Selected peptides targeted to the NMDA receptor channel protect neurons from excitotoxic death.

Excitotoxic neuronal death, associated with neurodegeneration and stroke, is triggered primarily by massive Ca2+ influx arising from overactivation of glutamate receptor channels of the N-methyl-D-aspartate (NMDA) subtype. To search for channel blockers, synthetic combinatorial libraries were assayed for block of agonist-evoked currents by the human NR1-NR2A NMDA receptor subunits expressed in amphibian oocytes. A set of arginine-rich hexapeptides selectively blocked the NMDA receptor channel with IC50 approximately 100 nM, a potency similar to clinically tolerated blockers such as memantine, and only marginally blocked on non-NMDA glutamate receptors. These peptides prevent neuronal cell death elicited by an excitotoxic insult on hippocampal cultures.

Microstructure and macroscopic properties of bioactive CaO-SiO2-PDMS hybrids.

CaO-SiO2-PDMS (polydimethylsiloxane) hybrid materials were synthesized as crack-free monoliths presenting in vitro bioactivity, i.e. able to be coated with a calcium phosphate-rich layer after having been soaked in simulated body fluid (SBF). A wide physical-chemical characterization of these materials was carried out to relate their microscopic structure and macroscopic properties. The effect of PDMS and the amounts of water used for the tetraethoxysilane (TEOS) hydrolysis on the mechanical properties of hybrid materials was investigated by three-point bending tests. For a given amount of water, as PDMS content in hybrids increased, the elastic modulus decreased. Furthermore, keeping the PDMS content constant, when the amount of H2O decreased, the elastic modulus increased. Regarding in vitro bioactivity and mechanical properties, the hybrid material obtained with molar ratios H2O/TEOS = 2 and TEOS/PDMS = 3.5 proved to be the best candidate for either soft tissue substitution or metallic implant coating since the hybrid material would promote bond to bone formation, simultaneously dampening the mechanical charges.

pH and ligand binding modulate the strength of protein-protein interactions in the Ca(2+)-ATPase from sarcoplasmic reticulum membranes.

The Ca(2+)-ATPase from sarcoplasmic reticulum (SR) membranes couples the Ca(2+) transport to ATP hydrolysis through phosphorylation in its cytoplasmic catalytic domain. Interactions between protein domains and the role of monomer-monomer interactions remain unclear. Here, we report a differential scanning calorimetric study of the thermal unfolding of this protein. In the pH range 6-8, thermal unfolding of the Ca(2+)-ATPase in glycogen phosphorylase-free SR membranes shows a major endothermic peak with a critical temperature midpoint ranging between 51 and 55 degrees C, depending on pH, Ca(2+), Mg(2+)-ADP and KCl concentrations. The enthalpy change of the overall unfolding process ranged between 250 and 300 kcal/mol of Ca(2+)-ATPase monomer. Thermal denaturation of the Ca(2+)-ATPase in SR membranes is well fitted to an irreversible process that can be rationalized in terms of a non-two state process, N (native)right harpoon over left harpoon I (intermediate)-->D (denatured). Thermodynamic analysis show that this protein has a compact structure, implying a tight structural interconnection between catalytic and Ca(2+) transport domains. The apparent cooperative unit, defined by the van 't Hoff enthalpy to the overall unfolding enthalpy ratio, increased from 1.1 at pH 6 to 1.8 at pH 8, showing that monomer-monomer interactions are stronger at weakly basic pH than at weakly acidic pH. While micromolar Ca(2+) concentrations had only a weak effect on the cooperativity of the unfolding process, this is clearly increased by millimolar Mg(2+)-ADP. In addition, high ionic strength lowered the apparent cooperative unit to approximately 1.0 in the pH range 6-8. Taken together, these results suggest that protein-protein interactions are altered by variables that modulate the catalytic activity of this enzyme.

Thermal unfolding of monomeric Ca(II), Mg(II)-ATPase from sarcoplasmic reticulum of rabbit skeletal muscle.

The thermal unfolding of monomeric and delipidated Ca(2+)-ATPase, solubilized in C12E8, can be appropriately described as a non-two-state irreversible denaturation, with only one endothermic peak. In the Ca2+ concentration range (0-0.5 mM) which stimulates the ATPase activity of solubilized monomeric ATPase, Ca2+ shifts the critical temperature midpoint of the denaturation process (Tm) from 42 to 50 degrees C without segregation of the endothermic peak into two separate components. Because 20 mM Mg2+ only shifts the Tm from 42 to 44 degrees C, we conclude that the effect of Ca2+ upon the Tm is likely to be due to binding to the high affinity Ca2+ sites in the ATPase. The effect of Ca2+ upon the enthalpy of denaturation is biphasic, suggesting the presence of low affinity Ca2+ sites (K0.5 in the millimolar range) in monomeric and solubilized ATPase.

