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[Treating depression? All secrets exposed! The tricks of the trade!].

Depression is highly prevalent in the general population and is also costly to society. Although a wide range of pharmacological and psychological antidepressant therapies is available, the vast majority of people with depression remain unrecognised and untreated. Most depressed patients will respond to appropriate treatment, but the clinical management of depression involves far more than antidepressant drugs alone. Treatment failure, or refractory depression, can be overcome when therapeutic strategies adopt a logical, comprehensive and long-term approach. Understanding the interplay of clinical and neurochemical factors associated with the pathogenesis of depression can help physicians to find effective therapeutic alternatives for most of the depressed patients under their care.

Adrenocorticotropic Hormone↗

A mathematical model of rat distal convoluted tubule. II. Potassium secretion along the connecting segment.

A simulation of the rat distal convoluted tubule (DCT) is completed with a model of the late portion, or connecting tubule (CNT). This CNT model is developed by relying on a prior cortical collecting duct (CCD) model (Weinstein AM. Am J Physiol Renal Physiol 280: F1072-F1092, 2001), and scaling up transport activity of the three cell types to a level appropriate for DCT. The major difference between the two tubule segments is the lower CNT water permeability. In early CNT the luminal solution is hypotonic, with a K(+) concentration less than that of plasma, and it is predicted that osmotic equilibration requires the whole length of CNT, to end with a nearly isotonic fluid, whose K(+) concentration is severalfold greater than plasma. With respect to potassium secretion, early CNT conditions are conducive to maximal fluxes, whereas late conditions require the capacity to transport against a steep electrochemical gradient. The parameter dependence for K(+) secretion under each condition is different: maximal secretion depends on luminal membrane K(+) permeability, but the limiting luminal K(+) concentration does not. However, maximal secretion and the limiting gradient are both enhanced by greater Na(+) reabsorption. While higher CNT water permeability depresses K(+) secretion, it favors Na(+) reabsorption. Thus in antidiuresis there is a trade-off between enhanced Na(+)-dependent K(+) secretion and the attenuation of K(+) secretion by slow flow. When the CNT model is configured in series with the early DCT, thiazide diuretics promote renal K(+) wasting by shifting Na(+) reabsorption from early DCT to CNT; they promote alkalosis by shifting the remaining early DCT Na(+) reabsorption to Na(+)/H(+) exchange. This full DCT is suitable for simulating the defects of hyperkalemic hypertension, but the model offers no suggestion of a tight junction abnormality that might contribute to the phenotype.

Acid-Base Equilibrium↗

Effects of testosterone on song, aggression, and nestling feeding behavior in male great tits, Parus major.

As outlined in the trade-off hypothesis of testosterone (T) secretion, fluctuations in T during the breeding season might reflect how males allocate their time and energy to competitive behaviors for mates and territories, associated with high T levels, and parental activities, associated with low T levels. In the present study, great tit, Parus major, males were implanted with T-filled or empty silastic capsules at the start of the breeding season and the behavior of these two male categories was compared during the entire breeding season. As a measure of competitive behavior we looked at song behavior and territorial responsiveness to a male decoy, during the three main stages of the breeding period (the egg-laying, incubation, and nestling stages). As a measure of parental care we looked at feeding behavior during the nestling stage. Our results only partly supported the trade-off hypothesis. T implants increased plasma androgen levels and enhanced spontaneous song activity and the production of aggressive vocalizations in response to a decoy. However, our results suggest that the degree of physical aggression might be less than fully coupled with T. First, approach to the decoy was not affected by the treatment. Second, although T levels are known to vary from high during egg laying to low while feeding young, control and T-treated males spent similar amounts of time close to the decoy in the three breeding stages. Our results thus suggest that vocal and physical aggression might be regulated differently in the great tit. Furthermore, in contrast with most other studies on temperate bird species but in agreement with a previous study on the great tit, T treatment did not affect male feeding rates. As the dose of T we used was lower than that typically used in other studies, we cannot at present completely exclude the possibility that the latter result reflects this lower dose of T rather than the species used.

Aggression↗

The negative Ca(2+) balance is involved in the stimulation of PTH secretion.

