Emerging roles of calcium-activated K channels and TRPV4 channels in lung oedema and pulmonary circulatory collapse.

It has been suggested that the transient receptor potential cation (TRP) channel subfamily V (vanilloid) type 4 (TRPV4) and intermediate conductance calcium-activated potassium (KCa3.1) channels contribute to endothelium-dependent vasodilation. Here, we summarize very recent evidence for a synergistic interplay of TRPV4 and KCa3.1 channels in lung disease. Among the endothelial Ca2+ -permeable TRPs, TRPV4 is best characterized and produces arterial dilation by stimulating Ca2+ -dependent nitric oxide synthesis and endothelium-dependent hyperpolarization. Besides these roles, some TRP channels control endothelial/epithelial barrier functions and vascular integrity, while KCa3.1 channels provide the driving force required for Cl- and water transport in some cells and most secretory epithelia. The three conditions, increased pulmonary venous pressure caused by left heart disease, high inflation pressure and chemically induced lung injury, may lead to activation of TRPV4 channels followed by Ca2+ influx leading to activation of KCa3.1 channels in endothelial cells ultimately leading to acute lung injury. We find that a deficiency in KCa3.1 channels protects against TRPV4-induced pulmonary arterial relaxation, fluid extravasation, haemorrhage, pulmonary circulatory collapse and cardiac arrest in vivo. These data identify KCa3.1 channels as crucial molecular components in downstream TRPV4 signal transduction and as a potential target for the prevention of undesired fluid extravasation, vasodilatation and pulmonary circulatory collapse.

Endothelial Small- and Intermediate-Conductance K Channels and Endothelium-Dependent Hyperpolarization as Drug Targets in Cardiovascular Disease.

Endothelial calcium/calmodulin-gated K channels of small (KCa2.3) and intermediate conductance (KCa3.1) produce membrane hyperpolarization and endothelium-dependent hyperpolarization (EDH)-mediated vasodilation. Dysfunctions of the two channels and ensuing EDH impairments are found in several cardiovascular pathologies such as diabetes, atherosclerosis, postangioplastic neointima formation, but also inflammatory disease, cancer, and organ fibrosis. Moreover, KCa3.1 plays an important role in endothelial barrier dysfunction, edema formation in cardiac and pulmonary disease, and in ischemic stroke. Concerning KCa2.3, genome-wide association studies revealed an association of KCa2.3 channels with atrial fibrillation in humans. Accordingly, both channels are considered potential drug targets for cardio- and cerebrovascular disease states. In this chapter, we briefly review the function of the two channels in EDH-type vasodilation and systemic circulatory regulation and then highlight their pathophysiological roles in ischemic stroke as well as in pulmonary and brain edema. Finally, the authors summarize recent advances in the pharmacology of the channels and explore potential therapeutic utilities of novel channel modulators.

Diagnosis of Parietaria judaica pollen allergy using natural and recombinant Par j 1 and Par j 2 allergens.

BACKGROUND: Parietaria judaica pollen is one of the main causes of allergic diseases in the Mediterranean area and contains two major allergens, called Par j 1 and Par j 2. OBJECTIVE: To evaluate the diagnostic potential of natural and recombinant forms of Par j 1 and Par j 2 in comparison with standardized P. judaica pollen extract. METHODS: Thirty patients allergic to P. judaica pollen and 15 control patients were investigated. Skin prick tests and determination of specific IgE levels were performed with commercial P. judaica extract, natural Par j 1 and Par j 2, and recombinant forms of both allergens expressed in P. pastoris. RESULTS: The whole group of patients with allergy to P. judaica had a positive skin test reaction to purified nPar j 1-Par j 2 and rPar j 2 at 5 microg/mL, and no false-positive reactions were detected. Natural and recombinant Par j 1 and Par j 2 showed no significantly different responses in skin tests compared with P. judaica extract. A high correlation was found between the serum-specific IgE levels to P. judaica extract vs. natural (R=0.996; P<0.001) and recombinant allergens (R=0.887 and 0.982 for rPar j 1 and rPar j 2, respectively; P<0.001). rPar j 2 displayed a 100% sensitivity and specificity among P. judaica-allergic patients. CONCLUSIONS: In vivo and in vitro diagnosis of P. judaica pollen allergy could be simplified using rPar j 2. This protein showed comparable IgE response and skin prick reactivity with those produced by P. judaica pollen extract.

Relapse of depression during pregnancy following antidepressant discontinuation: a preliminary prospective study.

