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Biomedical subjects

B M Carlson

Publications and source records attributed to B M Carlson.

At least 73 records · Page 4Linked to original sources
PubMed1986

Enzymatic differentiation of arterial and venous segments of the capillary bed during the development of free muscle grafts in the rat.

The revascularization of freely grafted muscles in the rat was studied by histochemical reactions that on frozen sections stain the arterial part of the capillary bed blue (alkaline phosphatase [AP] reaction) and the venous part of the capillary bed red (dipeptidyl peptidase IV [DPP IV] reaction). In 112 rats the extensor digitorum longus or soleus muscles were freely grafted and removed at various times up to 93 days following the surgery. In cross section, the capillaries of a normal muscle show a mosaic pattern of staining for the activity of the two enzymes. After grafting, DPP IV activity of capillaries is lost throughout the entire graft within a day or two; but within ischemic muscle, weak and diffuse AP staining persists in capillary remnants for up to 6 days. In the very periphery of the graft AP staining is also preserved in partially damaged capillaries. By 4 days, new AP-positive capillaries can be identified at the periphery of the graft, and in succeeding days AP-positive capillaries are found progressively nearer the center of the graft. At 7 days, the capillary/muscle-fiber ratios are 66% of normal in the periphery of the graft and 44% in the intermediate zone. DPP IV-stained capillaries are not seen until 7 days after grafting. By 60 days, when the grafts have become stabilized, the mosaic pattern of capillary staining has become reestablished. In mature grafts, the number of capillaries per unit area was slightly higher than that in control muscles, but the capillary/muscle-fiber ratio was slightly lower, owing to the smaller than normal cross-sectional areas of the regenerated muscle fibers.

Animals↗
PubMed1986

A method for combined gross skeletal staining and Feulgen staining of embryonic chick tissues.

This paper describes a combined technique for gross skeletal staining and Feulgen staining of avian embryonic limbs. The gross skeletal stain uses Victoria blue B, and the Feulgen stain is done en bloc before the skeletal stain is applied. The method has been useful in determining the cellular origins of supernumerary structures arising from experiments in which quail wing mesoderm is grafted into chick wing buds.

Animals↗
PubMed1986

Regeneration of entire skeletal muscles.

There are several experimental models for producing the regeneration of entire mammalian muscles. The most commonly used are mincing and free muscle grafting. Immediately after both mincing and grafting, the muscle is completely divorced from any connections with the host. To regenerate and become functional, the muscle must become reintegrated with the body of the host. The three major reintegrative phenomena--revascularization, reinnervation, and the reestablishment of tendon connections--are discussed in the context of muscle regeneration. The functional development of regenerating muscle closely resembles the normal ontogenetic pattern. Final functional differentiation of a regenerating muscle depends on the establishment of neuromuscular synapses.

Animals↗
PubMed1985

Postoperative diplopia and ptosis. A clinical hypothesis based on the myotoxicity of local anesthetics.

Postoperative diplopia and ptosis can be temporary or permanent complications in patients who have undergone ophthalmic surgery while under local anesthesia. We encountered six patients with such complications and hypothesize that some cases of postoperative diplopia and ptosis could be attributed to myotoxic effects of local anesthetics. These effects may cause the degeneration and subsequent regeneration of muscle fibers of the levator or extraocular muscles and result in temporary or permanent muscle weakness.

Aged↗
PubMed1985

Rat extraocular muscle regeneration. Repair of local anesthetic-induced damage.

Local anesthetics that are commonly used in ophthalmic surgery (0.75% bupivacaine hydrochloride, 2.0% mepivacaine hydrochloride, and 2.0% lidocaine hydrochloride plus 1:100,000 epinephrine) were injected into the retrobulbar area of rat eyes. Controls were injected with physiological saline. All three anesthetics produced massive degeneration of the extraocular muscles. Muscle degeneration is followed by regeneration of the damaged muscle fibers. In addition to muscle damage, severe damage was also seen in harderian glands, especially after exposure to mepivacaine and lidocaine plus epinephrine. With these findings in rats, it is hypothesized that the temporary diplopia sometimes seen in patients after ophthalmic surgery might be due to anesthetic-induced damage to the extraocular muscles.

