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In orders to search for possible events in the pathogenesis of Duchenne muscular dystrophy (DMD), the activity of erythrocyte superoxide dismutase has been determined in thirty-seven patients and fifteen carriers of DMD, comparison to fourty-five age-matched normal controls, seventeen cases of infantile, Kugelberg-Welander type spinal muscle atrophy. The results showed that superoxide dismutase activity were elevated especially in early periods of disease in DMD but not in other groups of patients. These findings suggest that alterations of SOD do not constitute the primary mechanism of inducing membrane damage. A considerable increased SOD activity in DMD patients may be a compensatory phenomenon secondary to muscle degeneration.

In extracts derived from whole blood, a high molecular weight fraction of the diphenoloxidase enzymes has a significantly diminished specific activity in patients and definite carriers (heterozygotes) of the X-linked, recessive (Duchenne) form of muscular dystrophy. This anomaly was studied using spots of blood which had been collected on absorbent paper and stored at 4 degrees C for variable periods of time. Fractions enriched in the enzymes were obtained by subjecting aqueous extracts of the spots to treatment with an anion exchange resin (DEAE Sephadex A 50) followed by gel filtration on Sephadex G-25. It is of interest that this anomaly was observed in some definite carriers of the mutant gene who had on several occasions a serum creatine kinase level in the normal range. The significance of these observations is discussed.

Thanks to the use of enzyme histochemical methods, substantial progresses have been made in muscle biopsy diagnosis in recent years. These methods not only permit detection of early alterations in known ("old") myopathies, they also have led to the discovery of numerous "new" neuromyopathies. They also have opened up the potential for additional, specific electron microscopic and biochemical tests. Some examples of the old and new myopathies are presented.

In myopathic disorders, abnormal serum enzyme activities are seen primarily in diseases of skeletal muscle where the condition involves the muscle fibers themselves. In denervation myopathies, serum enzyme activities are usually normal. The most dramatic increases of serum enzymes, particularly creatine kinase, are found in the dystrophic diseases, particularly Duchenne dystrophy. A review is given here of the many causes of abnormal serum enzyme activities where the source of enzymes is believed to be skeletal muscle. These include the dystrophies, various types of trauma, exercise, drug- and poison-induced causes including alcohol, malignant hyperthermia, inflammatory diseases, and miscellaneous causes. Tissue and serum activities are summarized for the commonly performed serum enzymes, i.e., CK, LD, AST, and aldolase. An extensive tabular and current description of the various types of dystrophies is given along with serum CK and pyruvate kinase activities.

We have carried out serum assays for myoglobin in parallel with the determination of serum CPK activity to assess its usefulness in raising the detectability rate of Duchenne muscular dystrophy carriers. Of the 14 carriers, ten (71.4%) had high serum levels of myoglobin and nine (64.3%) showed increased serum CPK levels. Either parameter revealed elevation in 11 (78.6%) of the 14 cases studied. Serum myoglobin determination is of noticeable value in the detection of Duchenne muscular dystrophy carriers.

The level of adenylosuccinase was measured in muscle from patients with Duchenne and other major forms of progressive muscular dystrophies and certain related neuromuscular diseases. The activity was found to be unaltered in all diseases that were examined.

