PubMed Health⌕ Search

Biomedical subjects

B M Carlson

Publications and source records attributed to B M Carlson.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1988

A test of positional properties of avian wing-bud mesoderm.

Supernumerary wing structures are readily produced by grafting pieces of wing-bud mesoderm into different locations of host wing buds, but the mechanism underlying their formation remains obscure. The major aim of this study was to examine the ability of posterior quail wing-bud mesoderm, cultured in vitro long enough to lose ZPA (zone of polarizing activity) activity, to stimulate or participate in the formation of supernumerary structures when grafted into anterior slits of host chick wing buds. Small pieces of anterior and posterior quail wing-bud mesoderm (HH stages 21-23) were placed in in vitro culture for up to 3 days. After 2 days, ZPA activity of cultured mesoderm was lost. After the grafting of 2- to 3-day cultured anterior quail wing-bud mesoderm into posterior slits of host chick wing-buds, a consistently high percentage (70%-90%) of grafts result in formation of supernumerary cartilage; in this experiment, however, only a low percentage of grafts resulted in supernumerary cartilage when 2- to 3-day cultured posterior mesoderm was grafted into anterior slits. Taken with controls, these results show that positional differences exist between cultured anterior and posterior wing-bud mesoderm. Serial-section analysis of numerous operated wings has shown several patterns of contribution to supernumerary structures by cells of graft and host. Single supernumerary digits induced by grafts of ZPA mesoderm into anterior slits were normally composed entirely of host cells, but graft cells regularly contributed to skeletal elements of more complex supernumerary structures. Cartilage rods produced by anterior-to-posterior grafts were composed mostly of graft cells, but cartilage nodules and the bases of some rods were often mosaics of chick and quail cells. The results support the proposition that mesodermal cells of the quail wing-bud possess a form of anteroposterior positional memory, but its nature and the means by which the memory of grafted cells interacts with host mesoderm are still not clear.

Animals↗
PubMed1988

Nuclear characteristics of cardiac myocytes following the proliferative response to mincing of the myocardium in the adult newt, Notophthalmus viridescens.

Amphibian cardiac myocytes are predominantly mononucleated and have been demonstrated to respond to injury with DNA synthesis and mitosis. The nature of this response with regard to nuclear number and ploidy is unclear. In this study, the apex of the newt ventricle was minced and replaced, increasing the reactive area of the wound. At 45 days after mincing following multiple injections of tritiated thymidine (2.5 microCi/animal, 20 Ci/mM) 15 to 20 days after mincing, three ventricular zones were isolated and fixed: Zone 1, the minced area; Zone 2, extending approximately 500 micron proximally from the amputation plane; and Zone 3, the portion proximal to Zone 2. Myocytes separated in 50% KOH were examined for DNA synthesis by autoradiography and for nuclear number and DNA content using a scanning microdensitometer on Feulgen-Naphthol yellow S-stained cells. No labeled myocyte nuclei were found in control hearts and 98.3% of the myocytes were 2C. At 45 days, 46.78% of myocyte nuclei within Zone 1 were labeled, while 13% were non-diploid. In Zone 2, 9.25% were labeled with 4.8% non-diploid. In Zone 3, 1.1% were labeled, with 2.8% non-diploid. The newt ventricle's response to injury apparently may involve complete mitosis and cytokinesis, resulting in mononucleated diploid cells.

Animals↗
PubMed1988

Reinnervation of long-term denervated rat muscle freely grafted into an innervated limb.

This experiment was designed to test the hypothesis that in the presence of regenerating nerve fibers long-term denervated skeletal muscle does not become reinnervated. This hypothesis was tested in rats by the transplantation of 22-month denervated extensor digitorum longus (EDL) muscles into the sites of EDL muscles in the contralateral, normally innervated legs. Two months after transplantation, the muscles contracted when stimulated via the motor nerve, and based on silver-acetylcholinesterase staining, all grafts possessed innervated motor end plates. Compared to values for control EDL muscles in old rats, the maximum force developed by standard free grafts in old rats was 19% and that of long-term denervated grafts was 7%. For standard free grafts, nerve stimulation produced a maximum force that was 81% of that produced by direct stimulation, and for control EDL muscles in young and old rats, the values were 96 and 90%, respectively. These results show that after long-term denervation rat muscles are capable of becoming functionally reinnervated, even though by the time of reinnervation the animals have attained an advanced age of 26 months.

