[The effects of pharmacological treatment with stimulants on circadian activity patterns in children with attention deficit hyperactivity disorder]

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is one of the most common mental disorders in childhood. The nuclear symptoms of ADHD are treated with stimulant medication such as methylphenidate; however, there's a lot of controversy regarding its side effects.

AIMS

To analyse the activity patterns in children with ADHD during a period of 24 hours for seven days, before and after taking pharmacological treatment with stimulants (methylphenidate) and observe the differences between the different presentations of ADHD (inattentive and combined subtype).

PATIENTS AND METHODS

A total of 30 children and adolescents (newly diagnosed with ADHD according to DSM-IV). Analyses were carried out through actigraphy, an instrument that allows us to monitor body movements by analysing movement patterns and differences between sleep and wakefulness.

RESULTS

There were significant differences before and after treatment showing higher activity levels in patients with ADHD before treatment, and a decrease in this situation after taking pharmacological treatment. There are also differences between inattentive and combined subtype, showing the last group, higher activity levels.

CONCLUSIONS

The level of activation presented by ADHD subjects is higher before taking stimulant treatment, influencing circadian patterns, sleep and quality of life. Pharmacological treatments help to decrease the level of activation.

Sleep disordered breathing and nocturnal hypoxemia are very prevalent in a lung cancer screening population and may condition lung cancer screening findings: results of the prospective Sleep Apnea In Lung Cancer Screening (SAILS) study

OBJECTIVE

Obstructive sleep apnea (OSA) can influence the appearance and proliferation of some tumors. The Sleep Apnea In Lung Cancer Screening (SAILS) study (NCT02764866) evaluated the prevalence of OSA and nocturnal hypoxemia in a high-risk population enrolled in a lung cancer screening program.

METHODS

This was a prospective study of the prevalence of OSA in a lung cancer screening program. Subjects met the National Lung Screening Trial (NLST) age and smoking criteria (age 55-75 years; pack-years >30). Participants in the study were offered annual screening with low-dose computed tomography (LDCT) and pulmonary function testing, as well as home sleep apnea testing (HSAT) and a sleep-specific questionnaire. Sleep study-related variables, symptoms, and epidemiologic data were recorded.

RESULTS

HSAT was offered to 279 subjects enrolled in our lung cancer screening program. HSAT results were available for 236 participants (mean age 63.6 years; mean tobacco exposure: 45 pack-years), of whom 59% were male and 53% were active smokers. Emphysema (74%) and chronic obstructive pulmonary disease (COPD) (62%) were common and in most cases mild in severity. OSA, including moderate to severe disease, was very common in this patient population. AHI distributions were as follows: AHI <5 (22.5%); 5-15 (36.4%); 15-30 (23.3%); and >30 (17.8%). Nocturnal hypoxemia (T90) (p = 0.003), diffusing capacity for carbon monoxide (DLCO) (p = 0.01), tobacco exposure (p = 0.024), and COPD (p = 0.023) were associated with OSA severity. Positive screening findings (nodules ≥6 mm) were associated with nocturnal hypoxemia on multivariate analysis adjusted for confounders (OR = 2.6, 95% CI = 1.12-6.09, p = 0.027).

CONCLUSION

Moderate to severe OSA is very prevalent in patients enrolled in a lung cancer screening program. Nocturnal hypoxemia more than doubles the risk of positive screening findings.

Membrane Lipid Microenvironment Modulates Thermodynamic Properties of the Na+-K+-ATPase in Branchial and Intestinal Epithelia in Euryhaline Fish In vivo

We have analyzed the effects of different native membrane lipid composition on the thermodynamic properties of the Na⁺-K⁺-ATPase in different epithelia from the gilthead seabream Sparus aurata. Thermodynamic parameters of activation for the Na⁺-K⁺-ATPase, as well as contents of lipid classes and fatty acids from polar lipids were determined for gill epithelia and enterocytes isolated from pyloric caeca, anterior intestine and posterior intestine. Arrhenius analyses of control animals revealed differences in thermal discontinuity values (Td) and activation energies determined at both sides of Td between intestinal and gill epithelia. Eyring plots disclosed important differences in enthalpy of activation (ΔH^‡) and entropy of activation (ΔS^‡) between enterocytes and branchial cells. Induction of n-3 LCPUFA deficiency dramatically altered membrane lipid composition in enterocytes, being the most dramatic changes the increase in 18:1n-9 (oleic acid) and the reduction of n-3 LCPUFA (mainly DHA, docosahexaenoic acid). Strikingly, branchial cells were much more resistant to diet-induced lipid alterations than enterocytes, indicating the existence of potent lipostatic mechanisms preserving membrane lipid matrix in gill epithelia. Paralleling lipid alterations, values of Ea₁, ΔH^‡ and ΔS^‡ for the Na⁺-K⁺-ATPase were all increased, while Td values vanished, in LCPUFA deficient enterocytes. In turn, Differences in thermodynamic parameters were highly correlated with specific changes in fatty acids, but not with individual lipid classes including cholesterol in vivo. Thus, Td was positively related to 18:1n-9 and negatively to DHA. Td, Ea₁ and ΔH^‡ were exponentially related to DHA/18:1n-9 ratio. The exponential nature of these relationships highlights the strong impact of subtle changes in the contents of oleic acid and DHA in setting the thermodynamic properties of epithelial Na⁺-K⁺-ATPase in vivo. The effects are consistent with physical effects on the lipid membrane surrounding the enzyme as well as with direct interactions with the Na⁺-K⁺-ATPase.

