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Biomedical subjects

M Müntener

Publications and source records attributed to M Müntener.

At least 37 records · Page 2Linked to original sources
PubMed1993

Human alpha and beta parvalbumins. Structure and tissue-specific expression.

alpha and beta parvalbumins are Ca(2+)-binding proteins of the EF-hand type. We determined the protein sequence of human brain alpha parvalbumin by mass spectrometry and cloned human beta parvalbumin (or oncomodulin) from genomic DNA and preterm placental cDNA. beta parvalbumin differs in 54 positions from alpha parvalbumin and lacks the C-terminal amino acid 109. From MS analyses of alpha and beta parvalbumins we conclude that parvalbumins generally lack posttranslational modifications. alpha and beta parvalbumins were differently expressed in human tissues when analyzed by immunoblotting and polymerase-chain-reaction techniques. Whereas alpha parvalbumin was found in a number of adult human tissues, beta parvalbumin was restricted to preterm placenta. The pattern of alpha parvalbumin expression also differs in man compared to other vertebrates. For example, in rat, alpha parvalbumin was found in extrafusal and intrafusal skeletal-muscle fibres whereas, in man, alpha parvalbumin was restricted to the muscle spindles. Different functions for alpha and beta parvalbumins are discussed.

Amino Acid Sequence↗
PubMed1993

Duration of pain and muscular adaptations in patients with dysfunction of the cervical spine.

Biopsies of the sternocleidomastoid and omohyoid muscle were taken from 24 patients who underwent arthrodesis for cervical dysfunction of different etiologies. The two muscles, which are involved differently in movements of the head and cervical spine, were investigated histochemically. Muscle fibers were classified as type I, IIA, IIB, or IIC (transitional fibers) according to the pH lability of myofibrillar ATPase and calculated relative distribution. In both muscles, fiber transformations (as evidenced by an increase in the relative amount of type-IIC fibers) were regularly observed within the first 2 years after the onset of the symptoms. The occurrence of the transformation processes was independent of the patient's age and sex and was the same for the different etiologies. Since the overall fiber composition of the muscles remained essentially unchanged, the fiber transformations must occur alternatingly in both directions (from "slow" to "fast" and the reverse). Muscles of patients with a long case history showed no greater signs of fiber transformation. Therefore, fiber transformations in response to cervical dysfunction occur in the initial stage of the disease and involve different types of muscles. The muscles then return to a "stable" condition, independent of the continuation of the dysfunction and the chronic neck pain.

Adaptation, Physiological↗
PubMed1990

Innervation and maturation of muscular tissue in testicular teratomas in strain 129/Sv-ter mice.

In strain 129/Sv-ter mice, teratomas develop spontaneously during the 13th day of gestation. These testicular germ cell tumors exhibit characteristics of different germ layers closely resembling normal embryonic tissue. We investigated the interrelationship between nervous and muscular tissues (often found side by side) in teratomas of 4-week-old 129/Sv-ter mice. In well-differentiated mouse teratomas, histochemically and immunohistochemically distinct muscle fiber types could be distinguished, but not with all reactions. According to its aerobic oxidative capacity, teratoma muscle tissue was comparable with normal muscles. However, with respect to myosin-related properties, fiber type differentiation was incomplete. The muscle fibers - generally arranged in bundles - contained one centrally located endplate which was contacted mostly by a single nerve terminal. From this, proper endplate zones within the fiber bundles were formed. Occasionally "type grouping" was encountered, suggesting collateral axonal branching paralleled by synapse elimination. Together with the earlier in vivo observation of muscular contractions, we assume that teratoma muscle fibers are innervated by nerve cells (within the nervous tissue compartments) corresponding to spinal motoneurons. Thus, myogenesis, maturation and innervation of skeletal muscular tissue in mouse teratomas are largely comparable to normal development.

Animals↗
PubMed1989

Delayed muscle fiber transformation after foreign-reinnervation of excessive muscle tissue.

