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Biomedical subjects

H Korneliussen

Publications and source records attributed to H Korneliussen.

At least 19 recordsLinked to original sources
PubMed1978

Myosatellite cells associated with different muscle fibre types in the Atlantic hagfish (Myxine glutinosa, L.).

The incidence of myosatellite cells associated with "white" and "red" muscle fibres of the parietal muscle and "red" fibres of the craniovelar muscle was estimated by quantitative electron microscopy in the Atlantic hagfish (Myxine glutinosa, L.). Myosatellite cell nuclei constitute 3, 11 and 23% of the total number of nuclei inside the basal lamina of the three types of muscle fibres, respectively. However, the total number of nuclei is highest in "white" fibres, most of the nuclei belonging to striated muscle cells. Myosatellite cell profiles in transverse sections constitute 23, 41 and 61% of the number of muscle fibre profiles of the three types, respectively. The intervals between adjacent myosatellite cells are approximately 135 micrometer in "white" fibres, approximately 55 micrometer in "red" parietal fibres, and only approximately 25 micrometer in craniovelar fibres. Since craniovelar fibres are also comparatively thin, myosatellite cells constitute a significant fraction of the volume inside the basal lamina in these fibres. The myosatellite cells are approximately 30-50 micrometer long and up to 5 micrometer thick. Some myosatellite cells possess few organelles, whereas others appear to contain many free ribosomes, granular endoplasmic reticulum, prominent Golgi apparatus and lysosome-like bodies.

Animals↗
PubMed1978

On T-tubule openings at the sarcolemma of white fast-twitch muscle fibres in fish and frog.

In "white" muscle fibres of a teleost fish T-tubule openings may occur regularly at all Z-disc levels between adjacent peripheral myofibrils, the T-tubule openings thus occurring at a density of ca. 0.9 micrometer-2. In frog "white" fibres, T-tubule openings are infrequently seen in material fixed like the fish material. In material prepared according to the albumin method of Gray (1975, 1976 a, b) which renders the muscle fibres swollen, straight tubules or sometimes chains of vesicles instead are seen opening at the sarcolemmal surface. Such tubules occur at a higher density than expected from experiments with local activation of contraction. Lability and dynamics within the T-system normally and during fixation are discussed.

Animals↗
PubMed1978

Histochemical definition of muscle fibre types in the trunk musculature of a teleost fish (cod, Gadus morhua, L.).

Cryostat sections incubated for myofibrillar ATPase, SDH, LDH, and alpha-GPDH as well as p-phenylene-diamine stained semithin sections were used to define muscle fibre types in the trunk musculature of the cod (Gadus morhua, L.). Three zones (superficial, intermediate, deep) containing different muscle fibre types are present within both epaxial and hypaxial parts of each myomere subjacent to the lateral line. Atypical relations concerning myofibrillar ATPase activity probably reflects instability of myosin during storage of frozen tissue. The histochemical reaction does not distinguish between myofibrillar and mitochondrial ATPase in cod muscle. Based on ATPase and SDH activities, seven different histochemical profiles of muscle fibres can be identified in trunk musculature of this teleost fish. Attempts to homologize these fibre types with those in cyclostomes or those in higher animals proved futile. The higher number of histochemically defined muscle fibre types in cod might be explained by developmental processes and an admixture of immature fibres throughout life.

Adenosine Triphosphatases↗
PubMed1977

Tubules invaginating from the sarcolemma in the subneural region of muscle fibers.

Sarcoplasmic tubules invaginating from the sarcolemma of the subneural region of muscle fibers are described in Atlantic hagfish and rat. In rat, the tubules invaginate from the bottoms of the secondary synaptic clefts. The density of tubule openings may be higher than the density of T-tubule openings elsewhere along muscle fibers.

Animals↗
PubMed1977

Morphogenesis and morphology of the brain stem nuclei of Cetacea. I. The hypoglossal nucleus.

