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Biomedical subjects

B M Carlson

Publications and source records attributed to B M Carlson.

At least 19 recordsLinked to original sources
PubMed1992

Formation of the peripheral nervous system during tail regeneration in urodele amphibians: ultrastructural and immunohistochemical studies of the origin of the cells.

In the regenerating newt tail, epimorphic regeneration--which recapitulates morphologically normal embryonic development--proceeds along a rostrocaudal differentiation gradient. Innervation of the new myomeres results from the spinal roots of segments rostral to the amputation plane and from ventral roots emerging from the lateroventral region of the regenerating spinal cord, in which motor neurons are differentiating. Electron microscopy and an indirect immunofluorescence study with anti-glial fibrillary acid protein (GFAP) confirm that the ventrolateral part of the regenerated ependymal tube gives rise to cells of the ventral root sheath and the spinal ganglia. Anti-GFAP and anti-neurofilament antibodies showed that ependymoglial cells and Schwann cells may play a role in neuronal pathfinding by helping guide and stabilize pioneering axons as they extend toward the myomeres. The carbohydrate epitope NC-1 is expressed in the spinal cord, in sheath cells of the spinal ganglia and in the non-myelin-forming Schwann cells of the peripheral nervous system. L1, a Ca++ independent neural cell adhesion molecule, was detected in the axonal compartments of the regenerating spinal cord, on immature and/or non-myelin-forming Schwann cells within the peripheral nervous system (PNS), and on nerve fibers within the regenerate. These immunohistochemical observations collectively support the hypothesis that Schwann cells already present in the blastema could be involved in organizing neural pathways.

Animals↗
PubMed1992

Expression of alpha-cardiac and alpha-skeletal actin mRNAs in relation to innervation in regenerating and non-regenerating rat skeletal muscles.

The expression of alpha-cardiac and alpha-skeletal actin mRNA in regenerating muscle was examined. Changes in mRNA levels were analyzed in autografted extensor digitorum longus (EDL) muscles in rats using alpha-isoform specific synthetic oligonucleotides and beta-actin cDNA as probes. After autografting, the expression of alpha-cardiac actin mRNA was induced; concomitantly that of alpha-skeletal actin mRNA was reduced. The pattern of alpha-actin mRNA expression appeared to be similar to that seen in embryonic skeletal muscle. In order to evaluate the effects of innervation on alpha-actin mRNA expression in regenerating muscle, nerveless, standard, and nerve-intact autografted muscles were examined. More complete innervation facilitated the recovery of alpha-skeletal actin mRNA to control levels, but had little effect on the amount of alpha-cardiac actin mRNA. We found that regenerating muscle shows that embryonic pattern of alpha-actin mRNAs in the early stage and concluded that the recovery of alpha-skeletal actin mRNA expression to the adult pattern is influenced by innervation, while alpha-cardiac actin mRNA expression is nerve independent.

Actins↗
PubMed1992

Extraocular muscle regeneration in primates. Local anesthetic-induced lesions.

Retrobulbar administration of several local anesthetics (0.75% bupivacaine, 2.0% mepivacaine or 2.0% lidocaine plus 1:100,000 epinephrine) in monkeys resulted in a low incidence of muscle fiber lesions in the extraocular muscles closest to the site of injection. Most lesions resulted in the degeneration and regeneration of muscle fibers on the surface of the muscles, but occasionally a massive internal lesion was seen. In contrast, large lesions were common in rectus muscles that received direct injections of local anesthetics in both monkeys and humans. The morphology and temporal sequence of muscle fiber degeneration and regeneration was similar to that seen in primate thumb muscles injured by anesthetic agents.

Adult↗
PubMed1992

Morphologic characteristics of muscles grafted in rabbits with neurovascular repair.

In 34 female white rabbits, rectus femoris (RFM) muscles were grafted with immediate anastomoses of the vasculature (VA) and with nerves either left intact (NI-VA) or with nerves repaired (NR-VA). The purpose of the study was to compare the morphologic changes that occur in NI-VA grafts and NR-VA grafts from 8 to 120 days after grafting. After 8 days, nearly complete survival of all muscle fibers was found. The muscle mass and single fiber cross-sectional area (CSA) of the NI-VA group remained near control values for the first 30 days and then declined to 82 percent and 62 percent of the control values, respectively. Little evidence of morphologic disruption was observed. The NR-VA grafts displayed a significant denervation atrophy within the first 15 days, with relative values 67 percent of the control value for mean mass and 53 percent for single fiber CSA. By 120 days, mass and CSA recovered to 80 percent and 62 percent of control values. Although the similarity of the deficits in the nerve-intact and nerve-repaired grafts suggest that tenotomy and repair, rather than innervation, were the major limitations, the mechanism was not resolved.