Representative enzyme activities of energy supplying metabolism were measured in muscle specimens of brachial biceps, deltoid or anterior tibial muscle of patients with affections of the peripheral nerves. Simultaneously performed measurements of the same enzyme activities in the contralateral normal muscles served as a control. 5 patients suffered from a lesion of the brachial plexus, 7 patients had a paralysis of the axillary nerve, and 8 patients had a peroneal paralysis. In all denervated muscles no electrophysiological signs of reinnervation were present. The activities of glycogen phosphorylase, triosephosphate dehydrogenase, lactate dehydrogenase and alpha-glycerophosphate dehydrogenase were found to be highest in the normal brachial biceps muscle. Lower activities were measured in the normal deltoid and anterior tibial muscle. The oxidative enzymes, 3-hydroxyacyl-CoA dehydrogenase and citrate synthase as well as hexokinase, showed no significant difference from the levels of the control. It is suggested that a probable factor determining the differences of the enzyme activities of glycogenolysis, glycolysis and alpha-glycerophosphate oxidation between brachial biceps, deltoid and anterior tibial muscle, might be the pattern of impulse activity in the motor nerves of these muscles. The enzyme activities of glycogen phosphorylase, triosephosphate dehydrogenase, lactate dehydrogenase and alpha-glycerophosphate dehydrogenase, decreased rapidly during the first 2 months after denervation in the brachial biceps, deltoid and anterior tibial muscle, whereas the decrease was slight during the following months. The activities of the oxidative enzymes (3-hydroxyacyl-CoA dehydrogenase and citrate synthase) showed no significant change after denervation. The metabolic difference of glycogenolysis, glycolysis and alpha-glycerophosphate oxidation between the three muscles was no longer maintained. The possible causes of the deeply decreased enzyme activities of glycogenolysis, glycolysis and alpha-glycerophosphate oxidation, as well as the causes of the unchanged oxidative enzyme activities and of the increased hexokinase activity after denervation in the human brachial biceps, deltoid and anterior tibial muscle, are discussed.

The authors emphasize the importance of adding a genetic criterion to the definition of Duchenne dystrophy. The clinical characteristics, however, on the basis of recent molecular genetic studies, are sufficiently precise to make the condition heterogeneous: two types of Duchenne dystrophy, with or without mental retardation in affected boys; muscular dystrophy in girls with mild symptomatic weakness in "manifesting carriers" up to severe myopathy in girls, found to be associated with reciprocal chromosomal translocation (X-autosome), always at the same site, Xp21. Diagnostic use of Xp21 probes is now as necessary as EMG, muscle biopsy and serum CK assay for the definition of Duchenne muscular dystrophy.

Experiments have been performed to determine if fibroblasts from patients with Duchenne muscular dystrophy (DMD) are defective in a process of membrane repair. Normal and DMD fibroblasts were treated with phospholipase C from Clostridium perfringens to degrade plasma membrane phosphatidylcholine, and then phosphatidylcholine synthesis was measured as the incorporation of [3H] choline into lipid. Phosphatidylcholine synthesis was stimulated by phospholipase C treatment to a similar extent in normal and DMD fibroblasts. The activity of CTP: phosphocholine cytidylyltransferase, the enzyme regulating phosphatidylcholine synthesis in phospholipase C-treated mammalian cells, was also stimulated to the same extent in both cell types. The subcellular location of the cytidylyltransferase was changed by phospholipase C treatment from mostly cytosolic to mostly particulate in both normal and DMD fibroblasts. It appears, therefore, that at least one type of membrane repair system functions normally in DMD fibroblasts.

The cation-stimulated adenosine triphosphatase (ATPase) activities of erythrocyte ghosts and erythrocyte ghost plasma membrane fragments of patients with Duchenne muscular dystrophy (DMD) were compared with activities in age-matched normal male controls. DMD Mg++-stimulated ATPase activity was within the normal range. The specific activity of DMD erythrocyte ghost Na+,K+-stimulated, Mg++-dependent ATPase was also normal, and was inhibited by 10(-4) M ouabain to an extent comparable with controls. Ca++-stimulated, Mg++-dependent ATPase activity of DMD erythrocyte ghost plasma membrane fragments, assayed at 0.5 mM free Ca++, was 21% above that in age-matched male controls (n = 22, 2-tailed paired t-test, P less than 0.01). Kinetic studies indicated that the DMD erythrocyte Ca++-stimulated, Mg++-dependent ATPase has greater affinity for MgATP than the enzyme in control erythrocytes.

