Search PubMed⌕ Search

Biomedical subjects

L Z Stern

Publications and source records attributed to L Z Stern.

At least 37 records · Page 2Linked to original sources
PubMed1982

Serial two-dimensional echocardiography in Duchenne muscular dystrophy.

Patients with Duchenne muscular dystrophy (DMD) are known to have progressive epicardial fibrosis of the free wall of the left ventricle, but standard noninvasive M-mode echocardiographic tests of left ventricular function are relatively insensitive detectors of this cardiomyopathy. We therefore used two-dimensional echocardiography to record three short axis levels of the left ventricle in 13 Duchenne patients. Serial studies were separated by 2 years for most patients. The two-dimensional echocardiographic technique allows qualitative evaluation of segmental contraction of the left ventricle. Four general principles were found during this study: (1) Obvious contraction abnormalities of the left ventricle were present in most patients with DMD. (2) In most patients, the contraction deficit was first noted in the left ventricular posterior free wall behind the mitral valve. (3) Once a contraction deficit was observed, the area of abnormal contraction progressed inferiorly to include additional areas of the left ventricular posterior free wall. (4) Standard M-mode left ventricular function techniques were unreliable for detecting individuals with segmental contraction abnormalities.

Adolescent↗
PubMed1981

Myopathy associated with sclerodermal facial hemiatrophy.

A patient who had linear scleroderma associated with ipsilateral hemiatrophy of the tongue and subsequent facial hemiatrophy was studied. Biopsy specimens of the plaque of scleroderma showed the skin changes of scleroderma as well as fascial and muscle changes. The fascia had an impressive plasma cell fasciitis with numerous plasma cells and scattered lymphohistiocytic cells. Histochemical study of the temporalis muscle underlying the plaque of circumscribed scleroderma disclosed severe localized atrophy of type 1 and type 2 fibers similar to the pathologic findings previously described in a patient with localized scleroderma.

Adult↗
PubMed1981

Glycogen debrancher deficiency is reproduced in muscle culture.

Muscle cultured from two adults with debrancher deficiency myopathy showed abnormal glycogen deposits by electron microscopy. Glycogen debranching activity was markedly decreased, but phosphorylase activity was normal. Lack of glycogen debranching activity in muscle cultures from debrancher-deficient patients contrasts with the presence of a fetal isoenzyme of phosphorylase in muscle cultured from patients with McArdle disease and suggests that the genetic control of the debranching enzyme does not change during muscle development.

Adult↗
PubMed1981

Alterations in creatine kinase in fresh muscle and cell cultures in Duchenne dystrophy.

Creatine kinase (CK) (total and isoenzymes) was measured in cultures obtained by dissociation and subsequent plating of cells from biopsied quadriceps muscle of 10 patients with Duchenne muscular dystrophy (DMD) and 20 controls. The total cellular CK and CK-MM reached highest values around 21 days in both DMD and control cultures, suggesting that DMD cultures do not show delayed myoblast fusion. There was a significant decrease of total cellular CK in DMD cultures at all stages, but the maximum differences were noted for the peak values. The CK isoenzyme pattern in DMD cultures demonstrated a higher percentage of CK-BB and CK-MB and a lower percentage of CK-MM than was observed in cultures from the controls. Addition of cytosine arabinoside after myoblast fusion to muscle cell cultures did not induce significant changes of CK isoenzyme pattern. There was no difference in the CK levels in culture medium from controls and DMD patients. The alterations of cellular CK were similar in fresh muscle and cell cultures from DMD patients.

Cells, Cultured↗
PubMed1981

Alterations in lipid incorporation in Duchenne muscular dystrophy. Studies of fresh and cultured muscle.

The incorporation of [3H] glycerol into lipids of fresh and cultured skeletal muscle obtained from patients with Duchenne muscular dystrophy (DMD), patients with myotonic dystrophy (My Dyst), controls, and aborted fetuses (10-12 weeks old) was studied. A significant increase of specific incorporation of [3H] glycerol into phosphatidylcholine (PCh), phosphatidylserine (PS), phosphatidylinositol (PI), and triglycerides (TRI) was found in DMD and fetal muscle in both fresh and cultured muscle. No significant differences, however, were noted between the values of glycerol incorporation in DMD and fetal muscle. The ratio between phospholipids and TRI changed significantly for fresh muscle in DMD (3.5) and fetal muscle (4.9) versus controls (24). The incorporation of glycerol into these lipids in My Dyst fresh and cultured muscle showed the same value as controls when expressed both as incorporation/mg protein and ratio between phospholipids and TRI.

Adolescent↗
PubMed1981

Altered polyamine excretion in Duchenne muscular dystrophy.

Increased urinary levels of the polyamines, putrescine, spermidine, and spermine are present in Duchenne muscular dystrophy (DMD) patients. Alterations in excretion are detectable when based on nanomoles per milligram creatinine, micromoles per 24-hour urine collection, or nanomoles per kilogram body weight per 24-hour urine collection. Evaluation of creatinine levels in spot collections of urine versus 24-hour collections suggests a more consistent urinary creatinine in spot urines from DMD patients and normals, with wider variability in 24-hour specimens. We postulate that polyamines may be useful markers to evaluate disease activity and to screen for drug efficacy, as they have proved useful in cancer patients in assessing alterations in tumor kinetic parameters.