Adipose Tissue↗
PubMed1991

A method for preparing skeletal muscle fiber basal laminae.

Previous attempts to prepare skeletal muscle basal laminae (BL) for ultrastructural analyses have been hampered by difficulties in successfully removing skeletal muscle proteins and cellular debris from BL tubes. In the present study we describe a two phase method which results in an acellular muscle preparation, the BL of which are examined by light, transmission electron, and scanning electron microscopy. In the first phase, excised rat extensor digitorum longus muscles are subjected to x-radiation and then soaked in Marcaine to inhibit muscle regeneration and to destroy peripheral muscle fibers. The muscles are then grafted back into their original sites and allowed to remain in place 7-14 days to allow for maximal removal of degenerating muscle tissue with minimal scar tissue formation. In the second phase, the muscle grafts are subjected sequentially to EDTA, triton X-100, DNAase, and sodium deoxycholate to remove phagocytizing cells and associated degenerating muscle tissue. These procedures result in translucent, acellular muscle grafts which show numerous empty tubes of BL backed by endomysial collagenous fibers. These preparations should be useful for morphological analyses of isolated muscle BL and for possible in vitro studies by which the biological activity of muscle BL can be examined.

Animals↗
PubMed1991

Early innervation of skeletal muscle during tail regeneration in urodele amphibians.

The innervation pattern of skeletal muscles was studied in the normal and regenerating tail of Notophthalmus viridescens. Silver staining for nerve endings and histochemical localization of acetylcholinesterase (AChE) were used for light microscopy. In In normal musculature, AChE positive reactions were localized at the ends of the muscle fibers where they are anchored on connective tissue septa by myotendinous junctions. At this level, silver staining shows nerve terminals forming endplates. During regeneration, positive reactions for AChE appear de novo as dense plates localized at the ends of the newly formed myotubes. The mechanisms involved in the localization of AChE on this surface seem to operate before previous local contacts by nerve terminals. From the ultrastructural data and immunohistochemical results with anti-laminin antibody, these observations suggest that regenerating muscle fibers determine a region of post-synaptic specialization in close relation with the organization of myotendinous regions and basement membrane formation. Nerve-muscle contacts appear at these levels at stage IV (15-20 days after amputation) in the stump and in the rostral part of the regenerate (transition zone). These nerve terminals are provided by the disorganized peripheral nervous system of the injured segment. In the regenerate a similar pattern of AChE reaction can be seen in every myotube, differentiating according to a rostro-caudal gradient. Innervation at the ends of the muscle fibers is in spatiotemporal relation with the exists of the ventral roots from the regenerating nerve cord as the regenerate continues to grow in length.

Animals↗
PubMed1991

Muscle fiber branching--difference between grafts in old and young rats.

Large numbers of branched muscle fibers occur in the freely grafted rat extensor digitorum longus muscle. The ratio of branched/non-branched muscle fibers in grafts is much higher in old (24 months) than in young (4 months) host rats. Cross-age transplants show that the proportion of branched muscle fibers is related to the age of the grafted muscle and not to the age of the host. This is in contrast to mass and maximum isometric tension, in which the age of the host, rather than the age of the grafted muscle, is the determinant of the success of the muscle graft.

Aging↗
PubMed1991

Induction of adult-type nicotinic acetylcholine receptor gene expression in noninnervated regenerating muscle.

Expression of adult-type nicotinic acetylcholine receptors at the neuromuscular junction is thought to result from selective induction of their genes in endplate-associated nuclei due to local neurotrophic control. However, denervation studies indicate that endplate-specific expression can be maintained in the absence of the nerve. We investigated the role played by the basal lamina in this expression by assaying for the adult-type-specific epsilon RNA in noninnervated regenerating muscle. We found that this RNA is locally expressed beneath the old endplates after 10 days of regeneration. At earlier times epsilon RNA is also found in areas other than the endplate region. These results indicate that in adult muscle the basal lamina contains all the components necessary to direct nicotinic acetylcholine receptor gene expression to the endplate.

Animals↗
PubMed1991

Rapid and complete recovery of responsiveness to adenosine and norepinephrine by regenerating arterioles of the tibialis anterior muscle of the hamster after in situ autografting.