In boys with Duchenne muscular dystrophy (DMD) plasma myoglobin levels remained approximately constant with age while creatine kinase (CK) activity progressively decreased. For carrier detection, plasma myoglobin level was found to be less reliable than CK activity. The myoglobin level was raised only in some of those subjects who also showed a raised CK activity and was normal in those with a normal CK activity. The myoglobin level in fetal muscle at 18-22 weeks gestational age was found to be low compared with adult skeletal muscle levels and, consequently, the myoglobin level in fetal plasma and in amniotic fluid was found to be negligible. It is concluded that measurement of myoglobin offers no advantage over CK for the investigation of any aspect of DMD.

Serum creatine kinase activity is the most useful test for Duchenne muscular dystrophy carrier detection, but only in 50-80% the carriers do have increased serum creatine kinase activity. To evaluate the diagnostic accuracy of post-exercise serum creatine kinase activity in identifying Duchenne muscular dystrophy carriers we did determine it in normal and possible Duchenne muscular distrophy carrier women. Creatine kinase activity was determined in basal conditions and at predetermined time intervals up to 10 hours after a constant exercise on a cycloergometer. Statistical analysis included: Fisher test on basal values; percent increase, difference between maximum and minimum values, absolute value after 8 hours and b coefficient of linear regression. Accuracy and sensitivity were evaluated for some of the data. Our results suggest that the activity of serum creatine kinase 8 hours after a quantified exercise can be useful to detect Duchenne muscular dystrophy carriers when basal activity is normal.

Membrane-bound enzyme activities and cardiac glycoside binding were determined in red blood cell membrane preparations from patients with myotonic dystrophy and in age matched controls. Na+-K+-activated ATPase activity was significantly increased in myotonic patients. [3H]Ouabain binding to erythrocyte membranes was also significantly increased in myotonic dystrophy patients. The Mg2+-ATPase (ouabain-insensitive) was, however, unchanged. The K+-stimulated paranitrophenyl phosphatase (KPNPPase) activity was markedly enhanced in myotonic patients as compared to controls. The kinetic analysis showed a marked change in Vmax of Na+-K+ ATPase with respect to the activation by Na+, K+ and ATP. However, the Km values were the same in control as well as in myotonic groups. The increased erythrocyte membrane Na+-K+-ATPase activity, KPNPPase and [3H]ouabain binding in myotonic patients supports the hypothesis that generalized membrane abnormality may be involved in pathogenesis of the human myotonic dystrophy.

Serum LDH isozymes render qualitative information which may be more specific than the quantitative changes of total serum LDH and total serum CPK in neuromuscular diseases. Muscle LDH isozymes vary with age, muscle, and species. Temporal study of serum LDH isozymes in experimental neurogenic atrophy demonstrated a temporary rise of serum LDH 5. In acute and progressive neurogenic diseases, a high serum LDH 5 was noted. Isozyme patterns were normal in chronic and non-progressive diseases. In Duchenne dystrophy, serum LDH 5 was low and stayed low until the final stages of the disease. This abnormality persisted long after serum total LDH and CPK returned to normal. This may reflect the leakage of genetically abnormal isozymes from the muscles to serum. It is concluded that the serum LDH isozyme pattern is a reliable qualitative test in the diagnosis of a genetic myopathy, and in differentiating progressive from static neurogenic atrophies.

Data are presented which suggest that Duchenne muscular dystrophy (DMD) may have some origin in a severe deficiency of total muscle adenine nucleotides. Using double-blind techniques, this possibility was tested in 16 DMD patients by giving oral allopurinol, a synthetic inhibitor of the purine catabolic enzyme xanthine oxidase. Sublingual procaine adenylate was also briefly tested. Instances of clinical improvement quickly occurred which were statistically significant; they were accompanied by a significant increase in physical strength. These improvements have been maintained for more than 6 mo by administration of a small amount of allopurinol daily. Procaine adenylate had little effect. These results support the above view of DMD and seem to indicate that existing purines, retained and recycled after allopurinol, can sustain such improvement, and that additional adenylate is unnecessary.

