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Biomedical subjects

M Persson

Publications and source records attributed to M Persson.

At least 163 records · Page 9Linked to original sources
PubMed1983

The role of movements in the development of sutural and diarthrodial joints tested by long-term paralysis of chick embryos.

Chick embryos were paralysed in ovo with a neuromuscular blocking agent between 8 and 20 days of incubation. To evaluate the rôle of muscular activity in the development of sutural articulations, sutures of the cranial vault of control and paralysed embryos were studied histologically and the findings compared with the effect of the agent on the development of the ankle joint and some synovial joints of the jaws. Paralysed embryos showed a consistent lack of development of joint cavities in synovial joints. In most embryos, fusion of opposing cartilaginous elements had occurred. In contrast to synovial joints, sutural articulation showed a micromorphology comparable to that of controls. The findings indicate that different embryonic factors regulate the development of sutural and synovial articulations. Movements of neuromuscular origin play no essential role in the morphogenetic development of sutures, but are a prerequisite for the formation of joint cavities and other specialised structures of synovial joints.

Animals↗
PubMed1982

Peripheral nerve fibre degeneration in protein-deprived young rats. An ultrastructural study.

In a previous study the occurrence of nerve fibre degeneration with a distribution as in dying-back neuropathies was described in young rats subjected to severe protein deprivation (Oldfors 1981). In this study the ultrastructural appearance of the degeneration of the nerve fibres at different levels of the longitudinal tail nerve in severely protein-deprived rats has been investigated. Various structural changes were noted, the most common being bands of Bŭngner indistinguishable from those seen in Wallerian degeneration. In nerve fibres which were less severely affected the most common finding was shrinkage of the axon with concomitant folding of the myelin sheath. Other structural changes included axonal accumulation of 10 nm filaments or mitochondria and other cell organelles, areas of demyelination, and projections of axolemma and Schwann cell membrane into the axon. Signs of axonal regeneration occurred but were infrequent. The degenerative changes seen at various levels of the nerves support the view that the neuropathy is of distal axonal type, but the structural appearance differs from several of the toxic dying-back neuropathies.

Animals↗
PubMed1982

Structural similarities among gastrointestinal hormones and related active peptides.

The amino acid sequences of gastrointestinal hormones were compared in fragments of variable spans. Similarities within each of three peptide groups are extensive, but non-unique alignments were also noticed in the glucagon group. Use of different spans demonstrated that structural similarities are unevenly distributed in the gastrin family. Correct phasing was detected even for proteins with few identities and multi-shifted alignments (alcohol dehydrogenases). Tests for alignments among different groups of peptides revealed similarities between bombesin and glucagon or secretin, as well as between caerulein and litorin. Recently determined extended structures suggested the presence of a few deletions/insertions close to the middle of the molecules (two such positions missing in the gastrin-releasing peptide in relation to glucagon). The alignments appear to structurally link large groups of peptide hormones and active peptides. Similarities concentrate in the C-terminal parts, and gaps in the middle. These facts are consistent with known correlations with bioactivities. They also suggest the possibility of evolutionary connections among different peptides as well as corresponding relationships among their receptors.

Amino Acid Sequence↗
PubMed1982

Roentgencephalometric standards for the facial skeleton and soft tissue profile of Swedish children and young adults. II. Comparisons with earlier Scandinavian normative data.

The purpose of this report is to compare a Swedish so-called normal material (Thilander et al.1983) with previously presented normal materials of Scandinavian origin and with standards for parameters in some frequently used roentgencephalometric systems. The material comprises Swedish children and young adults who fulfil special criteria of normal occlusion and harmonius skeletal relations and in whom roentgencephalometric data were collected. Parts of the material here reported are designated the 10-, 13- and 16-year-old groups. Comparison of the cephalometric data for the age-group 10 years in our material and a previously presented Norwegian normal material (Humerfelt 1970) showed remarkably good agreement for both angular and linear measurements in both sexes. Good agreement was also found between angular measurements in the 16-year-old group and those presented by Werner(1954) for Swedish 13-16-year-old children, but there seem to be differences for certain mandibular parameters. Comparison with data for 12-year-old Swedish boys with varying occlusion, presented by Björk(1947), reveals differences for several angular mandibular measurements. The highly significant differences between the linear measurements in the two materials are probably partly explained by age differences but also tend to corroborate the indications of differences in skeletal pattern suggested by the angular measurements, which are due to the selection criteria. Finally, comparison with the Bergen norms for the straight face (Hasund 1973) shows that the agreement is generally acceptable for angular measurements and the standards may be considered sufficiently reliable for use in clinical orthodontics. They should be supplemental with the age-related variations, however.

Adolescent↗
PubMed1981

Monoamine cell distribution in the cat brain stem. A fluorescence histochemical study with quantification of indolaminergic and locus coeruleus cell groups.

