4th Colloquium on Neuromuscular Diseases (24-28 June 1991, Montpellier, France).
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Biological Clocks↗
Biomedical subjects
K Schwartz
Publications and source records attributed to K Schwartz.
Changes in gene expression during cardiac growth.
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Animals↗
Industrial noise exposure and ambulatory blood pressure and heart rate.
Studies on the effects of long-term exposure to industrial noise on resting blood pressure have yielded inconsistent results. Ambulatory blood pressure and heart rate were monitored simultaneously with noise exposure in normotensive male industrial workers in Israel (85 aged 25 to 44 and 77 aged 45 to 65 years). In the younger group, average ambulatory systolic blood pressure was 3.2 mm Hg higher and diastolic blood pressure 2.3 mm Hg higher in subjects exposed to more than 85 dBa (P less than .001), after adjusting for potential confounding variables. In those aged 45 to 65, ambulatory systolic blood pressure was 3.3 mm Hg lower and diastolic blood pressure unchanged in noise-exposed subjects. Ambulatory heart rate was 2.7 and 2.6 beats per minute higher at the higher noise level (P = .002) in the respective age groups. These findings suggest that industrial noise exposure is associated with higher ambulatory blood pressure and heart rates in men under 45 years old, but the effect on blood pressure appears to diminish considerably with age.
Adult↗
Ca(2+)-ATPase and function of sarcoplasmic reticulum during cardiac hypertrophy.
The properties of the calcium pump system of sarcoplasmic reticulum (SR) were studied in a series of 34 rats subjected to cardiac overload and 19 sham-operated animals. Total homogenates of left ventricle were analyzed by measuring the oxalate-supported Ca2+ uptake rate, the steady-state level of the phosphorylated intermediate of Ca(2+)-adenosine triphosphatase (Ca(2+)-ATPase) (EP), and the amount of Ca(2+)-ATPase mRNA. All three parameters decreased gradually as a function of the relative left ventricular weight increase. The calcium-sensitivity curves showed that the velocity of Ca2+ transport in SR from the hypertrophied heart is diminished at low as well as optimal Ca2+ concentrations, with the dissociation constant (Kd) value for Ca2+ unchanged from that of the control preparation. Taken together with the results presented in our recent publication (De la Bastie, Levitsky, Mercadier, Marotte, Wisnewsky, Brovkovivh, Schwartz, and Lompré, Circ. Res. 66: 554-564, 1990), these data strongly indicate that differences in the Ca2+ pump activities of SR from normal and hypertrophied rat hearts are due to quantitative rather than qualitative changes of the Ca(2+)-ATPase protein.
Animals↗
Expression of sarcoplasmic reticulum Ca(2+)-ATPase and calsequestrin genes in rat heart during ontogenic development and aging.
Little is known concerning the molecular mechanisms responsible for changes in sarcoplasmic reticulum (SR) function during ontogenic development and aging except that the amount of SR Ca(2+)-ATPase mRNA varies in these conditions. The aim of the present work was to determine whether SR maturation requires expression of specific isoforms and synchronous accumulation of mRNAs encoding proteins located in SR. Thus, we have studied expression of SR Ca(2+)-ATPase and calsequestrin genes in the rat at different developmental stages from 14 fetal days to 24 months of age. Analysis of alternative splicing of the major Ca(2+)-ATPase gene expressed in heart by nuclease S1 mapping led us to conclude that the Ca(2+)-ATPase gene expressed in heart was not differentially spliced during ontogenic development and senescence. A single calsequestrin mRNA isoform was also detected in rat heart whatever the developmental stage. The amount of specific mRNA was then measured by dot blot and normalized to 18S ribosomal RNA or to myosin heavy chain mRNA. The amount of Ca(2+)-ATPase mRNA relative to 18S RNA increases substantially at the end of fetal life and in the early postnatal period (9.5 +/- 0.5% in the 14-15 day fetus versus 99 +/- 7% in the 4-day-old rat). A stable high level is observed during adulthood. In aged rats (24 months), Ca(2+)-ATPase mRNA represents only 44.6% the amount observed in young adults (1-2 months).(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Skeletal actin mRNA increases in the human heart during ontogenic development and is the major isoform of control and failing adult hearts.