Arginine-rich peptides are blockers of VR-1 channels with analgesic activity.

Vanilloid receptors (VRs) play a fundamental role in the transduction of peripheral tissue injury and/or inflammation responses. Molecules that antagonize VR channel activity may act as selective and potent analgesics. We report that synthetic arginine-rich hexapeptides block heterologously expressed VR-1 channels with submicromolar efficacy in a weak voltage-dependent manner, consistent with a binding site located near/at the entryway of the aqueous pore. Dynorphins, natural arginine-rich peptides, also blocked VR-1 activity with micromolar affinity. Notably, synthetic and natural arginine-rich peptides attenuated the ocular irritation produced by topical capsaicin application onto the eyes of experimental animals. Taken together, our results imply that arginine-rich peptides are VR-1 channel blockers with analgesic activity. These findings may expand the development of novel analgesics by targeting receptor sites distinct from the capsaicin binding site.

Structural determinants of the blocker binding site in glutamate and NMDA receptor channels.

Glutamate receptor channels of the NMDA-type (N-methyl-D-aspartate) and non-NMDA-type (GluR) differ in their pore properties. The N-site in the M2 transmembrane segment of NMDA receptors (NMDAR), or the corresponding Q/R-site in GluRs, is a pivotal structural determinant of their permeation and blockade characteristics. Substitutions at a second site in M2, the L-site (L577) in GluR1, drastically alter the receptor selectivity to divalent cations. Here we report that M2 mutants carrying an asparagine or a threonine residue at the Q-site of GluR1, along with a tryptophan residue at the L-site, form homomeric GluR1 channels that are highly sensitive to structurally diverse, uncompetitive NMDA antagonists such as arylcyclohexylamines, dibenzocycloheptenimines, and to morphinian and adamantane derivatives. Analysis of the voltage dependence of channel blockade locates the blocker binding site approximately 0.65 partway into the transmembrane electric field in both GluR1 mutants and NMDAR channels. Our results suggest that the homomeric GluR1 double mutants, L577W/Q582N and L577W/Q582T, fairly approximate the pore properties of the heteromeric NMDA receptor and support the structural kinship of their permeation pathways.

Tuberculous pleural effusion in children.

STUDY OBJECTIVES: To describe the age distribution, clinical, laboratory, radiographic, and bacteriologic findings of pediatric patients with tuberculous pleural effusion. DESIGN: A retrospective study. PATIENTS AND METHODS: We have identified all cases of primary pulmonary tuberculosis in children < 18 years, reported to the health department. We have collected information from medical records regarding demographics, clinical findings, bacteriologic results, and evolution. Chest radiographs obtained at the time of initial evaluation were reviewed independently by two groups of radiologists who were blind to the clinical and epidemiologic data. RESULTS: Between January 1983 and December 1996, 175 children < 18 years were diagnosed as having primary pulmonary tuberculosis. Among them, 39 patients (22.1%) showed pleural effusion on chest radiograph. The mean age of patients with tuberculous pleural effusion was significantly higher (13.52+/-0.5 years vs 6.97+/-0.42 years). The sensitivity of the tuberculin test is 97.4% for an induration > or = 5 mm. Pleural fluid analysis shows a lymphocytic exudative effusion. Chest radiograph review showed unilateral pleural effusion in all cases. Pleural effusion was the sole radiographic manifestation in 41% of cases. Parenchymal disease is associated in 23 cases (59%). Bacteriologic confirmation of tuberculosis was achieved in 22 cases (56.4%). Cultures of pleural fluid and biopsy material both yielded Mycobacterium tuberculosis in 15 of 34 (44.1%) and 12 of 18 (66.6%), respectively, for samples under study. Pleural biopsy specimens showed granulomatous inflammation in 18 of 23 cases (78.3%). Antituberculous therapy for 6 to 9 months was effective in all cases. Transient side effects occurred in 1 of 39 patients (2.9%). CONCLUSIONS: Pleural effusion accounts for 22.1% of cases of pediatric pulmonary tuberculosis. Parenchymal consolidation is the most common associated radiographic finding. Bacteriologic confirmation was achieved in 56.4% of cases. A short course of chemotherapy is effective.

