Molecular Characterization of the Viroporin Function of Foot-and-Mouth Disease Virus Nonstructural Protein 2B.

Nonstructural protein 2B of foot-and-mouth disease (FMD) virus (FMDV) is comprised of a small, hydrophobic, 154-amino-acid protein. Structure-function analyses demonstrated that FMDV 2B is an ion channel-forming protein. Infrared spectroscopy measurements using partially overlapping peptides that spanned regions between amino acids 28 and 147 demonstrated the adoption of helical conformations in two putative transmembrane regions between residues 60 and 78 and between residues 119 and 147 and a third transmembrane region between residues 79 and 106, adopting a mainly extended structure. Using synthetic peptides, ion channel activity measurements in planar lipid bilayers and imaging of single giant unilamellar vesicles (GUVs) revealed the existence of two sequences endowed with membrane-porating activity: one spanning FMDV 2B residues 55 to 82 and the other spanning the C-terminal region of 2B from residues 99 to 147. Mapping the latter sequence identified residues 119 to 147 as being responsible for the activity. Experiments to assess the degree of insertion of the synthetic peptides in bilayers and the inclination angle adopted by each peptide regarding the membrane plane normal confirm that residues 55 to 82 and 119 to 147 of 2B actively insert as transmembrane helices. Using reverse genetics, a panel of 13 FMD recombinant mutant viruses was designed, which harbored nonconservative as well as alanine substitutions in critical amino acid residues in the area between amino acid residues 28 and 147. Alterations to any of these structures interfered with pore channel activity and the capacity of the protein to permeabilize the endoplasmic reticulum (ER) to calcium and were lethal for virus replication. Thus, FMDV 2B emerges as the first member of the viroporin family containing two distinct pore domains.IMPORTANCE FMDV nonstructural protein 2B is able to insert itself into cellular membranes to form a pore. This pore allows the passage of ions and small molecules through the membrane. In this study, we were able to show that both current and small molecules are able to pass though the pore made by 2B. We also discovered for the first time a virus with a pore-forming protein that contains two independent functional pores. By making mutations in our infectious clone of FMDV, we determined that mutations in either pore resulted in nonviable virus. This suggests that both pore-forming functions are independently required during FMDV infection.

Structural analysis of APOB variants, p.(Arg3527Gln), p.(Arg1164Thr) and p.(Gln4494del), causing Familial Hypercholesterolaemia provides novel insights into variant pathogenicity.

Familial hypercholesterolaemia (FH) is an inherited autosomal dominant disorder resulting from defects in the low-density lipoprotein receptor (LDLR), in the apolipoprotein B (APOB) or in the proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. In the majority of the cases FH is caused by mutations occurring within LDLR, while only few mutations in APOB and PCSK9 have been proved to cause disease. p.(Arg3527Gln) was the first mutation in APOB being identified and characterized. Recently two novel pathogenic APOB variants have been described: p.(Arg1164Thr) and p.(Gln4494del) showing impaired LDLR binding capacity, and diminished LDL uptake. The objective of this work was to analyse the structure of p.(Arg1164Thr) and p.(Gln4494del) variants to gain insight into their pathogenicity. Secondary structure of the human ApoB100 has been investigated by infrared spectroscopy (IR) and LDL particle size both by dynamic light scattering (DLS) and electron microscopy. The results show differences in secondary structure and/or in particle size of p.(Arg1164Thr) and p.(Gln4494del) variants compared with wild type. We conclude that these changes underlie the defective binding and uptake of p.(Arg1164Thr) and p.(Gln4494del) variants. Our study reveals that structural studies on pathogenic variants of APOB may provide very useful information to understand their role in FH disease.

[Effectiveness and treatment satisfaction in patients with erectile dysfunction in Spain: EDOS study]. / Efectividad y satisfacción con el tratamiento en pacientes con disfunción eréctil en España: estudio EDOS.