OBJECTIVE: Pregnancy has frequently been referred to as a time of emotional well-being for patients. However, systematic data about the risk for relapse of depression during pregnancy are sparse. METHOD: We completed a longitudinal cohort study of thirty-two (N = 32) women with histories of depression who were euthymic at conception and who either discontinued or attempted to discontinue antidepressant therapy proximate to conception. Subjects were prospectively followed across pregnancy once per trimester using structured clinical interviews. Rates of relapse and time to relapse were examined. Factors distinguishing the population with respect to risk for relapse including demographic characteristics and illness history were also examined. RESULTS: Seventy-five percent (N = 24) of patients relapsed during pregnancy. The majority of relapses (79%, N = 19) occurred in the first trimester, and relapse was more prevalent in women with histories of more chronic depression. CONCLUSIONS: Pregnancy is not "protective" with respect to risk for relapse of depression. Careful treatment planning is necessary for those women on antidepressants who plan to conceive or who become pregnant.

Estudio sobre la incidencia de la incapacidad permanente para el trabajo, según sectores y ramas de actividad / Study about the incidence of permanent inability for working, related to different sections and branches of the economical activity

Introducción: Se analizan las posibles relaciones entre salud, medio laboral y capacidad para el trabajo, así como la importancia del conocimiento y cuantificación de dichas relaciones. Objetivos: Conocer y cuantificar las variaciones en la presentación de situaciones de Incapacidad Permanente para el trabajo en diferentes ramas de actividad económica; conocer y cuantificar la incidencia de daño laboral permanente en las diferentes ramas de actividad económica. Material y métodos: Se realiza un estudio descriptivo y transversal, analizando distintos indicadores de incapacidad laboral, en función de las diferentes ramas de actividad económica. El estudio parte de los expedientes de Incapacidad Permanente evaluados durante los años 1999-2000 por parte del Equipo de Valoración de Incapacidades del Instituto Nacional de la Seguridad Social de Soria. Resultados: Se observan grandes diferencias en las tasas de incidencia de Incapacidad Permanente demandada, según la rama de actividad económica, especialmente en los indicadores directos de daño laboral. Las tasas de Incapacidad Permanente global más elevadas corresponden a la industria de productos alimenticios y a la construcción. Las tasas de Incapacidad Permanente por contingencias profesionales obtienen valores máximos en la industria de madera y mueble para el accidente de trabajo, y en la industria de productos alimenticios para la enfermedad profesional. Conclusiones: Aunque existen problemas metodológicos y administrativos es posible analizar y conocer la incidencia de la Incapacidad Permanente para el trabajo y de indicadores específicos de daño laboral permanente, en los distintos sectores y ramas de actividad económica (AU)

Venlafaxine in the treatment of postpartum depression.

BACKGROUND: Although postpartum depression is a highly prevalent illness, antidepressant treatment studies of postpartum depression are sparse. Incomplete recognition and treatment of puerperal illness place women at risk for chronic depression and may have adverse effects on child development. METHOD: An 8-week, flexible-dose, open study of venlafaxine (immediate release; mean dose = 162.5 mg/day) was performed in a group of 15 women who met DSM-III-R criteria for major depressive disorder with onset within the first 3 months postpartum. Patients were assessed at baseline and every 2 weeks across the study. Measurements of outcome included the 17-item Hamilton Rating Scale for Depression (HAM-D), the Kellner Symptom Questionnaire, and the Clinical Global Impressions scale (CGI). RESULTS: Despite baseline scores of depression that were particularly high, response to treatment was robust. Twelve of 15 patients experienced remission of major depression (HAM-D score < or = 7 or CGI score < or = 2). Dramatic decrease in anxiety paralleled the decrease in depression across the sample. CONCLUSION: Venlafaxine is effective in the treatment of postpartum major depression. Early identification of women who suffer from postpartum mood disturbance is critical to minimize the morbidity associated with untreated mood disturbance and the effect of depression on children and families.

Bergerac-SH3: "frustation" induced by stabilizing the folding nucleus.