Animals↗
PubMed1988

Polyploidization of transplanted cardiac myocytes.

Pieces of cardiac ventricular tissue of late embryonic or 1-day postnatal rats, implanted beneath the kidney capsule of adult syngeneic hosts, formed viable, beating transplants. These transplants were investigated over a 40-day postoperative course. In the transplants, cellular binucleation and nuclear polyploidization occurred according to the same schedule as in the heart in situ. The composition of the classes of myocytes was identical both in the hearts in situ and in transplants, but the number of non-diploid myocytes in the intact heart reached 90%, whereas in transplants it varied from 30 to 60%. In contrast to the heart in situ, myocytes in transplants grew feebly after the phase of polyploidization. From these data one can conclude that under conditions of transplantation the temporal sequence of cellular binucleation and nuclear polyploidization follows the normal course, but that a greater number of myocytes remain in a diploid state than is the case in the normal heart. The growth of cardiac myocytes seems to be related to their level of function.

Animals↗
PubMed1988

A test for muscle lesions and their regeneration following intramuscular drug application.

A standard infiltration of the rat tibialis anterior muscle with 0.1 ml of local anesthetics was used as a model to help choose criteria for testing the intramuscular toxicity of drugs. Anesthetics used were 0.2% carbisocaine, 1% and 2% Lidocaine, 0.5% Marcaine, 1% and 2% Mesocaine, 1% and 2% Procaine. Increases in the serum levels of creatine kinase were monitored for 24 hours, and the weight, as well as macro- and microscopic changes in the muscle for a period of 1 month. Exposure of the muscle to local anesthetics resulted in 2 types of lesions. One was characterized by selective muscle fiber damage in the injected area. The other type of lesion was a generalized one that involved a number of cell types. To assess the intramuscular toxicity of drugs we defined the type of lesion, its size, and the rate of subsequent muscle regeneration. We recommend the following criteria for the assay of myotoxicity of new drugs being developed as pharmaceutical agents: 1) serum creatine kinase level 1 hour after intramuscular injection of the drug; 2) microscopic findings at 3, 7, and 21 days; 3) the cross-sectional area of the lesion at 3 days; and 4) the weight of the muscle at 7 and 21 days.

Anesthetics, Local↗
PubMed1987

Survival of myogenic cells in freely grafted rat rectus femoris and extensor digitorum longus muscles.

The objective of this study was to determine how long myogenic cells can survive in the central ischemic zone of early free muscle grafts in the rat. The study was conducted on free grafts of a large (rectus femoris) and a small (extensor digitorum longus) muscle. At times ranging from zero hr to five days post-grafting, the central zones were isolated, minced, and implanted under the back skin of mice. After five days the minces were removed and examined histologically for the presence of rat myotubes, which should form only in minces that contain viable myogenic cells. The results show that myogenic cells survive two to four hr in the ischemic centers of the large rectus femoris grafts; after longer post-grafting intervals, rat myotubes did not arise in central zone minces. In grafts of small muscles, myotubes consistently appeared in central zone minces. Since the formerly ischemic central areas of rectus muscle grafts are ultimately replaced by regenerating muscle fibers, we conclude that these regenerating muscle fibers are derived from precursor cells located outside of the ischemic zone.

Animals↗
PubMed1987

Microcirculatory adaptation to skeletal muscle transplantation.

