Acquisition and performance in a rat sequential reaction time task is not affected by subtotal ventral striatal 6-OHDA lesions.

Based on findings of experiments with humans, non-human primates and rodents, it is commonly accepted that dopaminergic basal ganglia processes play a crucial role in procedural and sequential learning. Primal evidence for this hypothesis came from serial reaction time tasks (SRTT) studies, demonstrating that healthy controls show increased reaction times when visual stimulus presentation switches from a previously learned sequence to random stimulus presentation. This so-called interference effect was reduced in patients with Parkinson's disease. Since ethical and methodical aspects limit neurobiological research in human subjects, we developed a rat version of the human SRTT, which can be used to study experimentally induced brain damage. In the present experiment we investigated the effects of bilateral 6-OHDA lesions of the ventral striatum on sequential learning. The lesions led to subtotal dopaminergic depletions in the ventral striatum (58-60%) and also minor depletions in the medial neostriatum (32-46%). These lesions impaired task acquisition only moderately and did not worsen sequential performance since lesion and control animals showed a comparable interference effect when the trained sequence was tested against random stimulus presentation or violated sequences. In contrast, in an earlier SRTT experiment with medial neostriatal dopaminergic lesions (58-66%), the lesion animals were clearly impaired in their sequential learning as compared to controls. Therefore, we assume that subtotal dopamine loss in the medial neostriatum, rather than the ventral striatum, has a substantial effect on sequential learning.

[Changes of short-time heart rate variability during hyperthermia treatment with infrared A whole body irradiation]. / Veränderungen der Kurzzeit-Herzfrequenzvariabilität bei Hyperthermiebehandlung mit Infraror-A-Ganzkörperbestrahlung.

BACKGROUND: Measures of heart rate variability (HRV) are widely recognized as being an important indicator method for autonomical function and cardiovascular neural regulation. The low-frequency component in spectral analysis is increased during conditions of raised sympathetic activation, the high-frequency component is closely correlated with vagal activity. Whole-body infrared-A irradiation (WBIAI) according to von Ardenne is a newly developed version of hyperthermia. In clinical use peripheral vasodilatation with significant increases in heart rate and hypotension were noted as acute effects of WBIAI. In order to evaluate the effect of WBIAI on autonomic function, we measured HRV during serial hyperthermias. PATIENTS AND METHODS: Power spectral density analysis of HRV during the first and the last of 4 serial WBIAI treatments with 30-60 min endurance was performed in 10 patients with chronic pain disorders. Tympanal body temperature was recorded continuously and was supposed to increase by 1 degrees C during treatment. Electrocardiographic monitoring was performed using a Marquette HoIter ECG. RR data were manually edited and standard frequency domain measures of the first and the last 5 min of treatment computed. The subjective efficacy of the treatment was rated by prestandardized interviews. RESULTS: Body temperature increased by 0.9 degrees C during the first treatment and 1.2 degrees C during the last treatment. In all patients the rise in body temperature due to treatment was accompanied by a significant increase in heart rate and a decrease of arterial blood pressure. During hyperthermia a slight decrease of absolute low-frequency and total power as well as a sharp decrease of high-frequency power and a significant increase of the low/high-frequency ratio could be noted. The rise in low/high-frequency ratio during WBIAI was less distinct at the last treatment compared to the initial treatment. Hyperthermia was regarded as a safe, well-tolerable and effective treatment. CONCLUSION: The results suggest that the cardiovascular response during WBIAI is accompanied by significant changes in autonomic cardiac regulation: A significant decrease of low-frequency power corresponding to depressed vagal activity results in an increase of Iow/high-frequency ratio. During serial hyperthermias the acute response is diminished suggesting an adaption of the autonomic response to hyperthermia. Further studies are necessary to investigate the long-standing autonomic effects of the treatment and include analysis of influencing factors such as the level of physical activity and constitutional individual conditions.

[Hyperthermia-induced priming effect in neutrophil granulocytes]. / Hyperthermie-induzierter priming-effekt bei neutrophilen granulozyten.

BACKGROUND AND OBJECTIVE: Whole-body infrared-A irradiation (WBIAI) according to Ardenne is a newly developed version of hyperthermia. In clinical use benefits for patients with chronic infections have been reported. In order to find out more about the immunological background of the method we studied the question whether hyperthermia leads to priming effects in human polymorphonuclear leukocytes (PMN). MATERIAL AND METHODS: We therefore investigated the production of reactive oxygen radical species (ROS) measured by lucigenin-dependent chemiluminescence after stimulation with N-formylpeptide (FMLP, 10(-6) and 10(-7) M), C5a complement (10(-7) and 10(-8) M) or phorbolester (PMA, 10(-7) and 10(-8) M) in isolated PMN of 8 volunteers undergoding a 60-min hyperthermia treatment with the WBIAI. Blood was drawn 0/60/240/510 min after the start of hyperthermia treatment. In addition, we measured blood pressure, pulse, and temperature. RESULTS: In 5 cases a significant increase in ROS (p < 0.05) could be measured beginning 240 min after start of hyperthermia and further increasing until the 510-min time point. These results suggest a priming effect in PMN lasting far beyond the actual treatment period. The increase of ROS production following stimulation with FMLP, C5a or PMA was 60.4 +/- 21.6, 86.0 +/- 23.3, and 63.3 +/- 15.9% (SEM), respectively. Moreover, in all probands the maximal ROS production in PMN was observed 510 min after the beginning of WBIAI treatment. In 3 cases no difference in ROS could be observed. There was no difference in temperature, blood pressure, and pulse between responders and nonresponders. CONCLUSIONS: Our results show a hyperthermia-dependent priming effect of ROS production in PMN, suggesting an increase in immune reaction within the observation period of 510 min. Further investigations are necessary in order to specify responders and nonresponders and to characterize the results in specific diseases and the constitutions of the patients.