The low calcium (Ca(2+)) dialysate have been developed to diminish the risk of hypercalcemia with the administration of active vitamin D and Ca(2+) carbonate as phosphate binder. Today, increasing numbers of hemodialysis (HD) patients have been on the low Ca(2+) dialysate (Ca(2+) = 2.5 mEq/l). However, the clinical consequences of a negative calcium net-balance which may be induced by the use of low Ca dialysate are not well evaluated. In the present study, we explored the effects of low Ca(2+) dialysate on the calcium balance and the PTH secretion. Eighty one chronic HD patients (male/female: 47/34; mean age: 60.2 +/- 1.5 years; mean HD periods: 11.1 +/- 0.8 years) who had been dialyzed with 3.0 mEq/l Ca(2+) dialysate were studied. All patients were transferred to the low Ca dialysate, which actually brought about a negative net-balance in Ca (mean: -94.5 mg) and an increase in serum intact PTH levels (mean: +23.7%: p = 0.03) during a single HD session. However, no changes in serum ionized Ca(2+) were found in spite of negative Ca(2+) balance. One month after change to the low Ca(2+) dialysate (total 12 sessions in each case), serum intact PTH levels increased significantly (186.7 +/- 19.5 vs. 216.2 +/- 21.9 pg/ml: p = 0.01) in spite of the fact that no changes were found in serum ionized Ca(2+), Pi and Mg. This result indicates that the negative Ca(2+) balance during low-Ca(2+) hemodialysis-stimulated PTH secretion, which offset the decrease of serum Ca(2+); a trade-off phenomenon between negative Ca balance and PTH. This suggests that low Ca(2+) dialysate may exaggerate the progression of secondary hyperparathyroidism.

Calcium↗

Production of recombinant proteins by hairy roots cultured in plastic sleeve bioreactors.

Plant-based expression of recombinant proteins offers significant advantages over transgenic animal-and cell-based systems. Unlike bacteria, plants perform the complex protein-processing steps required to produce eukaryotic proteins in active form. In order to facilitate protein production and purification we used hairy root cultures as a secretion-based in vitro plant system. We utilized the green fluorescent protein (GFP) as our model protein and expressed it for secretion in tobacco hairy root cultures. For large scale production of GFP, we adapted the Life-Reactor trade mark plastic sleeve bioreactor for growth of hairy roots in cultures containing up to 5 L of medium. Yields higher than 800 micro g of GFP per liter of culture were obtained after 21 d of incubation, representing almost 20% of the total secreted protein. The use of the plastic sleeve bioreactor system for expression of proteins in hairy roots allows for continuous or inducible production and recovery, while maintaining absolute containment, of the recombinant product.

Bioreactors↗

Regulation of parathyroid function in chronic kidney disease (CKD).

In chronic kidney disease (CKD), several abnormalities in bone and mineral metabolism develop in the majority of patients. The parathyroid plays a very important role in regulating bone and mineral metabolism; thus, control of parathyroid function is one of the main targets of the management of CKD-mineral and bone disorder (CKD-MBD). In the development of secondary hyperparathyroidism, it has recently been suggested that fibroblast growth factor 23 (FGF23) plays a crucial role, both as a phosphaturic factor and as a suppressor of active vitamin D (1,25D) production in the kidney. FGF23 is originally secreted to prevent hyperphosphatemia in CKD, but this occurs at the expense of low 1,25D and hyperparathyroidism ("trade-off" hypothesis revisited). Furthermore, recent data suggest that FGF23 could be another useful marker for the prognosis of hyperparathyroidism, because a high serum level may reflect the cumulative dose of vitamin D analogues previously administered. We have also demonstrated that severe hyperparathyroidism was associated with the production and secretion of a new form of parathyroid hormone (PTH) molecule, which can be detected by third-generation assays for PTH, but not by the second-generation assays. For the regression of already established nodular hyperplasia, the more advanced type of parathyroid hyperplasia, it is certainly necessary, in the near future, to develop new agents that specifically induce apoptosis in parathyroid cells. Until such agents are developed, prevention and early recognition of nodular hyperplasia is mandatory for the effective and safe management of hyperparathyroidism in CKD.

Animals↗

A neovascularized organoid derived from retrovirally engineered bone marrow stroma leads to prolonged in vivo systemic delivery of erythropoietin in nonmyeloablated, immunocompetent mice.