INTRODUCTION: Erectile dysfunction (ED) is a worldwide health problem with an ever increasing prevalence, affecting the quality of life of many patients. OBJECTIVE: The aim of this study was to describe treatment effectiveness and patient satisfaction with ED treatment in the Spanish cohort of the EDOS study. MATERIAL AND METHODS: This observational, pan-European study, assessed treatment effectiveness and patient satisfaction with ED treatment under routine clinical settings, using standard questionnaires. Men > or =18 years about to initiate or change ED treatment were enrolled. Patients were assessed at baseline, 3 and 6 months. RESULTS: A total of 1,029 patients were analyzed (12.8% of the total European sample). In general, the Spanish population characteristics are consistent with the overall population. At baseline 56.6% of patients received tadalafilo, 16.6% sildenafilo, 19.6% vardenafilo, and 7.2% received other treatments. At 3 months, a higher proportion of patients on tadalafil reported improved erections (GAQ 1: 96.5% tadalafil, 85.7% sildenafil and 87.2% vardenafil), satisfaction with treatment (EDITS: 84.2% tadalafil, 75.0% sildenafil and 76.0% vardenafil), and sexual self confidence (SF-PAIRS: 2.73 tadalafil, 2.39 sildenafil and 2.55 vardenafil), in comparison with sildenafil and vardenafil. At 6 months, differences between treatments were not significant. The mean+/-SD time elapsed from drug intake to sexual intercourse was higher for patients on tadalafil (18.6+/-26.4 h) compared to sildenafil (3.6+/-7.5) and vardenafil (8.6+/-19.4). CONCLUSION: The longer duration of action for tadalafil, and thus, the longer period of time between dosing and sexual intercourse may contribute to enhance sexual spontaneity, patient satisfaction with the treatment and greater self-confidence.

Efectividad y satisfacción con el tratamiento en pacientes con disfunción eréctil en España: Estudio EDOS / Effectiveness and treatment satisfaction in patients with erectile dysfunction in Spain: EDOS study

Introducción: La disfunción eréctil (DE) es un problema de salud mundial con una prevalencia creciente que afecta la calidad de vida de muchos pacientes. Objetivo: Analizar la efectividad y satisfacción con el tratamiento en la cohorte española de pacientes con DE incluidos en el estudio observacional de disfunción eréctil. Material y método: Estudio observacional, paneuropeo, que analizó la efectividad y satisfacción de los tratamientos para la DE en la práctica clínica habitual, utilizando cuestionarios estándares. Participaron varones ≥18 años que iniciaron o cambiaron su tratamiento para la DE. Los pacientes fueron evaluados en la visita basal, a los 3 y 6 meses. Resultados: Se analizaron 1.029 pacientes (12,8% de la muestra europea total). En general, las características de la población española son consistentes con las de la población global. En la visita basal 56,6% recibió tadalafilo, 16,6% sildenafilo, 19,6% vardenafilo y 7,2% otros tratamientos. A los 3 meses, una mayor proporción de pacientes con tadalafilo experimentó mejorías en la erección (cuestionario de evaluación global 1: 96,5% tadalafilo, 85,7% sildenafilo, 87,2% vardenafilo), se observó una mayor satisfacción con el tratamiento (inventario de satisfacción con el tratamiento para la DE: 84,2% tadalafilo, 75,0% sildenafilo y 76,0% vardenafilo) y mayor autoconfianza (escalas psicológicas y de relaciones interpersonales: 2,73 tadalafilo, 2,39 sildenafilo y 2,55 vardenafilo). A los 6 meses, las diferencias entre tratamientos no resultaron significativas. El tiempo medio±desviación estándar entre la toma del fármaco y la relación sexual fue mayor en los pacientes con tadalafilo (18,6±26,4h) vs. sildenafilo (3,6±7,5) y vardenafilo (8,6±19,4). Conclusiones: La mayor duración del efecto de tadalafilo y en consecuencia el mayor tiempo medio entre la toma y la relación sexual podría contribuir a aumentar la espontaneidad en las relaciones sexuales, la satisfacción con el tratamiento y mayor autoconfianza (AU)