The influence of an inserted exogenous independent folding element on the thermodynamics and folding properties of SH3 domain from alpha-spectrin has been investigated by creating a fused form between this small all-beta domain and a stable beta-hairpin (BH19). NMR analysis of synthetic peptides shows that insertion of BH19 nucleates formation of the original natural beta-hairpin (distal loop) that is part of the SH3 folding nucleus. The resulting protein (Bergerac-SHH) is more stable, folds faster and contains an elongated hairpin protruding from the globular domain as determined by 2D-NMR. "Protein engineering" analysis of the inserted region shows that it is folded in the transition state. Interestingly, stabilisation by insertion of the distal loop region results in the appearance of a compact intermediate revealed by a curved chevron plot at low denaturant concentration. This effect is eliminated at low salt concentrations by a single mutation of a hydrophobic residue within BH19 sequence, which is most probably involved in non-native interactions. Local stabilisation by enlargement and reinforcement of the folding nucleus, global compaction by the addition of salt and non-native interactions are shown to contribute to the observed deviation from the two-state behaviour.

Atomic resolution structure of a mutant of the spectrin SH3 domain.

The crystal structure of an alpha-spectrin Src-homology 3 (SH3) domain mutant has been refined at 1.12 A resolution. This X-ray structure is at the highest resolution achieved so far for an SH3 domain. The structure allows the identification of a complete set of specific interactions and is useful for the elucidation of relations between structure and pH-dependent thermodynamic stability in a series of SH3 domain mutants.

Response to lithium maintenance treatment in bipolar disorders: comparison of women and men.

OBJECTIVES: Possible sex differences in responses to mood-stabilizing treatment remain poorly defined. Since women with bipolar disorder reportedly have more features that may predict a poor prognosis (depression and rapid cycling), we tested the hypothesis that women respond less well to lithium maintenance treatment. METHODS: Clinical characteristics of 360 women and men with DSM-IV bipolar I or II disorder were compared before and during clinical lithium maintenance monotherapy in a mood disorders clinic by preliminary bivariate comparisons, multivariate analysis, and survival analysis of time stable during treatment. RESULTS: Women (n = 229) versus men (n = 131) were: more likely to have type II disorder (1.6 times), 3.2 years older at illness onset, more often depressed-before-manic (1.4 times), considered unipolar depressive 1.9 years longer and started maintenance treatment 5.5 years later. However, women differed little from men before treatment in overall morbidity, average episode frequency and risk of suicide attempts. Contrary to prediction, women showed non-significantly superior responses to lithium treatment, and a significant 60% longer median time before a first recurrence during treatment, despite 7% lower average serum lithium concentrations. CONCLUSIONS: Women were diagnosed as bipolar later than men with corresponding delay of lithium maintenance treatment that proved to be at least as effective as in men.

Sex differences in response to lithium treatment.

OBJECTIVE: Although sex differences occur with some psychotropic drug treatments, they are not well defined for mood-stabilizing agents, including lithium. The authors' goal was to investigate whether there are differences between the sexes in response to lithium. METHOD: Studies identified in a literature search were analyzed for reports of sex differences in clinical response to lithium in major affective syndromes. RESULTS: Data from 17 studies published in 1967-1998, involving 1,548 adults treated with lithium for a mean of 38.6 months (SD=30.5), yielded similar weighted response rates to lithium in 1,043 women (65.6% [N=684]) and 505 men (61.0% [N=308]). CONCLUSIONS: The results indicate little difference between the sexes in clinical response to lithium treatment of bipolar and related affective disorders.

Hemodynamic responses to ECT in a patient with critical aortic stenosis.

We present a case study of a 46-year-old woman with a psychotic depressive illness of 2 months' duration with the coexisting medical diagnoses of critical aortic stenosis, severe labile hypertension, renal failure necessitating hemodialysis of 7-years' duration, and systemic lupus. Because of unresponsiveness to an antidepressant drug regimen, severe motor retardation, mutism, and refusal of food and fluids by mouth, an urgent indication for electroconvulsive therapy (ECT) was established. However, the patient refused ECT, and to allow its initiation, a court order was obtained. In view of the coexisting diagnoses of critical aortic stenosis, labile hypertension, and renal failure, ECT represented a substantially increased risk in this patient because of severe arterial hypertension and tachycardia. The patient was successfully managed during each ECT, using a combination of metoprolol by mouth, which was supplemented by i.v. esmolol immediately prior to the application of the ECT stimulus, and sodium nitroprusside, which was infused for several minutes prior to the seizure and thereafter to attenuate arterial hypertension. Nevertheless, sudden death, a well-known complication of critical aortic stenosis, occurred 96 hours after the fourth ECT.

Risk of recurrence of bipolar disorder in pregnant and nonpregnant women after discontinuing lithium maintenance.

