["Post micturition residual; urodynamic"]. / <>

OBJECTIVES: To study the possible correlation between the existence of postmicturition residual (PR), both in men as in women, with other urodynamic parameters. MATERIAL AND METHODS: A retrospective study in a series of 121 patients (33 male, 88 female), age X=68.22 and SD=12.904 (16-90 years), with a significative PR had been underwent a videourodynamic study. All cases of neurogenic vesicourethral dysfunctions and post pelvic radiotherapy were excluded. Statistical study was performed between the PR and the presence of urinary symptoms, urodynamic data, and findings of physical examination. The study was conducted, both descriptive and with statistical correlations. We used the Spearman Rho and compared with the median chi-square. RESULTS: We found a positive correlation (men and women), between the PR and bladder capacity (p=0.001) and between the PR free flowmetry and PR test pdet/flow (r=0.450 p=0.001). In women, a positive correlation was found between the PR and the urethral resistance (URA) (p=0.001), and between PR and voiding by abdominal pressure (p<0,05). We found a negative correlation in men between the PR and the parameters of detrusor contraction (W80-W20) (p<0.05). Not found statistically significant correlation between the PR and cystometry, nor with the urodynamic diagnosis of obstruction, associated radiological semiology, hyperactive bladder and emptying symptoms in men. CONCLUSIONS: The PR behaved more as a parameter measurement of detrusor contractility, than a parameter of the lower urinary tract obstruction. The PR was not associated with any clinic or associated radiologic semiology.

«Correlaciones urodinámicas del residuo posmiccional» / ''Post micturition residual; Urodynamic''

Objetivos: Estudiar la correlación entre la existencia de residuo posmiccional (rp) con otros parámetros urodinámicos. Material y métodos: Estudio retrospectivo. 121 pacientes (33V, 88M). Edad=68,22 y S=12,904 (16–90 años) que presentaban rp realizándose estudio videourodinámico completo. Se excluyeron disfunciones neurógenas vésicouretrales y posradioterapia pélvica. Se estudiaron correlaciones estadísticas entre residuo y síntomas, parámetros urodinámicos y hallazgos de la exploración física. Se ha realizado estadística descriptiva y correlaciones (rho de Spearman y comparación de medianas [chi cuadrado]). Resultados: Se encontró correlación positiva (hombres y mujeres) entre rp y capacidad vesical (p=0,001), entre rp (flujometría libre) y el rp (test pdet/flujo) (r=0,450 p=0,001). En mujeres entre rp y resistencia uretral (p=0,001) y entre rp y micción con prensa abdominal (p<0,05) Se encontró correlación negativa (hombres) entre rp y parámetros de contracción istotónica del detrusor (W80–W20) (p<0,05). No se ha encontrado correlación entre rp y parámetros cistomanométricos, ni con el diagnóstico urodinámico de obstrucción, semiología radiológica asociada, vejiga hiperactiva, ni síntomas funcionales de vaciamiento en el hombre. Conclusiones: El rp urodinámicamente se comportó más como un parámetro de medida de contractilidad del detrusor que como un parámetro de obstrucción del tracto urinario inferior. El rp no presentó ninguna semiología clínica ni radiológica asociada específica (AU)

Objectives: To study the possible correlation between the existence of postmicturition residual (PR), both in men as in women, with other urodynamic parameters. Material and methods: A retrospective study in a series of 121 patients (33 male, 88 female), age X=68.22 and SD=12.904 (16–90 years), with a significative PR had been underwent a videourodynamic study. All cases of neurogenic vesicourethral dysfunctions and post pelvic radiotherapy were excluded. Statistical study was performed between the PR and the presence of urinary symptoms, urodynamic data, and findings of physical examination. The study was conducted, both descriptive and with statistical correlations. We used the Spearman Rho and compared with the median chi-square. Results: We found a positive correlation (men and women), between the PR and bladder capacity (p=0.001) and between the PR free flowmetry and PR test pdet/flow (r=0.450 p=0.001). In women, a positive correlation was found between the PR and the urethral resistance (URA) (p=0.001), and between PR and voiding by abdominal pressure (p<0,05). We found a negative correlation in men between the PR and the parameters of detrusor contraction (W80–W20) (p<0.05). Not found statistically significant correlation between the PR and cystometry, nor with the urodynamic diagnosis of obstruction, associated radiological semiology, hyperactive bladder and emptying symptoms in men. Conclusions: The PR behaved more as a parameter measurement of detrusor contractility, than a parameter of the lower urinary tract obstruction. The PR was not associated with any clinic or associated radiologic semiology (AU)

Human erythrocyte pyruvate kinase: characterization of the recombinant enzyme and a mutant form (R510Q) causing nonspherocytic hemolytic anemia.