Hippocampal Lipid Homeostasis in APP/PS1 Mice is Modulated by a Complex Interplay Between Dietary DHA and Estrogens: Relevance for Alzheimer's Disease

Current evidence suggests that lipid homeostasis in the hippocampus is affected by different genetic, dietary, and hormonal factors, and that its deregulation may be associated with the onset and progression of Alzheimer's disease (AD). However, the precise levels of influence of each of these factors and their potential interactions remain largely unknown, particularly during neurodegenerative processes. In the present study, we have performed multifactorial analyses of the combined effects of diets containing different doses of docosahexaenoic acid (DHA), estrogen status (ovariectomized animals receiving vehicle or 17β-estradiol), and genotype (wild-type or transgenic APP/PS1 mice) in hippocampal lipid profiles. We have observed that the three factors affect lipid classes and fatty acid composition to different extents, and that strong interactions between these factors exist. The most aberrant lipid profiles were observed in APP/PS1 animals receiving DHA-poor diets and deprived of estrogens. Conversely, wild-type animals under a high-DHA diet and receiving estradiol exhibited a lipid profile that closely resembled that of the hippocampus of control animals. Interestingly, though the lipid signatures of APP/PS1 hippocampi markedly differed from wild-type, administration of a high-DHA diet in the presence of estrogens gave rise to a lipid profile that approached that of control animals. Paralleling changes in lipid composition, patterns of gene expression of enzymes involved in lipid biosynthesis were also altered and affected by combination of experimental factors. Overall, these results indicate that hippocampal lipid homeostasis is strongly affected by hormonal and dietary conditions, and that manipulation of these factors might be incorporated in AD therapeutics.

Conceptual basis for an integrated system for the management of a protected area. Examples from its application in a mediterranean area

Improving the efficiency of management in protected areas is imperative in a generalized context of limited conservation budgets. However, this is overlooked due to flaws in problem definition, general disregard for cost information, and a lack of suitable tools for measuring costs and management quality. This study describes an innovative methodological framework, implemented in the web application SIGEIN, focused on maximizing the quality of management against its costs, establishing an explicit justification for any decision. The tool integrates, with this aim, a procedure for prioritizing management objects according to a conservation value, modified by a functional criterion; a project management module; and a module for management of continuous assessment. This appraisal associates the relevance of the conservation targets, the efficacy of the methods employed, both resource and personnel investments, and the resulting costs. Preliminary results of a prototypical SIGEIN application on the Site of Community Importance Chafarinas Islands are included.

Biophysical alterations in lipid rafts from human cerebral cortex associate with increased BACE1/AβPP interaction in early stages of Alzheimer's disease

In the present study, we have assessed the biophysical properties of lipid rafts from different brain areas in subjects exhibiting early neuropathological stages of Alzheimer's disease (AD). By means of steady-state fluorescence polarization analyses using two environment-sensitive fluorescent probes, we demonstrate that lipid rafts from cerebellum, and frontal and entorhinal cortices, exhibit different biophysical behaviors depending on the stage of the disease. Thus, while membrane anisotropies were similar in the cerebellum along stages, lipid rafts from frontal and entorhinal cortices at AD stages I/II and AD III were significantly more liquid-ordered than in control subjects, both at the aqueous interface and hydrophobic core of the raft membrane. Thermotropic analyses demonstrated the presence of Arrhenius breakpoints between 28.3-32.0 °C, which were not influenced by the disease stage. However, analyses of membrane microviscosity (ηapp) demonstrate that frontal and entorhinal lipid rafts are notably more viscous and liquid-ordered all across the membrane from early stages of the disease. These physicochemical alterations in lipid rafts do not correlate with changes in cholesterol or sphingomyelin levels, but to reduced unsaturation index and increased saturate/polyunsaturated ratios in phospholipid acyl chains. Moreover, we demonstrate that β-secretase/AβPP (amyloid-β protein precursor) interaction and lipid raft microviscosity are strongly, and positively, correlated in AD frontal and entorhinal cortices. These observations strengthens the hypothesis that physical properties of these microdomains modulate the convergence of amyloidogenic machinery toward lipid rafts, and also points to a critical role of polyunsaturated fatty acids in amyloidogenic processing of AβPP.

Quantifying long-range correlations and 1/f patterns in a minimal experiment of social interaction

In recent years, researchers in social cognition have found the “perceptual crossing paradigm” to be both a theoretical and practical advance toward meeting particular challenges. This paradigm has been used to analyze the type of interactive processes that emerge in minimal interactions and it has allowed progress toward understanding of the principles of social cognition processes. In this paper, we analyze whether some critical aspects of these interactions could not have been observed by previous studies. We consider alternative indicators that could complete, or even lead us to rethink, the current interpretation of the results obtained from both experimental and simulated modeling in the fields of social interactions and minimal perceptual crossing. In particular, we discuss the possibility that previous experiments have been analytically constrained to a short-term dynamic type of player response. Additionally, we propose the possibility of considering these experiments from a more suitable framework based on the use and analysis of long-range correlations and fractal dynamics. We will also reveal evidence supporting the idea that social interactions are deployed along many scales of activity. Specifically, we propose that the fractal structure of the interactions could be a more adequate framework to understand the type of social interaction patterns generated in a social engagement.

