Involvement of the phosphoryl transfer network on cardiac energetic metabolism during Staphylococcus aureus infection and its association to disease pathophysiology.

Evidences have suggested that the phosphoryl transfer network by the enzymatic activities of creatine kinase (CK), adenylate kinase (AK), pyruvate kinase (PK), and lactate dehydrogenase (LDH), shows new perspectives to understand some disturbances in the energy metabolism during bacterial infections. Thus, the aim of this study was to evaluate whether Staphylococcus aureus infection in mice could alter serum and cardiac activities of these enzymes and their association to disease pathophysiology. For that, we measured total leukocytes, lymphocytes and neutrophils (just 48 h of infection) that were lower in infected animals after 48 and 72 h in infected mice compared with negative control, while total protein and globulin plasma levels were higher after 72 h of infection. The serum CK activity was higher in infected animals 48 and 72 h post-infection compared to the control group, as well as observed for mitochondrial cardiac CK activity. The serum PK activity was higher in infected animals after 72 h of infection compared to the control group, and lower in the cardiac tissue. The cardiac AK activity was lower in infected animals 48 h and 72 h post-infection compared to the control group, while serum and cardiac LDH activities were higher. Based on these evidences, it is possible to conclude that the stimulation of CK activity exerts a key role as an attempt to maintain the bioenergetic homeostasis by the production of phosphocreatine to avoid a rapid fall on the concentrations of total adenosine triphosphate. In summary, the phosphoryl transfer network can be considered a pathway involved in the improvement on tissue and cellular energy homeostasis of S. aureus-infected mice.

Glucose metabolism in the erythrocytes of the buffalo (Bubalus bubalis).

14CO2 production from [1-14C] glucose, the rate of glycolysis measured by the value of lactate production and the activities of various enzymes were determined in buffalo erythrocytes. Buffalo red cell glycolytic metabolites were estimated and used for the calculation of the mass action ratios of reactions catalyzed by the glycolytic enzymes of Bubalus bubalis. A comparison of the values of the mass action ratios with the equilibrium constants of the various glycolytic reactions indicate that hexokinase, phosphofructokinase, phosphoglycerate kinase and pyruvate kinase reactions are displaced from equilibrium, suggesting a regulatory role for each of these enzymes in buffalo erythrocyte glycolysis.

Cold-sensitive cytosolic 3,5,3'-triiodo-L-thyronine-binding protein and pyruvate kinase from human erythrocytes share similar regulatory properties of hormone binding by glycolytic intermediates.

Similar cold-sensitive properties, values of dissociation constants (Kd = 1 x 10(-10) M), and regulatory effectors were found for the cold-sensitive cytosolic 3,5,3'-triiodo-L-thyronine (L-T3)-binding protein (CTBP) and pyruvate kinase from human erythrocyte. Various metabolites of the blood cell were assayed for their effects on CTBP activity after heat and cold preincubation treatments. Among these compounds, five- and six-carbon phosphorylated sugars were effective in protecting the CTBP activity against cold inactivation, whereas only ATP and dATP blocked activation by heat treatments. The effects of fructose 1,6-bisphosphate, fructose 2,6-bisphosphate, and ATP were obtained at physiological concentrations. Three-carbon phosphorylated intermediates of glycolysis, ADP, AMP, cAMP, and GTP had no effect on cold and heat treatments. The monomer-tetramer interconversion of the enzyme was also regulated by fructose 1,6-bisphosphate and ATP. The association is under the control of fructose 1,6-bisphosphate, whereas the dissociation is under ATP control. This regulation may have physiological relevance since the hormone binds to the tetrameric form of the enzyme at a site other than the active site.

A model to estimate the expression of the dystrophin gene in muscle from female Becker muscular dystrophy carriers.

The purpose of the present investigation was to assess the possibility of building a model to estimate, through dystrophin western blotting analysis, the expression of the DMD/BMD gene in muscle from heterozygotes. Dystrophin was analysed by mixing in increasing proportions (from 0% to 100%) aliquots of solubilised muscle from BMD patients with a qualitatively abnormal dystrophin and a normal male control. The intensity of the abnormal bands, which could be detected starting with 20% of muscle from the BMD patient, increased progressively according to the affected muscle concentration. In five obligate BMD carriers, two dystrophin bands were observed (corresponding to the products from the X bearing the normal and the BMD alleles), even among those with normal serum enzyme activities. Surprisingly, in the four obligate BMD carriers related to patients in whom an additional dystrophin fragment of 250 kd was present (two of them with raised serum enzymes), this band could not be seen, suggesting that the stability or the mechanism responsible for the synthesis of abnormal dystrophin products differs in heterozygotes compared to affected patients.

Limb-girdle syndrome: a genetic study of 22 large Brazilian families. Comparison with X-linked Duchenne and Becker dystrophies.

