Localisation of myocardial ischaemia from the magnetocardiogram using current density reconstruction method: computer simulation study

A computer simulation study is performed to investigate the method of current density reconstruction to localise myocardial ischaemia. A computer model of the entire human heart is used to simulate the excitation and repolarisation process in eight topographically different cases of myocardial ischaemia. The associated magnetocardiogram is calculated at 37 positions of the KRENIKON^* biomagnetic measurement equipment. The method of current density reconstruction is applied at the S-point (the last discemible deviation from the ST-segment at the end of the QRS-complex) of the MCG to find characteristics of the myocardial ischaemia simulated by the model. The results show that it is possible to determine the location of the ischaemia. The current density distribution may be interpreted physiologically in terms of the so-called ‘injury current’. This indicates that magnetocardiography might be a suitable method for noninvasive ischaemia diagnosis, and further investigations of the current density reconstruction method for the injury current should be performed on patients with ischaemic heart disease.     

Loss of heterozygosity at 18q21 region in gastric cancer involves a number of cancer-related genes and correlates with stage and histology,but lacks independent prognostic value

Identification of neuroendocrine differentiation in tumours has important implications for prognosis and therapy. The aim of the present study was to evaluate monoclonal antibodies against synaptic vesicle protein 2 (SV2) as histopathological markers for neuroendocrine differentiation in tumours of the gastrointestinal tract and pancreas. Paraffin blocks from 211 gastrointestinal tumours were examined by immunocytochemistry, using a monoclonal antibody against SV2. Virtually all endocrine tumours of the gastrointestinal tract (11/11 gastric, 53/53 ileal, 16/21 appendiceal, and 22/22 rectal) and pancreas (24/24) were positively labelled. SV2 labelling was also demonstrated in gastrointestinal pacemaker cell tumours (8/8), while adenocarcinomas of the gastrointestinal tract and pancreas were negative, with the exception of occasional adenocarcinomas demonstrating weak SV2 labelling (stomach 1/22, rectum 1/29, and pancreas 0/21). Western blotting of tumour biopsies confirmed expression of SV2 in endocrine tumours of the gastrointestinal tract and pancreas. No relationship was observed between SV2 expression in tumours and hormone production or malignant potential. In conclusion, SV2 is expressed in neuroendocrine tumours of the gastrointestinal tract and pancreas, but not in non-endocrine tumours. The SV2 monoclonal antibody can therefore be used as a general marker for neuroendocrine differentiation in gastrointestinal and pancreatic tumours.     

Neural Correlates of the Results-of-Action Acceptor in a Functional Biotechnical Complex

This report presents data illustrating the neurophysiological features of efferent-afferent convergence on cortical neurons. During combination of stimulus of pyramidal tract axons with electrocutaneous reinforcement, some of the study neurons were found to change the parameters of their activity evoked by stimulation of this tract: evoked responses started to reproduce the structure of responses to the reinforcement. The most dynamic rearrangements of pyramidal tract responses were obtained in experiments in which the study neurons were included in a biotechnical complex with feedback, the complex consisting of neuron-computer-stimulator-animal and actually being an analog of a natural functional system. The role of efferent-afferent convergence on CNS neurons in the development of the results-of-action acceptor of a functional system for a voluntary behavioral act is discussed.     

Clinical epidemiology of ciprofloxacin-resistant Proteus mirabilis isolated from urine samples of hospitalised patients

This study investigated the clinical characteristics of ciprofloxacin-resistant Proteus mirabilis isolates from urine samples associated with nosocomial infection or colonisation, and identified the risk-factors for ciprofloxacin resistance. Data for patients with ciprofloxacin-resistant P. mirabilis isolates (n=13) were compared with those for randomly selected patients with ciprofloxacin-susceptible P. mirabilis isolates (n=40) who were matched by temporal occurrence as control patients. The majority of ciprofloxacin-resistant P. mirabilis isolates were multiresistant, and ciprofloxacin resistance was associated significantly with previous use of fluoroquinolones and production of extended-spectrum beta-lactamases.     

Evoked field potential analysis of dopaminergic mechanisms in the isolated turtle olfactory bulb

Dopaminergic mechanisms were Anatyzed in an isolated preparation of the turtle olfactory bulb. Field potentials were evoked by antidromic or orthodromic stimulation, and the effects determined of pharmacological manipulations of the bathing medium. In the presence of dopamine or a dopamine agonist, apomorphine, there was a reduction of amplitude and delay of onset of the component of the field potentials due to granule cell responses; fluphenazine, a dopamine antagonist, had generally opposite effects. Using paired volleys, it was found that the suppression of the response to the second test volley was reduced in the presence of dopamine or apomorphine, but enhanced in the presence of fluphenazine.The most likely explanation of these results is that exogenous dopamine depresses the response of mitral cells, which in turn decreases the dendrodendritic synaptic excitation of granule cells and reduces their inhibitory feedback onto mitral cells. This suggests that the dopaminergic cells in the bulb may suppress mitral cells by modulating excitable mechanisms in the mitral dendritic membrane, or modulating long-lasting synaptic potentials.     