Polyamines transduce the nongenomic, androgen-induced calcium sensitization in intestinal smooth muscle

Androgens regulate body development and differentiation through a variety of genotropic mechanisms, mostly in reproductive organs. In recent years a different scenario for sex hormone actions has emerged: the intestinal muscle. Thus, although estrogens relax intestinal muscle, androgens are powerful inducers of mechanical potentiation. This effect of androgens was intriguing because it is observed at physiological concentrations, is mediated by nongenomic mechanisms, and involves a phenomenon of calcium sensitization of contractile machinery by stimulating phosphorylation of 20 kDa myosin light chain by Rho-associated kinase. Here we have deciphered the molecular mechanisms underlying calcium sensitization and mechanical potentiation by androgens in male intestinal muscle as well as its tight relationship to polyamine metabolism. Thus, androgens stimulate polyamine synthesis, and the inhibition of polyamine synthesis abolishes androgen-induced calcium sensitization and 20 kDa myosin light chain phosphorylation. We demonstrate that the first molecular step in the induction of calcium sensitization is a nonconventional activation of the adaptor protein RhoA, triggered by a transglutaminase-catalyzed polyamination of RhoA, which is then targeted to the membrane to activate Rho-associated kinase. Altogether, these results demonstrate that the physiological levels of androgens, through the modulation of polyamine metabolism and posttanslational modification of RhoA, activate a new signal transduction pathway in the intestinal smooth muscle to induce calcium sensitization. Furthermore, apart from being one of the few physiologically relevant nongenomic effects of androgens, these results might underlie the well-known gender differences in intestinal transits, thus expanding the nature's inventory of sex hormones effects.

Unique SERM-like properties of the novel fluorescent tamoxifen derivative FLTX1

Tamoxifen is a selective estrogen receptor modulator extensively used on estrogen receptor-positive breast cancer treatment. However, clinical evidences demonstrate the increased incidence of undesirable side effects during chronic therapies, the most life threatening being uterine cancers. Some of these effects are related to tissue-dependent estrogenic actions of tamoxifen, but the exact mechanisms remain poorly understood. We have designed and synthesized a novel fluorescent tamoxifen derivative, FLTX1, and characterized its biological and pharmacological activities. Using confocal microscopy, we demonstrate that FLTX1 colocalizes with estrogen receptor α (ERα). Competition studies showed that FLTX1 binding was totally displaced by unlabeled tamoxifen and partially by estradiol, indicating the existence of non-ER-related triphenylethylene-binding sites. Ligand binding assays showed that FLTX1 exhibits similar affinity for ER than tamoxifen. FLTX1 exhibited antiestrogenic activity comparable to tamoxifen in MCF7 and T47D cells transfected with 3xERE-luciferase reporter. Interestingly, FLTX1 lacked the strong agonistic effect of tamoxifen on ERα-dependent transcriptional activity. Additionally, in vivo assays in mice revealed that unlike tamoxifen, FLTX1 was devoid of estrogenic uterotrophic effects, lacked of hyperplasic and hypertrophic effects, and failed to alter basal proliferating cell nuclear antigen immunoreactivity. In the rat uterine model of estrogenicity/antiestrogenicity, FLTX1 displayed antagonistic activity comparable to tamoxifen at lower doses, and only estrogenic uterotrophy at the highest dose. We conclude that the fluorescent derivative FLTX1 is not only a suitable probe for studies on the molecular pharmacology of tamoxifen, but also a potential therapeutic substitute to tamoxifen, endowed with potent antiestrogenic properties but devoid of uterine estrogenicity.

Androgens are powerful non-genomic inducers of calcium sensitization in visceral smooth muscle

Androgens are recognized as genotropic inducers of a number of physiological functions mainly associated with the development of sexual characteristics. However, as in the case of estrogens, the number of studies evidencing androgen actions in non-reproductive tissues has steadily grown over the past years. Here, we show that androgens acutely ( approximately 30min) alter the frequency spectrum of peristaltic activity of intestinal smooth muscle and augment the amplitude agonist-induced contractile activity. Maximal stimulation occurred at physiological concentrations of androgens with EC(50) values in the picomolar range. Androgen-induced potentiation was prevented by preincubation with androgen receptor (AR) antagonists but unaffected by cycloheximide plus actinomycin D, indicating that potentiation was mediated by ARs via a non-genomic mechanism. The effects of androgens were mimicked by polyamines and were completely blocked by inhibitors of polyamine synthesis. Using ionomycin-permeabilized intestinal smooth muscle preparations, we demonstrate that androgens exert their effects by inducing a mechanism of sensitization to calcium and not by altering intracellular calcium homeostasis. Correspondingly, the potentiation of mechanical activity induced by androgens was accompanied by an increase in the phosphorylation of the regulatory myosin light chain (LC(20)) within the same time-course than calcium sensitization and mechanical potentiation. The pursuit of potential signalling pathways linking androgen receptor activation with calcium sensitization revealed that mechanical potentiation of intestinal muscle by androgens involve activation of the Rho pathway, whose downstream effector, Rho-associated kinase (ROCK), is eventually responsible for displacement of the phosphorylation/dephosphorylation state of LC(20) towards its phosphorylated form.