The differential clinical diagnosis between the X-linked muscular dystrophies (DMD and BMD) and autosomal recessive limb-girdle muscular dystrophy (LGMD), which is extremely important for genetic counseling, may be very difficult. The aim of the present report is to describe clinical and laboratory findings in patients from large families, with AR inheritance, in an attempt to characterize better cases which have been diagnosed as LGMD compared with the X-linked forms. The main features analysed are: age of onset and of confinement to a wheelchair, reproductive performance, serum enzymes (CK and PK) and dystrophin assessment (through immunohistochemistry and Western blot). Twenty-two families, with 62 affected patients diagnosed as limb-girdle muscular dystrophy, were included in this report. In 19 families, the patients had a milder clinical course, while in the remaining 3, the progression of the disease was continuous and clinically similar to X-linked DMD ("DMD-like"). A high consanguinity rate was observed among the parents of the affected patients (77%). No major clinical difference was observed between the X-linked and the AR forms. However, muscle dystrophin was found qualitatively and quantitatively normal in the autosomal forms but absent or abnormal in the X-linked ones. The reproductive performance was significantly higher for male than female patients. In addition, a surprising finding was the significantly greater fitness estimated for male LGMD cases as compared with Becker patients of comparable age studied in our center. The implications of such findings are discussed.

Serum creatine-kinase (CK) and pyruvate-kinase (PK) activities in Duchenne (DMD) as compared with Becker (BMD) muscular dystrophy.

Serum creatine-kinase (CK) activities were determined in 536 patients affected with X-linked muscular dystrophy (456 with Duchenne or DMD and 80 with Becker or BMD) and serum pyruvate-kinase (PK) in 360 among them (309 DMD and 51 BMD). The aim of this investigation was to assess the variability and rate of decrease in serum activity in DMD as compared with BMD as a function of age and in DMD as a function of Vignos scale as well. In DMD, maximum CK and PK activities were found around 1-6 years old and the average rate of decline according to age was estimated as 0.18 per year and 0.27-0.29 for both enzymes as a function of Vignos scale (assessed in 291 cases). For BMD, maximum serum enzyme levels were found around 10-15 years old and the rate of decline of serum activity per year was 0.06 for CK and 0.07 for PK. If maximum levels of serum enzyme reflect active muscle degeneration and the rate of decline per year to progressive loss of muscle mass (responsible for the release of muscle enzymes to the blood stream) our observations suggest: (a) active muscle degeneration occurs, on average, 5 years later in the group of outliers and 10 years later in BMD as compared with severe DMD; (b) the rate in which muscle mass is lost is significantly greater in DMD than in BMD and therefore serum enzyme determinations may represent an important test for evaluation of therapeutic trials; (c) serum enzymes determination may represent an important preliminary test to discriminate in a proportion of young patients if they will develop a severe or milder phenotype.

Estimates of genetic and environmental components of serum isocitrate dehydrogenase (ICDH) in normal twins.

Environmental (b2) and genetic heritability (h2) of serum isocitrate dehydrogenase (ICDH) were estimated in 96 pairs of healthy twins according to a path analysis model. The results showed significant heritability (0.42) and a very low environmental component (based on obesity and level of habitual physical activity), suggesting that these factors do not influence ICDH serum activity.

Detection of carriers of Duchene muscular dystrophy gene using logistic discriminating analysis: creatine-kinase and pyruvate-kinase

Foram determinadas as atividades da creatino-cinase (CK) e da piruvato-cinase (PK) em 160 amostras de soro: 87 de mulheres normais e 73 de 30 portadoras certas do gene para a distrofia muscular Duchenne (DMD), da faixa etária de 19-54 anos. Todas as determinaçöes de CK e PK foram realizadas em alíquotas da mesma amostra de soro. Foi usada análise discriminante logística para determinar a eficácia de cada enzima isoladamente ou das duas em combinacäo na identificaçäo de portadoras do gene da DMD. A uma amostra de soro, com um certo nível de CK ou de PK, isoladamente ou em combinaçäo, é atribuída uma probabilidade de que, se tomada oa caso de um "pool" de soros de mulheres normais e portadoras, provenha de uma portadora. A CK e a PK, cada uma isoladamente, mostraram eficiências de detecçäo de 73 e 37% respectivamente. Quando as duas enzimas foram usadas em combinaçäo a eficácia foi também de 73%, mostrando, assim, que o uso combinado da CK com a PK näo melhora a detecçäo quando comparado com o uso da CK isoladamente. Quando os dois testes aplicados a 28 mäes de casos isolados, 13 foram detectadas pela CK isoladamente e foram as mesmas 13 mulheres detectadas pela combinaçäo da CK com a PK. A PK isoladamente detectou 4 mäes de casos isolados, das quais duas apenas foram detectadas pelo uso combinado da CK com a PK

Genetic and environmental components of serum creatine kinase (CK) and pyruvate kinase (PK) in normal twins: implication for genetic risks estimates in Duchenne muscular dystrophy carriers.