Marrow stromal cells (MSCs) are postnatal progenitor cells that can be easily cultured ex vivo to large amounts. This feature is attractive for cell therapy applications where genetically engineered MSCs could serve as an autologous cellular vehicle for the delivery of therapeutic proteins. The usefulness of MSCs in transgenic cell therapy will rely upon their potential to engraft in nonmyeloablated, immunocompetent recipients. Further, the ability to deliver MSCs subcutaneously - as opposed to intravenous or intraperitoneal infusions - would enhance safety by providing an easily accessible, and retrievable, artificial subcutaneous implant in a clinical setting. To test this hypothesis, MSCs were retrovirally engineered to secrete mouse erythropoietin (Epo) and their effect was ascertained in nonmyeloablated syngeneic mice. Epo-secreting MSCs when administered as 'free' cells by subcutaneous or intraperitoneal injection, at the same cell dose, led to a significant - yet temporary - hematocrit increase to over 70% for 55+/-13 days. In contrast, in mice implanted subcutaneously with Matrigel trade mark -embedded MSCs, the hematocrit persisted at levels >80% for over 110 days in four of six mice (P<0.05 logrank). Moreover, Epo-secreting MSCs mixed in Matrigel elicited and directly participated in blood vessel formation de novo reflecting their mesenchymal plasticity. MSCs embedded in human-compatible bovine collagen matrix also led to a hematocrit >70% for 75+/-8.9 days. In conclusion, matrix-embedded MSCs will spontaneously form a neovascularized organoid that supports the release of a soluble plasma protein directly into the bloodstream for a sustained pharmacological effect in nonmyeloablated recipients.

Animals↗

Clinical correlates of 24-h cortisol and norepinephrine excretion among subjects seeking treatment following the world trade center attacks on 9/11.

UNLABELLED: Whereas trauma-associated arousal has been linked fairly consistently with elevations in both glucocorticoids and catecholamines, neuroendocrine correlates of hyperarousal in the context of posttraumatic stress disorder (PTSD) have been more variable. Further, neuroendocrine predictors of the development of PTSD following trauma have been related to prior exposure, and data from several laboratories suggests that hyperarousal may develop in a neuroendocrine milieu of relatively diminished basal glucocorticoid secretion. METHODS: In this article we examined 24-h cortisol and norepinephrine excretion in 42 treatment-seeking survivors of the 9/11 World Trade Center (WTC) attacks, 32 of whom met criteria for PTSD, and 15 of whom met criteria for major depression, at the time of evaluation; 14 of the 15 subjects meeting criteria for major depression also suffered from PTSD. RESULTS: PTSD subjects' 24-h cortisol excretion (46.3 +/- 20.0 microL/dL) was lower than that of the non-PTSD cohort (72.2 +/- 22.4 microL/dL; t = 3.18, df = 37, P = 0.003), and 24-h urinary cortisol was negatively correlated with the experience of the WTC attacks as a Criterion-A event (r = -0.427, P = 0.007), and with self-rated avoidance (r = -0.466, P = 0.003) and total score (r = -0.398, P = 0.012) on the PTSD Symptom Scale (PSS). In contrast, 24-h norepinephrine excretion was not associated with the development of PTSD or with PTSD-related symptoms, but was negatively correlated with days since 9/11 at the time of evaluation (r = -0.393, P = 0.015). DISCUSSION: The latter finding suggests a relationship of norepinephrine to a dimension of stress-related arousal not captured by the symptom-rating scales chosen for this study to reflect symptoms related to PTSD and other neuropsychiatric disorders, but instead, of one to that of the sudden multidimensional life disruption suffered by the WTC survivors that applied for treatment. These data also confirm, in a naturalistic sample, the previously observed negative association of urinary cortisol excretion with development of PTSD in the aftermath of severe trauma exposure.

Adult↗

The malignant lymphomas in Africa.

