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Biomedical subjects

W K Engel

Publications and source records attributed to W K Engel.

At least 181 records · Page 10Linked to original sources
PubMed1979

Lipid composition of erythrocytes. Findings in Duchenne's muscular dystrophy and myotonic atrophy.

The distribution of major erythrocyte phospholipids and fatty aldehydes and the total fatty acid composition of erythrocytes and plasma were compared from patients with Duchenne's muscular dystrophy, from definite carriers of the disease, from patients with myotonic atrophy, and from a number of normal controls. The data for normal controls closely agreed with the accepted values for these lipid components. Contrary to the published reports of others, no abnormalities in lipids were found in either disease or carrier groups.

Adolescent↗
PubMed1979

X-linked recessive congenital muscle fiber hypotrophy with central nuclei: abnormalities of growth and adenylate cyclase in muscle tissue cultures.

Muscle cells in cultures established from biopsy specimens of two children with an infantile-fatal form of X-linked recessive muscle fiber smallness with central nuclei showed an unusual ability to proliferate through numerous passages. Ultrastructurally, the cultured muscle fibers appeared very immature even after several weeks. The nuclei were large, the number of ribosomes was greatly increased, the myofibrils remained unstriated, and glycogen was accumulated in large lakes. The plasmalemma bound concanavalin A, alpha-bungarotoxin, and ruthenium red normally, but with tannic acid it did not show the dark binding of mature fibers. Biochemically, in the cultured muscle fibers, beta-adrenergic receptors were quantitatively normal. The level of adenylate cyclase in membranes was less than in cultured normal muscle; this defect could be responsible for impaired control mechanisms resulting in the other abnormalities observed.

Adenylyl Cyclases↗
PubMed1979

Autoradiographic visualization of beta-adrenergic receptors in normal and denervated skeletal muscle.

Autoradiographic localization of beta-adrenergic receptors in rat skeletal muscle in vivo was achieved utilizing [125I]-iodohydroxybenzylpindolol, a potent beta-adrenergic blocker with high affinity and specificity for those receptors. In normal muscle the beta-adrenergic receptors were localized mainly to blood vessels, arterioles greater than venules, with much less concentration of grains over the fascicles of muscle fibers. One week after denervation there was an increase in binding both to blood vessels and muscle fibers, more so in soleus and gactrocnemius than in extensor digitorum longus. While these results parallel in vitro biochemical studies, they dictate caution when inferring cellular localization of beta-adrenergic receptors (and other molecules) solely on the basis of biochemical techniques applied to subcellular fractions of whole-organ homogenates.

Animals↗
PubMed1979

The hemostatic imbalance of plasma-exchange transfusion.

Plasma exchange has been proposed as a treatment for multiple disorders. Three patients with amyotropic lateral sclerosis, who were hemostatically normal, were studied through a total of 11 4-liter exchanges. Plasma was replaced by an equal volume of 5% albumin or 5% plasma protein fraction. Serial studies revealed that immediately after the exchange transfusion, there was significant prolongation of the prothrombin, partial thromboplastin, and thrombin times with reduction of the fibrinogen and antithrombin III levels. Factors V, VII-X, IX, and X were all significantly decreased, as were the factor VIII antigen, procoagulant, and the ristocetin cofactor activities. Platelet counts were obtained before and after exchanges and revealed significant decreases. Four hours after exchange, all parameters remained abnormal except the factor IX, ristocetin cofactor, and factor VIII procoagulant activities. By 24 hr, all hemostatic parameters had returned to normal. These studies indicate that plasma-exchange transfusion with material devoid of coagulation factors results in a coagulation defect that may be of clinical significance in a hemostatically compromised patient.

Amyotrophic Lateral Sclerosis↗
PubMed1979

Cardiac findings in Charcot-Marie-Tooth disease. A prospective study of 68 patients.

