[Reflection on the physiological mechanisms of movements controlled by the spinal cord-brain interaction]

The process of communication between brain and spinal cord remains unclear. Therefore an attempt supported by spinal cord stereotaxy was made to disclose the physiological mechanism underlying the cooperation between brain and spine as generated by the spinal cord. The initializing stimulus was the discovery of motoneuron location in all spinal cord segments providing the organic substrate for spinal cord stereotaxy. What remained to be clarified were the anatomical structures of spinal cord, participating in the feedback between brain and spinal cord. Therefore two possible hypotheses were proposed by the authors. One is closely related to the analytic-synthetic mechanism of real object and thoughts depiction in the memory of the brain and in the form of concrete ideas forming the basis for concrete thinking. In the case of spinal cord, another more probable mechanism should be considered: The process of analysis and synthesis between the participating spinal motoneurons. The mutual neuronal connections in the spinal cord are capable of depicting the movement pattern and the movement is transferred by means of the described spinal cord pathways to the memory of the brain as a concrete movement idea. From here the ideas are transferred according to the individual needs backwards by means of another described spinal cord pathways back to the spinal cord and the spinal cord is the final effector. The process of thinking is the physiological correlate of technical software, but in the form of abstract thinking it is transferred to the form of abstract thinking.

Amount of introgression in flycatcher hybrid zones reflects regional differences in pre and post-zygotic barriers to gene exchange

Introgression is the incorporation of alleles from one species or semispecies into the gene pool of another through hybridization and backcrossing. The rate at which this occurs depends on the frequency of hybridization and the fitness of hybrids and backcrosses compared to 'pure' individuals. The collared flycatcher (Ficedula albicollis) and the pied flycatcher (F. hypoleuca) co-exist and hybridize at low to moderate frequencies in a clinal hybrid zone in Central Europe and on the islands of Gotland and Oland off the Swedish east coast. Data on hatching success suggest that hybrids are less fertile in Central Europe compared to on the islands. Direct fitness estimates using molecular markers to infer paternity are consistent with the demographic data. Applying a tag-array-based minisequencing assay to genotype interspecific substitutions and single nucleotide polymorphisms we demonstrate that the amount of introgression from the pied to the collared flycatcher is higher in the two island populations (Gotland and Oland) than in two geographically distinct areas from the Central European hybrid zone (Czech Republic and Hungary). In all areas the amount of introgression from collared to pied flycatchers is very low or seemingly absent. The different patterns of introgression are consistent with regional differences in rates of hybridization and fitness of hybrids. We suggest that barriers to gene exchange may have been partly broken down on the islands due to asymmetric gene flow from allopatry. Alternatively, or in addition, more pronounced reinforcement of prezygotic isolation in Central Europe might have increased post-zygotic isolation through hitchhiking, since genes affecting pre and post-zygotic isolation are both sex-linked in these birds. One of our genetic markers appears to introgress from pied to collared flycatchers at a much higher rate than the other markers. We discuss the possibility that the introgressed marker may be linked to a gene which is under positive selection in the novel genetic background.

[Proposal for a physiologic concept of thought based on the results of stereotaxic psychosurgery]

Authors have fifty years long experience with psychostereotactic surgery. On the bases of 209 operations of different types of mentally ill patients, authors built their own physiological conception of the central nervous system function. The new conception is described using block operators of thinking at the level of hypothalamus, limbic system, and neocortex in the hierarchic order. The basic physiological hypothalamic block contains two operators: stimulus evaluation and decision to act. Both operators together form reasonable, objective substantiation of thinking, which is transformed into psychological, subjective description at higher cerebral levels. New operator is added to the block diagram at the level of the limbic system: the choice of response base on experience stored in the high capacity memory. Vast neocortical memory creates a model of the individual world and it enables a new operator to be involved: prediction of the future events. Thinking, originally based on concrete images, is using abstract terms, subjected to the principles of grammar. Physiological basis of thinking enables the convergence of subjective and objective.

[A simple stereotaxic surgical apparatus]

A simple apparatus based on the classical stereotactic method of surgery offers the opportunity to master miniinvasive procedures in neurosurgery and neurotraumatology. This device is particularly helpful in evacuation of intracerebral spontaneous and traumatic haematomas and in stereobiopsies, i.e. the most frequent operations in clinical practice, without the need of general anaesthesia, craniotomy and interference with cerebral tissue. The reliability of the stereotactic apparatus was positively evaluated by three independent surgeons. The apparatus was registered for use in the health services.