Binding-protein expression is subject to temporal, developmental and stress-induced regulation in terminally differentiated soybean organs.

Binding protein (BiP) is a widely distributed and highly conserved endoplasmic-reticulum luminal protein that has been implicated in cotranslational folding of nascent polypeptides, and in the recognition and disposal of misfolded polypeptides. Analysis of cDNA sequences and genomic blots indicates that soybeans (Glycine max L. Merr.) possess a small gene family encoding BiP. The deduced sequence of BiP is very similar to that of other plant BiPs. We have examined the expression of BiP in several different terminally differentiated soybean organs including leaves, pods and seed cotyledons. Expression of BiP mRNA increases during leaf expansion while levels of BiP protein decrease. Leaf BiP mRNA is subject to temporal control, exhibiting a large difference in expression in a few hours between dusk and night. The expression of BiP mRNA varies in direct correlation with accumulation of seed storage proteins. The hybridization suggests that maturing-seed BiP is likely to be a different isoform from vegetative BiPs. Levels of BiP protein in maturing seeds vary with BiP mRNA. High levels of BiP mRNA are detected after 3 d of seedling growth. Little change in either BiP mRNA or protein levels was detected in maturing soybean pods, although BiP-protein levels decrease in fully mature pods. Persistent wounding of leaves by whiteflies induces massive overexpression of BiP mRNA while only slightly increasing BiP-protein levels. In contrast single-event puncture wounding only slightly induces additional BiP expression above the temporal variations. These observations indicate that BiP is not constitutively expressed in terminally differentiated plant organs. Expression of BiP is highest during the developmental stages of leaves, pods and seeds when their constituent cells are producing seed or vegetative storage proteins, and appears to be subject to complex regulation, including developmental, temporal and wounding.

Cotranslational Integration of Soybean (Glycine max) Oil Body Membrane Protein Oleosin into Microsomal Membranes.

Storage triglycerides in oil seeds are sequestered in discrete organelles termed oil bodies. They are bounded by a monolayer of phospholipids in which a few distinct proteins (oleosins) are embedded. Synthesis of soybean (Glycine max) 24-kD oleosin was analyzed by in vitro transcription and translation in reticulocyte lysate in the presence of canine microsomes. Our results show that 24-kD oleosin is cotranslationally integrated into microsomal membranes. We demonstrate that oleosin is integrated into a bilayer membrane in preference to the oil body monolayer membrane, indicating that oleosin is synthesized on the endoplasmic reticulum (ER). A new model of oil body assembly involving a conformational change through initial association with the ER membrane is proposed.

Isoforms of soybean seed oil body membrane protein 24 kDa oleosin are encoded by closely related cDNAs.

We have characterized two cDNA clones for 24 kDa soybean oleosin, the seed oil body membrane protein. Differences in the predicted amino acid sequences of the two clones and the presence of a doublet on immunoblots indicate that 24 kDa oleosin exists in at least two isoforms in soybean. The predicted amino acid sequence also contains a unique carboxy terminal region that is dominated by a series of different tandem amino acid repeats.

Nuclear scaffolds and scaffold-attachment regions in higher plants.

DNA in the nuclei of eukaryotic organisms undergoes a hierarchy of folding to be packaged into interphase and metaphase chromosomes. The first level of packaging is the 11-nm nucleosome fiber, which is further coiled into a 30-nm fiber. Evidence from fungal and animal systems reveals the existence of higher order packaging consisting of loops of the 30-nm fibers attached to a proteinaceous nuclear scaffold by an interaction between the scaffold and specific DNA sequences called scaffold-attachment regions (SARs). Support for the ubiquitous nature of such higher order packaging of DNA is presented here by our work with plants. We have isolated scaffolds from tobacco nuclei using buffers containing lithium diiodosalicylate to remove histones and then using restriction enzymes to remove the DNA not closely associated with the scaffold. We have used Southern hybridization to show that the DNA remaining bound to the scaffolds after nuclease digestion includes SARs flanking three root-specific tobacco genes. This assay for SARs is termed the endogenous assay because it identifies genomic sequences as SARs by their endogenous association with the scaffold. Another assay, the exogenous assay, depends upon the ability of scaffolds to specifically bind exogenously added DNA fragments containing SARs. The tobacco scaffolds specifically bind a well-characterized yeast SAR, and cloned DNA fragments derived from the 3'-flanking regions of the root-specific genes are confirmed to contain SARs by this exogenous assay.