Following partial denervation motor units can increase (by self-reinnervation) as much as four to five times their normal size. To investigate the still unknown quantitative reinnervation capacity of a motor nerve in the case of foreign-reinnervation, in adult male rats the denervated sternomastoid muscle was either self-reinnervated by its original nerve or foreign-reinnervation by the omohyoid nerve, which had to reinnervate the three times the amount of muscle fibers and six times the amount of muscle mass. After survival times of 7, 8, 9, or 10 months, nerves and muscles were investigated histochemically and immunohistochemically. The omohyoid nerve could fully reinnervate the sternomastoid muscle, but at 7 and 8 months this muscle still revealed nearly the same proportions of IIA and IIB fibers as were seen in the self-reinnervated sternomastoid at all stages. However, in the following 2 months a shift of the fiber pattern toward that of the normal omohyoid was observed, as evidenced by a strong increase in type IIB fibers (from 24% to 62%), at the expense of type IIA fibers. These findings are in contrast to those after foreign (cross) reinnervation of leg muscles where the fiber transformation (according to the foreign motor input) occurs in parallel with the reinnervation process during the first 2-3 months. The delayed fiber transformation observed could be the consequence of the highly enlarged peripheral field of the omohyoid motoneuron pool or could merely reflect a general difference between limb and neck muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Changes in the concentration of the calcium-binding parvalbumin in cross-reinnervated rat muscles. Comparison of biochemical with physiological and histochemical parameters.

The fast extensor digitorum longus (EDL) and the slow soleus (SOL) muscles were cross-reinnervated in both directions in the rat. During the following transformation of muscle type properties, the expression of the Ca2+-binding parvalbumin (parvalbumin, Mr = 12,000) was investigated. The combined biochemical, histochemical, and physiological results demonstrated that the amount of parvalbumin decreased in the fast to slow (X-EDL) and increased in the slow to fast (X-SOL) transformation. Alterations of parvalbumin-mRNA levels were similar to changes found at the protein level, indicating a tight transcriptional regulation of the parvalbumin expression. The close correlation, however, between parvalbumin and relaxation speed found in normal muscles had changed after cross-reinnervation. After the altered nervous input, a slow contracting/slow relaxing muscle may even contain more parvalbumin than a fast contracting/fast relaxing one. The expression of parvalbumin may depend on the nerve-muscle interaction, and parvalbumin may thus be used as a sensitive marker for early stages of muscular transformation and neurological disorders.

Animals↗
PubMed1987

Analysis of the Ca2+-binding parvalbumin in rat skeletal muscles of different thyroid states.

The Ca2+-binding parvalbumin (PV) is possibly involved in the relaxation of fast-twitch muscle fibers and believed to be a marker for early muscular disturbances. The muscular content of parvalbumin has been shown to change with alterations of the relaxation speed that follow an experimentally changed nervous input. In hypo- and hyperthyroidism isometric twitch contraction and half-relaxation times are also altered, namely increased in hypothyroidism and decreased in hyperthyroidism. These changes are largely paralleled by modifications in the fiber type composition. Therefore we investigated the distribution and concentration of parvalbumin in extensor digitorum longus, soleus, and gastrocnemius muscles of rats by immunohistochemical and biochemical methods. The combined results of both procedures showed that parvalbumin distribution and concentration were largely unaffected in all thyroid states. This suggests that the expression of parvalbumin is neuronally controlled and not by thyroid hormones. Additionally our findings support the view that the changes in physiologic properties and fiber type composition are generated by a direct action of thyroid hormone on muscle fibers, and not via their nervous input.

Adenosine Triphosphatases↗
PubMed1986

Fiber type and non-endplate acetylcholinesterase in normal and experimentally altered muscles.

