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B Sjölund

Publications and source records attributed to B Sjölund.

At least 37 records · Page 2Linked to original sources
PubMed1987

The elimination of trypsin--alpha-macroglobulin complexes from the blood circulation in pigs during acute pancreatitis and after massive intravenous trypsin infusion.

The elimination from plasma of intravenously injected 125I-labelled trypsin-alpha-macroglobulin complexes was studied in both healthy and diseased, anaesthetized pigs. The t1/2 for the 125I-labelled complexes was 5-10 min in healthy pigs as well as in two groups of pancreatitis pigs. Pre-loading of the eliminating capacity by massive intravenous trypsin infusion, raised t1/2 to 80-100 min. Thus, the eliminating capacity seems to be saturable. Elimination of the complexes from the blood circulation occurred within 4-5 h. Even massive intravenous amounts of trypsin-alpha-macroglobulin complexes gave no demonstrable complement or kinin activation. Neither were other deleterious effects seen during the experiment or during 7 days of follow-up. The results indicate that treatment of acute pancreatitis in humans with alpha 2-macroglobulin might be possible, without any danger arising from the protease-alpha 2-macroglobulin complexes formed.

Acute Disease↗
PubMed1983

Characterization of electrophoretically separable endorphins in human CSF.

Opioid peptides have been purified from large pooled samples of human cerebrospinal fluid. The purification steps involved chromatography on Sephadex G-10 and electrophoresis in agarose suspension. The purified material was further characterized by HPLC and radioimmunoassay. All procedures were guided by a specific radioreceptor assay. The Sephadex G10 fractionation yielded receptor activity in two discrete fractions, Fraction I (FI) and Fraction II (FII). A second Sephadex run of FII gave a partial resolution of two components, one of which was larger (FIIA). Electrophoresis resolved these fractions into several components, most of which showed a more basic behaviour than the enkephalins. Thus, FI separated into at least 4 components and FIIB into two components while FIIA remained a single peak. These components appeared to migrate as distinct peaks and some of them also chromatographed on a HPLC-column as single components. Considering their behaviour in electrophoresis and on HPLC, two components are suggested to represent known endorphin structures. The predominant FII component (FIIA) was thus indistinguishable from Met-enkephalin-Lys6 in all chromatographic systems and one of the most basic FI components showed close similarity with dynorphin. Each of these components occurs at a higher concentration than Met- or Leu-enkephalin, dynorphin or beta-endorphin.

Chromatography, High Pressure Liquid↗
PubMed1981

Morphological and functional studies on the serotoninergic innervation of the inferior olive.

The inferior olive of the cat has, with fluorescence histochemistry, been shown to receive a rich serotoninergic innervation. The distribution of this innervation agrees with the topography of spinal afferent termination as well as the olivo-cerebellar climbing fiber projection. This indicates that different olivary compartments are under different serotoninergic influence. The serotoninergic innervation of the dorsal accessory nucleus (DAO) of the inferior olive of the rat has been identified with electron microscopic radioautography after labelling with 3H-serotonin. The serotoninergic varicosities contain microcanaliculi, tubular-vesicular organelles and large granular vesicles. Few of the serotoninergic varicosities engage in typical synaptic junctions. However, non-junctional varicosities often display other ultrastructural indications of polarity and directed transmitted release. Electrophysiological results indicate that the harmaline-induced tremor, as well as the tremor component of the "serotonin-syndrome", depends on the serotoninergic innervation of the inferior olive. Thus, the sensitivity of different olivary compartments to the induction of rhythmic, synchronous activity by harmaline parallels the distribution of serotoninergic innervation. Neurotoxic destruction of the serotoninergic innervation leads to decreased sensitivity to harmaline. Further, the serotonin receptor agonist 5-methoxy-N,N-dimethyltryptamine, as well as monoamine oxidase inhibition + L-tryptophan loading, leads to rhythmic mass climbing fiber activity in the cerebellum and whole body tremor. A neuromodulatory effect of serotonin on the olivary action potential mechanisms is proposed.

5,6-Dihydroxytryptamine↗
PubMed1978

The ventral spino-olivocerebellar system in the cat. V. Supraspinal control of spinal transmission.