Intravital microscopy studies of small bundles of fibers of the extensor digitorum longus muscle grafted onto the hamster cheek pouch revealed a persistent reduction in the responsiveness of regenerated arterioles to vasoactive agents. We tested the hypothesis that the recovery of responsiveness to vasoactive agents by regenerating arterioles within whole, in situ autografted tibialis anterior muscles occurs earlier and more completely than that reported for regenerating arterioles within bundles of fibers of the extensor digitorum longus muscle grafted ectopically to the hamster cheek pouch. The tibialis anterior muscles of Syrian golden hamsters were excised and soaked in bupivacaine (0.75%) for 10 minutes to ensure uniform degeneration of muscle fibers. The tendons were resutured, and the graft became revascularized spontaneously. Fluorescent intravital microscopy was used to measure the responsiveness of 10-40-microns arterioles to topically applied adenosine and norepinephrine at 7, 14, and 30 days after grafting. Nine to 25 arterioles were studied at each time period. Both intravital and light microscopy were used at each time period to characterize the structural development of the microcirculation. We found that the responsiveness of regenerated arterioles returned to control values for topically applied norepinephrine by 14 days and for adenosine by 30 days. Light microscopy showed regenerated blood vessels in the center of the grafts early in the second week after grafting. The structure of the microcirculation at 7 days was characterized by a plexiform microvascular pattern, long spiderlike capillaries, and arterioles and venules that had irregular walls and an irregular branching pattern. Rhodamine-labeled albumin extravasated spontaneously. The 14-day grafts had a more linear capillary pattern, and the arterioles and venules often contained loops that had circular flow patterns. By 30 days, a parallel capillary structure had developed, no vascular loops were present, and the arteriolar-venular pattern was nearly normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1990

A histological study of local anesthetic-induced muscle degeneration and regeneration in the monkey.

Small amounts (1-2 ml) of local anesthetics (bupivacaine, lidocaine, and mepivacaine) were injected into the abductor pollicis brevis muscles of 35 monkeys. Control muscles were injected with saline. The muscles were preserved for histology from 4.5 h to 48 days after the injection. Histological damage to muscle fibers was evident from the time of the first sampling. Invasion of damaged muscle fibers by phagocytic cells was prominent by 2-3 days postinjection. At 4 to 5 days, areas of muscle fiber damage were characterized by dense concentrations of phagocytes and mononuclear myoblastic cells. At 6 days, fields of early myotubes were evident. Maturation of myotubes into immature cross-striated muscle fibers occurred over the next week. Occasional myotubes or immature regenerating muscle fibers were seen as late as 28 days. The topographical pattern of muscle fiber degeneration and regeneration showed a concentration along the surfaces of muscle fascicles or, if intrafascicular, around the presumed site of injection.

Anesthetics↗
PubMed1990

An electron microscopic study of local anesthetic-induced skeletal muscle fiber degeneration and regeneration in the monkey.

An electron microscopic study was done on abductor pollicis brevis muscles of 18 Rhesus monkeys after intramuscular injections of 0.75% bupivacaine, 2% mepivacaine, or 2% lidocaine + epinephrine. The muscles were examined for from 2 h to 28 days. Severe muscle fiber damage, consisting of breakdown of sarcolemma and myofibrils, was seen as early as 2 h. Phagocyte mediated fragmentation of the degenerating muscle fibers was at its peak during the third and fourth days. Myoblasts were abundant during the fourth day. Early myotubes appeared on the fifth and sixth days, and they matured during the second week. Satellite cells appeared alongside mature myotubes. Overall, the local anesthetic-induced breakdown and regeneration of skeletal muscle fibers in the monkey followed a course quite similar to that seen in the rat.

Anesthetics↗
PubMed1990

Alkaline phosphatase and dipeptidylpeptidase IV staining of tissue components of skeletal muscle: a comparative study.

A combined alkaline phosphatase (AP) and dipeptidlypeptidase IV (DPP IV) staining reaction has demonstrated enzymatic heterogeneity of the arterial and venous segments of capillaries in rat skeletal muscle. This study compared the staining reactions of skeletal muscles in many commonly used laboratory animals, including the axolotl, chick, quail, Monodelphys, rat, mouse, hamster, guinea pig, rabbit, dog, monkey, and human. DPP IV activity was found in the venous ends of the capillaries and in the endothelium of some larger veins in many of the species but was never demonstrated in the arterial side of the circulation. AP was found in the arterial ends of capillaries in all species except the axolotl, and it was also found in the endothelium of larger arteries of most species. AP activity was absent in venous endothelium of all species except for birds and Monodelphys. DPP IV activity was found in the perineurium of intramuscular nerves of most species, and AP activity was commonly seen in tendons and intramuscular connective tissue. The interspecies variability found in this study shows that care must be taken in comparing experimental data involving this technique from one species to another, but within a species the technique allows a fine level of discrimination between functionally distinct compounds of skeletal muscle tissue.