Expression of the two sarcomeric actins, alpha-skeletal and alpha-cardiac, is regulated in the rodent heart in response to developmental, hormonal, and hemodynamic stimuli. Little is known in man, except that both isogenes were found to be coexpressed in three adult ventricles. In this report, we investigated the isoactin mRNA composition in ventricles from 21 control patients (4 fetal, 5 juvenile, 12 adult) and from 15 patients undergoing cardiac transplantation (5 idiopathic dilated cardiomyopathies, 5 ischemic myopathies with myocardial infarcts, 5 diverse etiologies) by two different and complementary techniques: RNA dot blot analysis with specific cDNA probes, and primer extensions with an oligonucleotide common to alpha-cardiac and alpha-skeletal actins. In the case of dot blot analysis, quantification of each isoform was performed by using as standards RNA transcripts obtained from cloned human alpha-actin sequences, and the total amount of sarcomeric actin mRNA was evaluated as a function of total poly(A+)RNA. We found that both isogenes are always coexpressed, and that the isoactin pattern changes during development. In utero and in neonatal hearts, alpha-skeletal actin mRNA represents less than or equal to 20% of sarcomeric actins, it increases to 48 +/- 6% during the first decade after birth and becomes the predominant isoform of adult hearts (60.4 +/- 8.5%). The 15 adult failing hearts exhibited the same isoactin pattern as the control ones (62.84 +/- 11.06%), and there was no difference in expression between patients with dilated cardiomyopathy or ischemic heart disease. These observations demonstrate that cardiac development in man, in contrast to rodent heart, is characterized by an up-regulation of the skeletal actin gene, the expression of which does not change in hypertrophied and failing hearts, and suggest that the actin and myosin heavy chain families are independently regulated in human heart.
Actins↗
Cervical dystonia: clinical findings and associated movement disorders.
We studied 300 patients, 61% women, with mean age 49.7 years and mean duration of dystonia 7.8 years, to determine the demographic and clinical characteristics of cervical dystonia (CD) and its relationships to other movement disorders. Torticollis was present in 82%, laterocollis in 42%, retrocollis in 29%, and anterocollis in 25%; however, the majority (66%) had a combination of these abnormal postures. Scoliosis was present in 39%, local pain reported by 68%, and 32% had evidence of secondary cervical radiculopathy. In addition to CD, 16% of patients had oral dystonia, 12% mandibular dystonia, 10% hand/arm dystonia, and 10% had blepharospasm. Tremor was noted in 71% of patients; head-neck tremor was present in 60%, and tremor in other body regions was present in 32%. A family history of a movement disorder was present in 44% of the CD patients. Tardive dystonia was the cause in 6%; 11% had posttraumatic dystonia. Anticholinergic drugs provided moderate improvement in 33% of patients, but local intramuscular botulinum toxin injections relieved CD, local pain, or both in over 90% of all treated patients.
Adolescent↗
Botulinum toxin treatment of tremors.
We report the results of an open trial of botulinum toxin (Botox) in the treatment of 51 patients with disabling tremors, classified as dystonic (14), essential (12), combination of dystonic and essential (22), parkinsonian (1), peripherally induced (1), and midbrain (1). The average age of the patients was 55.8 years, and duration of symptoms was 13.9 years. During a total of 160 treatment visits, an average of 242 +/- 75 units of Botox was injected per visit in cervical muscles of 42 patients with head tremor and 95 +/- 38 in forearm muscles of 10 patients with hand tremor; one patient was injected in both. The average peak effect for all patients was rated as 3.0 (0 to 4 scale). Thirty-five (67%) patients improved (peak effect greater than or equal to 1). The average latency from injection to response was 6.8 days, and the average duration of maximum improvement was 10.5 weeks. Local complications, lasting an average of 20.6 days, were noted in 17 (40%) patients injected for head tremor, consisting chiefly of dysphagia in 12 (29%), transient neck weakness in four (10%), and local pain in two (5%). Six (60%) patients with hand tremor had transient focal weakness. EMG recordings showed decreased amplitude of EMG bursts after Botox treatment. The results of this pilot study indicate that Botox injections can be used to control tremor in patients in whom other forms of therapy have failed.
