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The clinical and radiological features in a baby thought to have Blomstrand chondrodysplasia are presented. The hallmarks of this rare lethal disorder are an increase in bone density and advanced skeletal maturation. A high incidence of parental consanguinity is consistent with autosomal recessive inheritance.
The lactate concentration in antecubital venous blood was determined in 33 patients before and after ischemic forearm exercise. Before exercise, there wa no significant difference in serum lactate level between uremic patients and controls. However, after ischemic exercise the means serum lactate level in uremic patients was significantly lower than that of controls. The results may lead to the conclusion that uremic patients have a markedly reduced ability to form lactate with anaerobic exercise probably due to inhibition of glycolytic enzymes of skeletal muscle.
Sixty crossbred barrows were used to study the effect of ractopamine (a phenethanolamine/beta-adrenergic agonist) treatment and its withdrawal on muscle growth and on the relative abundance of skeletal muscle alpha-actin (sk-alpha-actin) mRNA and of liver and longissimus muscle IGF-I mRNA at 4 wk. Ractopamine was fed (20 ppm) for periods of 2, 4, and 6 wk (six pigs per group). Additional pigs (four per group) were fed ractopamine (20 ppm) for 6 wk and then slaughtered 1, 3, and 7 d after withdrawal of ractopamine. Ractopamine increased (P < .05) longisimus muscle weight and protein content, although protein concentrations were not different. The increased muscle weight and protein content attained by feeding ractopamine for 6 wk was retained when ractopamine was withdrawn. The RNA and DNA concentrations did not change, whereas total DNA and RNA content per muscle was 18 and 26.7% greater, respectively, in ractopamine-treated pigs at 4 wk, but there were no differences at 2 or 6 wk or among the withdrawal groups. The relative abundance of sk-alpha-actin mRNA in the longissimus muscle was 41 and 62% greater (P < .05) in treated animals at 2 and 4 wk but was similar to that in controls at 6 wk and during the withdrawal period. The relative abundance of IGF-I mRNA in liver and longissimus muscle was not altered with ractopamine treatment for 4 wk. These results indicate that the ractopamine-enhanced muscle growth may result from increased myofibrillar gene expression at the pretranslational level, which is maximal with short-term treatment of ractopamine.(ABSTRACT TRUNCATED AT 250 WORDS)
Bisphosphonates (BP) are pharmacological compounds whose the most important biological effect is the reduction of bone remodelling, explaining the reason for their use in pathological conditions characterised by an increased bone resorption, such as osteoporosis, Paget's disease, malign hypercalcemia during myeloma and osteolytic bone metastasis. Nevertheless there are several experimental evidence that BP possess different extra-skeletal biological effects, ranging from analgesic properties, anti-inflammatory and pro-inflammatory effects and the capacity of modifying the biological activity of cells other than osteoblasts and osteoclasts, such as the immune system cells and other cells of mesenchymal origin. Several data report the beneficial effects of BP as anti-inflammatory agents in different inflammatory chronic articular diseases, which make BP suitable drugs for treatment of pathologies other than bone disease.
We report a 6 year old boy with multiple fractures owing to bilateral, peculiar, wave-like defects of the tibial corticalis with alternative hyperostosis and thinning. Furthermore, he had Wormian bones of the skull, dentinogenesis imperfecta, and a distinct facial phenotype with hypertelorism and periorbital fullness. Collagen studies showed normal results. His sister, aged 2 years, showed the same facial phenotype and dental abnormalities as well as Wormian bones, but no radiographical abnormalities of the tubular bones so far. The mother also had dentine abnormalities but no skeletal abnormalities on x ray. This entity is probably the same as that described in a sporadic case by Suarez and Stickler in 1974. In spite of the considerable overlap with osteogenesis imperfecta (bone fragility, Wormian bones, and dentinogenesis imperfecta), we believe this disorder to be a different entity, in particular because of the unique cortical defects, missing osteopenia, and normal results of collagen studies.
Naturally occurring and induced genetic anomalies of skeletal development offer a unique opportunity to identify all the genes that are relevant to the development, maintenance, and repair of the skeleton. Such studies also should provide new insights into the regulation of gene expression, the order of gene expression, interactions of the gene products, and the role of environmental factors in normal and abnormal skeletogenesis.