Androgens induce nongenomic stimulation of colonic contractile activity through induction of calcium sensitization and phosphorylation of LC20 and CPI-17

We show that androgens, testosterone and 5alpha-dihydrotestosterone (DHT), acutely (approximately 40 min) provoke the mechanical potentiation of spontaneous and agonist-induced contractile activity in mouse colonic longitudinal smooth muscle. The results using flutamide, finasteride, cycloheximide, and actinomycin D indicate that androgen-induced potentiation is dependent on androgen receptors, requires reduction of testosterone to DHT, and occurs independently of transcriptional and translational events. Using permeabilized colonic smooth muscle preparations, we could demonstrate that mechanical potentiation is entirely due to calcium sensitization of contractile machinery. In addition, DHT (10 nm) increased phosphorylation of both 20-kDa myosin light chain (LC(20)) [regulatory myosin light chain, (MLC)] and CPI-17 (an endogenous inhibitor of MLC phosphatase). Paralleling these findings, inhibition of Rho-associated Rho kinase (ROK) and/or protein kinase C (PKC) with, respectively, Y27632 and chelerythrine, prevented LC(20) phosphorylation and abolished calcium sensitization. In addition, inhibition of ROK prevents CPI-17 phosphorylation, indicating that ROK is located upstream PKC-mediated CPI-17 modulation in the signalling cascade. Additionally, androgens induce a rapid activation of RhoA and its translocation to the plasma membrane to activate ROK. The results demonstrate that androgens induce sensitization of colonic smooth muscle to calcium through activation of ROK, which in turn, activates PKC to induce CPI-17 phosphorylation. Activation of this pathway induces a potent steady stimulation of LC(20) by inhibiting MLC phosphatase and displacing the equilibrium of the regulatory subunit towards its phosphorylated state. This is the first demonstration that colonic smooth muscle is a physiological target for androgen hormones, and that androgens modulate force generation of smooth muscle contractile machinery through nongenomic calcium sensitization pathways.

Androgens differentially potentiate mouse intestinal smooth muscle by nongenomic activation of polyamine synthesis and Rho kinase activation

We demonstrate that testosterone and its active metabolite 5alpha-dihydrotestosterone acutely (approximately 30 min) potentiate mouse ileal, but not duodenal, muscle activity. Androgens augment the amplitude of spontaneous peak-to-peak oscillations, alter the spontaneous activity frequency spectrum, and increase the amplitude of calcium-induced and carbachol-induced contractions. Concentration-dependence analyses revealed that maximal potentiation (449-910%) occurred at physiological concentrations of androgens (100 pM to 10 nM) with EC50 values in the picomolar range (8-20 pM). Western blot analyses using an antiandrogen receptor (anti-AR) antibody revealed the presence of two different AR proteins migrating at 87 and 110 kDa in ileal, but not duodenal, extracts. Androgen-induced potentiation was prevented by preincubation with AR antagonists flutamide or cyproterone acetate but was unaffected by pretreatment with cycloheximide plus actinomycin D, indicating that potentiation was mediated by ARs via a novel nongenomic mechanism. Androgen effects were mimicked by polyamines putrescine and spermine and were blocked by the ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase inhibitors alpha-difluoromethylornithine and berenil, respectively. Accordingly, androgens increase alpha-difluoromethylornithine-sensitive ornithine-decarboxylase- mediated L-ornithine decarboxylation in ileal tissues within the same time course as isometric potentiation. Both putrescine and dihydrotestosterone induced Ca2+ sensitization of ionomycin-permeabilized ileal smooth muscle. Finally, inhibition of the Rho kinase (ROK) pathway with the specific inhibitor Y27632 completely prevented androgen-induced potentiation. In agreement, androgens elicited ROK-induced Ser19 phosphorylation of myosin light chain 2 in ileal muscle. These data indicate that androgens potentiate ileal contractile activity by an AR-dependent nongenomic mechanism involving intracellular polyamine signaling and Ca2+ sensitization via ROK activation.

Functional inhibition of intestinal and uterine muscles by non-permeant triphenylethylene derivatives

We have previously shown that the triphenylethylene antiestrogen tamoxifen reversibly inhibited spontaneous contractile activity in isolated duodenal muscle. Now, we have synthesized different quaternary ammonium salts of tamoxifen by changing the substituents on the nitrogen of the alkylaminoethoxy side-chain, to obtain plasma membrane impermeable compounds. Synthesized molecules were N-desmethyl-tamoxifen-hydrochloride, ethylbromide-tamoxifen and butylbromide-tamoxifen, which differed in the size of their ionic side-chain. All compounds rapidly and reversibly inhibited spontaneous and CaCl(2)-induced contractions in mouse duodenum and uterus. Dose-response analyses revealed a structure-activity relationship where the larger the side-chain the higher the inhibitory potency. Fourier analyses on triphenylethylene-relaxed duodenal tissues showed that harmonic components of contractile activity were readily recovered upon exposure to the L-type calcium channel agonist 1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-pyridine-3-carboxilic acid methyl ester (BAY-K644). Likewise, BAY-K644 completely reversed triphenylethylene-induced effects on uterine tonic tension. Our experiments suggest that impermeant tamoxifen derivatives relax visceral smooth muscle through a membrane-mediated non-genomic mechanism that involves inhibition of L-type calcium channels.