The activity of [Na+ + K+] Mg2+-ATPase of muscle surface membrane was investigated in 20 cases of the Duchenne type of progressive muscular dystrophy; it was found to be diminished and to have a changed reactivity to ouabain. There was nothing like it in cases of limb-girdle dystrophy and neurogenic muscular atrophies investigated for the purpose of comparisons, whereas in some cases of myotonic dystrophy and myotonia congenita the activity of the ATPase was indeed depressed, but the response to ouabain invariably remained normal.

In muscles from dystrophic mice the activity of alkaline phosphatase is 50-75% higher than in their control littermates. In the dystrophic animals all muscle fibres show strong enzyme activity. It is suggested that during dystrophy amounts of an already existing muscle alkaline phosphatase are produced rather than that a synthesis of a new isoenzyme should be initiated.

The level of the ATPase activity in the skeletal muscles nuclei with experimental muscular dystrophy and the sensitivity to bivalent (Mg2+, Ca2+) and univalent (Na+, K+) cations under conditions of delipidation were studied. It is established that among ATPases of the young rabbit skeletal muscles nuclei there is ATPase sensitive to monovalent cations: the presence of Na+ or K+ produces a 45% increase in its activity in some experiments as compared to the initial level. This activation is attributed to Mg2+, Ca2+-ATPase the action of which is not realized in the presence of EGTA-chelator of calcium ions. A decrease in the total ATPase activity in the skeletal muscles nuclei resulted from the experimental muscular dystrophy development occurs due to a decrease in the Mg2+, Ca2+-ATPase activity as the ability for activation by the monovalent cations is practically lost under these conditions. Delipidation of the skeletal muscles nuclei, which results in their loss of some phospholipids and cholesterin, is accompanied by the ATPase activity decrease. At the same time the nuclei ATPase activity lose its ability to activate by monovalent cations: Na+, K+. A conclusion is made that during delipidation the decrease in the total ATPase activity is due to a decrease in the activity of its Mg2+, Ca2+-part.

Serum pyruvate kinase and creatine kinase activities were measured in a group of patients with various neuromuscular diseases and in carriers of muscular dystrophy. Elevated values of PK were usually but not invariably associated with elevated levels of CK. THe data showed that PK activity was elevated in all patients with DMD, high values generally correlating inversely with age or disease duration. In definite carriers, the level of PK was raised simultaneously with CK, while in potential carriers, classified by their relationship with MD patients in mothers, sisters and other relatives, the PK levels were elevated in 23%, 44% and 10% respectively, indicating especially for sisters, an increased genetic probability of being a definite carrier. In this way, we have confirmed that the serum PK assay is more sensitive in younger subjects and that combined CK and PK measurement will be of value in detecting a higher proportion of potential carriers.

This report outlines the clinical, electrophysiologic, and morphologic findings in seven patients with adult acid maltase deficiency. The diagnosis was confirmed biochemically in four of these individuals. Adult acid maltase deficiency must be considered whenever clinical diagnoses of polymyositis, especially the chronic form, and limb-girdle muscular dystrophy are being entertained.

In a retrospective study, the serum myoglobin concentration (S-myoglobin) was determined in patients with neuromuscular diseases and in carriers of Duchenne muscular dystrophy (DMD). Myoglobin was quantified by a sensitive radioimmunoassay. Serum creatine kinase (CK, EC 2.7.3.2) activity (S-CK) and serum creatine kinase B-subunit activity (S-CKB) were determined for comparison. Sera from 70 patients with various neuromuscular diseases and from 17 female relatives of patients with DMD were analysed. Increased levels of S-myoglobin were found both in dystrophic and in spinal myopathies. Because of a marked overlap of the range of values between the different dystrophic myopathies and even between the dystrophic and the spinal myopathies, S-myoglobin is of little value in the final diagnosis of neuromuscular diseases. In the detection of carriers of DMD, simultaneous determination of S-myoglobin and S-CK gave a higher detection rate compared to the detection rate with S-CK. S-CKB was normal in all carriers and only elevated in some of the patients with DMD and limb girdle muscular dystrophy.