Microbiology of pediatric primary pulmonary tuberculosis.

OBJECTIVE: To determine the sensitivity of bacteriologic studies in pediatric pulmonary tuberculosis. PATIENTS AND METHODS: Between January 1988 and December 1996, 104 consecutive patients aged 0 to 18 years received a diagnosis of primary pulmonary tuberculosis at our institution. Demographic, clinical, laboratory, and bacteriologic data were collected. Clinical specimens were studied for acid-fast bacilli detection by Ziehl-Neelsen stain and cultured for Mycobacterium recovery by Lowenstein-Jensen culture medium. Statistical analysis was performed utilizing chi(2), t tests, and multivariate logistic regression analysis. RESULTS: Bacteriologic results were available for 57 patients (54.8%). A positive smear or culture result for Mycobacterium tuberculosis was obtained in 9 of 54 patients (16.6%) and 25 of 50 patients (50%), respectively. Confirmation of M tuberculosis disease was achieved in 28 patients (49.1%). Ziehl-Neelsen stain and Lowenstein-Jensen culture recovery rates were 10.3% (14 of 135) and 52% (48 of 92) of specimens studied, respectively. Sputum, pleural fluid, and biopsy material cultures yielded M tuberculosis in 55%, 75%, and 63% of patients, respectively. Mean +/- SD age (13.7 +/- 4.5 years vs 9.6 +/- 4.5 years) and number of samples submitted for culture (1.93 +/- 0.94 vs 1.31 +/- 0.97) were significantly higher in the confirmed tuberculosis disease group (p < 0.05). The presence of a pleural effusion was also more commonly found in the confirmed tuberculosis disease group (p < 0.05). CONCLUSION: The sensitivity of bacteriologic studies in pediatric pulmonary tuberculosis disease was 49.1%. Age is the main factor associated with the positivity of culture results.

Pediatric experience with autologous peripheral blood progenitor cell transplantation: influence of CD34+ cell dose in engraftment kinetics.

The aim of this study was to analyze factors affecting mobilization and engraftment in 40 children undergoing autologous peripheral blood progenitor cell transplantation for different malignancies: 19 patients with haematological malignancies and 21 patients with solid tumors. Patients received 4-5 days of rhG-CSF (12 micrograms/kg/day) subcutaneously. Apheresis was performed by continuous flow blood cell separation beginning on the fifth day of rhG-CSF. For patients weighing < or = 25 kg, the extracorporeal line was primed with irradiated red blood cells. After myeloablative conditioning regimens, patients were grafted with 7.21 +/- 7.8 x 10(6)/kg CD34+ cells. Days to achieve an absolute neutrophil count > 0.5 x 10(9)/1 and a platelet count > 20 x 10(9)/1 without platelet support were 9.50 +/- 1.2 (range 7-13) and 18.1 +/- 8.3 (range 9-37), respectively. The number of CD34+ cells infused was highly correlated with engraftment kinetics (P = 0.0001). The patient's body weight and the number of previous chemotherapy courses had a negative influence on CD34+ cells collected.

Processing dominance of global and local information in visual patterns.

The processing dominance of global and local levels of visual patterns was studied using two tasks: speeded classification and identification. Stimuli were presented with spatial certainty and controlled eccentricity. The results with both procedures showed global advantage: RTs to global level were faster than those to local level. In the same way, the interference effect was bidirectional between the global and local levels, the amount of interference being larger from the global level to the local one than vice versa.

[Mediastinal chordoma]. / Cordoma mediastínico.

We describe a patient with chordoma located in the mid-posterior mediastinum whose first clinical symptoms were respiratory. This, together with the patient's age at presentation, made this case unusual.

[Extracorporeal shock wave lithotripsy of urolithiasis in patients with urinary diversion]. / Litotricia extracorpórea en litiasis en pacientes con derivación urinaria.

We evaluate the efficacy of ESWL in the management of calculi in patients with urinary diversion. We treated 5 patients who suffered from urinary lithiasis after urinary diversion post cistectomy. We managed the patients with extracorporeal shock wave lithotripsy in monotherapy with a Siemens Lithostar Modularis device. Mean stone size (long axis) was 1.95 cm (range 1 to 3.5 cm). The mean shockwave number per session was 2.6 per patient. Stone free result was 100%. We conclude that ESWL technique can provide acceptable results in patients with urinary diversion and can be used as first choice treatment in these type of patients due to its minimal morbidity and excellent results, equivalent to those achieved in patients without urinary diversion.