1. The hypoglossal nucleus of whalebone whales is composed of four major subdivisions, forming four parallel columns, here called the dorsomedial, the dorsolateral, the ventromedial and the ventrolateral XII columns. 2. The ventromedial XII column extends throughout the hypoglossal nucleus, forming in whalebone whales the rostral as well as the caudal end of the nucleus. 3. The ventrolateral XII column is lamelliformed and splits into a dorsomedial and a ventrolateral part, the former intimately related topographically to the dorsomedial column. 4. The dorsomedial XII column is torpedo-shaped, tapering in rostral direction and terminating a little short of the rostral end of the ventromedial XII column, while the blunt end terminates immediately caudal to the obex. 5. The dorsolateral XII column is the shortest subdivision, approximately one fourth of the length of the entire hypoglossal nucleus. The blunt rostral end of the torpedo-shaped column blends with the dorsomedial XII column, its tapering caudal end terminating rostral to the obex. 6. The cells of the hypoglossal nucleus vary in size from small to medium-sized and large, the small ones dominating in the dorsomedial, the large ones in the dorsolateral and ventromedial XII columns. The ventrolateral column is characterized by spindle-shaped cells. 7. In the toothed whale Phocaena communis the differentiation of the hypoglossal nucleus is less clearcut than in whalebone whales, but a similar structural priniciple is recognizable.

Animals↗
PubMed1976

Ultrastructure of the new neuromuscular junctions formed during reinnervation of rat soleus muscle by a "foreign" nerve.

In rats the "fast" fibular nerve was transposed to the "slow" soleus muscle outside the original innervation band. Formation of new neuromuscular junctions was induced by cutting the soleus nerve after different periods of time. The morphological maturation of these junctions was studied by electron microscopy. New neuromuscular junctions do not form when the original innervation is left intact. Three to five days after denervation, vesicle-laden terminal boutons contact muscle fibers with only the basal lamina of the latter intervening. Three weeks after denervation, most boutons are larger and postsynaptic folds are present, although younger stages are also seen. Sixteen weeks after denervation, the neuromuscular junctions appear mature. This corresponds well with electrophysiological findings in the same material. The fully developed neuromuscular junctions sixteen weeks after denervation possess postsynaptic folds similar to those of normal "fast" muscle fibers. This suggests that the "fast" fibular nerve rather than the "slow" soleus muscle fibers determines the morphology of the postsynaptic folds. Possible trophic neuromuscular interactions are discussed.

Animals↗
PubMed1976

Morphological aspects of the elimination of polyneuronal innervation of skeletal muscle fibres in newborn rats.

The ultrastructure of neuromuscular junctions of rat soleus muscles 1-40 days postnatally was examined for possible morphological correlates of the transient polyneuronal innervation which is present in newborn rats. Several vesicle-laden profiles of terminal axons are seen to contact each muscle fiber up to 8 days postnatally. Axon terminals often lie close together, without Schwann cell intervention. Between days 8 and 16 the number of profiles of terminals on each muscle fibre is reduced, and both Schwann cells and ridge-like extensions of muscle fibre cytoplasm intervene between and separate axon terminals. No signs of degenerating intramuscular axons or axon terminals could be found. It is suggested that the redundant terminals are eliminated by retraction into the parent axons. This process is apparently accomplished without any morphological signs of degeneration.

Animals↗
PubMed1975

Fenestrated blood capillaries and lymphatic capillaries in rat skeletal muscle.

Capillary fenestrae occur in one of about 60 cross-sectioned blood capillaries in normal adult rat skeletal muscles. The fenestrae occur singly or in groups. Fenestrated capillaries are found close to muscle fibers as well as in the perimysial and perineurial connective tissue. Small numbers of lymphatic capillaries are also present, mostly in the perimysial connective tissue.

Animals↗
PubMed1975

Distribution and dimension of the T-system in different muscle fiber types in the atlantic hagfish (Myxine glutinosa, L.).

Triad density relative to sarcomeres, size of T-system tubules, sarcomere length, muscle fiber diameter in native and fixed states, and size of myofibrils were measured in four straited muscle fiber types in Atlantic hagfishes (Myxine glutinosa, L.) of different sizes. Traids occur at A/I-injunctions in all fiber types. The density of traids relative to sarcomeres is higher in "white" than in "red" muscle fibers. The T-tubules show no sign of branching. The area of the T-system tubules is 3-4 times the surface area in 80 mum "white" muscle fibers and 1-2 times that in 60 mum "red" fibers. The size of myofibrils is similar in "white", "intermediate", and "red" fibers of m. parietalis, and constant through a large span of animal size. In "white" fibers, increase in diameter up to 90 mum is accompanied by an increase in the number of myofibrils, not by an increase in the individual size of the myofibrils. Above 90 mum, "white" fibers grow by increasing the amount of intermyofibrillar space. This is reflected by an extensive shrinkage of the thicker "white" fibers during the preparative procedure for electron microscopy, a shrinkage that is limited only by complete packing of the myofibrils. "Red" fibers shrink much less.

Animals↗