All of 12 patients with Duchenne muscular dystrophy manifested raised activity of serum enolase but only 10 showed elevation of immunologically reacting muscle enolase (IRM-enolase). Total enolase was raised in 4 of 12 mothers and one of 8 sisters of the affected subjects but IRM-enolase was elevated in only one mother. These results are consistent with the view that enolase, unlike creatine phosphokinase which showed much more pronounced increase in the serum of patients and their female relatives, is associated with a structural component of the muscle cell distinct from the presumed site of molecular abnormality in this disease.

The postnatal development of extrafusal fibers in the slow-twitch soleus muscle of genetically dystrophic C57BL/6J dy2J/dy2J mice and their normal age-matched controls was investigated by histochemical and quantitative methods at selected ages of 4, 8, 12, and 32 weeks. The majority of fibers in the soleus consisted of two kinds, fast-twitch oxidative-glycolytic (FOG) and slow-twitch oxidative (SO), according to reactions for alkaline-stable and acid-stable myosin ATPase and the oxidative enzyme, NADH-tetrazolium reductase. A minor population of fibers, stable for both alkaline- and acid-preincubated ATPase, but variable in staining intensity for NADH-TR, were designated "atypical" fibers. With age, the normal soleus exhibited a gradual increase in the number and proportion of SO fibers and a reciprocal, steady decline in the percentage of FOG fibers. Atypical fibers were numerous at 4 weeks, but were substantially diminished at later ages. Since total extrafusal fiber number remained relatively constant between the periods examined, this change in relative proportions reflects an adaptive transformation of fiber types characteristic of normal postnatal growth. A striking alteration in the number and distribution of fiber types was associated with the dystrophic soleus. At 4 weeks an 18% reduction in total fiber number was already noted. Subsequently, by 32 weeks a further 22% diminution in overall fiber number had occurred. With age, the absolute number and proportion of dystrophic SO fibers were drastically reduced. In contrast, the percentage of dystrophic FOG fibers increased significantly while their absolute numbers between 4 and 32 weeks remained relatively constant. Atypical fibers in the dystrophic solei were found in elevated numbers at all age groups, particularly at 12 weeks. They may, in part, represent attempts at regeneration or an intermediate stage in fiber-type transformation. Microscopically, both of the major fiber types appeared affected, albeit differently, by the dystrophic process. We suggest that a failure or retardation in the normal postnatal conversion of fiber types within the soleus muscle occurs in this murine model for muscular dystrophy.

Myosin ATPase activity was fine-structurally examined in various skeletal muscle lesions including atrophy, degenerations, necrosis, "deltashaped subsarcolemmal lesion", and apparently normal fibers from seven patients of Duchenne muscular dystrophy (D M D). The enzyme activity was almost completely lost in the foci of necrosis, and more or less markedly diminished in various kinds of degenerations, while it was well preserved in the apparently normal and simply atrophic fibers. The results suggested that there were two different lesions in wasting of the skeletal muscles in D M D; necrotic process with degenerations in which myosin-ATPase activity was affected and simply atrophic process which had little influence on the enzyme activity. The former lesion might be related with direct or indirect damages such as proteolysis, while the latter seemed to be an expression of basically different process such as disuse or denervation, or a more mild expression basically of the same process ultimately resulting in necrosis.

