Multiple unit activity study of brain stem and limbic structures during environmental habituation and circadian rhythm

Multiple unit activity (MUA) of brain stem, hypothalamic and limbic structures was studied during habituation to a novel environment and circadian rhythm in chronically implanted freely moving rats. MUA was analysed in the mesencephalic reticular formation (MRF), area hypothalami posterior (PH), basal nuclear group of amygdala (AMY), area septalis (SEPT), dorsal hippocampus (HIPP) and area hypothalami anterior (AH). It was found that in the novel environment MUA of all subcortical structures increased to a high level. During habituation MUA in each phase of wakefulness--sleep cycle decreased to stable low level both in brain stem and forebrain structures. Gradual decrease in MUA was characteristic to MRF, and a sharp decrease occured in AH and AMY. The environmental habituation proved to be a long lasting process in rat. During all phases of wakefulness--sleep cycle activity was significantly higher in the light period than in the dark, and MUA base level showed circadian variation both in brainstem and limbic structures. Close correlation was found between the actual MUA level and responsiveness to various sensory modalities both during habituation and circadian rhythm. The higher the MUA level, the higher the responsiveness, and a fall in activity was accompanied by decreased neuronal responsiveness.     

Use of two parallel oxygenators in a very large patient (2.76 m2) for an acute "A" dissecting aortic aneurysm repair

The very large patient (weight 142 kg, height 197 cm, body surface 2.76 m2) was referred to acute operation with dissecting type A ascending aortic aneurysm. The calculated blood flow was 6.63 l/min. To anticipate potential difficulties with perfusion and oxygenation two oxygenators connected in parallel were incorporated into the circuit. Bentall procedure with ACB to the RCA was performed. The perfusion was uneventful. Bypass time was 259 minutes, cross clamp time 141 minutes, circulatory arrest 7 minutes. The highest oxygenators gas flow was 2.6 l/min with maximum FiO2 0.42. The use of two in parallel connected oxygenators is a very effective, easy and safe method in such extreme perfusions, offering to the perfusionist a great reserve of oxygenator output.     

Molecular comparison of the fibre proteins of bovine adenovirus subtype A and subtype B

The fibre gene of the bovine adenovirus type 2 (BAdV2) subtype B was prepared for sequencing by using cloning, sub-cloning and PCR amplification techniques. The nucleotide sequence of the total fibre gene was determined, and it was found to consist of 1,647 nucleotides, coding for a polypeptide of 549 amino acids. The fibre gene regions of BAdV2 A and B subtypes were aligned. The nucleotide identity of the total fibre gene was found to be 60.5%; however, the homology showed great differences in the different subregions coding for the shaft and knob part of the fibre, and the two subtypes were almost identical in the tail subregion. Remarkable changes indicating deletion, insertion and point mutations were found in the shaft subregion when BAdV2/A and B subtypes were compared. We concluded that the differences found in the haemagglutinating activity of the two subtypes of BAdV2 can mostly be explained by the changes in the polypeptide structure of the fibre shaft.     

Spatial EEG Synchronisation Over Sensorimotor Hand Areas in Brisk and Slow Self-Paced Index Finger Movements

The changes of spatial EEG synchronisation during brisk and slow voluntary self-paced movements of the right and left index finger were analysed in 12 right-handed and 11 left-handed subjects. EEG was recorded from the left and right sensorimotor area using 24 closely spaced electrodes. A novel measure of spatial EEG synchronisation, -complexity, was computed separately for the left and right sensorimotor area in 64 overlapping one-second epochs representing 4.5 s of the pre-movement and 3.5 s of the post-movement period. -complexity was higher, hence spatial synchronisation was lower, in slow than in brisk movements, especially in the right-handed. A sustained increase of -complexity was observed during execution of a slow movement. A decrease of -complexity which was often associated with a brief burst of spatially synchronised 10-Hz oscillations occurred at the onset of extensor muscle contraction. We suggest that increased spatial EEG synchronisation at movement onset may prevent spillover of excitation from the sensorimotor hand area to other cortical regions. During movement, the cortical neuronal assemblies subserve distinct, specialised functions manifesting in increased -complexity.     

Effects of melanotan II,a melanocortin agonist,on grooming and exploration in rats after repeated restraint/immobilization

2 mg/kg melanotan II (MTII, administered i.p.), a cyclic peptide analog of α-melanocyte stimulating hormone, at a single dose increased grooming in naive rats placed in an unfamiliar open-field device without changing locomotion or rearing. Male rats exposed to restraint/immobilization stress (IS) for 1 h on three consecutive days displayed increased grooming after the second stressor exposure, compared to pre-stress levels. MTII, administered to the rats after IS, enhanced the grooming response compared both to the pre- and post-stress values. The increase was greatest after the first dose and declined over the following two applications. As to the locomotion of rats in the entire experimental space, IS reduced the distance moved only after the first two stressor exposures; MTII did not influence these alterations. Locomotion in the central part of arena was not reduced by the stressor or by MTII, on the contrary, there was an increase in both groups after the third intervention. The only observed change in rearing was an increase in the MTII group after the third restraint exposure. Thus, MTII selectively increased grooming without markedly affecting the spatio-temporal structure of locomotor behavior in the open-field. The decline of MTII enhanced grooming over the three test days may be interpreted in terms of adaptation to the stressor and of the developing tolerance to the peptide.     