Acute relaxation of mouse duodenum [correction of duodenun] by estrogens. Evidence for an estrogen receptor-independent modulation of muscle excitability

17-beta-Estradiol, the stereoisomer 17-alpha-estradiol and the synthetic estrogen diethylstilbestrol (DES), all caused a rapid (<3 min) dose-dependent reversible relaxation of mouse duodenal spontaneous activity, reduced basal tone and depressed the responses to CaCl(2) and KCl. The steroidal antiestrogen 7alpha-[9-[(4,4,5,5,5,-pentafluoropenty)sulphinyl]nonyl]-estra-1,3,5(19)-triene-3,17beta-diol (ICI182,780) failed to either mimic or prevent the effect of 17-beta-estradiol. The effect of estrogens was unrelated to activation of nitric oxide (NO), mitogen-activated protein kinase (MAPK), protein kinase A (PKA), protein kinase G (PKG) or protein kinase C (PKC). Estrogen-induced relaxation was partially reversed by 1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-pyridine-3-carboxilic acid methyl ester (BAY-K8644), depolarization, or by application of tetraethylammonium or 4-aminopyridine, but not by glibenclamide, apamin, charybdotoxin, paxilline or verruculogen. The effects of BAY-K8644 and K(+) channel blockers were synergistic, and allowed relaxed tissues to recover spontaneous activity and basal tone. We hypothesize that the rapid non-genomic spasmolytic effect of estrogens on mouse duodenal muscle might be triggered by an estrogen-receptor-independent mechanism likely involving activation of tetraethylamonium- and 4-aminopyridine-sensitive K(+) channels and inhibition of L-type Ca2(+) channels on the smooth muscle cells.

Isolation and characterization of enterocytes along the intestinal tract of the gilthead seabream (Sparus aurata L.)

Epithelial cells were successfully isolated along the intestine of the gilthead seabream using a dissociation method based on intracellular-like solutions. Biochemical and physiological tests revealed highly viable cells from all intestinal segments. Image analysis was used to identify cell types in the epithelial preparations which were highly enriched in enterocytes (>95%) over mucous cells. Several digestive hydrolases were determined in the isolated cells. Maltase (M), sucrase (S), leucine aminopeptidase (LA), 5'nucleotidase (5'N), but not gamma-glutamyl transferase (gamma-GT) or alkaline phosphatase (AP) activities were found to be enriched in the epithelial preparations versus the corresponding intestinal homogenates. Comparison of digestive hydrolases revealed the existence of a clear heterogeneity in their expression pattern in the enterocytes, along the intestine. Na(+)-K(+)-ATPase, Na(+)-ATPase and Cl(-)-ATPase activities were also determined in the membrane fraction of isolated cells. Analyses of enzymatic profiles revealed a clear asymmetry in the distribution of all Mg(2+)-dependent ATPases; that is, maximal Na(+)-K(+)- and Na(+)-ATPase activities were observed in the enterocytes from pyloric caeca, while Cl(-)-ATPase activity was about twice as high in the enterocytes from anterior and posterior intestines compared with pyloric caeca. This is the first report demonstrating the existence of heterogeneous metabolic and enzymatic profiles in different enterocyte populations from euryhaline teleosts.

Regulation of L-alanine transport systems A and ASC by cyclic AMP and calcium in a reptilian duodenal model

The regulation of neutral amino acid transport by cyclic AMP (cAMP) and calcium across the isolated duodenum of the lizard Gallotia galloti has been studied under short-circuit conditions. Active L-alanine transport was stimulated by forskolin, theophylline and dibutyryl cyclic AMP (db-cAMP). All these agents increased transmural potential difference (PD) and short-circuit current (I(sc)) in a manner consistent with the activation of a chloride secretory pathway. Both forskolin and theophylline increased intracellular cAMP levels in the lizard duodenal mucosa. Addition of calcium ionophore A23187 rapidly reduced mucosa-to-serosa L-alanine fluxes and diminished net L-alanine transport. Despite the reduction of alanine fluxes by A23187, transepithelial PD and I(sc) values were increased by the ionophore. Analyses of the responses of isolated transport pathways indicated that the Na(+)-independent L-alanine transport system was unaffected by db-cAMP or calcium ionophore. By contrast, Na(+)-dependent transport activities were profoundly modified by these agents. Thus, while system A [alpha-methylamino-isobutiric acid (MeAIB)-transporting pathway] was stimulated by increased calcium, system ASC activity was nearly abolished. Calcium ionophore also potentiated the electrogenic response of system A. Forskolin strongly stimulated system ASC activity but left system A activity unchanged. Activation of system ASC by forskolin was clearly electroneutral, as pre-incubation of the tissues with the chloride channel blocker diphenylamine-2-carboxilic acid (DPC) completely prevented forskolin-induced transepithelial electrical responses. It is concluded that intracellular messengers cAMP and calcium oppositely modulate active Na(+)-dependent (L)-alanine transport in the lizard intestine. The different sensitivity exhibited by individual transport pathways may well account for the changes observed in overall alanine transport.

Purification and characterization of two hemolysins from Stichodactyla helianthus

Two hemolysins, Sticholysin I (St I) and Sticholysin II (St II) were purified from the sea anemone Stichodactyla helianthus combining gel filtration and ion exchange chromatography. The amino acid composition of both cytolysins was determined revealing a high proportion of glycine, lysine, tyrosine and non-polar amino acids (alanine, leucine and valine). Cysteine was not found in either polypeptide. Molecular masses of St I and St II were 19401 and 19290 Da, respectively. N-terminal sequence analysis of St I and St II showed a high homology between them suggesting they are isoforms of the same cytolysin. Compared with other sea anemone cytolysins, St I and St II contain a 22 amino acid insertion fragment also present in Eq T II/Tn C and probably in CaT I and Hm T and absent in C III, the major hemolysin previously reported in this anemone.