Human erythrocyte pyruvate kinase plays an important role in erythrocyte metabolism. Mutation on the gene results in pyruvate kinase deficiency and is an important cause of hereditary nonspherocytic hemolytic anemia. Because of difficulties in isolating the mutant enzymes from patients, these mutations have not been fully studied. In this study, a complementary DNA (cDNA) encoding the human erythrocyte pyruvate kinase was generated. The cDNA was cloned into several expression vectors, and the protein was expressed and purified. The tetrameric protein exhibited properties characteristic of authentic human erythrocyte pyruvate kinase, including response to substrate, phosphoenolpyruvate, activation by fructose 1,6-bisphosphate, and inhibition by adenosine triphosphate (ATP). The N-terminal segment of the protein was highly susceptible to proteolysis, but only 2 of the 4 subunits were cleaved and lacked 47 N-terminal amino acid residues. A mutant protein, R510Q, which is the most frequently occurring mutation among Northern European population, was also generated and purified. The mutant protein retained its binding capacity to and could be activated by fructose 1,6-bisphosphate and showed similar kinetics toward phosphoenolpyruvate and adenosine diphosphate as for the wild-type enzyme. Conversely, the mutant protein has a dramatically decreased stability toward heat and is more susceptible to ATP inhibition. The enzyme instability decreases the enzyme level in the cell, accounting for the clinically observed "pyruvate kinase deficiency" of patients who are homozygous for this mutation. This study provides the first detailed functional characterization of human erythrocyte pyruvate kinase. These findings will allow the establishment of a fine correlation between molecular abnormalities and the clinical expression of the disease.

The allosteric regulation of pyruvate kinase.

Pyruvate kinase (PK) is critical for the regulation of the glycolytic pathway. The regulatory properties of Escherichia coli were investigated by mutating six charged residues involved in interdomain salt bridges (Arg(271), Arg(292), Asp(297), and Lys(413)) and in the binding of the allosteric activator (Lys(382) and Arg(431)). Arg(271) and Lys(413) are located at the interface between A and C domains within one subunit. The R271L and K413Q mutant enzymes exhibit altered kinetic properties. In K413Q, there is partial enzyme activation, whereas R271L is characterized by a bias toward the T-state in the allosteric equilibrium. In the T-state, Arg(292) and Asp(297) form an intersubunit salt bridge. The mutants R292D and D297R are totally inactive. The crystal structure of R292D reveals that the mutant enzyme retains the T-state quaternary structure. However, the mutation induces a reorganization of the interface with the creation of a network of interactions similar to that observed in the crystal structures of R-state yeast and M1 PK proteins. Furthermore, in the R292D structure, two loops that are part of the active site are disordered. The K382Q and R431E mutations were designed to probe the binding site for fructose 1, 6-bisphosphate, the allosteric activator. R431E exhibits only slight changes in the regulatory properties. Conversely, K382Q displays a highly altered responsiveness to the activator, suggesting that Lys(382) is involved in both activator binding and allosteric transition mechanism. Taken together, these results support the notion that domain interfaces are critical for the allosteric transition. They couple changes in the tertiary and quaternary structures to alterations in the geometry of the fructose 1, 6-bisphosphate and substrate binding sites. These site-directed mutagenesis data are discussed in the light of the molecular basis for the hereditary nonspherocytic hemolytic anemia, which is caused by mutations in human erythrocyte PK gene.

Micellar electrokinetic chromatography as a complementary method to sodium dodecyl sulfate-polyacrylamide gel electrophoresis for studying limited proteolysis of proteins.

Micellar electrokinetic chromatography (MEKC) has been utilized as an analytical method to perform investigations on limited proteolysis of proteins. To this purpose partial proteolysis experiments with a series of proteinases were performed, utilizing as model protein pyruvate kinase (PK) from Escherichia coli, an enzyme that is regulated allosterically by fructose 1,6-bisphosphate (FBP). Data obtained with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and MEKC were compared; the profiles generated by submitting digests of PK treated with different proteinases in the presence and absence of FBP to electrophoretic analysis provided a useful adjunct for a better understanding of the effects of the allosteric activator on the conformation of the model enzyme. MEKC was also found to be a convenient technique for determining the kinetics of substrate proteolysis.