Directly bone-anchored implants for fixation of aural epistheses

In cases of missing outer ears, generally, epistheses are attached to eye-glasses which gives insecure attachment and a fairly poor cosmetic result. A new method for stable episthesis attachment is being tested in Gothenburg, Sweden. Threaded, cylindrical titanium implants are inserted with a meticulous technique in the temporal bone of the patient. At the next stage, 3–4 months later, the implants are connected to abutments which are allowed to penetrate the skin, To these abutments a silicone episthesis is attached. Presently, 7 patients who had no outer ear because of congenital disorders, hereditary diseases or status post trauma or tumour surgery have been operated and followed for up to $\text{1}\text{2}$ have been no problems reported with the bone anchorage or the skin penetration.     

Pyramidal input to the basal ganglia in the cat

Summary In cats with mesencephalic decerebration sparing the cerebral peduncles and ablation of sensorimotor cortex, changes in firing of single neurons of caudate nucleus (CD), putamen (PU), globus pallidus (GP) and entopeduncular nucleus (EN) were studied following stimulation of the ipsilateral medullary pyramidal tract (MPT). Cells in CD and PU were not extensively influenced by impulses backfired from MPT (14.7% and 18.7%, respectively). Conversely, a larger number of GP cells (28.1%) and especially EN cells (46.9%) exhibited pronounced changes in their firing following MPT stimulation. The MPT-induced effects on CD and PU were either inhibition or excitations, the latter appearing at latencies greater than 11 ms. The responses observed in GP and EN cells were most frequently excitations, some of which appeared with latencies below 5 ms.     

Resolution of late-developing periprosthetic breast infections without prosthesis removal

Based on prior experience with implant exposure, an aggressive regimen to eradicate periprosthetic infections has proven successful in delayed gram-positive and gram-negative bacterial infections and in atypical microbacterial infections. The objective of the salvage procedure is to retain a prosthesis, to maintain breast contour, and to avoid psychological and physical consequences of prosthesis removal. The salvage procedure involves topical antisepsis, contracture release if needed, systemic and topical antibiotics with intermittent or continuous irrigation, and reinforcement of incision lines in selected cases using local tissue flaps.     

Projection systems and terminal localization of dorsal column afferents: an autoradiographic and horseradish peroxidase study in the rat

Projection systems from the gracile nucleus and the cuneate nuclear complex to their terminal sites in the mesencephalon, diencephalon, and cerebellum were examined by means of anterograde autoradiography and retrograde horseradish peroxidase methods. Three projection systems emerge from the dorsal column nuclei, decussate via internal arcuate fibers, and form the contralateral medial lemniscus (ML). At the obex, some fibers split off the ML and course dorsolaterally, forming an ascending lateral system which fits the "lemniscal adjunct channel" (LAC) concept of Graybiel ('72). The ML continues rostrally as the "main lemniscal line channel" (MLLC). At the inferior colliculus, some LAC fibers terminate in the pontine nuclei, parabrachial, dorsal reticular nuclei, and the external and ventral medial part of the central nucleus of the inferior colliculus. More rostrally at the level of the superior colliculus, terminal fields are found in the medial nucleus of the medial geniculate body, the suprageniculate, pretectal, and mesencephalic reticular nuclei, marking the end of the LAC. In the diencephalon, gracile fibers leave the MLLC and form a crescentlike terminal field along the extreme lateral border of the ventral posterior lateral nucleus (VPL) of the thalamus. Cuneate MLLC fibers terminate in a bandlike formation in the VPL medial to the gracile termination. The third fiber system, the cuneocerebellar projection, emerges from the cuneate, the external cuneate nuclei, and the "cellular bridge" and immediately enters the ipsilateral inferior cerebellar peduncle. Upon entering the cerebellum, the major fiber component remains ipsilateral and terminates as vertical bands in vermal and paravermal lobules, and lobules I through IVa. The posterior cerebellar lobe contains terminal bands in lobules VII-IX, the copula pyramidis, and the paramedian lobule. It is concluded that the dorsolateral fiber system conforms to Graybiel's LAC. It is more divergent and probably less modality specific, whereas the medial lemniscal system conforms to the MLLC, which is said to be modality specific, less divergent, and locked to specific sensory-motor response characteristics. The topography of cerebellar terminal bands indicates that there is sensory-motor representation from all parts of the body to all parts of the cerebellum, at least in the rat.