Membrane mechanisms for electrogenic Na(+)-independent L-alanine transport in the lizard duodenal mucosa

The active Na(+)-independent transport of L-alanine across the duodenal mucosa of the lizard Gallotia galloti was studied in Ussing-type chambers using a computer-controlled voltage clamp. Addition of L-alanine to the Na(+)-free bathing solutions resulted in a significant L-alanine absorption (J(net)) that was paralleled by an increase in transepithelial short-circuit current (I(sc)) and potential difference (PD) without apparent changes in the tissue conductance. The concentration dependence of J(net), PD, and I(sc) displayed Michaelis-Menten kinetics. L-alanine-induced electrical changes were completely inhibited by external alkaline pH or by the H(+)-ionophore carbonyl cyanide m-chlorophenyl-hydrazone in the bathing solution. The alanine-induced electrogenicity was dependent on the presence of extracellular K(+) and could be blocked by serosal Ba(2+) or mucosal orthovanadate. These results suggest the existence of an H(+)-coupled L-alanine cotransport at the apical membrane of enterocytes. The favorable H(+) driving force is likely to be maintained by an apical vanadate-sensitive H(+)-K(+)-ATPase, allowing the extrusion of H(+) in an exchange with K(+). Potassium exit through a basolateral barium-sensitive conductance provides the key step for the electrogenicity of L-alanine absorption.

Relevance of presenting white blood cell count and kinetics of molecular remission in the prognosis of acute myeloid leukemia with CBFbeta/MYH11 rearrangement

BACKGROUND AND OBJECTIVES

The detection of CBFbeta/MYH11 transcripts by RT-PCR has became a valuable and widely used technique in the accurate cytogenetic and molecular classification of acute myeloid leukemia (AML), but the clinical value of RT-PCR for monitoring minimal residual disease (MRD) during follow-up remains unclear.

DESIGN AND METHODS

We analyzed the factors predicting relapse and the value of MRD monitoring by RT-PCR in a series of 16 patients with CBFb/MYH11-positive AML (15 M4Eo; 1 M4). Fifteen were newly diagnosed cases (CR1) and one was studied after first relapse (CR2). Eight patients had clinical relapse at 6 to 19 months from the achievement of CR.

RESULTS

Presenting WBC count had a significant prognostic influence on disease-free survival (p=0.001). All four patients with a WBC count >100x10(9)/L relapsed, while only four additional relapses occurred among the eleven patients who had an initial WBC count below 100x10(9)/L. With regards to molecular monitoring, all relapses but one occurred in patients who showed persistent RT-PCR positivity during hematologic remission. By contrast, conversion to a repeatedly PCR-negative status was observed in the seven patients who remained in CR1 after a median follow-up of 48 months (range 31-79 months), as well as in the transplanted patient who was monitored in CR2. In these patients a PCR-positivity could be detected up to 24 months after diagnosis (median time to conversion to PCR-negative: 8 months).

INTERPRETATION AND CONCLUSIONS

In conclusion, marked hyperleukocytosis (>100x10(9)/L) confers poor prognosis to the patient with CBFbeta/MYH11-positive AML. In addition, slow kinetics of molecular remission was observed in this subset of AML, but the CBFb/MYH11 fusion transcript is no longer detectable in long-term survivors, indicating that molecular remission is an important therapeutic goal.

A modified AIDA protocol with anthracycline-based consolidation results in high antileukemic efficacy and reduced toxicity in newly diagnosed PML/RARalpha-positive acute promyelocytic leukemia. PETHEMA group

The Spanish PETHEMA group designed a protocol for newly diagnosed PML/RARalpha-positive acute promyelocytic leukemia (APL) in which induction and consolidation followed the original AIDA regimen, except for the omission of cytarabine and etoposide from consolidation. Induction consisted of 45 mg/m(2) all-trans retinoic acid (ATRA) daily until complete remission (CR) and 12 mg/m(2) idarubicin on days 2, 4, 6, and 8. Patients in CR received 3 monthly chemotherapy courses: idarubicin 5 mg/m(2)/d x 4 (course no. 1), mitoxantrone 10 mg/m(2)/d x 5 (course no. 2), and idarubicin 12 mg/m(2)/d x 1 (course no. 3). Maintenance therapy consisted of 90 mg/m(2)/d mercaptopurine orally, 15 mg/m(2)/wk methotrexate intramuscularly, and, intermittently, 45 mg/m(2)/d ATRA for 15 days every 3 months. Between November 1996 and December 1998, 123 patients with newly diagnosed PML/RARalpha-positive APL from 39 centers were enrolled. A total of 109 patients achieved CR (89%; 95% confidence interval [CI], 83 to 95), 12 died of early complications, and the remaining 2 were resistant. Consolidation treatment was associated with very low toxicity and no deaths in remission were recorded. Molecular assessment of response by reverse transcriptase-polymerase chain reaction (RT-PCR) showed conversion to PCR-negative in 48 of 99 (51%) and 82 of 88 patients (93%) after induction and consolidation, respectively. The 2-year Kaplan-Meier estimates of overall survival and event-free survival were 82% +/- 4% and 79% +/- 4%, respectively. For patients who achieved CR, the 2-year disease-free survival (DFS) was 92% +/- 3%. These data indicate that a significant reduction in toxicity might be obtained in APL using a less intensive consolidation without apparently compromising the antileukemic effect. These results also suggest a minor role for cytarabine and etoposide in the treatment of newly diagnosed PML/RARalpha-positive APL patients.