[Cerebral ischemia and neuroprotection from the viewpoint of the neurosurgeon]

Cerebral ischemia is a frequent and dangerous consequence of some cerebrovascular diseases. Ischaemia may be used also electively in the course of neurosurgery. Therefore new possible ways are sought how to reduce the danger of ischaemia or to prevent it. In the submitted paper some methods of neuroprotection are described and their potential or actual applicability in clinical neurosurgery are discussed. In addition to influencing the brain cell and pretentious methods in the sphere of molecular biology and genetics the induction of systemic hypertension supplemented alternatively by other methods such as hypothermia, the use of mannitol, haemodilution and hypervolaemia seem natural. A higher blood pressure helps to make leptomeningeal and cortical anastomoses patent and strengthens the collateral circulation from marginal zones of ischaemia, penumbra to the ischaemic centre and to prevent thus cerebral infarction.

[Anatomic and functional basis for the effect of systemic hypertension on focal cerebral ischemia]

Contemporary vascular neurosurgery cannot sometimes avoid electively used focal brain ischemia. In aneurysm surgery, for example, it is sometimes necessary to close temporarily the parent vessel for a safer dissection of the aneurysm sac. Also carotid endarterectomy cannot be done without a temporary closure of the artery. One of possible neuroprotective methods to be used during this controlled focal ischemia is a systemic hypertension. The knowledge of anatomical and functional capabilities of the brain circulation is crucial for understanding the advantages but also the limits of this neuroprotective method.

[Cerebral blood flow measurement]

A cerebral blood flow measurement is an important part of studying various brain pathologies, particularly brain ischemia. The methods of measurement are still improving, although the physical substance of many of them, like Fick's or Doppler's principles, outlasts further. A change in quality in last several years came with the use of isotopes and a computer technique. New options in imaging of circulatory changes with the help of magnetic resonance technology seem to be particularly perspective. If there were no economical obstacles, this method, which is able to disclose non-invasively a brain perfusion disorder in the very beginning, would be certainly immediately applied in the broad clinical practice.

[Development of European medicine to the time of Vesalius (16th century)]

Mythical Greece, Egyptian Alexandria and ancient Rome were the cradle of ancient medicine where the beginnings of anatomy and physiology were combined with nature philosophy of great personalities such as Hippocrates and Galen. A modern contribution i.e. medical chemistry, to European medicine was made by Arab physicians Rhazes and Avicena. Only when clerical dogmatism was overcome, after the discovery of the New world and the development of universities the road to scientific progress ws opened on which started the great surgeon and physician Andreas Vesalius.

[Minimally invasive treatment of traumatic cerebral hematoma. Further experience with stereotaxic evacuation]

The authors summarise their experience with 16 post-traumatic cerebral haematomas which they evacuated using stereotactic technique. Based on the achieved results they reached the conclusion that stereotactically aimed treatment of haematomas is an advance, for the patient's benefit. The evacuation cannula is safely inserted to its target from a transcutaneous drill hole of the skull and thus the patient is spared the surgical trauma associated with craniotomy and further brain damage. If necessary, the focus of haemorrhage can be reached again by puncture via the channel in the bone which navigates the cannula. Surgery under local anaesthesia is rapid and the results of promising. Extension of the new method depends, however, on the availability of simple stereotactic equipment which starts to play a part in the surgery of traumatic haematomas.

[Surgical findings in stereotaxic therapy of spontaneous cerebral hemorrhage]

Observation of stereotactic evacuation of haematomas in the deep structures of the brain in 41 patients and in the white matter of the cerebral lobes in 33 patients revealed that in the surgical technique and results no substantial difference can be found. The tactics of the intervention in deep hypertensive haemorrhages call however for greater care to avoid a new haematoma and also a greater effort to crush possible blood clots.

[Stereotaxic therapy of post-traumatic cerebral hemorrhage]

The authors present five case-histories pertaining to stereotactic evacuation of lobar traumatic cerebral haematomas and indicate new ways of their treatment. It ensure already from initial observations of the authors that stereotactic operation of these haemorrhages is justified and useful in haematomas affecting several cerebral lobes simultaneously or in case of symmetrical haematomas.

[Stereotactically aimed biopsy of vertebral body l2.]

The authors describe successful use of an whole-body stereotactic apparatus for collection of pathological tissue samples from the vertebral body L2. Key words: whole-body aiming apparatus, stereotactic biopsy, vertebral body.

Preliminary experimental experiences with xenotransplantations

In our xenotransplantation experiments has been a major aim to induce specific tolerance. The results from the meeting of the donor's and the recipient's immunocompetent systems already in the period of embryonic development and/or the influence of methylprednisolone are described.