Africa, the "dark continent" and the source of such wonderful tales as King Solomon's Mines and Jock of the Bushveld, has an equally enthralling story to tell about malignant disease in general and the lymphomas in particular as they occur among its varied people. It is uncertain how far back in history contact existed with the rest of the world, primarily in the form of slave trading and colonization by, among others, the Portuguese and the British. Until recent times, however, Africa's secrets have remained largely undisturbed. Fragments of medical information are recorded in the diaries of those early, intrepid explorers, such as Albert Cook, Henry Stanley, David Livingstone, and Albert Schweitzer. However, it is only in recent years that the great natural experiments that have for so long been underestimated, and very much less understood, belatedly started to attract attention. Examples are the systematic studies by Denis Burkitt, who through perseverance unraveled the lymphoma that now bears his name, and the thought-provoking description of the immunoproliferative small intestinal disease carried out by the Cape Town group, with both illustrating the axiom that "the study of man is man." Despite such occasional outstanding achievements, there is still considerable paucity of data pertaining to the various lymphoreticular malignancies, so that only limited conclusions are possible. Certainly, lymphoma in Africa differs from that elsewhere in the world. In part, this may reflect a background of immunologic disturbance attributable to parasitic infestation, viral infection, rampant malnutrition, and the impact of a wide variety of vectors, such as mosquitoes, in disease transmission. Striking differences exist in the distribution of these tumors as the incidence and pattern are followed from the equator to the milder climates in the south. This confirmed phenomenon gives rise to the tantalizing suggestion that, to some significant extent, the changes reflect the influence of geography. Thus, there may be associated alterations in the fauna and flora that determine the presence of intermediary hosts that have an impact on the eventual expression of the malignant clone. Many questions remain unanswered. For example, how can the lower incidence of Hodgkin's disease and the predominance of high-grade malignancies in the tropics and subtropics be explained? To what extent does the lymphocytic and plasmacytic hyperplasia, ascribed to intense antigenic stimulus in Burkitt's lymphoma and myeloma--perhaps even other lymphomas, such as IPSID--predispose the host to a mutational event that leads to the emergence of each distinctive neoplasm?(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗

Standardized immune monitoring for the prediction of infections after cardiopulmonary bypass surgery in risk patients.

BACKGROUND: Infections are the most common cause of late complications in cardiopulmonary bypass (CPB) surgery patients, and are difficult to predict. Here we studied the diagnostic value of a standardized immune monitoring program based on recent advances in flow cytometry (exact quantification of surface-marker expression) and cytokine determination (semiautomatic systems). METHODS: CPB patients (56) at risk for complications (age >70 years and/or preoperative left-ventricular ejection fraction < 25 %) were classified into three groups: without (33), with suspected (14), and with confirmed (9) infection. Applying the Quantibrite trade mark -system, we daily quantified the expression of CD11b, CD64, CD71, CD86, and HLA-DR on monocytes/granulocytes. Furthermore, the ex vivo secretion of tumor necrosis factor (TNF)-alpha as well as the plasma interleukin (IL)-10 levels were determined by a semiautomatic system. Ex vivo elastase release was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: All patients showed signs of granulocyte activation and monocyte deactivation. Monocytic HLA-DR and plasma IL-10 were the best markers to discriminate patients with infection from those without as early as day 1. Using a cutoff of 5792 HLA-DR molecules per cell, both sensitivity and negative predictive value for patients who developed microbiologically confirmed infection was 1.0, and the area under the curve (AUC) was 0.85. CONCLUSIONS: Our data suggest that a standardized immune monitoring at day 1 might be useful for early discrimination of patients at elevated risk for infections.

Adult↗

Female Iberian wall lizards prefer male scents that signal a better cell-mediated immune response.

In spite of the importance of chemoreception in sexual selection of lizards, only a few studies have examined the composition of chemical signals, and it is unknown whether and how chemicals provide honest information. Chemical signals might be honest if there were a trade-off between sexual advertisement and the immune system. Here, we show that proportions of cholesta-5,7-dien-3-ol in femoral secretions of male Iberian wall lizards (Podarcis hispanica) were related to their T-cell-mediated immune response. Thus, only males with a good immune system may allocate higher amounts of this chemical to signalling. Furthermore, females selected scents of males with higher proportions of cholesta-5,7-dien-3-ol and lower proportions of cholesterol. Thus, females might base their mate choice on the males' quality as indicated by the composition of their chemical signals.

Animals↗

Antagonism between pineal peptides and catecholamines. II. The action of a pineal peptide extract on the process of endogenous catecholamines secretion-excretion.

To determine the processes of adrenaline and noradrenaline secretion-excretion in rats and rabbits with/without associated insulin lente administration (20 U.I./kg rat b.w. and 6 U.I./kg rabbit b.w.), the authors used a pineal peptide extract that has now become available under the trade name of "Crinofizin". Under conditions of natural light, environmental temperature of 18-20 degrees C and fed ad libitum, Crinofizin did not cause significant alterations in the rat 24 hrs urinary excretion of catecholamines. Administration of insulin induced a more than two-fold increase in the two catecholamines both in the rabbit and the rat. Administration of Crinofizin one hour before insulin prevented totally or partially these effects of insulin. The drug acted as a blocking agent in the processes of endogenous adrenaline and noradrenaline secretion-excretion under hormonal stimulation, but not under basal conditions.

Adrenal Cortex Hormones↗

Mechanistic trade-offs between local and long-range signaling activity in natural and synthetic morphogens.