A cDNA for rabbit fast skeletal muscle troponin I (TnI) was isolated and sequenced. The clone contains a coding sequence predicting a 182-amino-acid protein with a molecular mass of 21,162 daltons. The translated sequence is different from that reported by Wilkinson and Grand (Wilkinson, J. M., and Grand, R. J. A. (1978) Nature 271, 31-35) in that Arg-153, Asp-154, and Leu-155 must be inserted into their original sequence. Amino acid sequencing of adult rabbit TnI confirmed this result. In order to investigate the role of the NH2 terminus of TnI in its biological activity, we have expressed a recombinant deletion mutant (TnId57), which lacks residues 1-57, in a bacterial expression system. Both wild type TnI (WTnI) and TnId57 inhibited acto-S1-ATPase activity and this inhibition could be fully reversed by troponin C (TnC) in the presence of Ca2+. Additionally both WTnI and TnId57 bound to an actin affinity column. Thus, both inhibitory actin binding and Ca(2+)-dependent neutralization by TnC were retained in TnId57. TnC affinity chromatography was used to compare the binding of TnI and TnId57 to TnC. Using this method, two types of interaction between TnC and TnI were observed: 1) one which is metal independent (or structural) and 2) one dependent on Ca2+ or Mg2+ binding to the Ca(2+)-Mg2+ sites of TnC. The same experiments with TnId57 demonstrated that the type 1 interaction was weakened, and type 2 binding was lost. This method also revealed an interaction between TnC and TnI which is dependent upon Ca2+ binding to the Ca(2+)-specific sites of TnC and which is retained in TnId57. Taken together, these results suggest that the NH2 terminus of TnI may constitute a Ca(2+)-Mg(2+)-dependent interaction site between TnC and TnI and play, in part, a structural role in maintaining the stability of the troponin complex while the COOH terminus of TnI contains a Ca(2+)-specific site-dependent interaction site for TnC as well as the previously demonstrated Ca(2+)-sensitive inhibitory and actin binding activities.
In the course of pretherapeutic diagnostics of bronchogenic carcinoma, bone marrow biopsy revealed in ten out of 116 patients (9%) and radiographic skeletal survey in 16 out of 62 patients (26%) metastases to the skeleton. The two methods are complementary with reference to anaplastic and oat-cell carcinomas. On account of our experiences, we never fail to control the skeleton before the beginning of a local curative therapy in bronchial carcinoma.
UNLABELLED: This cephalometric study was made to investigate the effects of chin cap therapy. The subjects were 21 Japanese females of skeletal class III who were treated without tooth extraction. The periods before treatment, during improvement of anterior teeth and after treatment were compared to see where and how effective the therapy had been. RESULTS: 1. Characteristics before the treatment period: These cases had backward position of the maxilla and forward position of the mandible with over growth. In the denture pattern there was a remarkable labioaxiversion of U-1. 2. Characteristics after the treatment period: There was improvement in the backward position of the maxilla. In the forward mandible, once these cases improved their position by improving the overjet, there was a regression followed by gradual forward growth as treatment continued. The denture pattern showed labioaxiversion of U-1 as before. 3. Before the treatment period, these cases showed large Go-Po and Ar-Go in the dimensional linear analysis. After treatment, these analysis showed normal sizes.
The number of muscle fibres per mm2 is age dependent, and therefore briefly denoted as age specific number (Alterskennzahl AK). We determined the AKs for the age groups up to 25 years, separated after the sexes and for M. vastus lateralis et deltoideus. According to the trend of the original data the approximations have been carried out applying 4 functions of organismic growth in modified form, i.e. the Pütter (1920), Bertalanffy (1934), Richards (1959), Janoschek extended by Sager (1984) and Richards extended after Sager (1980). Curve fitting is reached by regression analysis and nonlinear regressions using the sums of the linear deviations as a criterion for the goodness of fit. Results including initial as well as final values are summarized in tables with the parameters of the calculation methods added. The AKs allow judging the degree of maturity in the skeletal musculature during childhood. Transposing of the equations for AK = W yields t as a function of the normally adjunctive age specific number. The difference against real age reveals to which degree the musculature is eventually underdeveloped. Concerning the interpretation the fact should be kept in mind that biological processes are involved. The relation of the fibre types too implies a characteristic age dependency. This statement and the fibre diameters gained from the same material allow a mutual control and an exact fixation in each case.
Skeletal muscle morphology and mitochondrial oxidative phosphorylation capacity were examined in a family whose members showed very combinations of mental subnormality, cardiomyopathy and muscle weakness. Light and electron microscopic findings suggested a neuropathic process, while tests of mitochondrial function indicated a state of tight coupling of oxidative phosphorylation, a feature in marked contrast to those in biochemical studies so far reported.