[Mucinous adenocarcinoma of the urachus synchronic with colorectal adenocarcinoma. Value of immunohistochemistry in the differential diagnosis]. / Adenocarcinoma mucinoso de uraco sincrónico con adenocarcinoma colorrectal. Valor de la inmunohistoquímica en el diagnóstico diferencial.

The coincidence of an urachal adenocarcinoma with another similar tumour in other location makes necessary to separate a true primary from a metastatic adenocarcinoma. We report the case of a 66-years-old-man with an urachal mucinous adenocarcinoma and two colonic adenocarcinoma excised in the same surgical act, showing both macro and microscopic studies together with immunohistochemical techniques, that were useful to differentiate the origin of both neoplasms. Among them, the antibody to keratin 7, a cytoplasmic epithelial protein, was positive in the urachal and negative in the colonic tumour.

[Antimicrobial susceptibility of Escherichia coli isolated from bacteriurias in Bierzo health area during 2003]. / Sensibilidad microbiana de Escherichia coli en bacteriurias en el área sanitaria del Bierzo en el año 2003.

OBJECTIVE: Sensitivity to antibiotics of Escherichia coli isolated from intrahospital and extrahospital bacteriurias is analyzed. MATERIAL AND METHODS: Sensitivity to nineteen antibiotics used in the clinical practice was determined in strains of Escherichia coli isolated from intrahospital and extrahospital bacteriurias. RESULTS: The prevalence of in-vitro susceptibilities to antibiotics were (hospital, state health service clinic, health center-primary-care): imipenem (100%-100%-100%; p=NS), amikacin (100%-100%-99.7%; p=NS), fosfomicyn (98.6%-98.4%-99.6%; p=NS), cefepime (96%-96.9%-98.3%; p=NS), piperacillin-tazobactam (96%-95.3%-96.6%; p=NS), aztreonam (93.5%-94.7%-97.7%; p<0.001), ceftazidime (93.5%-94.3%-97.8%; p<0.001), cefotaxime (93.1%-95%-97.7%; p<0.001), cefixime (92.7%-94.6%-96.7%; p<0.05), nitrofurantoin (92%-94.7%-94.7%; p=NS), cefuroxime (88.4%-93.1%-95%; p<0.001), amoxicillin-clavulanic (87.7%-88.7%-93.8%; p<0.001), tobramicyn (87%-93.7%-93.8%; p<0.001), gentamcin (85.9%-92.8%-93%; p<0.001), cefazolin (84.4%-88.7%-91.6%; p<0.01), ciprofloxacin (63.8%-71.4%-78.4%; p<0.001), norfloxacin (63%-70.8%-78.2%; p<0.001), cotrimoxazole (65.2%-68.6%-74.9%; p<0.01) and ampicillin (35.5%-42.5%-47.8%; p<0.01). (*NS= No significant differences). CONCLUSIONS: The knowledge of the sensitivity of uropathogens to antimicrobians can allow us to initiate empirical therapy of urinary tract infections.

[Transvesical repair of non-complicated vesicovaginal fistula]. / Reparación transvesical de fístulas vesicovaginales no complicadas.

OBJECTIVE: The management of vesicovaginal fistula still remains controversial in regard to the timing of repair and type of approach. We review the relevant literature and describe our experience with the transvesical management of uncomplicated vesicovaginal fistulas after gynecological surgery. MATERIAL AND METHODS: We reviewed retrospectively 6 consecutive women who presented with uncomplicated vesicovaginal fistula, repaired at our institution between 1995 and 1998. Four cases underwent early repair after a trial of conservative management. One case underwent intraoperative repair and another case after 19 months because of delayed diagnosis. Postoperative follow up ranges from 4 to 35 months. RESULTS: All patients were cure. The fistula tract was excised totally in all patients. There were no postoperative complications. CONCLUSIONS: Early repair of uncomplicated vesicovaginal fistulas after gynecological surgery offers reliable success, according with literature records and our own experience. On the other hand, transvesical repair offers an easy operative approach, with a high successful rate.

[Conservative surgery for renal carcinoma]. / Cirugía conservadora en el carcinoma renal.

