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B W Festoff

Publications and source records attributed to B W Festoff.

At least 91 records · Page 5Linked to original sources
PubMed1989

Environmental influence on altered receptor function in a genetic disease: insulin and glucose affect insulin receptors in myotonic dystrophy.

Insulin action in vivo and insulin binding to monocytes in vitro were correlated in patients with myotonic dystrophy (MyD) and compared with healthy controls. Confirming our previous studies and those of others, the present results show that the glucose infusion rate (DR), an estimate of in vivo insulin sensitivity, was significantly diminished in MyD. At the same per cent of ideal body weight DR in MyD patients was considerably less than controls suggesting that obesity could not solely account for decreased insulin sensitivity in MyD. The relative capacity (RC), and relative affinity (ED50) of the insulin receptor in monocytes was significantly less in patients. The relative affinity (ED50) was improved by changing environmental insulin levels while receptor numbers (RC) were not. Insulin sensitivity and RC showed a trend toward a positive correlation although this did not reach statistical significance. Our data suggest that the alteration of the insulin receptor in MyD is different from obesity and from other disorders of the motor unit such as amyotrophic lateral sclerosis, where insulin sensitivity and RC are reduced but ED50 is unchanged. Thus, in MyD the receptor may be one of the loci where the resistance occurs.

Adult↗
PubMed1989

Decrease in plasminogen activator correlates with synapse elimination during neonatal development of mouse skeletal muscle.

Previous studies have implicated proteases, acting extracellularly, in the mechanism of polyneuronal synapse elimination. Most studies have focused on mammalian, especially rodent, skeletal muscle, where retraction of subordinate nerve terminals occurs during a narrow time window 2-3 weeks after birth. To date no specific protease(s) has been detected that (i) coincides in time with maximal synapse elimination and (ii) is known to act extracellularly on specific extracellular matrix proteins. In previous studies of denervation in adult mouse muscle, rapid activation of urokinase-type plasminogen activator, a neutral serine protease, was detected. This enzyme, by activation of plasminogen to plasmin, specifically degrades matrix components such as fibronectin, type IV collagen, and laminin in muscle. We now present evidence for an initial increase and subsequent decrease in soluble urokinase-type PA--and, to a lesser extent, tissue PA--in developing muscle, suggesting postnatal developmental regulation of these enzymes during the period of maximal synapse elimination. Although considerably higher in specific activity, membrane-bound PA activity followed the wave of synapse elimination, possibly indicating a longer half-life of membrane-bound enzyme(s).

Aging↗
PubMed1988

Serine proteases and serpins: their possible roles in the motor system.

A review of the importance of the extravascular fibrinolytic enzymes and their inhibitors in the neuromuscular system is discussed. We present data showing the role of specific serine proteases, the plasminogen activators, during neuromuscular development as well as after nerve injury and regeneration through their action on muscle basement membrane components. We show the presence in muscle of protease nexin I, a member of the serine protease inhibitors (serpins) family, where it is highly concentrated in the neuromuscular junction. These data have lead us to propose a model where the extravascular components of the fibrinolytic cascade and cellular derived serpins, such as protease nexin I, would act in the formation and maintenance of the neuromuscular synapse. Our conclusion is that future studies with these molecules, including their regulation at several levels, are warranted in a number of neuromuscular and neuro-degenerative diseases.

Amyloid beta-Protein Precursor↗
PubMed1987

Proteoglycan synthesis by primary chick skeletal muscle during in vitro myogenesis.