Sarcoplasmic reticulum Ca2+-ATPase, acylphosphatase and other soluble enzymes (creatine kinase, lactate dehydrogenase, aldolase and pyruvate kinase) were assayed in muscle biopsies from patients affected by Duchenne muscular dystrophy (DMD) and from normal controls. Specific activities of all the soluble enzymes were decreased in dystrophic muscle, acylphosphatase exhibiting the most marked and significant decrease comparable to that of creatine kinase, in spite of a moderate increase in serum levels. Also, Ca2+-ATPase, particularly the calcium-dependent activity, was decreased in dystrophic muscle. A positive correlation, higher than with the other soluble enzymes, was obtained between acylphosphatase specific activity and the percentage of Ca2+-activation of Ca2+-ATPase. These findings: suggest an impairment of microsomal calcium uptake which could be, at least in part, responsible for sarcoplasmic calcium accumulation observed in DMD; do not disagree with an hypothesized role of acylphosphatase in intracellular calcium homeostasis, consistent with the enzyme's demonstrated hydrolytic activity on the phosphorylated intermediate of Ca2+-ATPase.

1. Procedures are given for the syntheses of alpha,omega-dinucleoside 5'-polyphosphates as inhibitors of adenylate kinases. The following order for the ability of inhibiting pig muscle adenylate kinase was observed: Ap5A greater than 1:N6-etheno-Ap5A greater than Ap6A greater than Gp5A greater than Ap4A greater than Up5A. The synthesis of adenosine tetraphosphate, the starting material for Ap5A, is also described. 2. One molecule of pig muscle adenylate kinase binds one molecule of Ap5A. The difference spectrum of Ap5A-adenylate kinase with its maximum of 5050 M-1 - cm-1 at 271 nm, as well as the fluorescence properties of 1:N6-etheno-Ap5A can be used for kinetic and binding studies. 3. The specific binding of the negatively charged Ap5A was exploited in the preparation of human muscle adenylate kinase. The enzyme was purified to homogeneity with an overall yield of 65%, the absolute value being 70 mg per kg of muscle. 4. The effect of Ap5A on adenylate kinase in extracts of various cells and cell organelles was tested. A ratio of 1:50 (mol/mol) for Ap5A to other nucleotides was used for suppressing the adenylate kinase activity in extracts of mammalian and insect skeletal muscel, of human erythrocytes and of Staphylococcus aureus. A ratio of 1:5 was found to be necessary for the adenylate kinase from tobacco leaves and spinach chloroplasts, and a ratio of 2:1 was needed for suppressing the adenylate kinase from bovine liver mitochondria, human kidney homogenate and from Escherichia coli. Ap5A appears not to be metabolized in any of the above extracts. These results indicate that Ap5A can be used for evaluating the contribution of adenylate kinase to the production of ATP fro ADP in energy-transducing systems. 5. Contaminating adenylate kinase can be inhibited by a concentration of Ap5A which does not interfere in the study of many (phospho)kinases and ATPases. The applications of Ap5A in the assay for nucleoside diphosphokinase and in the study of mechanical and biochemical properties of contractile proteins are representative examples. The use of Ap5A makes it possible to study the effect of ADP per se in such systems. 6. Sepharose-bound Ap5A was used for removing traces of adenylate kinase from samples of myosin and creatine kinase. 7. In the presence of Ap5A the activity of creatine kinase was measured in hemolytic serum of venous blood, in plasma of capillary blood and in samples of whole blood after complete hemolysis had been induced. The clinical significance of these findings are shown for cases of myocardial infarction and muscular dystrophy.

Activity of the guanine nucleotide-binding regulatory (N protein) component of adenylate cyclase can be measured in extracts of whole blood, using a modification of an assay previously applied to erythrocyte membranes. N protein activities in the blood of three patients with Duchenne muscular dystrophy and eight heterozygous carriers of the disease did not differ significantly from activities measured in blood of seven normal subjects. In contrast, the modified assay showed a 50% deficiency of N protein activity in blood of four patients with pseudohypoparathyroidism, type I, in whom erythrocyte studies had previously demonstrated a comparable degree of N deficiency.