1. The transmission from the flexor reflex afferents (FRA) and from tracts running in the ipsilateral half of the spinal cord to the spino-olivocerebellar paths ascending through the ventral funiculus (VF-SOCPs; Oscarsson and Sjölund, 1977) was compared with the transmission from these sources to segmental reflex arcs. The climbing fibre responses evoked in Purkinje cells by electrical stimulation of limb nerves and spinal tracts were monitored by recording the mass activity at the cerebellar surface simultaneously from several termination zones, while the activity in flexor motoneurones was recorded from a flexor nerve and the primary afferent depolarization from a dorsal filament. 2. Changes in the segmental reflex response were produced by release from the tonic inhibition of transmission from the FRA in decerebrate preparations and by conditioning electrical stimulation of dissected spinal funiculi containing inhibitory descending tracts. 3. The changes of the transmission from the FRA to two of the paths, the a- and b2-VF-SOCPs, parallelled the changes of the transmission to the segmental reflex arcs. On the other hand, the monosynaptic transmission from the FRA to the c1- and c3-VF-SOCPs was not significantly influenced by the inhibitory descending control systems. 4. The a- and b2-VF-SOCPs but not the c1- and c3-VF-SOCPs received polysynaptic excitation from tracts running in the ipsilateral half of the spinal cord. 5. The suggestion that the a- and b2-VF-SOCPs carry information related to interneuronal activity in segmental centres, whereas the c1- and c3-VF-SOCPs forward information mainly related to peripheral events (Andersson and Sjölund, 1978) is supported by the present findings.

Afferent Pathways↗
PubMed1978

The ventral spino-olivocerebellar system in the cat. IV. Spinal transmission after administration of clonidine and L-dopa.

1. The transmission from the flexor reflex afferents (FRA) to the spino-olivocerebellar paths ascending through the ventral funiculus (VF-SOCPs; Oscarsson and Sjölund, 1977) was compared with the transmission from the FRA to segmental reflex arcs in cats with the spinal cord transected in the third cervical segment sparing only the ventral funiculus on one side. The climbing fiber responses evoked in Purkinje cells by electrical stimulation of limb nerves were monitored by recording the mass activity at the cerebellar surface simultaneously from several termination zones, while the flexion reflex was recorded from a flexor nerve and the primary afferent depolarization (PAD) from a dorsal root filament. 2. Changes in the segmental reflex responses were produced by i.v. injections of l-Dopa and Clonidine. L-Dopa produced the expected depression of the flexion reflex and the FRA-induced PAD in the FRA, whereas Clonidine depressed only the flexion reflex but did not affect or even enhanced the FRA-induced PAD in the FRA. 3. The changes in transmission to one of the ascending paths, the a-VF-SOCP, parallelled that in the flexion reflex arc. The transmission to another path, the b2-VF-SOCP, parallelled that in the pathway responsible for the FRA-induced PAD in the FRA. 4. The remaining hindlimb paths, the c1- and c3-VF-SOCPs, monosynaptically activated from primary afferents, were little influenced by the changes induced in the segmental reflex arcs. 5. It is suggested that the a- and b2-VF-SOCPs carry information related to interneuronal activity in segmental centers, whereas the c1- and c3-VF-SOCPs forward information mainly related to peripheral events.

Afferent Pathways↗
PubMed1977

The indolaminergic innervation of the inferior olive. 2. Relation to harmaline induced tremor.

The possible involvement of serotoninergic mechanisms in the induction of harmaline generated tremor in the inferior olive has been investigated electrophysiologically in the cat and rat. Mass recordings of Purkinje cell activity in the cat showed that harmaline induces strong, synchronous and rhythmic activity in those parts of the climbing fibre system originating in the caudal part of the medial accessory olive and the caudolateral parts of the dorsal accessory nucleus. These are the areas of the cat olive shown to receive a dense serotoninergic innervation. In the rat, the selective removal of the serotoninergic innervation--produced by an intraventricular injection of 5,6-dihydroxytryptamine, or 5,7-dihydroxytryptamine in combination with desipramine--caused a significant attenuation of both the tremor and the climbing fibre activity induced by an intravenous harmaline injection. In the 5,6-dihydroxytryptamine-treated animals the reappearance of the harmaline tremor seemed to parallel the regrowth of new serotoninergic axon sprouts in the inferior olive. On the basis of the present results it is proposed that the serotoninergic afferents to the accessory olivary nuclei are of critical importance for the tremor induction of harmaline in the inferior olive. It is suggested that harmaline, rather than acting directly on the olivary neurones, exerts its effect through an interference with a serotoninergic (possibly inhibitory) innervation of these cells.

5,6-Dihydroxytryptamine↗
PubMed1977

The ventral spino-olivocerebellar system in the cat. I. Identification of five paths and their termination in the cerebellar anterior lobe.

1. The spino-olivocerebellar paths ascending through the ventral funiculus (VF-SOCPs) and projecting to the cerebellar anteior lobe were investigated in cats with the spinal cord transected in the third cervical segment sparing only the ventral funiculus on one side. The climbing fibre responses evoked in Purkinje cells by limb nerve stimulation were studied by recording the mass activity at the cerebellar surface or in the molecular layer. 2. Five VF-SOCPs were distinguished on the basis of their receptive fields, response latencies, and projection areas. 3. The projection areas consist of narrow sagittal zones. Three zones (a, b1 and b2) lie in the vermis and extend throughout lobules II--V. Two zones (c1 and c3) lie in the pars intermedia and are restricted to the classical hindlimb area, lobules II--IV. The VF-SOCPs are labelled according to their termination zones: a-VF-SOCP, b1-VF-SOCP, etc. 4. The a-, c1- and c3-paths are activated from the ipsilateral hindlimb, whereas the b1- and b2-paths are activated bilaterally from the forelimbs and hindlimbs, respectively. The latencies of the responses evoked from the ipsilateral hindlimb are relatively short for the c1-path and successively longer for the c3-, b2- and a-paths. 5. The olivary transmission showed fluctuations in efficacy independent for the different VF-SOCPs. The effect of anaesthetics on this transmission also differed between the paths. 6. It is concluded that the five VF-SOCPs relay in different compartments of the inferior olive which are tentatively identified.