Adult↗
[Improvement of an in vitro transcription method in nuclei isolated from heart myocytes from control and hemodynamically overloaded rats].
The expression of genes crucial for different cardiac functions changes during ontogenic development and during hypertrophy due to hemodynamic overload. To determine if these changes are transcriptional or post-transcriptional, we describe here an optimized method to analyze in vitro the transcriptional activity of nuclei isolated from control and hemodynamically overloaded hearts of 23-day-old rats. Similar results were obtained with both types of hearts: (1) 3 to 6 million nuclei were isolated per gram of ventricular tissue; (2) nuclear incorporation of UTP32P increases with time, plateaus after about 10 to 20 min. and attains an average of 0.17 cpm per nucleus; (3) alpha-amanitin decreases total incorporation by 56%; (4) the sizes of the majority of transcribed RNA are between 0.2 and 4 kb, although a significant fraction of high molecular weight transcripts are also seen (between 4 and 6 kb). All this indicates that mRNAs are transcribed to a significant extent, suggesting that it is now possible, given appropriate nucleotide probes, to analyze the transcription of any given gene during cardiac growth.
Animals↗
Digoxin-like immunoreactivity in saliva and plasma of pregnant women.
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Blood Proteins↗
Myosin, from the gene to the circulating forms.
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Animals↗
Effect of thyroid hormone on the accumulation of mRNA for skeletal and cardiac alpha-actin in hearts from normal and hypophysectomized rats.
Skeletal alpha-actin gene products are coexpressed with cardiac alpha-actins in cardiac tissue of adult humans, cows, and pigs; in prenatal rats; and during hypertrophy due either to increased hemodynamic load or the administration of alpha-adrenergic agonists. Because there is preferential synthesis of the beta-myosin heavy chain in each case, it has been suggested that the synthesis of skeletal alpha-actin in cardiac tissue is linked to that of beta-myosin heavy chain. To test this hypothesis, thyroid hormone, which causes cardiac hypertrophy with preferential synthesis of alpha-myosin heavy chain, was administered to normal and hypophysectomized rats. Animals were sacrificed from 2 to 24 hr after the injection of either 1 or 5 micrograms of hormone per 10 g of body weight. The relative amount of mRNA for skeletal and cardiac alpha-actin was measured by using the technique of primer extension. Thyroid hormone caused a rapid increase in the amount of skeletal alpha-actin mRNA relative to controls, more than 7 times in hearts from normal animals and 15 times in hearts from hypophysectomized animals. A small increase in cardiac alpha-actin mRNA also occurred. The rapid increase in transcripts for skeletal alpha-actin under conditions where the isoform of myosin heavy chain that is being synthesized is primarily alpha demonstrates independent patterns of activation of the actin and myosin heavy chain multigene families during cardiac growth in mammals.
Actins↗
Biological signals of cardiac hypertrophy.
Chronic increases in haemodynamic load modify the expression of cardiac genes, leading to a new phenotype better adapted to the new functional demand. Several mechanisms such as the global activation of genes, the modulation of single genes and/or differential expression of multigene families may account for these modifications. Changes in gene expression of isomyosin shift are permanent and have been associated with modifications of the physiological properties of cardiac muscle. The exact cellular and molecular mechanisms which either do or do not initiate and maintain these changes in cardiac expression remain to be elucidated. Recent technical advances in cellular and molecular biology provide a foundation for understanding those cellular mechanisms that control cardiac muscle growth. This is a review of some transient changes in gene expression induced by mechanical overload such as the expression of cellular oncogenes, heat shock protein and alpha-skeletal actin genes. The biological functions of these genes are not yet precisely defined, some of them could interfere in the process of myocyte hypertrophy.
