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Biomedical subjects

L Z Stern

Publications and source records attributed to L Z Stern.

At least 19 recordsLinked to original sources
PubMed1987

Accumulation of CK-MM is impaired in innervated and contracting cultured muscle fibers of Duchenne muscular dystrophy patients.

No specific abnormalities have been reproducibly manifested in aneurally cultured muscle of Duchenne muscular dystrophy (DMD) patients. We now report that the accumulation of the muscle-"specific" isozyme of creatine kinase (CK-MM) was significantly and preferentially impaired in long-term innervated contracting muscle fibers cultured from 4 DMD patients (DMD-InnCMFs) compared to: i) their noninnervated sister-cultured muscle fibers, and ii) innervated contracting control cultured human muscle fibers (Control-InnCHMFs). Accumulation of other muscle-"specific" isozymes (MSIs), viz. glycogen phosphorylase, phosphoglycerate mutase, and lactic dehydrogenase, was not significantly impaired. We have not observed preferentially-impaired CK-MM accumulation in any Control-InnCHMFs from 22 patients (children and adults) with a variety of neuromuscular diseases. There was no apparent difference between DMD-InnCMFs and Control InnCHMFs regarding: acceptance of innervation; neuronally-driven, virtually continuous muscle-fiber contractions; characteristic myofiber organization by phase-contrast microscopy, and increased longevity of the innervated fibers.

Animals↗
PubMed1987

L-dopa in uremic patients with the restless legs syndrome.

Restless legs syndrome (RLS) is a poorly understood, often distressing condition that is particularly prevalent among patients with chronic renal failure. A wide variety of medications have been used to treat RLS with variable results. In order to evaluate the efficacy of carbidopa/levodopa therapy, eight consecutive uremic patients with RLS on maintenance hemodialysis were treated with doses ranging from 25/100 to 25/250 twice daily. Six of eight patients obtained satisfactory relief which has continued for 3 months follow-up. Carbidopa-levodopa appears to be an effective opinion in management of RLS in patients with chronic rental failure.

Aged↗
PubMed1986

Occurrence of alkaline phosphatase-positive fibers in experimental muscle disorders.

The alkaline phosphatase (AP) reaction was carried out on muscle sections from a large series of rats under various experimental neuromuscular disorders. Only denervated and non-innervated muscle fibers stained positively with the AP reaction. In other conditions including degenerating, regenerating, tenotomized and immature muscles the AP reaction was negative. This suggests that the presence of AP-positive fibers in human neuromuscular disorders reflects a concomitant denervation process.

Alkaline Phosphatase↗
PubMed1985

Altered rat skeletal muscle carnitine with age and after denervation.

We investigated the effect of denervation on the concentration of total free, and acyl carnitine in the soleus (S), extensor digitorum longus (EDL), and anterior tibial (AT) muscles of the rat. Soon after denervation there was a marked decrease in total carnitine in all three muscles. Acyl carnitine levels decreased concomitantly with changes in total carnitine. In control but not in denervated muscle, the carnitine concentration was age-dependent during the period of rapid growth of the animals. The highest carnitine concentration was observed at 14 weeks of age. The results of this study suggest that normal innervation significantly influences carnitine-mediated lipid metabolism in skeletal muscle.

Age Factors↗
PubMed1985

Chronic myopathy induced by repeated bupivacaine injections.

The effect of recurrent cycles of muscle fiber degeneration-regeneration was studied by repeated bupivacaine injections into the rat anterior tibial muscle. Injections of 0.6 ml of 0.75% bupivacaine were performed weekly for 6 months. The rats were allowed to recover for another 2 months and then killed. Histological and histochemical stains showed striking changes, including marked variability in fiber size, numerous internal nuclei, extensive fiber splitting and many whorled fibers. Combined staining for end-plate cholinesterase and terminal axons showed a markedly enlarged zone of terminal innervation. These findings suggest that the observed morphological changes usually attributed to a primary myopathic process may instead be the manifestations of impaired and incomplete regeneration occurring after cycles of degeneration-regeneration.

Adenosine Triphosphatases↗
PubMed1985

Verbal perseveration of dementia patients.

Patterns of perseveration and frequency of carrier phrases were studied in the verbal descriptive discourse of dementia patients controlled for etiology and severity. Dementia patients were found to perseverate significantly more frequently than normals and severity of dementia was more strongly associated than etiology with increased perseveration. Frequency of carrier phrases did not distinguish the descriptive discourse of dementia patients from normals. Discontinuous perseveration was more common than continuous perseveration, and perseveration of ideas after an intervening response was the perseverate most typical of the dementia patient. Findings of the study are related to prominent theories of the cause of perseveration.

Adult↗
PubMed1985

Changes in end-plate cholinesterase and axons during muscle degeneration and regeneration.

Injection of bupivacaine into the rat anterior tibial muscle produced rapid necrosis with disintegration of muscle fibres and phagocytic infiltration within two days. Regenerating myotubes appeared four days after injection, and muscle structure was restored seven days after injection. One day after injection, axons and end-plate cholinesterase appeared normal in spite of the underlying muscle fibre necrosis. Intensity of cholinesterase staining was gradually reduced through the second and third day but axons remained intact. On the fourth day, newly formed end-plates delineated by cholinesterase stain were seen on myotubes. Some were innervated by thin regenerating axons. Axonal outgrowth appeared to compensate for occasional neuronal degeneration and for the greater number of end-plates on myotubes. In some areas, not all end-plates were innervated by the fourth day but were by the fifth day. On the sixth and seventh day after myotube maturation, a process of degeneration of superfluous end-plates and axons occurred, reducing their number to the number of muscle fibres. Fourteen and 28 days after injection, the innervation pattern was normal except for a slight increase in terminal innervation band width. These results indicate that injection of bupivacaine does not directly affect intramuscular nerves and that the changes observed in this experimental model are the consequence of muscle fibre degeneration and regeneration.