Introduction: Erectile dysfunction (ED) is a worldwide health problem with an ever increasing prevalence, affecting the quality of life of many patients. Objective: The aim of this study was to describe treatment effectiveness and patient satisfaction with ED treatment in the Spanish cohort of the EDOS study. Material and methods: This observational, pan-European study, assessed treatment effectiveness and patient satisfaction with ED treatment under routine clinical settings, using standard questionnaires. Men ≥18 years about to initiate or change ED treatment were enrolled. Patients were assessed at baseline, 3 and 6 months. Results: A total of 1,029 patients were analyzed (12.8% of the total European sample). In general, the Spanish population characteristics are consistent with the overall population. At baseline 56.6% of patients received tadalafilo, 16.6% sildenafilo, 19.6% vardenafilo, and 7.2% received other treatments. At 3 months, a higher proportion of patients on tadalafil reported improved erections (GAQ 1: 96.5% tadalafil, 85.7% sildenafil and 87.2% vardenafil), satisfaction with treatment (EDITS: 84.2% tadalafil, 75.0% sildenafil and 76.0% vardenafil), and sexual self confidence (SF-PAIRS: 2.73 tadalafil, 2.39 sildenafil and 2.55 vardenafil), in comparison with sildenafil and vardenafil. At 6 months, differences between treatments were not significant. The mean±SD time elapsed from drug intake to sexual intercourse was higher for patients on tadalafil (18.6±26.4 h) compared to sildenafil (3.6±7.5) and vardenafil (8.6±19.4). Conclusion: The longer duration of action for tadalafil, and thus, the longer period of time between dosing and sexual intercourse may contribute to enhance sexual spontaneity, patient satisfaction with the treatment and greater self-confidence (AU)

Setting reaction of polyacid modified composite resins or compomers.

The hardening of modified polyacid composite resins (compomers) and glass-ionomers have been studied using infrared spectroscopy. The acid-base reaction in Ketac-fil, a glass ionomer, was followed by the ratio between the COOH band located around 1715 cm⁻¹ and that corresponding to COO⁻ located around 1570 cm⁻¹. The combination of infrared analysis and band narrowing treatments enable us to propose in the glass-ionomer two maturation steps. First, a very rapid equilibrium acid-base related, and second the cross-linking of polycarboxylate with the metal ions present in the cement. In compomers, a new reaction has been described involving polymerization induced by free radicals besides the two steps associated with the acid-base reaction. Using infrared spectroscopy and band narrowing techniques, it is shown that water is essential to complete the hardening process but no acid-base reaction is produced since the COO⁻ band does not appear. The reaction associated with free radicals could be described as a polymerization of methacrylate monomers together with an aqueous dilution of the filling particles releasing different metal cations that would chelate with the polymer molecules to form a macromolecular structure.

Specific aspects of erectile function in urology/andrology.

The urologist/andrologist is the specialist responsible for diagnosis and treatment of health problems related to the genitourinary tract, and his or her participation in comprehensive care for a patient with erectile dysfunction (ED) is fundamental and often indispensable. The urologists/andrologists should characterize the origin of ED because of their knowledge and familiarity of all diagnostic tests and second- and third-line therapy. The origin of ED is important to determine for various reasons, such as young people suitable for etiologic treatment, medicolegal reasons, or patients' wishes for a better understanding of their condition. A review of the diagnostic tests available as well as indications for second- and third-line therapy is presented. The close relationship between ED and urological disorders, such as benign prostatic hyperplasia, prostate cancer and their treatments, and renal failure, in association with penile conditions like Peyronie's disease, priapism, and possible androgen deficiency in men older than 50 years, places the urologist at the center of integrated treatment of male ED.