OBJECTIVE: Pregnancy poses major challenges for the treatment of bipolar disorder, and information to guide clinical care remains very sparse. The authors sought to determine the illness recurrence risk for women with bipolar disorder who discontinue lithium maintenance during pregnancy. METHOD: The authors retrospectively compared recurrence rates and survival functions for 101 women with DSM-IV bipolar disorder (68 type I, 33 type II) during pregnancy and postpartum (N=42) or during equivalent periods (weeks 1-40 and 41-64) for age-matched nonpregnant subjects (N=59) after either rapid (1-14 days) or gradual (15-30 days) discontinuation of lithium. Recurrence rates also were obtained for the year before discontinuing lithium. RESULTS: Rates of recurrence during the first 40 weeks after lithium discontinuation were similar for pregnant (52%) and nonpregnant women (58%) but had been much lower for both in the year before treatment was discontinued (21%). Among subjects who remained stable over the first 40 weeks after lithium discontinuation, postpartum recurrences were 2.9 times more frequent than recurrences in nonpregnant women during weeks 41-64 (70% versus 24%). Depressive or dysphoric-mixed episodes were more prevalent in pregnant than nonpregnant women (63% versus 38% of recurrences). Recurrence risk was greater after rapid than after gradual discontinuation, and for patients with more prior affective episodes, but was similar for diagnostic types I and II. CONCLUSIONS: Rates of recurrence during the first 40 weeks after lithium discontinuation were similar for pregnant and nonpregnant women but then sharply increased postpartum. Risk was much lower during preceding treatment and less with gradual discontinuation. Treatment planning for potentially pregnant women with bipolar disorder should consider the relative risks of fetal exposure to mood stabilizers versus the high recurrence risks after discontinuing lithium.

Comparison of the frequency of behavioral disinhibition on alprazolam, clonazepam, or no benzodiazepine in hospitalized psychiatric patients.

Several case reports have suggested that treatment with the benzodiazepine alprazolam can result in behavioral disinhibition. To address this question, the authors reviewed the medical records (blinded to all pharmacologic treatments the patients received) of 323 psychiatric inpatients treated with alprazolam (108 patients), clonazepam (111 patients), or no benzodiazepine (104 patients) between January 1989 and June 1990. During benzodiazepine treatment, there were no significant differences among the three groups on the following measures: (1) acts of self-injury (alprazolam, 1.9%; clonazepam, 1.8%; no benzodiazepine, 2.9%); (2) assaults on staff or other patients (alprazolam, 0%; clonazepam, 0.9%; no benzodiazepine, 1.0%); (3) need for seclusion or restraints (alprazolam, 3.7%; clonazepam, 6.3%; no benzodiazepine, 4.8%); (4) increased need for observation by hospital staff (alprazolam, 8.3%; clonazepam, 7.2%; no benzodiazepine, 6.7%); and (5) decrease in patient privileges (alprazolam, 11.1%; clonazepam, 12.6%; no benzodiazepine, 11.5%). The results indicate that in an inpatient psychiatric population, the frequency of behavioral disturbances with alprazolam, clonazepam, or no benzodiazepine does not differ. This suggests that alprazolam does not possess unique disinhibitory activity. Second, these data suggest that disinhibition may not be an important clinical problem associated with benzodiazepine use. The design of the study does not allow one to establish a relationship between the prescription of the benzodiazepine and worsening behaviors, and the findings need to be interpreted conservatively because it was a retrospective review of a heterogeneous population. However, it is noteworthy that the incidence of adverse events was low even in this high-risk population, and because the patients were in the hospital and under constant observation, the objective assessment of so-called paradoxical reactions was undertaken in a controlled setting.

Stable proline box motif at the N-terminal end of alpha-helices.

We describe a novel N-terminal alpha-helix local motif that involves three hydrophobic residues and a Pro residue (Pro-box motif). Database analysis shows that when Pro is the N-cap of an alpha-helix the distribution of amino acids in adjacent positions changes dramatically with respect to the average distribution in an alpha-helix, but not when Pro is at position N1. N-cap Pro residues are usually associated to Ile and Leu, at position N', Val at position N3 and a hydrophobic residue (h) at position N4. The side chain of the N-cap Pro packs against Val, while the hydrophobic residues at positions N' and N4 make favorable interactions. To analyze the role of this putative motif (sequence fingerprint hPXXhh), we have synthesized a series of peptides and analyzed them by circular dichroism (CD) and NMR. We find that this motif is formed in peptides, and that the accompanying hydrophobic interactions contribute up to 1.2 kcal/mol to helix stability. The fact that some of the residues in this fingerprint are not good N-cap and helix formers results in a small overall stabilization of the alpha-helix with respect to other peptides having Gly as the N-cap and Ala at N3 and N4. This suggests that the Pro-box motif will not specially contribute to protein stability but to the specificity of its fold. In fact, 80% of the sequences that contain the fingerprint sequence in the protein database are adopting the described structural motif, and in none of them is the helix extended to place Pro at the more favorable N1 position.