A standard whole muscle graft, in which all neural and vascular connections with the host tissue are severed, reinnervates and revascularizes spontaneously. The extent to which a standard graft regains structure and function depends largely on the degree and timing of revascularization. Whether the endothelial cells that form the first capillary tubes in a whole muscle graft originate inside or outside of the graft is unknown. Blood vessel growth into a graft proceeds in a centripetal fashion and precedes muscle fiber regeneration. Abnormalities have been observed in the structure of capillaries and of the larger vessels in stable muscle grafts. The ability of the vascular bed in large standard grafts to regulate blood flow in response to twitch contractions is impaired, as is the ability of arterioles in small grafts to respond following topical application of norepinephrine and adenosine. The dysfunction of arterioles in standard grafts may be related to structural abnormalities. Blood flow at rest and in response to twitch contractions in stable grafts in which nerves and blood vessels are left intact is not different from control muscles. The following should be investigated to provide further insights into the revascularization process in regenerating skeletal muscle and the structure and function of the microcirculation in stable muscle grafts: the origin of mitotic endothelial and smooth muscle cells; the stimulus for blood vessel growth; the overall architecture and organization of the vascular bed; the presence or absence of adrenergic innervation of blood vessels; and the development of receptors involved in blood flow regulation in muscle grafts.

Animals↗
PubMed1987

A monoclonal antibody stains myogenic cells in regenerating newt muscle.

Monoclonal antibodies have been used to study minced muscle regeneration in the adult newt, Notophthalmus viridescens. The contralateral limb was amputated and the immunostaining patterns in the regenerating blastema were compared with the minced tissue in sectioned material. Staining with a myofibre-specific antibody, called 12/101 (Kintner & Brockes, 1984), showed that myofibre degeneration was complete by 8-10 days after mincing, with myogenesis commencing 2 days later. Another monoclonal antibody, called 22/18, previously shown to label a subset of cells in the regeneration blastema of the newt (Kintner & Brockes, 1984, 1985), was found also to recognize a population of cells in regenerating minced muscle. At 6 days after mincing, the number of 22/18-positive (22/18+) cells was low but by days 12-16, during the period of myogenesis, their number had increased to become a major population within the minced tissue. A small number of the 22/18+ cells could be double labelled with 12/101 at this time. Prior to this, there was a phase in which 12/101 staining had disappeared from the mince. Cells immunoreactive with both antibodies after this phase confirm that at least some of the 22/18+ cells are myogenic. The number of 22/18+ cells decreased as muscle repair and maturation progressed. These results show that 22/18 is not specifically associated with blastemal cells but is a more general marker for regenerating systems in the newt. They further suggest an alternative interpretation of the double-labelled cells used by Kintner & Brockes (1984) as evidence for myofibre dedifferentiation in limb regeneration. Instead, we propose that such cells represent new myogenesis occurring by tissue repair of locally damaged muscle fibres.

Animals↗
PubMed1986

Enzymatic heterogeneity of the capillary bed of rat skeletal muscles.

This study of the capillaries in rat skeletal muscle involved the use of a histochemical method that allows one to distinguish between arterial and venous portions of capillaries. Under controlled staining conditions, the arterial portion of the capillary bed reacts positively for alkaline phosphatase (AP) activity, and the venous portion is positive for dipeptidyl peptidase IV (DPP IV) activity. A short transitional capillary segment is positive for the activity of both enzymes. Capillaries of the normal soleus muscle and the red and white portions of the sternomastoid muscle have been quantitatively analyzed. Quantitative data demonstrated differences in capillary dimensions among the muscles studied. Capillaries of the white part of the sternomastoid were the longest, and they had the shortest DPP IV-positive segment (8% of the total capillary length). Capillaries of the soleus muscle were the shortest, and they also had short DPP IV-positive segments (16%). In contrast, the DPP IV-positive segments of the red part of the sternomastoid occupied 60% of the total capillary length. Survey cross sections reveal a mosaic distribution of patches of capillaries stained for AP and DPP IV activity. This study reveals that within given bundles of muscle fibers, the capillaries that run parallel to the muscle fibers are aligned relative to one another in such a manner that their arterial and venous segments are in register.

Animals↗