[Therapeutic approach in adrenal melanoma. Review of the literature]. / Actitud terapéutica en el melanoma suprarrenal. Revisión de la literatura.

OBJECTIVE: To review the treatment strategies for adrenal melanoma and to emphasize the role of curative surgical resection and adjuvant treatment in selected patients with melanoma metastatic to the adrenal gland versus chemotherapy alone in the treatment of patients with advanced malignant melanoma. METHODS: A case of adrenal gland metastasis of a cutaneous melanoma (Clark IV, Breslow 5 mm.) treated by excision one year before that was referred to the Urology Department for Wünderlich syndrome is presented. RESULTS: The analyzed series of programmed adrenalectomy for adrenal metastases from melanoma describe survivals of 26 (3), 36 (9), 59 (3) and 72 (5) months. In our case the patient died at home one month later due to stroke, although concomitant brain metastasis is suspected. Autopsy was not performed. CONCLUSIONS: In the differential diagnosis of an incidentaloma, metastatic disease is likely in a patient with a history of malignant disease. The frequency of malignant melanoma among metastatic adrenal disease varies between 1% and 8.6%; the majority are asymptomatic and incidental findings. We believe that in selected patients with advanced malignant melanoma, with no major coexisting morbidity factors who have isolated melanoma metastatic to the adrenal gland or with limited extra-adrenal sites of disease, curative surgical resection and adjuvant treatment may improve their survival. It must be emphasized that all patients should be followed after surgical resection of the primary tumor because it will facilitate staging of the disease and avoid emergency situations of ruptured friable metastases that make complete resection difficult.

DNA-induced alpha-helical structure in the NH2-terminal domain of histone H1.

It is important to establish the structural properties of linker histones to understand the role they play in chromatin higher order structure and gene regulation. Here, we use CD, NMR, and IR spectroscopy to study the conformation of the amino-terminal domain of histone H1 degrees, free in solution and bound to the DNA. The NH(2)-terminal domain has little structure in aqueous solution, but it acquires a substantial amount of alpha-helical structure in the presence of trifluoroethanol (TFE). As in other H1 subtypes, the basic residues of the NH(2)-terminal domain of histone H1 degrees are clustered in its COOH-terminal half. According to the NMR results, the helical region comprises the basic cluster (Lys(11)-Lys(20)) and extends until Asp(23). The fractional helicity of this region in 90% TFE is about 50%. His(24) together with Pro(25) constitute the joint between the NH(2)-terminal helix and helix I of the globular domain. Infrared spectroscopy shows that interaction with the DNA induces an amount of alpha-helical structure equivalent to that observed in TFE. As coulombic interactions are involved in complex formation, it is highly likely in the complexes with DNA that the minimal region with alpha-helical structure is that containing the basic cluster. In chromatin, the high positive charge density of the inducible NH(2)-terminal helical element may contribute to the binding stability of the globular domain.

Induction of secondary structure in a COOH-terminal peptide of histone H1 by interaction with the DNA: an infrared spectroscopy study.

We have studied the conformation of the peptide Ac-EPKRSVAFKKTKKEVKKVATPKK (CH-1), free in solution and bound to the DNA, by Fourier-transform infrared spectroscopy. The peptide belongs to the COOH-terminal domain of histone H1(0) (residues 99-121) and is adjacent to the central globular domain of the protein. In aqueous (D(2)O) solution the amide I' is dominated by component bands at 1643 cm(-1) and 1662 cm(-1), which have been assigned to random coil conformations and turns, respectively. In accordance with previous NMR results, the latter component has been interpreted as arising in turn-like conformations in rapid equilibrium with unfolded states. The peptide becomes fully structured either in 90% trifluoroethanol (TFE) solution or upon interaction with the DNA. In these conditions, the contributions of turn (1662 cm(-1)) and random coil components virtually disappear. In TFE, the spectrum is dominated by the alpha-helical component (1654 cm(-1)). The band at 1662 cm(-1) shifts to 1670 cm(-1), and has been assigned to the COOH-terminal TPKK motif in a more stable turn conformation. A band at 1637 cm(-1), also present in TFE, has been assigned to 3(10) helical structure. The amide I' band of the complexes with the DNA retains the components that were attributed to 3(10) helix and the TPKK turn. In the complexes with the DNA, the alpha-helical component observed in TFE splits into two components at 1657 cm(-1) and 1647 cm(-1). Both components are inside the spectral region of alpha-helical structures. Our results support the presence of inducible helical and turn elements, both sharing the character of DNA-binding motifs.