The proteoglycans synthesized by primary chick skeletal muscle during in vitro myogenesis were compared with those of muscle-specific fibroblasts. Cultures of skeletal muscle cells and muscle fibroblasts were separately labeled using [35S] sulfate as a precursor. The proteoglycans of the cell layer and medium were separately extracted and isolated by ion-exchange chromatography on DEAE-Sephacel followed by gel filtration chromatography on Sepharose CL-2B. Two cell layer-associated proteoglycans synthesized both by skeletal muscle cells and muscle fibroblasts were identified. The first, a high molecular weight proteoglycan, eluted from Sepharose CL-2B with a Kav of 0.07 and contained exclusively chondroitin sulfate chains with an average molecular weight greater than 50,000. The second, a relatively smaller proteoglycan, eluted from Sepharose CL-2B with a Kav of 0.61 and contained primarily heparan sulfate chains with an average molecular weight of 16,000. Two labeled proteoglycans were also found in the medium of both skeletal muscle and muscle fibroblasts. A high molecular weight proteoglycan was found with virtually identical properties to that of the high molecular weight chondroitin sulfate proteoglycan of the cell layer. A second, smaller proteoglycan had a similar monomer size (Kav of 0.63) to the cell layer heparan sulfate proteoglycan, but differed from it in that this molecule contained primarily chondroitin sulfate chains with an average molecular weight of 32,000. Studies on the distribution of these proteoglycans in muscle cells during in vitro myogenesis demonstrated that a parallel increase in the relative amounts of the smaller proteoglycans occurred in both the cell layer and medium compared to the large chondroitin sulfate proteoglycan in each compartment. In contrast, muscle-derived fibroblasts displayed a constant ratio of the small proteoglycans of the cell layer and medium fractions, compared to the larger chondroitin sulfate proteoglycan of the respective fraction as a function of cell density. Our results support the concept that proteoglycan synthesis is under developmental regulation during skeletal myogenesis.

Animals↗
PubMed1987

Degradation of muscle basement membrane zone by locally generated plasmin.

The turnover of basement membrane macromolecules in injured skeletal muscle has not been studied in contrast to other biologic systems undergoing remodeling. Plasminogen activators and other neutral proteases that are able to degrade these basement membrane macromolecules are secreted by cultured muscle cells. We sought to determine if locally released plasminogen activators could act on basement membrane components. Such degradation might be implicated in the disadhesion of nerve from muscle after motor nerve denervation. To test this hypothesis, we first undertook a study of the sensitivity of muscle extracellular matrix antigens following in vitro exposure to various proteases on frozen muscle sections. Fibronectin was found to be most sensitive, followed by type IV collagen and laminin. Of serine proteases, trypsin was the most active but was not selective, digesting matrix and sarcoplasmic components alike in less than 30 min. Purified urokinase was inactive unless plasminogen (also inactive alone) was previously added to tissue sections, at which time only matrix antigens were digested. Little if any observable degradation of sarcoplasmic proteins took place under these conditions. Using a highly sensitive and selective assay, we found that plasminogen activators were present in muscle tissue and increased 8- to 10-fold after 10 days of denervation. Using an extract of denervated muscle in the presence of plasminogen, we observed degradation of matrix antigens. No degradation was observed with control muscle extract. We next evaluated the degradation of these antigens in denervated muscle during a temporal study. The results, analyzed by quantitative image analysis, indicates that with increasing time after denervation a marked decrease of fibronectin and type IV collagen, followed by laminin occurred but, again, only in the present of plasminogen. These results indicate a selective sensitivity of basement membrane antigens of muscle and a role for plasminogen activators in the degradation of these adhesive basement membranes macromolecules after denervation.

Animals↗
PubMed1987

Reduction in insulin receptors in amyotrophic lateral sclerosis correlates with reduced insulin sensitivity.

Abnormal glucose and insulin metabolism have often been reported in patients with amyotrophic lateral sclerosis. Recently, we have demonstrated reduced insulin sensitivity in this disease and suggested that muscle wasting was not the principal determinant of this reduction. In the current studies, insulin binding to circulating mononuclear leukocytes from 10 amyotrophic lateral sclerosis patients and 16 controls were compared. The relative capacity and affinity of monocyte insulin binding sites were estimated, and simultaneous plasma insulin levels were also obtained. A 2 1/2-fold reduction in the number of binding sites (percent 125I-insulin bound to monocytes) was found in the patients compared with controls (p = 0.001). No differences were obtained when ED50 plots (relative affinity) were compared (p = 0.5). Ideal body weight was similar in both groups (approximately 100%) and plasma insulin levels were not elevated in the patients, suggesting that "down-regulation" from increased ambient hormone levels was not a factor in the lowered receptor numbers. A definite correlation was not found when numbers of insulin receptors were compared with disease progression, body weight, or plasma insulin levels. However, future studies with larger numbers of patients along with quantitation of disease progression may indicate such a trend.

Adult↗
PubMed1986

Collagenase activity in skin fibroblasts of patients with amyotrophic lateral sclerosis.