Anesthetics, Local↗
PubMed1985

Contractile properties of standard and nerve-intact muscle grafts in the rat.

The contractile properties of standard and nerve-intact grafts of extensor digitorum longus muscles of rats were compared in vitro. Fourteen days after grafting, the time to peak tension and the half-relaxation times of nerve-intact grafts were shorter than those of standard grafts, but both were longer than control values. By 60 days, these variables attained normal values. At every sample period, the tetanic tensions of nerve-intact grafts were higher than those of standard grafts. Even at the early sampling periods, the twitch-tetanic tension ratios of nerve-intact grafts were close to normal values, whereas those of standard grafts were higher than normal. Stabilized nerve-intact grafts had a larger mass and greater maximum tetanic tension development than standard grafts, but were more fatigable. Compared with control EDL muscles, stable nerve-intact grafts show no differences except for lessened fatigability, whereas standard grafts demonstrate significant functional deficits.

Age Factors↗
PubMed1984

The formation of supernumerary structures after grafting anterior quail wing bud mesoderm of various ages into chick wing buds.

Wedges of anterior quail mesoderm grafted into posterior slits in the wing buds of chick embryo hosts result in the formation of rods and nodules of supernumerary cartilage in a high percentage of cases. Identifiable digits do not form unless the ectoderm is allowed to remain on the grafts. Control experiments have shown that wedges of anterior or posterior wing mesoderm placed into homologous locations of host wing buds produce few or no supernumerary skeletal structures. Anterior-to-posterior grafts of stage 17 mesoderm evoke a 71.4% incidence of supernumerary cartilage. This percentage increases to 100% with stage 22 donor mesoderm. The percentage of supernumerary structures formed declines markedly with donor mesoderm of stages 24-30. By stages 35-36, only 10% of the grafts result in the formation of supernumerary structures. The period of decline coincides with the onset of overt cytodifferentiation within the donor mesoderm.

Age Factors↗
PubMed1984

The preservation of the ability of cultured quail wing bud mesoderm to elicit a position-related differentiative response.

A previous study showed that grafting wedges of fresh anterior quail wing mesoderm into posterior slits of chick wing buds resulted in the formation of rods and nodules of cartilage in a high percentage of cases (B. Carlson, 1983, Dev. Biol. 101, 97-105). The purpose of the present study was to determine if a similar response could be elicited by grafting pieces of mesoderm that had been cultured in vitro. When pieces of 1-day cultured anterior mesoderm from stage 17-24 donors were grafted into standard posterior slits of chick wing buds, the percentages of supernumerary structures differed little from those which formed after the grafting of pieces of fresh mesoderm. In a time series, grafts of stage 22-23 anterior mesoderm which had been cultured for 1-4 days retained the ability to form cartilage after being grafted into posterior locations. A time series showed that the duration of this retention was longer in cultured mesoderm than it was in mesoderm that remains in the donor wing bud.

Age Factors↗
PubMed1983

Restoration of full mass in nerve-intact muscle grafts after delayed reinnervation.

A rat muscle freely grafted with the motor nerve intact becomes restored to full mass and contractile function, in contrast to the reduced weight of a standard free graft. By crushing the nerve to a nerve-intact graft and delaying reinnervation, full mass is still restored. One can conclude that earlier reinnervation is not the reason for the success of nerve-intact grafts, but that it is rather due to reinnervation along preserved Schwann cell channels.

Animals↗
PubMed1983

The regeneration of skeletal muscle fibers following injury: a review.

Regeneration is a unique adaptation of skeletal muscle that occurs in response to injury. Following direct trauma or disease, regeneration results in restoration, to some degree, of the original structure and function of the muscle. Our purpose is to summarize the main features of the regeneration of skeletal muscle fibers and entire muscles with an emphasis on aspects of regeneration that may be important to the understanding and treatment of sports injuries. The regeneration of skeletal muscle is compared structurally and functionally with its embryonic development. The free muscle graft is used as a model to illustrate the integration of regenerating muscle with the rest of the body. Finally, the breakdown and regeneration of skeletal muscle fibers are discussed in relation to local anesthetics, sports injuries, and disease.