High and low affinity binding sites for tetrodotoxin have been found in rat skeletal muscle cells in vitro using a radiolabeled tetrodotoxin derivative and 22Na+ flux studies. High affinity binding sites for tetrodotoxin (KD(tetrodotoxin) = 1.6 nM) cannot be detected at the myoblast stage. They appear and increase in density as myoblasts fuse into myotubes to reach a maximum binding capacity of 50 fmol/mg of proteins. Na+ channel structures with a high affinity for tetrodotoxin cannot be activated by neurotoxins specific for the Na+ channel such as veratridine and sea anemone toxinII. They are not expressed in the action potential. Na+ channels with a low affinity for tetrodotoxin (IC50(tetrodotoxin) = 1 microM) are functional since they can be activated by veratridine and sea anemone toxinII. They are already expressed in myoblasts and their density is not modified during the fusion of myoblasts into myotubes; they remain functional throughout the differentiation process. It is suggested that neuronal factors are not required for the synthesis of structures with high affinity binding sites for tetrodotoxin in the rat muscle and that they are only involved for the maturation of these structures from a nonfunctional to a functional form.
The plaster-cast immobilization of the right hind limbs of rats has been investigated. Examinations were performed on the changes in weight of both types of skeletal muscles, i.e. the fast and the slow ones, the m. extensor digitorum longus and the m. gastrocnemius on the one hand, and the m. soleus on the other. The most significant loss in weight was observed in the gastrocnemius muscle. The ATP-Ca2+-induced isometric tension as well as the speed of contraction of glycerine-treated myofibrillar preparations considerably decreased as a result of 28-day immobilization. The most marked change was observed in the soleus muscle. There was a similar decrease in the specific activity of myofibrillar myosin ATPase prepared from immobilized muscles. The specific activity of K+-EDTA myosin ATPase did not change.
Individual LDH-5 preparations from rat skeletal muscles have been obtained by differential fractionation with (NH4)2SO4 and precisional ion exchange chromatography. According to the data of ultracentrifugation, electrophoresis in acrilamide gel, enzyme-electrophoresis and agar precipitation reaction with antimuscle serum, these preparations have no admixtures of other isoenzymes of foreign proteins. Examination of antigenic properties of these LDH-5 preparations may suggest the availability of common antigenic determinates in the liver extract and in the LDH-5 preparation.
To evaluate two different methods of managing segmental skeletal defects, 15 patients treated with the open bone graft (Papineau) technique were compared with 17 patients who had intercalary bone transport (Ilizarov) management. The treatment time was identical for both groups: 1.9 months in fixation for each centimeter of defect reconstructed. Both techniques shared several fixator-associated problems such as implant site sepsis and patient discomfort. Each method of treatment, however, had its own unique problems. For the bone grafted group, limited graft availability, donor site morbidity (three patients), and graft fractures (two patients) occurred. For the bone transport group, the main problems were failure of the docking site to unite without a supplementary graft (seven patients) and joint contractures (seven patients). A new synthesis of both techniques is described.
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Some patients with pre end-stage congestive heart disease do not receive a significant hemodynamic benefit from dynamic cardiomyoplasty because, during prolonged preoperative immobilization, their latissimus dorsi muscle (LDM) becomes extremely weak. It is the authors' hypothesis that the local administration of an anabolic steroid into an electrically stimulated LDM will produce a thicker and stronger muscle with significant resistance to fatigue. The electrical stimulation training protocol of sheep continued for 8 weeks. For localized anabolic steroid administration an osmotic pump was placed in a subcutaneous pocket and the catheter was introduced into the LDM. The contractile force of electrically stimulated and unstimulated control muscle was studied. Control data were calculated as 100% and all other data were corrected to control. After 4 weeks there was no decrease in contractile force. The change seen was from 88 to 100% with different preloads (10, 15, and 20 g/kg) and amplitudes of impulses (5 and 10 V). After 8 weeks, the LDM was more powerful than before electrical stimulation, with a change of 97-133%. Usually after 8 weeks of electrical stimulation alone, contractile force decreases to 70-75%. During a fatigue test (30 min, 100 bursts per minute, 10-25 Hz, ripple frequency, 10 V impulse amplitude) after 4 and 8 weeks of our protocol, the LDM lost only 12% of its initial force, whereas control muscle lost 40%. Thus local anabolic steroid administration makes the LDM stronger and more useful for cardiomyoplasty.