[Computer tomography in functional stereotactic neurosurgery]

The authors describe their own modification of visualization and construction of coordinates of a stereotactic object for functional stereotaxis controlled by computed tomography (CT). This method was applied so far in four functional stereotactic operations (twice for parkinsonian tremor, once for retrocollis and once for epilepsy). In three patients where coagulation of the surgical objective was made, on the 4th or 5th day after operation there was a check-up CT examination and the size and character of the lesion was evaluated. Based on their own experience and reports in the literature, the authors emphasize the advantages of CT as compared with formerly used ventriculography in the control of functional stereotactic operations.

[Directed photonucleolysis of the intervertebral disk and its herniation. Preparation for percutaneous laser diskectomy]

Under model conditions it proved possible, using a whole-body stereotactic apparatus, to focus on a human intervertebral disc and its prolapses and eliminate them by photocoagulation, using a laser. The suitable cannulae have a 3 mm diameter and an output of 6 to 12 W. The necessary lesion is reached in a fractionated manner within 1 minute. Thus the conditions were created for the new technique of percutaneous disectomy which has been done hitherto by means of chemical substances or mechanically by incision and suction.

[A multipurpose vacuum mattress in health care]

The authors draw attention to vacuum mattresses which are a modern appliance for the immobilization of casualties and patients. They present their initial experience with the use of these mattresses during examinations on a computed tomograph, during all-body stereotaxis and minor surgical operations. The material from which the mattress is made allows X-rays to penetrate, therefore it can be used also for immobilization of restless patients and children during X-ray examinations. It is, however, possible to manufacture also various types of vacuum splints for fixation of the extremities after injuries.

[Transplantation of embryonal nerve tissue into the brain of donors under experimental and clinical conditions]

The authors, stimulated by the results of transplantations of embryonic nervous tissue under experimental conditions and by findings on the biochemical background of some manifestations of mental diseases, dared to use for the first time transplantation of portions of human embryonic brain in the treatment of schizophrenia. Before the experiment they evaluated the bilateral xeno as well as autotransplantations in ten cats. Under clinical conditions they used transplantation of embryonic nervous tissue in two patients with the acute and chronic form of schizophrenia. The operation was performed, using Mundinger's stereotactic apparatus controlled by a computer. The tissue from the central portion of the embryonic brain from the 5th and 7th week of gestation with a high serotonin content was deposited bilaterally in the septal area in the recipient's brain. They recorded improvement in particular in a case of acute schizophrenia. By monitoring the foci of transplanted tissue by computed tomography and magnetic resonance, they provided evidence that embryonic nervous tissue is incorporated in the recipient's brain without reverting into malignant growth and that it is not rejected by the immune system of the recipient.

[The role of the whole-body stereotaxic apparatus in directed interventions in humans]

All-body aiming apparatuses in conjunction with computed tomography are a new promise in the diagnostic and therapeutic complex. They make it possible to reach any point inside the body from any point on its surface. The space where the target is found is operated by the arms of the apparatus in three planes normal to each other and by rotating two angles round the longitudinal and transverse axis. Guiding of the apparatus on the target is controlled by the computer programme. Immobilization of the patient is achieved by a vacuum cushion. The apparatus was tested under model conditions and is ready for clinical use.

[Perspectives in the treatment of some types of pain using lasers. Histological correlation with experimental results]

Treatment of some painful syndromes in the innervation area of spinal ganglia, particular in persisting pain after operations of prolapsed intervertebral discs or operations of the discs, call for new therapeutic methods. Promising possibilities are elimination of the spinal ganglion or nucleolysis of the disc by laser rays, as revealed by experimental studies in vitro and histological check-up of the affected tissue. Three concentric layers of the focus, the carbonization zone, the zones of evaporization and coagulation display irreversible changes which are prerequisites of a permanent effect.

[The first transplantation of embryonic nerve tissue into the brain in schizophrenia]

Transplantation of embryonic nervous tissue into the septal area of the brain in a 21-year-old female patient with schizophrenia revealed the therapeutic effect and favourable effect on memory. However, the favourable effect lasted only 6 months. Among different questions such as whether the transplant was not exhausted, or was rejected, there is the uncertainty whether we did not damage it by repeated CT examinations. We proved, however, that transplantation of embryonic nervous tissue into the brain of the recipient does not involve the danger of uncontrolled growth of the transplanted tissue. Therefore retransplantation, possibly into a different part of the brain, can be considered.