Evaluation of a predictive kinetic procedure for the enzymatic measurement of creatinine in serum

We have evaluated the analytical performance of a predictive kinetic procedure for the enzymatic measurement of serum creatinine in comparison with equilibrium and kinetic fixed-time procedures. The procedure uses commercially available reagents and is based on calculating the total change in absorbance expected if the reaction were to proceed to equilibrium by fitting the initial part of the absorbance-time curve to a three-parameter function by non-linear regression. Total imprecision for different concentrations of creatinine ranges from 1.47 to 1.86% and is significantly better than that obtained for the fixed-time procedure. The results with the predictive procedure are less dependent on creatinine amidohydrolase activity in the reagent, pH of the reagent and temperature of analysis than are the results with the fixed-time procedure. All the procedures are interfered with by bilirubin and ascorbic acid to about the same extent. Recovery and linearity are quite acceptable, and the estimated accuracy is below 2.1%. However, in comparison with the equilibrium procedure, the predictive procedure tends to underestimate creatinine concentrations at values below 100 micromol/l, and the results obtained by the two procedures are not transferable. In conclusion, the predictive approach substantially improves the imprecision but not the specificity of the enzymatic assay of serum creatinine.

Effect of morphine and abstinence syndrome on [3H]bromoxidine binding to alpha 2-adrenoceptors in rat brain

At 4 days after the implantation of two subcutaneous 75 mg morphine pellets in the back skin, rats were morphine-dependent. In the three layers studied in the occipital cortex we found that the values of the alpha 2-adrenergic agonist [3H]bromoxidine binding increased with respect to animals implanted with placebo pellets. Typical behavioral and physiological symptoms of the abstinence syndrome appeared 30 minutes after administration of naloxone, [3H]bromoxidine binding values being similar to those obtained in animals implanted with placebo pellets. The pattern of response of the [3H]bromoxidine binding was similar in the hippocampus and the superficial gray layer of the superior colliculus of the mesencephalon, but the differences were not statistically significant in these areas. This paper concludes that exist brain regional differences in the alpha 2-adrenoceptors response under morphine-treatment and possibly under naloxone-induced morphine abstinence syndrome.

Late cardiac toxicity of doxorubicin, epirubicin, and mitoxantrone therapy for Hodgkin's disease in adults

Cardiotoxicity is a well recognized side effect of anthracyclines (doxorubicin and epirubicin) or antracenadiones (mitoxantrone) at cumulative or high doses. However the side effects have not been evaluated in adults with Hodgkin's disease who received therapeutic doses of these drugs. We analyzed the cardiac function studying the left ventricular ejection fraction (LVEF) at rest in 136 patients with Hodgkin's disease treated with doxorubicin, epirubicin or mitoxantrone used in combination with vinblastine, bleomycin and decarbazine. No other risk factors, such as radiation therapy to the mediastinum, were considered. The follow-up is 5 to 8 years for patients in complete remission. Forty-five patients received doxorubicin (from 325 to 685 mg/m2, median 475 mg/m2), 51 patients received epirubicin (from 310 to 610 mg/m2, median 510 mg/m2) and 40 patients were treated with mitoxantrone (from 70 to 165, median 125 mg/m2). The median time between the end of treatment and the evaluation was 6.7 years. Thirty seven percent of the patients (similar rates in the three groups) showed abnormalities in the LVEF with decreased rates independent of the drug dosage. These were compared with two control groups, 46 patients treated with the MOPP combination (mechlorethamine, vincristine, prednisone and procarbazine) or LOPP (chlorambucil, for mechlorethamine) and 35 healthy volunteers. We believe that the use of anthracyclines or antracenadione will produce late cardiac effects in a fraction of patients independently of the doses used and that the indications for these drugs be carefully monitoring so as to evaluate the development of late side effects.

Autoradiographic localization of alpha 2-adrenoceptors in chick brain

alpha 2-Adrenoceptors were localized in the chick brain by 'in vitro' receptor autoradiography using [3H]UK 14304 as a ligand. High or very high densities of binding sites were found in the hyperstriatum, tuberculum olfactorium, hypothalamic nuclei, tectum opticum and some medullary nuclei. Comparatively, intermediate densities were observed over the thalamic nuclei and locus ceruleus, among others. Low densities of alpha 2-adrenoceptors were detected in the paleostriatum, hippocampus and cerebellum. Our data indicate that alpha 2-adrenoceptors in the chick brain present similar properties and homologous anatomical distribution to those reported in mammalian brain.

[Cutaneous response to 2 and 10 units of tuberculin in infants]

A study was done in 322 healthy, well nourished infants, 3 to 18 months old from day care centers of metropolitan Santiago, Chile, that were given BCG immunization in their neonatal period: 304 (94.4%) of them showed BCG scars and were included in a double blind open study, to determine the cutaneous responses to 2 TU and 10 TU tuberculin (PPD). There were no differences in the mean size of cutaneous reactions nor in percent positive responses (greater than or equal to 10 mm), but cutaneous reactions greater than or equal to 15 mm were more frequent in infants tested with PPD 10 TU. In 184 out of 304 infants (60.5%) tuberculin reactions were negative (less than or equal to 10 mm). Eighteen out of 322 infants (5.6%) that didn't show BCG scars were injected with PPD 2 TU: tuberculin reactions sized 6 to 9 mm were recorded in 3/18 of these infants but none of them attained 10 mm. Fifty five infants whose tuberculin reactions were 5 mm or less were retested: a booster effect was likely from the appearance of enhanced dermal response after a second tuberculin test done with the same or higher tuberculin strength than the first one in 12/47 of these infants with BCG scar (25%) and in only 1/8 such subjects without BCG scar.