Muscle biopsies in 4 cases of Duchenne muscular dystrophy and two normal controls were examined by electron microscopy using lanthanum as a tracer for assessment of the T-system. Lanthanum was localized in the extracellular spaces, the basement membranes, intercellular spaces between muscle fibers and satellite cells, subsarcolemmal vesicles (caveola), motor end-plate, and the T-system in the controls. The T-system was sometimes connected with the caveolae, and was located at right angles to the myofibrils in the controls. In Duchenne muscular dystrophy, the T-system showed irregularities of position, tangle formations and dilatation of the diameters when observed using lanthanum as a tracer, even in muscle fibers which under light- and electron-microscopic examinations did not show any changes. Structure of the triad was destroyed and lanthanun was localized in the sarcoplasmic reticulum (SR). The changes of the T-system and triad seemed to play an important role in the high level of creatine phosphokinase (CPK) in the serum of Duchenne muscular dystrophy patients who do not show any clinical symptoms. Because of the destruction of the triad, CPK will easily flow out to the exterior of muscle fibers via the T-system.

Observations in 12 normal women and 12 female carriers of X-linked recessive Duchenne muscular dystrophy (DMD), of whom 4 had symptoms and 8 had none, were compared between all 4 groups and with those in 2 DMD boys, one active and one crippled. Carrier symptoms were readily ascertained by systematic examination. Measurement of both lower legs in all 24 women showed neither calf enlargement nor asymmetry in carriers beyond normal variation. Two DMD carrier daughters were noted of the same DMD carrier mother but by different fathers. Whole body counting showed the biological half-life of previously administered 86Rb to be much reduced in DMD, but no differences were found between normal women and any group of carriers. The test is thus valueless for carrier detection, and reasons are given why it should be so. Simultaneous measurement of total body K+, with subsequent determination by isotope dilution of total body water as 3H2O space and extracellular water as NH4 82Br space, showed increased intracellular water and reduced intracellular K+ concentration in all carriers, as if due to osmotic causes, with actual loss of muscle mass and slight diminution of serum K+ in the 4 symptomatic carriers only. Because of diurnal and other variations, the means and standard deviations for six serum enzymes from six fortnightly assays in all subjects were used to measure precise individual status. Their coefficients of variation were abnormal only in symptomatic carriers and ambulant DMD, easily overtexed by even accustomed exertion. This is shown to support previous propositions on the pathogenesis of DMD and the escape of muscle cell content into the circulation.

Cultured muscle cells from patients with Duchenne muscular dystrophy differed from cells of normal individuals and of patients with other muscle diseases. In Duchenne cells, basal activity of adenyl cyclase of myotubes was higher and was not stimulated significantly by epinephrine or isoproterenol, as it was in fused control cells, and the response to fluoride was less. The genetic defect in this disease may be an abnormality of the sruface membrane of muscle.

The activities of erythrocyte superoxide dismutase and glutathione peroxidase in patients with Duchenne muscular dystrophy were normal compared with healthy male controls, as were the levels of thiobarbituric acid-reactive compounds produced during incubation of erythrocytes in the presence of 10 mmol.1-1 hydrogen peroxide. These results suggest that the chief mechanisms for protecting the erythrocyte membrane from peroxidative damage are unimpaired and do not support the idea that the reported erythrocyte abnormalities in this disease result from increased susceptibility to lipid peroxidation.

We failed to confirm the suggestion that serum lactate dehydrogenase isoenzyme 5 (LDH-5) levels are as sensitive an indicator of the carrier status in Duchenne muscular dystrophy (DMD) as are serum levels of creatine kinase. In particular, serum LDH-5 was not increased in carriers when the serum creatine kinase level was normal.

Four cases of congenital muscular dystrophy are reported. Muscular weakness and hypotonia, with different clinical severity, was present from birth in three patients; in the fourth one, it began at two months old. Three cases had joint contractures. One patient died by respiratory infection. Serum CK level was very high in all of them. Muscle biopsies showed pathologic changes consistent with muscular dystrophy with endomysial and perimysial fibrosis and fatty infiltration. Authors analysed this illness emphasizing clinical and biochemical (CK) data so that an early diagnosis can be suspected.