Alkaline Phosphatase↗
PubMed1989

Muscle transplantation between young and old rats: age of host determines recovery.

As compared with age-matched controls, extensor digitorum longus (EDL) muscles autografted in young rats regenerated significantly greater mass (1.8 times) and developed greater maximum contractile force (2.6 times) than EDL muscles autografted in old rats. A cross-age transplantation study showed that the mass and maximum force of old muscles grafted into young hosts were not significantly different from those of young muscles grafted into the same young hosts. Conversely, young muscle grafted into old hosts regenerated no better than old muscles grafted into the same old hosts. We conclude 1) that chronological age alone is not a factor that limits the intrinsic ability of a muscle to regenerate and 2) that the poor regeneration of muscles in old animals is a function of the environment for regeneration provided by the old host.

Aging↗
PubMed1989

[Effect of the innervation on the structural state of F-actin in rat fast muscles].

Effect of denervation and damage of the spinal cord on the structural state of F-actin in muscle extensor digitorum longus of a rat was studied by polarized microfluorimetry in the ultraviolet light region. The ability of F-actin to change its conformation at ATP binding was used as a test. The character of the changes in tryptophan polarized fluorescence induced by ATP binding was different at muscle denervation and at the damage of the spinal cord. A suggestion is made that the structural state of F-action in muscle fibres may depend on muscle innervation.

Actins↗
PubMed1989

Ultrastructure of mepivacaine-induced damage and regeneration in rat extraocular muscle.

Adult rats were given a single retrobulbar injection of 50 microliters of 2.0% mepivacaine and the lateral rectus muscles were examined ultrastructurally at intervals from 15 min to 30 days post-injection. There were three purposes of the study: (1) to determine the extent of muscle fiber damage caused by the anesthetic; (2) to document the subsequent course of muscle fiber regeneration; and (3) to relate these findings to clinical data on possible adverse effects of local anesthetics on human extraocular muscle function. The lateral rectus muscle was massively damaged by exposure to the anesthetic, with membrane lesions seen as early as 15 min after the injection. Intracellular damage was followed by the phagocytic removal of the remnants of the damaged muscle fibers. The activation of satellite cells to myoblasts began during the phase of phagocytosis, and between 3 and 4 days after injection multinucleated myotubes actively forming sarcomeres appeared. Even during later stages of muscle fiber regeneration, evidence of damage was seen in muscle fibers that were not destroyed during the first 2 days post-injection. The results of this experiment show (1) that the vast majority of lateral rectus muscle fibers are rapidly broken down by the anesthetic, but that the destroyed muscle fibers are replaced by regenerating ones; and (2) that the ultrastructure of regeneration of extraocular muscle fibers differs little from the regeneration of somatic muscle fibers. The myotoxic effects of retrobulbarly applied local anesthetics in rats seem to be much greater than they are in primates.

Animals↗
PubMed1988

Preservation of the ability of dissociated quail wing bud mesoderm to elicit a position-related differentiative response.

Previous studies showed that grafting wedges of fresh or cultured anterior quail wing mesoderm into posterior slits in chick wing buds resulted in the formation of supernumerary cartilage in a high percentage of cases. When anterior quail mesoderm, which had been dissociated into single cells and pelleted by centrifugation, was grafted into posterior slits of host chick wing buds, supernumerary rods or nodules of cartilage formed in 74.3% of the cases. Few supernumerary skeletal structures formed following control operations in which pelleted dissociated anterior or posterior mesoderm was grafted into homologous locations in host chick wing buds. When pelleted, dissociated anterior mesoderm was cultured in vitro for 1 or 2 days prior to being implanted in posterior locations, the incidence of supernumerary cartilage formation increased to 95.5% and 93.8%, respectively. The incidence of supernumerary cartilage formation following control orthotopic grafts of cultured mesoderm was 11.8% for 1-day and 31% for 2-day cultured anterior mesoderm; for 1- and 2-day cultured posterior mesoderm, the incidence of supernumerary cartilage formation was 20% and 41.7%, respectively. Longer-term culture resulted in a substantial decrease in the percentage of supernumerary cartilage after anterior to posterior grafts and an increase in the incidence of supernumerary cartilage from control grafts. The results demonstrate that quail anterior wing bud mesodermal cells do not need to maintain constant contact with one another in order to retain the ability to form or stimulate the formation of supernumerary cartilage after being grafted into a posterior location in a host wing bud. This ability is retained when the pelleted dissociated mesoderm is cultured in vitro outside the limb field for at least 1 to 2 days.

Animals↗