The distribution of monoaminergic cell bodies in the brainstem of the cat has been examined with Falck-Hillarp fluorescence histochemical technique. Quantitative determinations indicate that the cat brainstem contains about 60,300 indolaminergic (IA) cells. The majority of these (about 46,700, or 77.5%) are located within raphe nuclei. The largest number is contained within nucleus raphe dorsalis (RD), accounting for around 24,300 IA cells, while raphe pallidus (RP) holds about 8,000 raphe centralis superior (RCS) 7,400, raphe magnus (RM) 2,400, raphe obscurus (RO) 2,300, linearis intermedius (LI) 2,100, and the raphe pontis (RPo) only some 280 IA cells. The IA cells represent, however, only part of the neuronal population of raphe nuclei, which, in addition, hold varying numbers of other medium-sized and small-sized neurons. Thus, quantification in Nissl-stained material indicate that the IA cells make up about 70% of the medium-sized cells in RD, 50% in RP, 35% in RCS and RO, 25% in LI, 15% in RM, and only 10% in RPo. The substantial numbers of small-sized perikarya observed in all raphe nuclei may represent interneurons. Significant numbers of IA cells were consistently located outside the raphe nuclei at all brainstem levels. In all, these amounted to approximately 13,600, or 22.5% of the total number of IA cells. Thus, IA cells occurred in the myelinated bundles, and sometimes in reticular formation, bordering the raphe nuclei; in the ventral brainstem forming a lateral extension from the ventral raphe (RP, RM, RPo, RCS, and LI) to the position of the rubrospinal bundle; in the periventricular gray and subjacent tegmentum of dorsal pons and caudal mesencephalon; in the locus coeruleus (LC) complex; around the motor trigeminal nucleus; caudal to the red nucleus; and in the interpeduncular and interfascicular nuclei. The wide distribution of IA cells leads to a considerable mixing with catecholaminergic (CA) cell groups. Our observations on CA cell distribution are essentially in accordance with previous reports. Quantifications indicate that the LC complex contains about 9,150 CA cells, unilaterally. A previously unnoticed group of scattered CA cells was found in relation to the vestibular nuclei and extending dorsally toward the deep cerebellar nuclei.

Animals↗
PubMed1981

Scattered catecholaminergic cells in the dorsolateral tegmentum caudal to locus coeruleus in cat.

In the cat brain stem, extending from the caudal locus coeruleus, scattered catecholaminergic (CA) cells are distributed over a large area. This includes a periventricular region dorsolateral to the fourth ventricle corresponding to the A4 group, the white matter separating vestibular and intracerebellar nuclei, and lateral to the vestibular complex in relation to the restiform body. In all, these CA cells were found to number 122 +/- 54 (mean +/- S.D.), unilaterally.

Animals↗
PubMed1981

Alcohol and polyol dehydrogenases are both divided into two protein types, and structural properties cross-relate the different enzyme activities within each type.

Sorbitol dehydrogenase from sheep liver shows similarities to mammalian and yeast alcohol dehydrogenases. Comparisons based on peptides from segments of sorbitol dehydrogenase reveal that homologous regions with 38% identity include two ligands to the active site zinc atom in liver alcohol dehydrogenase, as well as further important residues. Similarities in in other regions are less extensive, exactly as they are between different alcohol dehydrogenases. In all aspects, sorbitol dehydrogenase appears as a typical member of the alcohol dehydrogenase family. On the other hand, alcohol dehydrogenase from Drosophila, which has a shorter subunit, is not closely related to either of these enzymes, except for a region that probably corresponds to the first part of the coenzyme binding domain in many dehydrogenases. Instead, Drosophila alcohol dehydrogenase in its supposed catalytic region shows similarities toward Klebsiella ribitol dehydrogenase, which also has a small subunit. It may be concluded that both alcohol and polyol dehydrogenases show two types of protein subunit, reflecting an early subdivision of polypeptide types into "long" and "short" subunits rather than into different enzymatic specificities or quaternary structures. The relationships explain known properties of all these enzymes and provide insight into functional mechanisms and evolutionary interpretations.

Alcohol Oxidoreductases↗
PubMed1979

Description of an indolaminergic cell component in the cat locus coeruleus: a fluorescence histochemical and radioautographic study.

Using Falck-Hillarp fluorescence histochemical and radioautographic techniques, it has been found that, in addition to the well-known catecholaminergic cells, the locus coeruleus (LC) of the cat contains a sizeable component of indolaminergic neurons. Indolaminergic cell bodies occur in all subdivisions of the LC complex. They are most numerous in the LC proper and subcoeruleus area, but are also present in the medial and lateral parabrachial, and Kölliker-Fuse nuclei. In all, the indolaminergic cells are estimated to make up 7-10% of the monoaminergic neuronal population of the LC complex. With the exception of the Kölliker-Fuse nucleus, where somewhat larger cells occur, the indolaminergic cell bodies in different parts of the LC complex share a common fluorescence histochemical appearance. They display round to fusiform shapes and measure 30 x 18 micron on the average, which makes them cytoarchitectonically similar to the small type of noradrenergic cells in the LC. The formaldehyde-induced fluorescence of the indolaminergic cells in the LC complex was analyzed microspectrofluorometrically and the recorded excitation and emission spectra (maxima at 370 and 530 nm, respectively) were found to be identical with those recorded from midline raphe neurons. No evidence of noradrenaline content was found in the indolaminergic cells of the LC. Radioautographic experiments after intratissular injections of tritiated serotonin showed that the indolaminergic cells of the LC complex possess uptake mechanisms for serotonin. Taken together these results provide strong evidence for serotonin being the transmitter of the indolaminergic neurons discovered in the LC of the cat.

Animals↗
PubMed1978

Pathogenicity in mice of strains of Candida albicans with different in vitro sensitivity to 5-fluorocytosine.

The pathogenicity in mice of 7 strains of Candida albicans with different in vitro susceptibility to 5-fluorocytosine (5-FC) was investigated. Resistant strains were not less virulent than susceptible strains. This is contradictory to findings reported for candida strains resistant to polyene antibiotics, which were less pathogenic than susceptible strains. The implications of these findings are discussed.

Animals↗
PubMed1978

Sutural closure in rabbit and man: a morphological and histochemical study.

Some aspects of normal obliteration of sutures in rabbit and man were studied histologically and it was found that suture closure took place by intramembranous ossification in specific areas of trans-suturally arranged, tendon-like tissue. Histochemically these areas demonstrated high activity of oxidative enzymes.

Adolescent↗