Animals↗
PubMed1977

The ventral spine-olivocerebellar system in the cat. II. Termination zones in the cerebellar posterior lobe.

1. Five spine-olivocerebellar paths ascending through the ventral funiculus (VF-SOCPs) have previously been distinguished on the basis of different receptive fields, different response latencies and different projection zones in the cerebellar anterior lobe (Oscarsson and Sjölund, 1977). These paths are denoted the a-, b1-, b2-, c1 and c3-VF-SOCPs according to the labelling of their projection zones. The projection zones of these paths in the posterior lobe have noew been investigated. 2. The a-VF-SOCP projects to a medial zone in the pyramis. 3. The b1-and b2-VF-SOCPs do not project to the posterior lobe. 4. The c1-VF-SOCP projects to the medial one third of the pars copularis and caudalmost folium of the pars posterior of the paramedian lobule and to the most lateral part of the pyramis. 5. The c3-VF-SOCP projects mainly laterally to the caudalmost one or two folia of the pars copularis of the paramedian lobule. The c3 projection zone merges medially with the c1-zone. 6. The a-, c1- and c3-zones in the posteior lobe are innervated by climbing fibres which also send branches to the corresponding zones in the anterior lobe. 7. The VF-SOCP projection zones are tentatively identified with the sagittal zones described by Groenewegen and Voogd (1976) on the basis of anatomical studies.

Animals↗
PubMed1977

The ventral spino-olivocerebellar system in the cat. III. Functional characteristics of the five paths.

1. Five spino-olivocerebellar paths ascending through the ventral funiculus (VF-SOCPs) with different projection zones in the cerebellar cortex have been distinguished (Oscarsson and Sjöuld, 1977). The paths are denoted the a-, b1-, b2-, c1- and c3-VF-SOCPs according to the labelling of the projection zones. The functional organization of these paths has now been investigated. 2. All five paths are activated by the flexor reflex afferents from wide receptive fields (one or more limbs). Distal nerves are more effective in evoking responses than proximal nerves. 3. The a-, c1- and c3-paths are activated from the ipsilateral hindlimb only. The b1- and b2-paths are activated bilaterally from the forelimbs and hindlimbs, respectively. 4. The a-, b1- and b2-paths have long segmental delays indicating a polysynaptic linkage between the primary afferents and the tract neurones, whereas the c1- and c3-paths have short delays demonstrating a monosynaptic linkage. 5. The neurones giving origin to the paths are situated within a few segments of the dorsal root entrance. The axons cross the midline, ascend through the contralateral ventral funiculus, and activate the olivary neurones monosynaptically. 6. The spino-olivary tract of the c3-path has an upper conduction velocity of 30 m/s, whereas the other paths have upper conduction velocities of 40--45 m/s. 7. The segmental delay of the b1-VF-SOCP is much longer (mean 8.7 ms) than that of the b2-VF-SOCP (mean 3.9 ms). As a result simultaneous stimuli to the hindlimbs and forelimbs are signalled to reach the cerebellar cortex at the same time. 8. It is suggested that the information carried by the different paths is concerned with the segmental motor control.

Animals↗
PubMed1976

Correlation between dominant EEG frequency, cerebral oxygen uptake and blood flow.

In 32 chronic patients the EEG in temporal and occipito-parietal bipolar leads was analyzed with a manual method giving a period frequency index. The cerebral oxygen uptake (CMRO2) was calculated from the arteriovenous oxygen difference between samples from the internal carotid artery and the jugular bulb respectively, and from measurement of cerebral blood flow with the 133Xenon clearance method. A strong correlation (r = 0.78, P less than 0.001) was found between the EEG frequency indices and the CMRO2 of the hemisphere from which the EEG was recorded. Significant correlations between the EEG indices and gray matter cerebral blood flow were also demonstrated, while the correlation between the EEG indices and the blood flow of the white matter was weak. No correlation at all was found between the EEG indices and the relative weight of the gray matter. We conclude that the EEG carries information about the metabolic activity of the brain tissue. The EEG frequency also correlates with the blood flow of the gray matter of the brain when tissue anoxia has not uncoupled the normal function--flow relationship prevailing in the brain.

Adult↗