Charcot-Marie-Tooth disease (peroneal muscular atrophy) has been reported to cause cardiac arrthymias and conduction disturbances in association with peripheral muscle atrophy. To establish more accurately the frequency of such cardiac disorders in this disease, 68 patients with Charcot-Marie-Tooth disease were evaluated prospectively for evidence of cardiac involvement. Cardiac findings were limited to five patients with conduction defects, two patients with supraventricular tachycardia, two patients with ischemic heart disease, and 20 with mitral valve prolapse. The frequency of each of the abnormal cardiac findings, with the possibly emalities in the population at large. The low incidence of cardiac involvement in patients with Charcot-Marie-Tooth disease may be helpful in distinguishing this disorder from Friedreich's ataxia, an entity that may mimic Charcot-Marie-Tooth disease but that is frequently associated with heart disease.

Adult↗
PubMed1978

Myoglobinaemia in Duchenne muscular dystrophy patients and carriers: A new adjunct to carrier detection.

Myoglobinaemia was detected in 14 of 18 patients with Duchenne muscular dystrophy (D.M.D.) with a sensitive specific complement-fixation assay. Myoglobinaemia was also detected in 10 of 16 known D.M.D. carriers, including 4 with normal serum-creatine-phosphokinase activity. 9 of 27 possible carriers also had myoglobinaemia. It is suggested that this assay is a useful adjunct to present methods of carrier detection in D.M.D.

Adolescent↗
PubMed1978

Leptomeres in cultured human muscle.

Leptomeres, the laminated structures consisting of bundles of very fine filaments separated into bands about 260 nm wide by periodic transverse dense lines 20--80 nm wide, were observed frequently in cultured muscle fibers of 8 patients with acid maltase deficiency, 4 with sporadic, adult-onset idiopathic "autophagic" vacuolar myopathy (that is not acid-maltase deficient) and one with abnormal mitochondria, but in only one of greater than 50 other cultures of normal and denervated human muscle. They were also induced abundantly in cultured normal human muscle by exposure to 0.5 mM DNP.

Culture Techniques↗
PubMed1978

The effect of pharmacologic acetylcholine receptor on fibrillation and myotonia in rat skeletal muscle.

Myotonic discharges in rats given 20, 25-diazacholesterol hydrochloride and fibrillation discharges in denervated rat muscle both were silenced by procaine hydrochloride, tetrodotoxin or ischemia, or potassium chloride (after initial activation). They both were activated by succinylcholine, but only the fibrillations were silenced by alpha-bungarotoxin or atropine sulfate. It is hypothesized that fibrillations and diazacholesterol-induced myotonia are mediated through mechanisms involving ionic channels, that both can be produced by activation of the junctional/nonjunctional acetylcholine receptors (or some mechanism coupled to the receptors), but that an unfettered alpha-bungarotoxin-binding portion of the acetylcholine-receptor molecule and an unblocked atropine-binding site are obligatory only for production of fibrillations.

Acetylcholine↗
PubMed1978

Malignant hyperthermia and central core disease in a child with congenital dislocating hips.

We describe a development of a malignant hyperthermia (MH) syndrome, partially aborted by therapy, in a child with central core disease and congenital dislocating hips. Patients with central core disease appear to be more susceptible to MH; possibly those with elevated serum creatine phosphokinase levels, as in our patient, are especially susceptible. We review the clinical and pathologic aspects, possible pathogenesis, and treatment of the MH syndrome. An increased calcium level within the muscle fiber is suggested as the major cytodestructive factor, and that increase could be consequent to a plasmalemmal susceptibility to the provoking drugs hypothesized to be the basic defect in MH. Prevention of the full manifestations of MH is predicated on (1) a high index of suspicion in the search for history of anesthetic complications in the patient and his family, with or without evident neuromuscular disease, (2) recognition that there is a somewhat greater risk of MH developing in a patient who has certain "musculoskeletal" abnormalities or muscle weakness but that is not-except for central core disease-a classic clinicopathologically defined disease, (3) close monitoring of patients during anesthesia, and (4) if the syndrome develops, prompt therapeutic measures, including cessation of anesthesia.

Adult↗
PubMed1978

Depletion of serum hemopexin in fulminant rhabdomyolysis. Evidence for an interaction of hemopexin with myoglobin-derived heme.