Child↗
PubMed1980

Echocardiographic determination of contraction and relaxation measurements of the left ventricular wall in normal subjects and patients with muscular dystrophy.

Boys with Duchenne's muscular dystrophy (DMD) usually have a cardiomyopathy characterized by fibrosis of the epicardial half of the left ventricle. This cardiomyopathy is difficult to detect by noninvasive techniques. We report a technique that evaluates incremental left ventricular posterior wall thickening and thinning. High-quality left ventricular posterior wall echoes in 24 boys with DMD and 32 controls were recorded at chordal level two times 1 year apart. Endocardial and epicardial echoes and a timing ECG were digitized and analyzed by minicomputer. Left ventricular wall amplitudes were determined at standardized temporal increments during contraction and relaxation. To compare with this left ventricular assessment technique, systolic ejection times, shortening fraction and mean velocity of circumferenial fiber shortening (Vcf) were also computed in the standard way. Mean year-to-year changes were minor. Mean Vcf, the ratio of preejection period to left ventricular ejection time and shortening fraction during the first year were statistically similar to those of the controls. Shortening fraction decreased slightly during the second year and became significantly different from the control, but remained within the normal range. Left ventricular wall thickness and cavity size were significantly less in boys with DMD than in controls. Therefore, we had to normalize incremental wall thickness to determine if any significant difference occurred. To do this, we evaluated the percentage of maximal wall thickness which occurred at a given percent of systole and diastole. Using this technique, it was shown that thickening during systole was a nearly linear process with respect to time in both groups. However, relaxation was significantly different between the groups. Relaxation was found to be an alinear process, and most thinning occurred in the first 40% of diastole. The major findings of this investigation was that the left ventricular wall of boys with DMD thinned at a slower rate than that of normal subjects. This new technique appears to be sensitive and demonstrates subtle changes in the left ventricular posterior wall.

Adolescent↗
PubMed1980

Factors influencing osmotic fragility of red blood cells in Duchenne muscular dystrophy.

Factors affecting osmotic fragility were studied in red blood cells of patients with Duchenne muscular dystrophy. The mean osmotic fragility (MOF), operationally defined as the NaCl concentration for 50% hemolysis, was found to be higher by 3.63 +/- 0.51 mM in Duchenne cells than in normal cells having an MOF of 60.1 +/- 0.5 mM NaCl buffered with 10 mM sodium phosphate at pH 7.0. However, about 20% of Duchenne patients had red cells indistinguishable from their age- and sex-matched controls. Temperature, pH, preincubation in plasma, and proteolytic digestion all affected Duchenne and normal cells to the same extent. However, after salt loss, induced either by preincubation in isotonic nonelectrolyte solutions or by exposure to ionophore A23187, Duchenne cells showed a greater change in MOF. Osmotic fragility of Duchenne cells was increased even in younger blood cells, suggesting that the membrane was abnormal in the early stages of red cell maturation.

Adolescent↗
PubMed1979

Stimulatory effects of drugs for protein synthesis on muscle cell cultures in Duchenne dystrophy.

The influence of the membrane-stabilizing agents diphenylhydantoin (DPH) and orgotein (a drug with superoxide dismutase activity) on protein synthesis was studied in cultured human muscle cells obtained from 7 patients with Duchenne muscular dystrophy (DMD) and 14 controls. The cultures were obtained by dissociation and subsequent plating of cells from biopsied quadriceps muscle. These cultures were then labeled with tritiated leucine in the presence and absence of the membrane-stabilizing drugs. Total protein synthesis (cpm/mg noncollagen protein) in first-passage muscle cell cultures from DMD patients showed a 35% decrease, but myosin synthesis revealed normal values. DPH and orgotein increased total protein synthesis by 35 and 50%, respectively, in dystrophic cultured cells, but only by 7 and 8%, respectively, in control cultured cells.

Cells, Cultured↗
PubMed1979

Debrancher deficiency: neuromuscular disorder in 5 adults.

Five patients, 4 men and 1 woman, had adult-onset and slowly progressive weakness. There was distal wasting in 2, hepatomegaly in 3, and congestive heart failure in 2. Electromyography showed a mixed pattern with abundant fibrillations. Serum creatine phosphokinase was increased 5- to 45-fold. Blood glucose failed to respond to epinephrine or glucagon, and venous lactate did not rise after ischemic exercise. Muscle biopsy showed vacuolar myopathy affecting both fiber types. By electron microscopy the vacuoles corresponded to large pools of glycogen not limited by a membrane. Glycogen concentration was 3 to 5 times normal in muscle and 7 to 21 times normal in erythrocytes. In the presence of iodine, muscle glycogen showed a spectrum characteristic of phosphorylase-limit-dextrin. Debrancher activity was measured by a spectrophotometric assay and by a radioactive reverse reaction. The activity was lacking in muscle and erythrocytes of 4 patients according to both assays; in 1 patient the reverse reaction was not impaired. Though previously reported in only 5 patients, debrancher deficiency myopathy may not be rare and should be considered in the differential diagnosis of adult-onset hereditary myopathies.

Adolescent↗