OBJECTIVES: To report on our experience in conservative surgery for renal cell carcinoma, pointing at indications, surgical techniques and results. We also make a review of the literature. MATERIAL AND METHODS: From 1975 until 1997, 231 patients underwent surgical treatment of renal cell carcinoma. In 17 cases conservative surgery was done. 11 patients were male and 6 female, with age range 33-78 years. Polar nephrectomy was done in 4 cases and tumorectomy in 13 cases. The indication was elective in 10 cases, and imperative in 7 due to: 4 bilateral carcinomas, 1 chronic renal failure, 1 von Hippel Lindau disease and 1 tumor associated with surgical lithiasis of the kidney. RESULTS: 58.8% of the patients did not have clinical symptoms and the diagnose was incidental. The average size of the tumors was 3.8 cm. The pathological stage was: 3 cases T1N0M0 and 12 T2N0M0. All the T1 cases had an incidental diagnose. The complications were: 1 urinary fistula, 1 haematoma, and 1 case of postoperative fever. All these complications were solved in a conservative way. We had tumoral recurrence in one patient affected with von Hippel Lindau disease. It appeared 4 years after the surgical procedure and required radical nephrectomy. One patient died 24 months after surgery because of causes not related with renal tumor. The rest of the patients are alive, with no tumoral recurrence, within an average follow-up of 49.6 months. None of the patients needed dialysis. CONCLUSIONS: Our experience, though not great is enough to demonstrate the benefits of conservative surgery for renal cell carcinoma. Partial nephrectomy in selected patients and with the appropriate surgical technique offers short-term results similar to those obtained with radical nephrectomy. It is indispensable to make the resection and intraoperative pathological study of a margin of renal parenchyma surrounding the tumor, and also to examine the whole surface of the kidney to search for satellite tumoral nodules. It is very important to do a close follow up of these patients after the surgery.

[Utility of prostate-specific antigen in pleural fluid for the diagnosis of metastatic effusion secondary to prostate cancer]. / Utilidad del antígeno prostático específico en líquido pleural para el diagnóstico del derrame metastático por cáncer de próstata.

Pulmonary or pleural involvement from prostate cancer is an uncommon clinical finding. We report on a patient with prostate cancer and a diagnosis of malignant pleural effusion made by determination of pleural fluid prostate specific antigen.

[Ectopic prostatic tissue in the bladder]. / Tejido prostático ectópico en vejiga urinaria.

We report the case of a 58-year-old man with ectopic prostatic tissue at the bladder trigone. The diagnosis was by chance during study and treatment of benign prostatic hyperplasia. The appearance was pseudocystic. It occupied completely the bladder trigone. On histology, the lesion was formed by prostatic type-glands, which were positive for the presence of prostatic specific antigen by using inmunoperoxidase technique. It was partially covered by normal urothelium. Ten months later, no trace of recurrence has been evidenced.

[Microbial sensitivity of Escherichia coli in community-acquired urinary tract infections]. / Sensibilidad microbiana de Escherichia coli en infecciones urinarias extrahospitalarias.

OBJECTIVE: For effective empiric therapy of urinary tract infections in the extra-hospital setting the susceptibility pattern of uropathogens should be considered. Moreover, the evolution in sensitivity can be observed when comparing with susceptibility patterns in the previous years. This paper presents an analysis of our experience with Escherichia coli. MATERIAL AND METHODS: During 2002 and 1998, 895 and 595 strains of Escherichia coli respectively, isolated from extrahospitalary bacteriurias were collected in ten health centers in Bierzo (León, Spain). Sensitivity to nine most commonly antibiotics used in the clinical practise was determined. The existence of significant differences of susceptibility among years (2002-1998) was analyzed by the chi square test. RESULTS: Escherichia coli accounted for 63.4% of all isolates in 2002 and 50.8% in 1998. The prevalence of in-vitro susceptibilities to antibiotics were (2002-1998): fosfomycin (99.2%-99.3%; p = NS*), cefixime (98.3%-92.9%; p < 0.001), cefuroxime (96.5%-94.1%; p < 0.05), nitrofurantoin (94.5%-86.9%; p < 0.001), amoxycillin-clavulanic acid (93.1%-90.1%; p < 0.05), ciprofloxacin (77.1%-81.6%; p < 0.05), norfloxacin (75.8%-80.3%; p < 0.05), cotrimoxazole (71.5%-73.4%; p = NS*) and ampicillin (44%-41.4%; p = NS*). (*NS = No significant differences). CONCLUSION: The knowledge of the sensitivity of uropathogens to antimicrobians in a specific medium can allow us to use antibiotics rationally and initiate empirical therapy.

[Scrotal leiomyoma]. / Leiomioma de escroto.

A case of a 32-year-old patient with a diagnosis of leiomyoma of the scrotum was studied. Histologic analyses did not yield evidence of malignancy. Full excision of tumor was achieved and the postoperative period was uneventful.