Hedgehog family morphogens present an interesting paradox: Despite being hydrophobic because of dual-lipid modifications, they form spatial concentration gradients that are highly conserved and essential for many aspects of metazoan development. Using live-cell single-molecule tracking and engineered synthetic signaling ligands, we isolated the distinct contribution of each lipid modification to Hedgehog diffusion and signaling potency. We found that although both lipid modifications enhance signaling potency, they do so through different mechanisms. Palmitate directly promotes receptor engagement, whereas cholesterol topologically confines secreted morphogens on the cell surface, effectively using the lipid membrane as a nonsignaling co-receptor that enriches ligands locally at the cost of restricting long-range diffusion. Our results on the function of cholesterol point to an intrinsic trade-off between signaling potency and gradient formation, with implications for the evolution and mechanism of nonsignaling co-receptors.

Signal Transduction↗

WINSTODEC: a stochastic deconvolution interactive program for physiological and pharmacokinetic systems.

Deconvolution allows the reconstruction of non-accessible inputs (e.g. hormone secretion rate) from their causally-related measurable effects (e.g. hormone plasma concentration). Deconvolution is challenging under several aspects both general (e.g. determination of a suitable trade-off between data fit and solution smoothness in order to contrast ill-conditioning, assessment of the confidence intervals) as well as specific of physiological systems (e.g. non-uniform and infrequent data sampling). Recently, a stochastic regularization approach has been proposed and validated to handle these difficulties (De Nicolao et al., Automatica 33 (1997) 851-870). In this paper, an interactive program, WINSTODEC, is presented to allow the clinical investigator to easily obtain the solution of a deconvolution problem by this approach.

Humans↗

Mistabron in the intensive care unit.

Mistabron is the trade-name of a new mucolytic agent, that has certain advantages over older mucolytic agents. This drug has been used to a great extent in patients with tracheobronchial secretions in the department of intensive care medicine. Its application makes expectoration easier while its preventive administration diminishes greatly the incidence of lung complications.

Humans↗

M1 muscarinic agonists can modulate some of the hallmarks in Alzheimer's disease: implications in future therapy.

M1 muscarinic receptors (M1 mAChRs) play a role in an apparent linkage of three major hallmarks of Alzheimer's disease (AD): beta-amyloid (Abeta) peptide; tau hyperphosphorylation and paired helical filaments (PHFs); and loss of cholinergic function conducive to cognitive impairments. We evaluated the M1 muscarinic agonists AF102B (Cevimeline, EVOXAC trade mark : prescribed for Sjøgren's syndrome), AF150(S), and AF267B on some of these hallmarks of AD. Activation of M1 mAChRs with these agonists leads, inter alia, to enhanced secretion of amyloid precursor protein (alpha-APP), (via alpha-secretase activation), to decreased Abeta (via gamma-secretase inhibition), and to inhibition of Abeta- and/or oxidative stress-induced cell death. In several animal models mimicking different aspects of AD, these drugs restored cognitive impairments, and in select cases induced a decrease in brain Abeta elevation, with a high safety margin, following po administration. Notably, in mice with small hippocampi, unlike rivastigmine and nicotine, AF150(S) and AF267B restored cognitive impairments also on escape latency in a Morris water maze paradigm, in reversal learning. Studies from other labs showed that AF102B and talsaclidine (another M1 agonist) decreased cerbrospinal fluid (CSF) Abeta in AD patients following chronic treatment, being the first reported drugs with such a profile. The clinical significance of these studies remains to be elucidated, yet based on in vivo (rabbits) and in vitro studies (cell cultures), our M1 agonists can decrease brain Abeta, owing to a novel and dual complementary effect (e.g., inhibition of gamma-secretase and activation of alpha-secretase). Remarkably, although M1 agonists can decrease CSF Abeta in AD patients, an increased AD-type pathology in Parkinson's disease was recently been associated with chronic antimuscarinic treatment. In another aspect, these agonists decreased tau hyperphosphorylation in vitro and in vivo. Notably, nicotinic agonists or cholinesterase inhibitors increased tau hyperphosphorylation. In summary, the M1 agonists tested are effective on cognition and behavior and show unique disease-modifying properties owing to beneficial effects on major hallmarks of AD. This may place such drugs in the first line of modern AD therapies (e.g., beta- or gamma-secretase inhibitors, vaccines against Abeta, statins, and inhibitors of tau hyperphosphorylation).

Alzheimer Disease↗