Interaction of cholesterol with sphingomyelin in mixed membranes containing phosphatidylcholine, studied by spin-label ESR and IR spectroscopies. A possible stabilization of gel-phase sphingolipid domains by cholesterol.

The ESR spectra from different positional isomers of sphingomyelin and phosphatidylcholine spin-labeled in their acyl chain have been studied in sphingomyelin(cerebroside)-phosphatidylcholine mixed membranes that contain cholesterol. The aim was to investigate mechanisms by which cholesterol could stabilize possible domain formation in sphingolipid-glycerolipid membranes. The outer hyperfine splittings in the ESR spectra of sphingomyelin and phosphatidylcholine spin-labeled on the 5 C atom of the acyl chain were consistent with mixing of the components, but the perturbations on adding cholesterol were greater in the membranes containing sphingomyelin than in those containing phosphatidylcholine. Infrared spectra of the amide I band of egg sphingomyelin were shifted and broadened in the presence of cholesterol to a greater extent than the carbonyl band of phosphatidylcholine, which was affected very little by cholesterol. Two-component ESR spectra were observed from lipids spin-labeled on the 14 C atom of the acyl chain in cholesterol-containing membranes composed of sphingolipids, with or without glycerolipids (sphingomyelin/cerebroside and sphingomyelin/cerebroside/phosphatidylcholine mixtures). These results indicate the existence of gel-phase domains in otherwise liquid-ordered membranes that contain cholesterol. In the gel phase of egg sphingomyelin, the outer hyperfine splittings of sphingomyelin spin-labeled on the 14-C atom of the acyl chain are smaller than those for the corresponding spin-labeled phosphatidylcholine. In the presence of cholesterol, this situation is reversed; the outer splitting of 14-C spin-labeled sphingomyelin is then greater than that of 14-C spin-labeled phosphatidylcholine. This result provides some support for the suggestion that transbilayer interdigitation induced by cholesterol stabilizes the coexistence of gel-phase and "liquid-ordered" domains in membranes containing sphingolipids.

Early stages of LDL oxidation: apolipoprotein B structural changes monitored by infrared spectroscopy.

Changes in the conformation of apoliprotein B-100 in the early stages of copper-mediated low density lipoprotein oxidation have been monitored by infrared spectroscopy. During the lag phase no variation in structure is observed, indicating that copper binding to the protein does not significantly affect its structure. In the propagation phase, while hydroperoxides are formed but the protein is not modified, no changes in secondary structure are observed, but the thermal profile of the band corresponding to alpha-helix is displaced in frequency, indicating changes in tertiary structure associated with this conformation but not with beta-sheet components. When aldehyde formation starts, a decrease of approximately 3% in the area of bands corresponding to alpha-helix and beta-sheet is produced, concomitantly with an increase in beta-turns and unordered structure. The two bands corresponding to beta-turns vary as well under these conditions, indicating changes in these structures. Also at this stage the thermal profile shows variations in frequency for the bands corresponding to both alpha-helix and beta-sheet. The results are consistent with the hypothesis that as soon as the polyunsaturated fatty acids from the particle core are modified, this change is reflected at the surface, in the alpha-helical components contacting the monolayer.

Differential interaction of equinatoxin II with model membranes in response to lipid composition.