Electrical properties and fluxes of Na+ and Cl- across lizard intestine

Electrical parameters and unidirectional Na+ and Cl- fluxes were determined in vitro across the duodenum, ileum and colon of lizard (Gallotia galloti). Electrical potential difference (PD) and short circuit current (Isc) were low in the three segments studied, whilst tissue conductance (Gt) was high. A net active transport of Na+ and Cl- was observed in the three segments. Net Na+ absorption was higher across duodenum and ileum than across the colon, while net Cl- absorption was similar in duodenum, ileum and colon. Ouabain virtually abolished Isc, PD and net Na+ and Cl- fluxes in all the segments. Amiloride abolished net Cl- flux in duodenum, ileum and colon, whereas net Na+ flux was abolished in colon but decreased in duodenum and ileum. PD and Isc were not affected by the presence of the diuretic.

Intestinal glucose and galactose transport in the cultured gilthead bream (Sparus aurata)

1. Electrical parameters and transepithelial glucose and galactose transport were determined in vitro across anterior and posterior intestine of the culture fish Sparus aurata. 2. Electrical potential difference (PD) and short-circuit current (Isc) were serosa-positive in anterior intestine, while they were serosa-negative or near zero in posterior intestine. 3. Tissue conductance (Gt) was higher in posterior than in anterior intestine. In both parts it was decreased when the Na ion was omitted in mucosal and serosal reservoirs. 4. Addition of glucose or galactose to the mucosal side of intestine caused an increase in PD and Isc in posterior intestine but did not significantly change PD and Isc in anterior intestine. 5. Isotopic flux of glucose and galactose measurements in short-circuit conditions showed a net active glucose and galactose absorption in posterior intestine, while in anterior intestine active transport of glucose or galactose was not observed. 6. The net transport of glucose and galactose in posterior intestine was decreased to zero in the absence of Na in mucosal and serosal reservoirs or in the presence of ouabain (1 mM) in serosal solution.

Effect of theophylline on ion transport in the lizard colon

1. The effect of theophylline on ion transport was examined using an in vitro short-circuited preparation of lizard colon. 2. Theophylline increased short circuit current (Isc) and transmural potential difference (PD). This increase caused by theophylline was accompanied by a small increase in transmural conductance (Gt). 3. Theophylline did not inhibit the absorption of Na+ but reversed Cl- absorption to secretion. This latter effect was due to an increase of the serosal-to-mucosal flux of Cl-. 4. Ion substitution experiments revealed that the effect of theophylline was Na+- and HCO3(-)-dependent and that these ions were required in the bathing solution. 5. These results with lizard colon are compared with those reported for mammalian colon and the mechanism of theophylline-induced Cl- secretion in these epithelia is discussed.

Transport of galactose and sodium across lizard duodenum

Electrical parameters and transepithelial Na+ and galactose transport were determined in vitro across isolated duodenum of Lacerta galloti lizard. Electrical potential difference (PD) and short-circuit current (Isc) were dependent on the presence of Na+ in the bathing solutions. PD and Isc were affected by addition of galactose to the mucosal solution. Isotopic flux of Na+ measurements across short-circuited duodenum showed a net active Na+ absorption. The net flux of Na+ (JNa+net) accounted for the observed Isc. Both (JNa+net) and Isc were increased by the addition of galactose 5 mM to the mucosal solution. Isotopic flux galactose measurements in open-circuit conditions showed a net active galactose absorption. The net transport of galactose was decreased to zero in the absence of Na+ in mucosal and serosal reservoirs. Galactose has been used to induce changes in short-circuit current (delta Isc) across intestine. delta Isc was a hyperbolic function of galactose concentration characterized by the parameters Vmax (maximum change in delta Isc) and Km (concentration needed to attain a velocity equal to half the Vmax).

Bioelectric parameters and sodium and chloride fluxes across the intestine of Blennius parvicornis

Simultaneous measurements of the electric potential difference and the short-circuit current intensity were taken, as well as measurements of unidirectional fluxes of sodium and chloride in the posterior intestine of Blennius parvicornis fish. On incubating the tissue in standard Ringer solution, a potential difference of--0.9 mV, a mean net flux of sodium of 2.49 mu Eq/h x cm2 were obtained. In the absence of sodium (choline as substitute), the net chloride flux and the Isc were completely blocked. In the absence of chloride (isocyanate as substitute) the net sodium flux and the Isc were equally blocked. Ouabain lessened the sodium and chloride fluxes in the mucosa-serosa direction to the point of nulling the net fluxes of both ions. The values of the bioelectric parameters were also blocked in the presence of this inhibitor. Acetazolamide did not significantly affect the values of either the unidirectional fluxes or the net fluxes of sodium and chloride. Nor did it affect the values of the bioelectric parameters. A mechanism for the absorption of sodium and chloride is proposed in which these ions enter the cell in a coupled form and in 1:1 proportion, the transport being independent of the bicarbonate ion.