The non-endplate (sarcoplasmic) acetylcholinesterase (AChE) was investigated in eight different muscles of the rat. Serial consecutive sections were stained for AChE, myofibrillar ATPase (after alkaline and acid preincubation), and cytochrome C-oxidase. The following general correlation could be established: within a given muscle the sarcoplasmic AChE was highest in type IIB fibers, lowest in type I and intermediate in type IIA. Additionally, the intensity of the reaction was directly proportional to the size of the type IIA fibers. The distribution of sarcoplasmic AChE was correlated to the ATPase fiber types but was complementary to the cytochrome C-oxidase staining pattern. In single fiber preparations, accumulation of AChE at the myotendinous junction was found to occur in "cap-like" form exclusively in fibers with very low or absent sarcoplasmic AChE. To study the role of innervation in the expression of the sarcoplasmic AChE, we cross-reinnervated the extensor digitorum longus (EDL) muscle with the soleus (SOL) nerve and vice versa (X-EDL, X-SOL). In the X-EDL the sarcoplasmic AChE was transformed to that of a normal SOL as were also the ATPase and the cytochrome oxidase. Surprisingly, in the X-SOL the high AChE activity typical for a normal EDL was present after 3 weeks but decreased steadily to very low levels lacking any correlation with ATPase and cytochrome oxidase. The results suggest that the cytoplasmic AChE of the SOL muscle depends more on the load-bearing function of the muscle than on the imposed impulse pattern. There is additional evidence for a retrograde effect of the X-SOL upon its motoneurons.

Acetylcholinesterase↗
PubMed1985

Parvalbumin in cross-reinnervated and denervated muscles.

The extensor digitorum longus (EDL) muscle was cross-reinnervated by the soleus (SOL) nerve, leading to the well-known transformation toward a slow muscle. Nine weeks after the operation, the quantitative analysis of the Ca2+-binding protein, parvalbumin (PV), using high-performance liquid chromatography, showed a threefold reduction of PV in the cross-reinnervated EDL muscle. Denervation of the EDL muscle, which leads to an increase of the half-relaxation time, resulted in a 20% decrease of the PV concentration within 4 days. This significant lower PV level was detectable prior to any change of the myofibrillar adenosine triphosphatase (ATPase). Normal PV concentrations were reached after 9 weeks following self-reinnervation of the EDL muscle. The experiments support the view that PV is involved in the relaxation of rat fast skeletal muscles and that its expression is dependent on nerve-muscle interaction. Since PV changes preceded histochemical changes after denervation, this protein may be a sensitive marker for early stages of neuromuscular disturbances.

Adenosine Triphosphatases↗
PubMed1985

Muscle fiber transformation in capsaicin-treated rats.

Rats were injected with capsaicin or solvent on the 2nd day of life. Nine weeks later both animal groups were further subdivided: one was untreated and the other group underwent surgery consisting in either (a) removal of one sternohyoid superior muscle or (b) a sham operation. The sternohyoid superior muscles were removed at 3-day intervals and investigated for their myofibrillar ATPase reaction. Capsaicin application alone produced a primary (baseline) muscle fiber transformation from fast to slow which was reflected in a considerable increase in the type IA fiber population (almost lacking in normal controls). However, at all stages investigated the degree of transformation (i.e., the amount of IA fibers) displayed a great individual variability. In addition to this basic transformation, both surgical procedures elicited a concordant behavior of the muscles and an undulating time course of the number of type IA fibers. This secondary reversible muscle fiber transformation was superimposed on the primary one. There is evidence that the operative treatments caused a synchronization of the on-going transformation processes in the labile primary transformed fiber population rather than fiber changes per se.

Animals↗
PubMed1984

Changes of myosin and its ATPase in "neuronally" and "mechanically" contralateral muscles after cross-reinnervation in normal and capsaicin-treated rats.