Equinatoxin II is a 179-amino-acid pore-forming protein isolated from the venom of the sea anemone Actinia equina. Large unilamellar vesicles and lipid monolayers of different lipid compositions have been used to study its interaction with membranes. The critical pressure for insertion is the same in monolayers made of phosphatidylcholine or sphingomyelin (approximately 26 mN m(-1)) and explains why the permeabilization of large unilamellar vesicles by equinatoxin II with these lipid compositions is null or moderate. In phosphatidylcholine-sphingomyelin (1:1) monolayers, the critical pressure is higher (approximately 33 mN m(-1)), thus permitting the insertion of equinatoxin II in large unilamellar vesicles, a process that is accompanied by major conformational changes. In the presence of vesicles made of phosphatidylcholine, a fraction of the protein molecules remains associated with the membranes. This interaction is fully reversible, does not involve major conformational changes, and is governed by the high affinity for membrane interfaces of the protein region comprising amino acids 101-120. We conclude that although the presence of sphingomyelin within the membrane creates conditions for irreversible insertion and pore formation, this lipid is not essential for the initial partitioning event, and its role as a specific receptor for the toxin is not so clear-cut.

[Differential diagnosis of epididymal leiomyoma. Report of a new case]. / Diagnósticos diferenciales del leiomioma de epidídimo. Aportación de un nuevo caso.

OBJECTIVE: A case of epididymal leiomyoma is presented. This lesion is uncommon and sometimes misdiagnosed. The literature is briefly reviewed. METHODS/RESULTS: A 29-year-old patient presented with a tumor in the tail of the right epididymis that was initially diagnosed as scrotal hematoma or complex cyst in the tail of the epididymis. RESULTS/CONCLUSIONS: Ultrasound has an important role in distinguishing testicular from epididymal tumors. However, if the diagnosis is unclear, surgical resection and subsequent anatomopathological analysis must be performed.

[Primary neuroectodermal tumor (PNET) of the kidney: 26 cases. Current status of its diagnosis and treatment]. / Tumor neuroectodérmico primitivo renal (PNET): 26 casos. Estado actual de su diagnóstico y tratamiento.

OBJECTIVE: To report a case of primitive neuroectodermal tumor (PNET) of the kidney and review the literature and the 25 cases previously reported as PNET. METHODS: A 39-year-old man who consulted for nephric colic is described. Ultrasound evaluation disclosed a mass arising from the left kidney. The clinical, radiological and pathologic features, treatment and differential diagnosis of small cell tumors are discussed, as well as the important role of immunohistochemical techniques (positive staining with O13 or 12E7 antibodies) and cytogenetic analysis [a characteristic chromosomal translocation t(11;22) (q24;q12) or variant translocation, such as t(21;22) (q22;q12), may be detected by fluorescence in situ hybridization (FISH) or polymerase chain reaction-reverse transcriptase (PCR-RT)]. RESULTS: Survival of our patient was 20 months. Only three of the 25 previously reported cases had a longer survival: 60, 48 and 24 months. Mean survival was 10 months. 95.24% of the cases were positive for NSE. Immunostaining (CD99) was performed in 16 patients and was found to be positive in all cases. Cytogenetic and molecular analyses were performed in 11 cases; PCR-RT was negative in two, as well as in the case described herein. CONCLUSIONS: PNET is a highly aggressive neoplasm that tends to recur locally and to metastasize. Despite the poor response to standard therapy combining surgical resection, postoperative irradiation and chemotherapy, the results might change due to current research on genetic therapy based on creating antisense oligonucleotides against the EWS-FLI 1 fusion gene.

Do sequence repeats play an equivalent role in the choline-binding module of pneumococcal LytA amidase?