In the current study we have measured collagenase activity released from skin explants and fibroblasts of patients with both Guam-type and sporadic amyotrophic lateral sclerosis and controls. The rationale for such a study derives from work reported more than 20 years ago demonstrating abnormalities in skin collagen metabolism in patients with the disease. We were not able to find significant differences in collagenase activity when fibroblasts were compared relative to the total protein secreted. This is explained, in part, by our finding of an increase in total protein released from fibroblasts of the amyotrophic lateral sclerosis patient group. Increased collagenase release did occur when activity was expressed per number of cells plated but was not statistically significant. In addition, increased release followed a 3-day lag period in skin organ culture. These results suggest that collagenase and other enzymes known to activate collagenase, such as plasminogen activator, capable of degrading extracellular matrix components might be responsible for the increased collagenolytic activity previously observed in amyotrophic lateral sclerosis patients' skin. Further evaluation of extracellular-acting degradative enzymes from skin, muscle, nerve and central nervous system may be important to follow-up such leads in understanding the pathogenesis of this enigmatic and fatal disorder.

Amyotrophic Lateral Sclerosis↗
PubMed1986

Plasminogen activator in mammalian skeletal muscle: characteristics of effect of denervation on urokinase-like and tissue activator.

Analyses were made of the fibrinolytic, plasminogen-activating system in skeletal muscle to determine if a regulating influence of the nerve could be detected on these enzymes. Young male mice underwent right sciatic neurectomy. Extracts were prepared from denervated muscle at 2-17 d after axotomy and compared with controls. Using a cascade-style biochemical assay (Rånby, M., B. Norrman, and P. Wallén, 1982, Thromb. Res., 27:743-748) we found that low levels of plasminogen activator (PA) were present in adult, innervated mouse muscle, but that denervation resulted in a marked time-dependent increase in enzyme activity. Qualitative separation showed an eightfold increase in urokinase-like PA with moderate elevation of tissue PA activity after 10 d. Fibrin zymography (Granelli-Piperno, A., and E. Reich, 1978, J. Exp. Med., 148:223-234) revealed clear zones of lysis corresponding to molecular masses of 48 kD for urokinase-like PA and 75 kD for tissue PA, consistent with the molecular masses found for these enzymes in other tissues of the mouse (Danø, K., P. A. Andreasen, J. Grøndahl-Hansen, P. Kristensen, L. S. Nielsen, and L. Skriver, 1985, Adv. Cancer Res., 44:139-266). In other studies we have shown that PA-activated plasmin readily attacks critical adhesive basement membrane molecules. The present results indicate that enzymes involved in plasminogen activation, particularly urokinase-like PA, rapidly increase after axotomy, suggesting they may have a role early in muscle denervation. Similar alterations in PA activity might underlie the elimination of polyneuronal innervation during mammalian muscle development. Certain neuromuscular diseases may also involve activation of these enzymes, resulting in degradation of basement membrane zone components and, therefore, warrant further study.

Animals↗
PubMed1985

Extracellular matrix (ECM) synthesis in muscle cell cultures: quantitative and qualitative studies during myogenesis.

When the synthesis of extracellular matrix components was examined in G8-1 murine skeletal muscle cells as a function of differentiation, non-collagen and to an even greater extent collagen synthesis was increased. Specifically, collagen types I, III, IV, laminin and fibronectin were identified by SDS-PAGE. Immunoprecipitation, with specific antibodies revealed that both the cell layer and medium of differentiated multinucleated myotubes contained increased levels of type IV collagen and laminin, decreased levels of type III collagen and fibronectin and equivalent levels of type I collagen compared to mononuclear myoblasts.

Animals↗
PubMed1985

Extracellular-matrix synthesis by skeletal muscle in culture. Major secreted collagenous proteins of clonal myoblasts.

We have previously shown that G8-1, a murine clonal skeletal-muscle cell line, produces a substrate-attached extracellular matrix [Beach, Burton, Hendricks & Festoff (1982) J. Biol. Chem. 257, 11437-11442]. To examine further the expression of extracellular-matrix proteins by muscle cells, we have analysed the collagenous proteins secreted by G8-1 myoblasts. We have found that collagens and/or procollagens, corresponding to genetic types I, III and IV (and possibly V), are produced and secreted by G8-1 myoblasts. The major secreted collagenous polypeptides were identified as alpha 1 type I and its precursors by using pulse-chase studies, pepsin and collagenase digestions and CNBr fragmentation. The presence of lesser amounts of the other collagens was determined by immunoprecipitation. These results demonstrate that clonal skeletal-muscle cells, in the absence of fibroblasts and an exogenous collagen substrate, are able to synthesize and secrete several extracellular-matrix collagenous proteins in proportions similar to those which are commonly found in muscle tissue and mixed cultures of muscle cells and fibroblasts.