The extensor digitorum longus (EDL) muscle was cross-reinnervated by the soleus (SOL) nerve in normal and neonatally capsaicin-treated rats. After 5 months the muscles were investigated for their myofibrillar ATPase reaction and their myosin light and heavy chain composition. Besides the well known transformation of the cross-reinnervated EDL toward a slow muscle, muscular changes were also found in the contralateral leg. Although these changes were hardly detectable in the EDL muscle, a remarkable (70 to 100%) reduction of the fast type IIA fiber population was found in the SOL. The decrease of the number of IIA fibers (compared with time-matched controls) was paralleled by corresponding changes in the myosin light and heavy chain patterns. After the cross-reinnervation of a muscle, two kinds of contralaterality must be distinguished. In the experiments reported the cross-reinnervated EDL muscle remains "mechanically" contralateral to the EDL muscle of the other leg, while it becomes "neuronally" contralateral to the SOL muscle. Our results are interpreted as a symmetric "slowing down" of these "neuronally" contralateral muscles. Neonatal capsaicin treatment that decreased considerably the number of unmyelinated group IV afferent fibers did not influence the outcome of these experiments.

Adenosine Triphosphatases↗
PubMed1983

Changes of myosin and its ATPase in experimentally induced fiber transformation in the rat.

It has been reported that a reversible muscle fiber transformation was effected within a short time in the sternohyoid muscle of the rat by the removal of the contralateral muscle. In the present investigation the muscles were analyzed histochemically and biochemically. The fiber transformation was easily detected histochemically by the appearance of slow type I fibers, as this fiber type is almost lacking in control muscles. In two-dimensional electrophoresis the light chain pattern of the experimental and control muscles was similar. However, the peptide pattern of the heavy chains revealed clear differences between control and experimental muscles. The muscle fiber transformation found was reflected in the myosin heavy chain which is the site of ATPase activity. For transformation of the light chain pattern probably a much stronger stimulus is needed.

Adenosine Triphosphatases↗
PubMed1980

The ansa cervicalis and the infrahyoid muscles of the rat. II. Motor and sensory neurons.

Perikarya of motoneurons and spinal ganglion cells attributed to infrahyoid muscle nerves of the rat were labelled by retrogradely transported horseradish peroxidase (HRP). For the differentiation of motor and sensory axons cross sections of the nerves were stained for acetylcholinesterase. Numbers and diameter distributions of perikarya and myelinated axons were determined. Motoneuronal perikarya innervating the infrahyoid muscles are located from the transition zone brain stem/spinal cord to the segment C 3. They are found mostly in the medial part of the Rexed laminae VII and VIII at the level of C 1 and C 2 and more ventrolaterally in C 3 and are therefore located to a large extent in areas until now not recognized to contain motoneurons. Our results provide evidence for a somatotopic organization of the motoneurons in the upper cervical spinal cord. The diameter distributions of motoneuronal perikarya and axons are in most cases bimodal, the two modes corresponding to alpha- and gamma-motoneurons. In relation to the diameters of their perikarya alpha-axons are significantly thicker than gamma-axons. In contrast to the motoneurons no clear correlation could be established between the sizes of perikarya of spinal ganglion cells and their peripheral processes.

Animals↗
PubMed1979

Short time observations of morphological changes and cholinesterase distribution in lymphatic organs of the mouse after corticosteroid and X-ray treatment.

The changes in thymus, spleen and lymph nodes of the mouse after a single cortisone application or a single whole body x-irradiation were investigated morphologically and histochemically. During 24 h the alterations following the cortisone application are at all stages examined indistinguishable from those following the x-irradiation. The first signs of lymphocyte destruction can be observed already in the first two hours after treatment. Almost at the same time macrophages accumulate at the sites of cell death in the lymphatic organs studied. The eosinophils display a different behaviour. While they accompany the macrophages in the thymus already at the first stages, they appear in the spleen and lymph nodes with a latency of 6 and 8 h, respectively. The highest amount of necrotic cells is found ten hours after both treatments. At the same time the accumulation of macrophages and eosinophils reaches its maximum. The cholinesterase in the lymphatic organs is largely the true cholinesterase. The enzyme-activity increases in the cortex of the thymus gradually 6 h after treatment, showing the highest deposit of reaction product at 10 h. In spleen and lymph nodes the cholinesterase shows only slight variations. The possible role of the cholinesterase-activity in these non-cholinergic tissues is discussed.

Animals↗