Suggestions for the assessment of the allergenic potential of genetically modified organisms

The prevalence of allergic diseases has been increasing continuously and, accordingly, there is a great desire to evaluate the allergenic potential of components in our daily environment (e.g., food). Although there is almost no scientific evidence that genetically modified organisms (GMOs) exhibit increased allergenicity compared with the corresponding wild type significant concerns have been raised regarding this matter. In principle, it is possible that the allergenic potential of GMOs may be increased due to the introduction of potential foreign allergens, to potentially upregulated expression of allergenic components caused by the modification of the wild type organism or to different means of exposure. According to the current practice, the proteins to be introduced into a GMO are evaluated for their physiochemical properties, sequence homology with known allergens and occasionally regarding their allergenic activity. We discuss why these current rules and procedures cannot predict or exclude the allergenicity of a given GMO with certainty. As an alternative we suggest to improve the current evaluation by an experimental comparison of the wild-type organism with the whole GMO regarding their potential to elicit reactions in allergic individuals and to induce de novo sensitizations. We also recommend that the suggested assessment procedures be equally applied to GMOs as well as to natural cultivars in order to establish effective measures for allergy prevention.     

Effect of a new synthetic serum replacement on insulin and somatostatin secretion from isolated rat pancreatic islets in long-term culture

Summary Serum contains insulin degrading components. We have evaluated the insulin and somatostatin secretion from isolated rat pancreatic islets during a 2-wk culture period using three different serum-containing media, and one serum-free medium with a synthetic serum replacement. Islets incubated in serum-free medium elicited significantly higher daily insulin and somatostatin secretions than islets incubated in the serum-containing media. After a 2-wk culture period, islets from the serum-free medium secreted significantly more insulin and somatostatin than islets cultured in other media when stimulated with 25 mmol/liter glucose together with 15 mmol/liter theophylline. We conclude that the serum-free medium is superior for long-term culture of rat pancreatic islets.     

Open-field behavior, habituation and passive avoidance learning: Effect of ACTH and hydrocortisone on Normal and adrenalectomized rats

Exploratory behavior (GMA) and habituation rate (IH) were studied in an open-field situation in normal and adrenalectomized rats. Following this procedure the rats were subjected to passive avoidance learning (PA). Wide-spreading individual differences were observed in the exploratory behavior and the tendency of habituation of normal rats. As compared to the normal values, either the adrenalectomy which was performed 24 hr, 7 days and 28 days prior to the experiments or the ACTH and hydrocortisone treatment failed to modify the GMA and the IH significantly. An improvement of PA was found in the normal rats following ACTH and hydrocortisone treatment. In the adrenalectomized animals the hydrocortisone proved to be effective, whereas ACTH did not influence PA. No correlation was found between GMA, IH versus PA values and the influence of ACTH and hydrocortisone administration on these parameters. It is concluded that the direction of PA is unpredictable on the basis of the open-field test performed on R-Amsterdam strain of rats, and the effect of ACTH on passive avoidance learning is mediated through the adrenal glands.     

Lymphoproliferative disease after transplantation

Herein we describe 7 cases of posttransplantation lymphoproliferative disease (PTLD), 5 in men and 2 in women (aged from 25 to 62 years), occurring from 4 months to 12 years (mean, 7 years) after transplantation. Our patients were recipients of kidney, kidney and pancreas, heart, and autologous peripheral haematopoetic stem cells. Four cases were diagnosed as monomorphic and three as polymorphic type of PTLD according to the WHO classification. Monoclonal immunoglobuline heavy chain gene rearrangement was detected in two monomorphic lesions and one polymorphic lesion by polymerase chain reaction (PCR). In the two cases of polymorphic and the one case of monomorphic PTLD, the presence of EBV was visualised by immunohistochemical staining of some transformed lymphoid cells for latent membrane protein (LMP) of EBV. The presence of type A EBV was demonstrated by PCR. The patients were treated by reduction or discontinuation of immunosuppression and by chemotherapy. In 2 cases, a part of the organ affected by lymphoma (sigmoid colon and pancreas) was surgically resected. Four patients died of causes related to PTLD (2 to 15 months after the diagnosis), mainly of infectious complications. Two other patients who achieved remission died of unrelated causes. Only the youngest man is alive and in the complete remission 10 months after the diagnosis of PTLD.     

Pathogenesis of primary respiratory disease induced by isolates from a new genetic cluster of bovine viral diarrhea virus type I

The pathogenesis of infection induced by cytopathogenic isolates from the newly identified genetic cluster Id of bovine viral diarrhea virus (BVDV) type I was studied in two experimental infections of previously seronegative, immunocompetent calves. Experiment 1 focused on the evaluation of clinical patterns, viremia, and serological responses. All infected calves in this experiment developed respiratory symptoms and seroconverted to BVDV positivity. Contact calves also contracted a respiratory tract infection following exposure to infected animals. Viremia was demonstrated between postinfection days 2 and 17, and the virus was detected in organ specimens of all but one each of the infected and contact calves. In experiment 2, the distribution of BVDV in various tissues of calves euthanized at defined days postinfection was studied. In two of these calves recurrent shedding of BVDV in nasal secretions was shown. BVDV was detected in various tissues of all infected calves throughout the experiment and also following seroconversion and the clearance of BVDV from the circulatory system. Despite the widespread distribution of the virus in various organs, significant tissue damage was found mainly in respiratory tract and lymphoid tissues. These experiments revealed that viruses from cluster Id of BVDV are able to induce primary respiratory disease in previously seronegative, immunocompetent calves. Contact transmission and virus recurrence, contrary to observations from acute experimental infections with noncytopathogenic BVDV, are likely to reflect differences in biological features of these cytopathogenic isolates. Virus shedding and its presence in tissues following peripheral clearance and in the presence of antibodies may have implications in the diagnosis, pathogenesis, and epidemiology of BVDV-induced syndromes in cattle.