Actins↗
Botulinum toxin treatment of cranial-cervical dystonia, spasmodic dysphonia, other focal dystonias and hemifacial spasm.
In the past five years, 477 patients with various focal dystonias and hemifacial spasm received 3,806 injections of botulinum A toxin for relief of involuntary spasms. A definite improvement with a global rating greater than or equal to 2 on a 0-4 scale, was obtained in all 13 patients with spasmodic dysphonia, 94% of 70 patients with blepharospasm, 92% of 13 patients with hemifacial spasm, 90% of 195 patients with cervical dystonia, 77% of 22 patients with hand dystonia, 73% of 45 patients with oromandibular dystonia, and in 90% of 21 patients with other focal dystonia who had adequate follow up. While the average duration of maximum improvement lasted about 11 weeks after an injection (range seven weeks in patients with hand dystonia to 15 weeks in patients with hemifacial spasm), some patients benefited for over a year. Only 16% of the 941 treatment visits with follow up were not successful. Except for transient focal weakness, there were very few complications or systemic effects attributed to the injections. This study supports the conclusion that botulinum toxin injections are a safe and effective therapy for patients with focal dystonia and hemifacial spasm.
Adolescent↗
Myocardial adaptation to creatine deficiency in rats fed with beta-guanidinopropionic acid, a creatine analogue.
A creatine analogue, beta-guanidinopropionic acid (GPA), was fed to 12 young rats for several weeks. Another 12 animals were kept in the same conditions and age matched. Six pairs of animals were used to measure some energetic and mechanical parameters of the isovolumic perfused heart and to measure the accumulation of the phosphorylated form of GPA (GPAP) by 31P-nuclear magnetic resonance (NMR) spectroscopy. As a result of GPAP accumulation, phosphocreatine and ATP content decreased by 90 and 40%, respectively, and mechanical performance was impaired. Six other pairs of animals were used to assess the mechanical performances of Triton X-100-skinned fibers and the myosin isoenzyme distribution. It was found that the maximal force, Ca and ATP sensitivities, and myofibrillar creatine kinase efficacy of creatine-depleted hearts were similar to control values. There was, however, a decrease in the rate of cross-bridge cycling, and the isoenzymic expression of myosin was changed from the fast myosin V1 to the slower forms V2 and V3. In all animals, hypertrophy was observed in both right and left ventricles. We conclude that rat hearts subjected to a slow and persistent decrease in creatine and phosphocreatine respond with both quantitative and qualitative changes. These alterations, which most probably lead to an improvement in the economy of cardiac contraction, are nonetheless not sufficient to maintain maximal force.
Adaptation, Physiological↗
Function of the sarcoplasmic reticulum and expression of its Ca2(+)-ATPase gene in pressure overload-induced cardiac hypertrophy in the rat.