Animals↗
PubMed1985

Trismus. An unusual sign in polymyositis.

Neuromuscular disease is an unusual cause of trismus. However, we describe two patients with severe polymyositis who had difficulty opening their mouths during the acute phase of the illness. Electromyography demonstrated involvement of the masseters, and there was no evidence of myasthenia. The mechanism appeared to be decreased elasticity of the masseter because of inflammation, edema, and perhaps contractures.

Adult↗
PubMed1985

Treatment of central nervous system sarcoidosis with radiotherapy.

This report documents the twelve-year follow-up of a patient with neurosarcoidosis with multiple progressive central nervous system manifestations. Increased somnolence and seizure activity were associated with proliferation of nodular enhancing brain lesions, as seen on serial computed tomographic (CT) scans. Initially he responded to corticosteroid treatment, but gradually this response became unsatisfactory. After whole-brain irradiation with a total dose of 3,000 rads, his clinical symptoms improved with disappearance of the enhancing brain lesions seen on CT scan.

Adult↗
PubMed1985

Specificity of chicken and mammalian transferrins in myogenesis.

Chicken transferrins isolated from eggs, embryo extract, serum or ischiatic-peroneal nerves are able to stimulate incorporation of [3H]thymidine, and promote myogenesis by primary chicken muscle cells in vitro. Mammalian transferrins (bovine, rat, mouse, horse, rabbit, and human) do not promote [3H]thymidine incorporation or myotube development. Comparison of the peptide fragments obtained after chemical or limited proteolytic cleavage demonstrates that the four chicken transferrins are all indistinguishable, but they differ considerably from the mammalian transferrins. The structural differences between chicken and mammalian transferrins probably account for the inability of mammalian transferrins to act as mitogens for, and to support myogenesis of, primary chicken muscle cells.

Animals↗
PubMed1984

Peripheral nerve extract promotes long-term survival and neurite outgrowth in cultured spinal cord neurons.

The hypothesis that peripheral, skeletal muscle tissue contains a trophic factor supporting central neurons has recently been investigated in vitro by supplementing the culture medium of spinal cord neurons with muscle extracts and fractions of extract. We extended these studies asking whether or not a trophic factor is present in peripheral nerves, the connecting link between muscle and central neurons via which factors may be translocated from muscle to neurons by the retrograde transport system. Lumbar, 8-day-old chick spinal cords were dissociated into single cells and then cultured in the presence of peripheral nerve extract. Cytosine arabinoside was added to inhibit proliferation of nonneuronal cells. In the presence of nerve extract, spinal cord neurons survived for more than a month, extended numerous neurites, and showed activity of choline acetyltransferase. In the absence of extract, neurons attached and survived for a few days but then died subsequently in less than 10 days. Neurite outgrowth did not occur in the absence of extract. Withdrawal of extract from the medium of established neuronal cultures caused progressive loss of both cells and neurites. Other tissues also contained neuron supporting activity but less than that found in nerve extract. These studies indicate that peripheral nerves contain relatively high levels of spinal cord neuron-directed trophic activity, suggesting translocation of neurotrophic factor from muscle to central target neurons. The neurotrophic factor has long-term (weeks) effects, whereas short-term (days) survival is factor independent.

Animals↗
PubMed1984

Insulin resistance in amyotrophic lateral sclerosis.

Over the last 30 years glucose intolerance has been reported in a significant percentage of patients with amyotrophic lateral sclerosis (ALS). Currently, a controversy exists in determining whether the carbohydrate abnormality is disease-specific or secondary to decreased glucose utilization due to muscle atrophy. A reduction in glucose receptor space had been postulated for a number of neuromuscular diseases including ALS. In order to clarify this issue we have estimated in vivo insulin sensitivity, using the euglycemic insulin clamp technique, in ALS patients and two control groups, matched according to percent ideal weight. The results showed that the glucose infusion rate, an estimate of in vivo insulin sensitivity, ws significantly diminished in ALS patients compared to both normal and disease controls. These results demonstrate that the insulin resistance in this disorder cannot be explained by a decrease in glucose-receptor space and suggest a primary carbohydrate aberration in the disease process itself.

Adult↗