Anesthetics, Local↗
PubMed1981

Cytosolic androgen receptor in regenerating rat levator ani muscle.

The development of the cytosolic androgen receptor was studied after degeneration and regeneration of the rat levator ani muscle after a crush lesion. Muscle regeneration appears to recapitulate myogenesis in many respects. It therefore provides a model tissue in sufficiently in large quantity for investigating the ontogenesis of the androgen receptor. The receptor in the cytosol of the normal levator ani muscle has binding characteristics similar to those of the cytosolic receptor in other androgen-sensitive tissues. By day 3 after a crush lesion of the levator ani muscle, androgen binding decreased to 25% of control values. This decrease was followed by a 4-5 fold increase in hormone binding, which attained control values by day 7 after crush. Androgen binding remained stable at the control value up to day 60 after crushing. These results were correlated with the morphological development of the regenerating muscle after crushing. It is concluded that there is little, if any, androgen receptor present in the early myoblastic stages of regeneration; rather, synthesis of the receptor may occur after the fusion of myoblasts and during the differentiation of myotubes into cross-striated muscle fibres.

Anal Canal↗
PubMed1981

Histochemical patterns of dehydrogenase activity in the development of free muscle grafts in the rat.

Patterns of activity of six dehydrogenase enzymes were studied histochemically in 42 free muscle grafts in the rat. Within hours, the surviving peripheral muscle fibers can be distinguished from the central ischemic muscle fibers. The surviving muscle fibers retain their characteristic pattern of staining throughout the post-transplantation period. The central ischemic muscle fibers stain abnormally and by five or six days they lose their enzymatic activity. The zone of regeneration, between the surviving and the ischemic muscle fibers, initially shows little dehydrogenase activity, but as the regenerating muscle fibers mature, they develop first a homogeneous staining pattern and, later, differences in staining intensity among different types of muscle fibers.

Animals↗
PubMed1981

Comparison between grafts with intact nerves and standard free grafts of the rat extensor digitorum longus muscle.

Standard grafts and nerve-intact grafts of the extensor digitorum longus muscle were compared in the rat. In standard grafts the muscle was completely removed from its bed and replaced; nerve-intact grafts were treated in an identical manner except that the muscle nerve was not severed. Nerve-intact grafts underwent the same sequence of skeletal muscle fibre degeneration and regeneration as standard grafts. In nerve-intact grafts the intramuscular portions of the nerve fibres initially degenerated, but within a week new nerve fibres had regenerated back to the original zone of motor end-plates. By 60 days the weight of nerve-intact grafts approached those of control muscles. Contractile tension in nerve-intact grafts was greater than that of standard grafts. In standard and nerve-intact grafts choline acetyltransferase activity rapidly decreased to low values and then increased along curves roughly paralleling the muscle weights. In nerve-intact grafts, neuromuscular transmission was established early in the second week whereas a considerably later return was seen in standard grafts. Either the early onset or the topographical pattern of reinnervation are potentially major factors in determining the success of free muscle grafts.

Animals↗
PubMed1980

Revascularization of the freely grafted extensor digitorum longus muscle in the rat.

The process of revascularization of free grafts of the extensor digitorum longus muscle in rats has been studied by gross, histological and electron microscopic methods. During the first day after transplantation the muscle is entirely avascular, and it consists of a thin peripheral zone of surviving muscle fibers and a large central area of ischemic muscle. The original blood vessels of the graft undergo a sequence of intrinsic and cell-mediated destruction. Scattered sinusoidal vessels begin to grow into the graft starting on the second day, and ingrowing blood vessels progressively invade the deeper tissues of the graft. Most new vessels form in the connective tissues, but some vessels, especially larger ones, grow into persisting basal laminae from preexisting fibers and nerves. The differentiation of new arterioles and venules in free muscle grafts is described. By the end of the first week, the entire graft is revascularized, and ultimately a fairly normal relationship between new capillaries and regenerating muscle fibers is established. In mature grafts, however, irregularities are sometimes found in the organization of smooth muscle cells associated with larger vessels.

Animals↗