The reduction in Ca2+ concentration during diastole and relaxation occurs differently in normal hearts and in hypertrophied hearts secondary to pressure overload. We have studied some possible molecular mechanisms underlying these differences by examining the function of the sarcoplasmic reticulum and the expression of the gene encoding its Ca2(+)-ATPase in rat hearts with mild and severe compensatory hypertrophy induced by abdominal aortic constriction. Twelve sham-operated rats and 31 operated rats were studied 1 month after surgery. Eighteen animals exhibited mild hypertrophy (left ventricular wt/body wt less than 2.6) and 13 animals severe hypertrophy (left ventricular wt/body wt greater than 2.6). During hypertrophy we observed a decline in the function of the sarcoplasmic reticulum as assessed by the oxalate-stimulated Ca2+ uptake of homogenates of the left ventricle. Values decreased from 12.1 +/- 1.2 nmol Ca2+/mg protein/min in sham-operated rats to 9.1 +/- 1.5 and 6.7 +/- 1.1 in rats with mild and severe hypertrophy, respectively (p less than 0.001 and p less than 0.001, respectively, vs. shams). This decrease was accompanied by a parallel reduction in the number of functionally active CA2(+)-ATPase molecules, as determined by the level of Ca2(+)-dependent phosphorylated intermediate: 58.8 +/- 7.4 and 48.1 +/- 13.5 pmol P/mg protein in mild and severe hypertrophy, respectively, compared with 69.7 +/- 8.2 in shams (p less than 0.05 and p less than 0.01, respectively, vs. shams). Using S1 nuclease mapping, we observed that the Ca2(+)-ATPase messenger RNA (mRNA) from sham-operated and hypertrophied hearts was identical. Finally, the relative level of expression of the Ca2(+)-ATPase gene was studied by dot blot analysis at both the mRNA and protein levels using complementary DNA clones and a monoclonal antibody specific to the sarcoplasmic reticulum Ca2(+)-ATPase. In mild hypertrophy, the concentrations of Ca2(+)-ATPase mRNA and protein in the left ventricle were unchanged when compared with shams (mRNA, 93.8 +/- 10.6% vs. sham, NS; protein, 105.5 +/- 14% vs. sham, NS). in severe hypertrophy, the concentration of Ca2(+)-ATPase mRNA decreased to 68.7 +/- 12.9% and that of protein to 80.1 +/- 15.5% (p less than 0.001 and p less than 0.05, respectively), whereas the total amount of mRNA and enzyme per left ventricle was either unchanged or slightly increased. The slow velocity of relaxation of severely hypertrophied heart can be at least partially explained by the absence of an increase in the expression of the Ca2(+)-ATPase gene and by the relative diminution in the density of the Ca2+ pumps.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Altered sarcoplasmic reticulum Ca2(+)-ATPase gene expression in the human ventricle during end-stage heart failure.
A decrease in the myocardial level of the mRNA encoding the Ca2(+)-ATPase of the sarcoplasmic reticulum (SR) has been recently reported during experimental cardiac hypertrophy and failure. To determine if such a deficit occurs in human end-stage heart failure, we compared the SR Ca2(+)-ATPase mRNA levels in left (LV) and right ventricular (RV) specimens from 13 patients undergoing cardiac transplantation (6 idiopathic dilated cardiomyopathies; 4 coronary artery diseases with myocardial infarctions; 3 diverse etiologies) with control heart samples using a rat cardiac SR Ca2(+)-ATPase cDNA probe. We observed a marked decrease in the mRNA for the Ca2(+)-ATPase relative to both the 18S ribosomal RNA and the myosin heavy chain mRNA in LV specimens of patients with heart failure compared to controls (-48%, P less than 0.01 and -47%, P less than 0.05, respectively). The LV ratio of Ca2(+)-ATPase mRNA to 18S RNA positively correlated with cardiac index (P less than 0.02). The RV ratio correlated negatively with systolic, diastolic and mean pulmonary arterial pressures (P less than 0.02, P less than 0.02, and P less than 0.01, respectively). We suggest that a decrease of the SR Ca2(+)-ATPase mRNA in the myocardium plays an important role in alterations of Ca2+ movements and myocardial relaxation reported during human end-stage heart failure.
Adult↗
Botulinum toxin injections for cervical dystonia.
We followed 205 of 232 patients with medically intractable cervical dystonia for at least 3 months and up to 4 years, during which time they received 1,074 injections in 505 visits. One hundred forty-five of the 205 patients (71%) improved substantially (global rating greater than or equal to 2; from 0 = no response to 4 = marked improvement in severity and function) after 1 or more visits. Of the 89 patients who reported pain, 68 (76%) had almost complete relief of their pain. While most patients noted improvement within the 1st week after injection, some had a latency of up to 8.5 weeks. Duration of maximum benefit lasted up to 12.5 months in some, but the average was 11.2 weeks. Only 58 of 205 (28%) patients, seen in 76 of 505 visits (15% of all visits), had complications, primarily mild dysphagia (35 patients) or neck weakness (17 patients). We conclude that botulinum toxin is a safe and effective therapy for most patients with cervical dystonia.
Adolescent↗