Animals↗
PubMed1984

Alterations in creatine kinase, ornithine decarboxylase, and transglutaminase during muscle regeneration.

Creatine kinase (CK), transglutaminase (TGase) and ornithine decarboxylase (ODC), enzymes implicated in the regulation of growth processes, were studied during muscle regeneration subsequent to the injection of bupivacaine into rat tibialis anterior. Within 2 days, the percent BB isozyme of CK detected in the muscle was elevated 70-fold coincident with a marked decrease in total CK activity. The MB isozyme also increased and was 15-fold of control at 4-5 days postinjection. TGase activity was increased significantly to greater than 2-fold of control within 2 days of injection and significantly decreased at days 3 through 7 compared to controls. ODC activity was elevated significantly to 2- to 3-fold of control from 2-7 days after injection. These results suggest an early alteration in the expression of a coordinated battery of genes in this model of muscle degeneration-regeneration. The increased expression of MB and BB isozymes of CK in various human neuromuscular diseases may be a manifestation of an ongoing process of degeneration-regeneration.

Acyltransferases↗
PubMed1984

Changes in muscle carnitine during regeneration.

Carnitine in rat skeletal muscle was measured before, during, and after muscle regeneration. Early regenerating tibialis anterior muscle consequent to bupivacaine injection was found to have smaller amounts of total, free, and acyl carnitine per milligram wet weight, but returned toward normal values as muscle regeneration was completed. Accumulation of DL-[3H]carnitine per milligram wet weight in regenerating muscle was less than one-half that of control muscle at day 4 (P less than 0.005), but was not significantly different from the control value at day 7. Our results are consistent with the hypothesis that the reported decrease in muscle carnitine content in several different human neuromuscular diseases is in part a manifestation of muscle fiber regeneration.

Animals↗
PubMed1984

Increased activities of MB and BB isozymes of creatine kinase in denervated neonatal and adult rat muscle.

Creatine kinase (CK) activity and isozyme patterns were assessed in newborn and adult rat anterior tibial muscle in response to denervation. Total CK activity was low in the control neonatal muscle, gradually increasing to the adult level within 1 month. Denervation prevented this normal increase, and, therefore, CK activity was reduced to 25% of control at 2 months. In the denervated adult muscle, total CK activity decreased to 50% of control within 3 weeks and remained at that level. Denervation of neonatal muscle resulted in a greater conservation of MB isozyme compared with controls. The alteration in BB isozyme expression was even more dramatic with a 33-fold difference expressed at 2 months in terms of percent total CK in denervated vs. control muscle. In denervated adult muscle, MB and BB isozyme activities increased gradually, attaining levels 3-fold and 13-fold, respectively, above control muscle at the end of the experimental period.

Aging↗
PubMed1983

Serial left ventricular wall measurements in Duchenne's muscular dystrophy.

In 19 patients with Duchenne's muscular dystrophy, left ventricular wall thickness in end-systole and end-diastole was determined serially every 12 months by echocardiography and compared with ventricular wall growth in normal subjects. In the normal subjects, left ventricular wall thickness increased linearly with increasing body surface area. A control group of wheelchair-bound patients with a variety of neurologic disorders, although not followed serially, had a distribution of end-diastolic wall thickness values similar to that of the normal subjects. In patients with muscular dystrophy, wall thickness increased linearly with respect to body surface area for some time and then began to thin. The time at which thinning began was not directly related to age, although it was more common in older than in younger patients. Those patients who died demonstrated marked deviation from normal wall growth. Free wall thinning is probably a result of fibrosis and loss of myofibrils.

Adolescent↗
PubMed1982

Hereditary proximal spinal and bulbar motor neuron disease of late onset. A report of six cases.

Six cases of a comparatively rare motor neuron disease are described. Essential features of this syndrome include (1) X-linked inheritance; (2) adult onset in the fourth to fifth decades; (3) slow progression; (4) predominant proximal and bulbar muscle involvement; and (5) absence of sensory or pyramidal tract signs. The previously reported finding of gynecomastia was absent, whereas longitudinal midline furrowing of the tongue was present in only one case. Electromyography in five patients revealed neurogenic changes. Muscle biopsies in two patients showed fiber type grouping with type I fiber predominance. The coexistence of this form of motor neuron disease and diabetes mellitus is prominent in family 2. It is important to recognize that these patients have a chronic, slowly progressive illness. The prognosis for longevity is good, although severe disability is inevitable. Management includes reassurance, supportive therapy, genetic counseling, and periodic testing for diabetes.

Chromosomes↗
PubMed1982

Drug trial of superoxide dismutase in Duchenne's muscular dystrophy.

A multicenter, randomized, double-blind, placebo-controlled drug trial in Duchenne's muscular dystrophy, evaluating a superoxide dismutase in 51 ambulatory patients for 18 months was conducted. Fourteen aspects of muscle strength and five of functional ability, as well as serum creatine phosphokinase (CPK) level were studied. The total change in strength, function, and CPK level did not differ significantly in the two groups. The testing method used was reliable in assessing the natural history of Duchenne's dystrophy and would, therefore, be useful in future multicenter drug trials.

Child, Preschool↗