The serum activity of creatine kinase (CK) and pyruvate kinase (PK) was measured in 98 pairs of same-sex Brazilian twins. The purpose of this study was to estimate the genetic and environmental components of serum activity levels for both enzymes. Heritabilities were estimated separately by path analysis in each sex. The results showed that CK and PK activities are under genetic control in normal males and females. Environmental components were not statistically significant for CK or PK. The genetic component of both enzymes estimated in females has implications in the calculation of genetic risks for Duchenne muscular dystrophy carriers.

Serum creatine-kinase and pyruvate-kinase levels in females of different racial background at risk for Duchenne muscular dystrophy

As atividades séricas das enzimas creatino-cinase (CK) e piruvato-cinase (PK) foram determinadas em 146 mulheres beterozigotas certas quanto ao gene da distrofia muscular de Duchenne (DMD) e 187 mäes de casos isolados, pertencentes a dois grupos raciais: caucasóide e negroide. A atividade da CK foi medida em 206 mulheres caucasoides e 127 mulheres negroides e a da PK em 148 caucasoides e 92 negroides. Os resultados desta pesquisa mostraram um aumento da média de atividade enzimática no grupo de mulheres heterozigotes e mäes de casos isolados negroides em comparaçäo ao grupo de mulheres caucasoides. Entretanto, as diferenças foram estatísticamente significantes apenas para a CK sérica. Sugere-se portanto, que os resultados da atividade sérica da CK de mulheres em risco de serem portadoras do gene da DMD sejam comparados com os de mulheres normais de mesmo grupo racial

Enzymatic (PK, CK) levels and genetic counseling in Duchenne muscular dystrophy

Vinte e nove pacientes afetados por diferentes formas de distrofia muscular foram localizados e estudados clinicamente. Os 21 com o tipo Duchenne, tiveram, além disso, seus níveis de piruvato quinase (PK) e creatino quinase (CK) determinados. Sessenta e oito mulheres aparentadas a eles e controles normais foram investigados da mesma maneira. Entre os pacientes os níveis enzimáticos séricos mostraram um aumento da ordem de 15x(PK) e 112x(CK); e seis das oito heterozigotas obrigatórias foram discriminadas usando ambas as enzimas (enquanto a sua utilizaçäo isolada detectou cinco dentre elas). Coeficientes de correlaçäo entre os níveis de PK e CK foram geralmente altos (r:0,79-0,84) para pacientes e portadoras obrigatórias, declinado à medida que a probabilidade de ter o gene anormal também decrescia. O uso concomitante de ambas as enzimas combinado com o máximo de informaçäo disponível para cada genealogia possibilitou estimativas de riscos de heterozigose altos (acima de 80%) e abaixo de 20%) para 80% das mulheres aparentadas a pacientes que solicitaram aconselhamento genético

Duchenne muscular dystrophy: comparison among different racial groups.

We have compared 232 patients with Duchenne muscular dystrophy belonging to three racial groups: caucasoids, negroids, and mongoloids. Clinical evolution, serum creatine-kinase, and pyruvate-kinase levels were analysed in the three groups. The results of this investigation show that the clinical evolution did not differ significantly among these three racial groups. For serum enzyme activities a statistically significant difference was found only for CK between negroids and mongoloids.

Acquired erythroenzymopathy in a monozygotic twin with acute myeloid leukemia.

The specific activity of several red cell enzymes was studied in a pair of monozygotic twins, one of whom presented acute myeloblastic leukemia. When the intrapair variation of these twins was compared with that of a series of nine normal twins, a significant decrease in phosphoglycerate kinase, diphosphoglycerate mutase, pyruvate kinase, lactic dehydrogenase, adenylate kinase and glucose-6-phosphate dehydrogenase activities and an increase in 6-phosphogluconate dehydrogenase activity were demonstrable for the leukemic twin. The heat stability of the leukemic proband's pyruvate kinase at pH 8.0 and 56 degrees C was less than that of the normal twin, suggesting an acquired qualitative disorder.

Clinical trial of young red cell transfusions.

The lower mean cell age and prolonged 51Cr-labeled red cell survival of the top layer of centrifuged red blood cells suggest that this product may reduce blood requirements in patients with transfusion-dependent anemias. In a prospective clinical trial, we compared the effect of regular administration of young red cells with that associated with use of conventional frozen cells. Six patients with thalassemia major received 192 units of young red cells prepared from single donor units of whole blood using the IBM 2991 Cell Processor. The mean transfusion requirement to maintain the hemoglobin level greater than 9.0 gm/dl was 110 +/- 17 ml RBC/kg during the year of young cell transfusions, in comparison with 130 +/- 20 and 131 +/- 23 ml RBC/kg when conventional frozen cells were administered in the years before and after the young cell trial, respectively. Blood requirements in individual patients were reduced by 8% to 24% (mean 15.8%); the hemoglobin level remained constant. Although young cells of consistent quality can be prepared regularly in a clinical setting with little difficulty, the cost of the product is high and the effect on transfusion requirements is less than predicted from studies in vitro and from labeling experiments.