LytA amidase breaks down the N-acetylmuramoyl-l-alanine bonds in the peptidoglycan backbone of Streptococcus pneumoniae. Its polypeptide chain has two modules: the NH(2)-terminal module, responsible for the catalytic activity, and the COOH-terminal module, constructed by six tandem repeats of 20 or 21 amino acids (p1-p6) and a short COOH-terminal tail. The polypeptide chain must contain at least four repeats to efficiently anchor the autolysin to the choline residues of the cell wall. Nevertheless, the catalytic efficiency decreases by 90% upon deletion of the final tail. The structural implications of deleting step by step the two last (p5 and p6) repeats and the final COOH-tail and their effects on choline-amidase interactions have been examined by comparing four truncated mutants with LytA amidase by means of different techniques. Removal of this region has minor effects on secondary structure content but significantly affects the stability of native conformations. The last 11 amino acids and the p5 repeat stabilize the COOH-terminal module; each increases the module transition temperature by about 6 degrees C. Moreover, the p5 motif also seems to participate, in a choline-dependent way, in the stabilization of the NH(2)-terminal module. The effects of choline binding on the thermal stability profile of the mutant lacking the p5 repeat might reflect a cooperative pathway providing molecular communication between the choline-binding module and the NH(2)-terminal region. The three sequence motives favor the choline-amidase interaction, but the tail is an essential factor in the monomer <--> dimer self-association equilibrium of LytA and its regulation by choline. The final tail is required for preferential interaction of choline with LytA dimers and for the existence of different sets of choline-binding sites. The p6 repeat scarcely affects the amidase stability but could provide the proper three-dimensional orientation of the final tail.

[Stromal tumor of the rectum and leiomyosarcoma of the prostate as a cause of urinary syndrome attributable to BPH]. / Tumor estromal de recto y leiomiosarcoma de próstata como causa de síndrome miccional atribuible a HBP.

OBJECTIVE: To discuss the classifications of patients with lower urinary tract symptoms ascribed to BPH, in order to define the indication for treatment for patients with similar features but of a different etiology. The literature is also reviewed. METHODS/RESULTS: Two patients, aged 62 and 63 years, diagnosed as having BPH were found to have a gastrointestinal stromal tumor (GIST) and a leiomyosarcoma of the prostate, respectively. The first patient had undergone retropubic resection. Frozen section analysis revealed a GIST. The second patient had undergone TURP twice. A perineal biopsy at the last medical examination showed a leiomyosarcoma of the prostate. This patient finally underwent pelvic tumorectomy. The international classification of BPH is discussed: PQSF (P: prostatic weight determined by transrectal US or DRE; Q: quality of life assessment; S: international prostate symptom score (IPSS); F: maximum urinary flow rate by uroflowmetry--Qmax). CONCLUSIONS: The classifications are practical, but should be improved. In our view, details useful in orienting the diagnosis could be lost by oversimplification.

Structure and dynamics of membrane proteins as studied by infrared spectroscopy.

Infrared (IR) spectroscopy is a useful technique in the study of protein conformation and dynamics. The possibilities of the technique become apparent specially when applied to large proteins in turbid suspensions, as is often the case with membrane proteins. The present review describes the applications of IR spectroscopy to the study of membrane proteins, with an emphasis on recent work and on spectra recorded in the transmission mode, rather than using reflectance techniques. Data treatment procedures are discussed, including band analysis and difference spectroscopy methods. A technique for the analysis of protein secondary and tertiary structures that combines band analysis by curve-fitting of original spectra with protein thermal denaturation is described in detail. The assignment of IR protein bands in H2O and in D2O, one of the more difficult points in protein IR spectroscopy, is also reviewed, including some cases of unclear assignments such as loops, beta-hairpins, or 3(10)-helices. The review includes monographic studies of some membrane proteins whose structure and function have been analysed in detail by IR spectroscopy. Special emphasis has been made on the role of subunit III in cytochrome c oxidase structure, and the proton pathways across this molecule, on the topology and functional cycle of sarcoplasmic reticulum Ca(2+)-ATPase, and on the role of lipids in determining the structure of the nicotinic acetylcholine receptor. In addition, shorter descriptions of retinal proteins and references to other membrane proteins that have been studied less extensively are also included.