A thermodynamic analysis of a family of small globular proteins: SH3 domains.

The stability and folding thermodynamics of two SH3-domains, belonging to Fyn and Abl proteins, have been studied by scanning calorimetry and urea-induced unfolding. They undergo an essentially two-state unfolding with parameters similar to those of the previously studied alpha-spectrin SH3 domain. The correlations between the thermodynamic parameters (heat capacity increment, delta Cp,U, the proportionality factor, m, and the Gibbs energy, delta Gw298) of unfolding and some integral structural parameters, such as polar and non-polar areas exposed upon domain denaturation, have been analyzed. The experimental data on delta Cp,U and the m-factor of the linear extrapolation model (LEM) obey the simple empirical correlations deduced elsewhere. The Gibbs energies calculated from the DSC data were compared with those found by fitting urea-unfolding curves to the LEM and the denaturant-binding model (DBM). The delta Gw298 values found with DBM correlate better with the DSC data, while those obtained with LEM are systematically smaller. The systematic difference between the parameters calculated with LEM and DBM are explained by an inherent imperfection of the LEM.

Thermodynamic analysis of alpha-spectrin SH3 and two of its circular permutants with different loop lengths: discerning the reasons for rapid folding in proteins.

The temperature dependences of the unfolding-refolding reaction of a shorter version of the alpha-spectrin SH3 domain (PWT) used as a reference and of two circular permutants (with different poly-Gly loop lengths at the newly created fused loop) have been measured by differential scanning microcalorimetry and stopped-flow kinetics, to characterize the thermodynamic nature of the transition and native states. Differential scanning calorimetry results show that all these species do not belong to the same temperature dependency of heat effect. The family of the N47-D48s circular permutant (with 0-6 Gly inserted at the fused-loop) shows a higher enthalpy as happens with the PWT domain. The wild type (WT) and the S19-P20s permutant family have a more similar behavior although the second is far less stable. The crystallographic structure of the PWT shows a hairpin formation in the region corresponding to the unstructured N-terminus tail of the WT, explaining the enthalpic difference. There is a very good correlation between the calorimetric changes and the structural differences between the WT, PWT, and two circular permutants that suggests that their unfolded state cannot be too different. Elongation of the fused loop in the two permutants, taking as a reference the protein with one inserted Gly, results in a small Gibbs energy change of entropic origin as theoretically expected. Eyring plots of the unfolding and refolding semireactions show different behaviors for PWT, S19-P20s, and N47-D48s in agreement with previous studies indicating that they have different transition states. The SH3 transition state is relatively close to the native state with regard to changes in heat capacity and entropy, indicating a high degree of compactness and order. Regarding the differences in thermodynamic parameters, it seems that rapid folding could be achieved in proteins by decreasing the entropic barrier.

Discontinuing lithium maintenance treatment in bipolar disorders: risks and implications.

OBJECTIVE: To review research findings on clinical effects of discontinuing lithium maintenance treatment. METHODS: Data from studies reported since 1970 plus our recent findings were updated. RESULTS: Discontinuing lithium maintenance treatment led to marked increases of early affective morbidity and suicidal risk. Gradual discontinuation markedly reduced early recurrences of mania or depression, did so more in bipolar II than I disorder patients, and also tended to reduce suicidal risk. Similar effects were found in pregnant and nonpregnant women after lithium discontinuation. Long-term retreatment with lithium following discontinuation was only slightly less effective than in initial trials. CONCLUSIONS: Recurrences increased sharply soon after discontinuing lithium, but were markedly limited and not merely delayed, by slow discontinuation. Similar reactions may follow discontinuation of other drugs, evidently as responses to long-term pharmacodynamic adaptations. Discontinuing treatment is not equivalent to not-treating. Post-discontinuation relapse risk has implications for the design, management, and interpretation of protocols involving discontinuation of long-term treatments that should be considered in both clinical management and research.