Hemopexin is a normal serum glycoprotein that functions as a carrier for intravascularly liberated free heme. Although its role is well established in the reutilization of hemoglobin-derived heme, there have been no previous clinical data to support its suspected interaction with heme released in the degradation of myoglobin. In a patient with fulminant rhabdomyolysis, we found depletion of serum hemopexin in the presence of high serum levels of myoglobin with normal levels of haptoglobin and hemoglobin. This combination of laboratory findings is evidence for an interaction between myoglobin-derived heme and hemopexin and implies a role for hemopexin in the catabolism of myoglobin. These findings support the proposed induction mechanism for observed increases of serum hemopexin in Duchenne muscular dystrophy and in polymyositis.

Acute Disease↗
PubMed1978

Elevations of hemopexin levels in neuromuscular disease.

Hemopexin, a serum glycoprotein that binds free heme and transports it to hepatic parenchymal cells, has been measured by radial immunodiffusion. We have confirmed elevation of serum hemopexin concentration in Duchenne's muscular dystrophy patients and carries, and demonstrated elevations in dermatomyositis/polymyositis and myasthenia gravis, but not in amyotrophic lateral sclerosis. In monkeys, elevations of hemopexin levels were specifically induced by hematin injections, muscle-crush, or myoglobin injections. Myoglobin leakage is the likely explanation of hemopexin level elevation in Duchenne's dystrophy patients and carriers and in dermatomyositis/polymyositis. In myasthenia gravis there might be a slight myoglobin leakage not heretofore suspected; or, the elevation of hemopexin levels might be a new reflection of a dysimmune state in myasthenia gravis, and perhaps as such is a further incrementing factor in dermatomyositis/polymyositis. Hemopexin, presumably as a longer-phase reactant, is sometimes an index of neuromuscular disease when other data are negative or equivocal.

Animals↗
PubMed1978

Decreased spinal cord cGMP in murine (wobbler) spontaneous lower motor neuron degeneration.

Of the secondary messengers, cyclic quanosine monophosphate, but not cyclic adenosine monophosphate, was reduced by 80% in the cervical spinal cord and by 56% in the cerebellum of clinically affected homozygote "wobbler" mice compared to sex- and age-matched litter-mate clinically unaffected control mice. A neurotransmitter, gamma aminobutyric acid, and high-energy intermediates, adenosine triphosphate and phosphocreatine, were not significantly different in affected or unaffected mice.

Animals↗
PubMed1978

Leukoencephalopathy in oculocraniosomatic neuromuscular disease with ragged-red fibers. Mitochondrial abnormalities demonstrated by computerized tomography.

In a group of 13 patients affected by oculocraniosomatic neuromuscular disease with mitochondrial abnormalities and ragged-red fibers, a major, diffuse leukoencephalopathic process was recognized by computerized tomography (CT) in three cases. Clinically, these three patients were the most severely affected. The areas involved by the leukoencephalopathic process did not show enhancement after contrast medium injection. In several of the remaining ten cases, various forms and grades of CSF cavity dilation were encountered. Four of the 13 patients had very high CSF protein levels, three had CT-demonstrated leukoencephalopathy, and the fourth had substantial sulcal dilation. The CT findings in this group of patients corresponded well to the previously reported histopathological observations and indicated the clinical usefulness of CT in identifying brain involvement in this syndrome.

Adolescent↗
PubMed1978

Reincarnation in cultured muscle of mitochondrial abnormalities. Two patients with epilepsy and lactic acidosis.

Two unrelated 9-year-old boys failed to thrive from ages 5 and 4 years, and had focal cerebral seizures followed by transcent hemipareses. Histochemistry of their muscle biopsies showed "ragged-red" fibers, which ultrastructurally contained clusters of mitochondria having loss of crisp delineation of crista membranes and contained amorphous inclusion material and parallel-packed cristae and sometimes paracrystalline inclusions. In the patients' cultured muscles, similar mitochondrial abnormalities were present. 2,4-Dinitrophenol, introduced to the medium of cultures of normal human muscle, produced mitochondrial abnormalities similar to those of the patients', and the medium of the patients' muscle cultures worsened the mitochondrial abnormalities. This study, in demonstrating a mitochondrial defect reproducible in the cultured muscle fibers and, therefore, intrinsic to the ragged-red muscle fibers themselves, raises the possibility of a collateral mitochondrial defect in CNS cells as part of a multicellular mitochondriopathy.

Acidosis↗