[Neurophysiologic techniques in the diagnosis of erectile dysfunction: study of 105 cases]. / Técnicas neurofisiológicas en el diagnóstico de la disfunción eréctil: estudio de 105 casos.

OBJECTIVE: To present the results of the neurophysiological diagnostic evaluation in patients with erectile dysfunction. METHODS: 105 consecutive patients with complaints of erectile dysfunction were evaluated. The patients were divided into five groups according to their history: surgery/trauma, diabetes, vascular disease, toxicity, and no antecedents. Neurophysiological examination, laboratory tests, hormone and vascular studies were performed. Patient evaluation included neurophysiological studies on nerve conduction velocity (NCV), bulbocavernosus reflex (BCR), spinal and scalp somatosensory evoked potentials from the posterior tibial nerves (SEPt) and from the dorsal penile nerve (SEPp). In selected cases, electromyography and neuroimaging studies were done. RESULTS: 71 patients (67.62%) showed organic alterations; 57 of these patients had abnormal neurophysiological tests. Ranked in order of incidence, the tests were abnormal for NCV in 46/105 patients, SEPt 37/105, BCR 35/105 and SEPp in 30/105 patients. The incidence of BCR abnormalities was higher than that of the NCV only in the surgery/trauma group, probably due to a higher prevalence of local injuries, while NCV showed the highest incidence of abnormal results in the other groups of patients. Only 8 patients showed normal NCV with abnormal BCR, SEPp and/or SEPt (14.04% of patients had neurophysiological disturbances). CONCLUSION: In this study, most of our patients showed vascular, neurologic or both abnormalities, and were rarely associated with other factors. In our view, NCV is the technique of choice in the assessment of neurological disorders in patients with erectile dysfunction, whereas the other less sensitive tests are considered to be indicated basically in erectile dysfunction highly suspected as having an underlying neurogenic cause.

pH-dependent thermal transitions of lentil lectin.

The thermal stability of lentil lectin in the 5.0-10.0 pH range was studied by high-sensitivity differential scanning calorimetry and infrared spectroscopy. The thermally induced transitions for protein were irreversible and strongly dependent upon the scan rate at all pH values, suggesting that the denaturation is under kinetic control. It is shown that process of lentil lectin denaturation can be interpreted with sufficient accuracy in terms of the simple kinetic scheme, N-->D, where k is a first-order kinetic constant that changes with temperature, as given by the Arrhenius equation, N is the native state, and D is the denatured state. On the basis of this model, the parameters of the Arrhenius equation were calculated.

Thermal and pH-induced conformational changes of a beta-sheet protein monitored by infrared spectroscopy.

The stability of a lentil lectin, an all-beta protein, has been perturbed by changes in pH and temperature. In the pH interval 5.0 --> 10.0, the overall secondary structure does not undergo significant changes. However, if the individual components of the infrared amide I band are considered, changes in band components attributed to variations in beta-sheet and beta-turns cross-interactions are detected. The combined effects of pH and temperature reveal that the protein is more compact at pH 7.5 with lower denaturation temperatures at pH 5.0 or 10.0, indicating a less stable protein under those conditions. According to our results, the structural stability of the beta-sheet would depend not only on the intermolecular interactions among the strands but also on the conformation of the segments connecting these strands. The protein infrared band assignment has also been examined since the three-dimensional structure of the lentil lectin protein is known from X-ray diffraction studies. Two of the bands observed are attributed to beta-sheet. The one at 1620 cm-1, not affected if the medium is deuterated, is assigned to hairpins composed by two strands connected by a rigid turn whereas that located at 1633 cm-1 corresponds to strands associated by more flexible segments. The band appearing at 1645 cm-1 in H2O corresponds to the open, flexible loops that are connecting the beta-strands. The simplest assumption of the various secondary structure components having identical IR extinction coefficients is enough to provide IR-derived data that are in good agreement with the structure solved by X-ray diffraction.