The effects of diethylstilbestrol (DES) and prednisolone (Pr), administered alone or in combination, on the serum enzyme activities in Duchenne's muscular dystrophy (DMD) have been evaluated. When DES and Pr were given simultaneously to four boys with DMD, the mean creatine phosphokinase and lactate dehydrogenase levels fell to about one half those achieved with either agent alone. No untoward or unexpected side effects were encountered. These observations, and our previous demonstration that both agents reduce enzyme efflux from skeletal muscle, give promise that a safe combination therapy may be found to approximately normalize the serum in DMD. This will permit us to test the hypothesis that lowering the serum enzymes, by reducing their loss from skeletal muscle, will slow or arrest the muscle deterioration characteristic of this disease.

Total activity of creatine kinase (CK), lactate dehydrogenase (LD), aldolase (Ald), glutamico-oxaloacetic transaminase (GOT), and LD-isoenzyme distribution was studied in serum and muscle biopsies from normal persons and 117 patients with different types of muscular dystrophy: 82 Duchenne type (DMD), 12 BEcker type, 7 facioscapulohumeral (FSHMD), and 16 limb girdle (LGMD). Total enzyme activity in sera and muscle homogenates was determined by spectrophotometric assays. LD isoenzymes were separated by electrophoresis on agarose gel plates in barbital buffer (pH 8.6), scanned and quantitated. The amounts of the 2 types (M and H) of LD isoenzymes were calculated and the ratio of M/H in serum and muscle was used as an index to differentiate among the types of muscular dystrophy. Serum enzyme activity was elevated to variable degrees reflecting a corresponding decrease in muscle enzymes in the different muscular dystrophies. Patterns of LD isoenzymes in serum and muscle were specific to each type of muscle disease. Increase in serum LD5 (the muscle LD fraction) was a common feature in muscle damage. Changes in the amounts of M and H types in the subunits of LD correlated to the existence and severity of muscle damage. The mean muscle M/H ratio was 6.4 in controls, 1.8 in early DMD, 0.1 in late DMD, 3.0 in Becker type, 3.8 in FSHMD and 3.9 in LGMD. The muscle LD isoenzyme distribution in DMD showed a shift toward a more aerobic fetal muscle pattern. This is a result of the gradual disappearance of the mature anaerobic LD-type (M) and the increase in synthesis of the aerobic fetal LD-type (H) during the progression of the disease. This report provides a comparative study of the LD isoenzyme patterns in muscular dystrophies which may help in differential diagnosis.

Eight patients with Duchenne muscular dystrophy (DMD) and seven normal children of similar age were studied with a new electromyographic method for coherent displays of potentials. Five hundred motor unit potentials (MUPs) were analyzed in 20 proximal and distal muscles representing a wide spectrum of dystrophy. The progressive MUP disintegration by dropping out of muscle fibers was documented, as well as a high incidence of spontaneous fibrillation. A total of 386 late component (LC) potentials followed the 500 MUPs at consistent latencies. No LC occurred in normal children. The LCs result from motor axon sprouts innervating muscle fibers that are newly formed either by segmentation of existing muscle fibers (focal neucrosis and membrane repair) or by muscle regeneration. Axons in DMD can thus collaterally innervate additional muscle fibers. These processes must delay the onset and progression of clinical weakness in DMD patients.

We studied the behaviour of serum myoglobin in 32 children affected by Duchenne muscular dystrophy, in 30 mothers (10 definite carriers and 20 possible carriers), in 5 sisters (possible carriers) and in 40 healthy women (control). The serum myoglobin was always increased in the patients affected by Duchenne muscular dystrophy; the greatest values were in the patients who were still ambulant, with a behaviour similar to creatine kinase. In the carriers the myoglobinemia showed a significant increase in definite carriers, while there was no significant difference between the possible carriers and the controls.