.7% presented with the alcohol dependence syndrome or harmful use, 61.7% had current somatic problems or disorders. Probands with alcohol dependence had significantly more frequent somatic disorders in total, more cerebral degeneration, liver disease or alcoholic polyneuropathies. Multiple stepwise regression identified alcoholism, life-satisfaction, duration of homelessness and lacking social support as significant explanatory factors for having a somatic disorder. Alcoholism increased the risk of physical ill-health more than fourfold. CONCLUSION: Alcoholism is a major contributor to the physical ill-health of homeless people. Treatment or rehabilitation of addictive behaviour among the homeless should be of major concern for adequate service planning or provision.

Alcoholism↗

PubMedDate not supplied

Substantial decrease of psychiatric comorbidity in chronic alcoholics upon integrated outpatient treatment - results of a prospective study.

It is far from clear how comorbidity changes during alcoholism treatment. This study investigates: (1) the course of comorbid Axis I disorders in chronic alcoholics over 2 years of controlled abstinence in the outpatient long-term intensive therapy for alcoholics (OLITA) and (2) the effect of comorbid Axis I and II disorders in this group of patients on subsequent drinking outcome over a four-year follow-up. This prospective treatment study evaluates psychiatric variables of 89 severely affected chronic alcohol dependent patients on admission (t(1)), month 6 (t(2)), 12 (t(3)) and 24 (t(4)). Drinking outcomes have been analyzed from 1998 to 2002. On admission, 61.8% of the patients met criteria for a comorbid Axis I disorder, 63.2% for a comorbid personality disorder. Axis I disorders remit from t(1) (59.0% ill), t(2) (38.5%), t(3) (28.2%) to t(4) (12.8%) (p < 0.0001). Anxiety disorders remit more slowly from t(1) (43.6%) to t(3) (20.5%, p = 0.0086), whereas mood disorders remit early between t(1) (23.1%) and t(2) (5.1%, p = 0.0387) with a slight transient increase at t(3) (10.3%). During the four-year follow-up, the cumulative probability of not having relapsed amounts to 0.59. Two predictors have a strong negative impact on abstinence probability: number of inpatient detoxifications (p = 0.0013) and personality disorders (p = 0.0106). The present study demonstrates a striking remission of comorbid Axis I disorders upon abstinence during comprehensive long-term outpatient alcoholism treatment. The presence of an Axis II rather than an Axis I disorder on admission strongly predicts drinking outcome over a four-year follow-up.

Adult↗

PubMedDate not supplied

MR spectroscopy in Alzheimer's disease: gender differences in probabilistic learning capacity.

Degenerative alterations of cortical and subcortical regions in Alzheimer disease (AD) can be estimated by the extent of brain metabolite changes as measured by magnetic resonance spectroscopic imaging (MRSI). A neuropsychological assessment may correlate with metabolite levels and could evaluate underlying degenerative processes. Probabilistic-related classification learning, which represents one form of procedural learning, is associated with the neostriatum. The present study was aimed at examining the correlation of spectroscopic imaging in subcortical regions with the evaluation of specific neuropsychological findings. Twenty-two patients with Alzheimer's disease were compared to 15 healthy elderly control subjects. Proton MRSI of the basal ganglia (BG) and thalamus region was performed for detection of N-acetylaspartate (NAA), trimethylamine (TMA) and creatine ((P)Cr). In addition, a probabilistic-related classification learning task (Weather Prediction Task (WT)) was applied. We observed that in patients a high TMA signal in the basal ganglia region was correlated with a poorer performance in the probabilistic learning task (Spearman rank order correlation (SROC)=-0.6, P<0.009). Although Alzheimer's patients, as a group, did not differ from controls with regard to probabilistic learning capacity (PLC), male AD patients, as compared to male controls, displayed an impairment in the task performance by 28% (P<0.03) and showed a 16% elevation in TMA signaling (P<0.04). The altered metabolite signals and ratios in combination with the cognitive performance might suggest gender-related neuronal degeneration and dysfunction within subcortical regions in AD.

Aged↗