Whether Immunostimulants Are Effective in Susceptible Children Suffering From Recurrent Respiratory Tract Infections: A Modeling Analysis Based on Literature Aggregate Data.

Immunostimulants are gradually being used in the prevention and treatment of recurrent respiratory tract infections in susceptible children, but their drug effects have not been quantified. The purpose of this study was to confirm the efficacy of immunostimulants in the prevention and treatment of recurrent respiratory tract infections in susceptible children. A model-based meta-analysis was used to describe the time course of placebo and immunostimulants in the prevention of respiratory tract infections in children. The cumulative number of respiratory tract infections was used as an indicator of efficacy. A meta-analysis was used to analyze the incidence of drug-related adverse events. Fourteen articles with 2400 pediatric subjects were finally included in the analysis. The results showed that the cumulative number of respiratory tract infections increased linearly with time, with the incidence of respiratory tract infections in the placebo group being 0.65 (95% confidence interval [CI], 0.55-0.75) per month. OM-85 BV and pidotimod reduced the incidence of respiratory tract infections by 0.21 (95%CI, 0.16-0.26) and 0.19 (95%CI, 0.17-0.21) compared to placebo per month, respectively. Pidotimod and OM-85 BV can effectively reduce the incidence of respiratory tract infections in susceptible children, with no significant increase in the incidence of drug-related adverse events when compared with placebo (risk ratio values were 1.07 [95%CI, 0.66-1.71] and 1.31 [95%CI, 0.54-3.19], respectively). This study provides quantitative support for the application of immunostimulants for the prevention of recurrent respiratory tract infections in children.

A Model for SARS-CoV-2 Infection with Treatment.

The current emergence of coronavirus (SARS-CoV-2) puts the world in threat. The structural research on the receptor recognition by SARS-CoV-2 has identified the key interactions between SARS-CoV-2 spike protein and its host (epithelial cell) receptor, also known as angiotensin-converting enzyme 2 (ACE2). It controls both the cross-species and human-to-human transmissions of SARS-CoV-2. In view of this, we propose and analyze a mathematical model for investigating the effect of CTL responses over the viral mutation to control the viral infection when a postinfection immunostimulant drug (pidotimod) is administered at regular intervals. Dynamics of the system with and without impulses have been analyzed using the basic reproduction number. This study shows that the proper dosing interval and drug dose both are important to eradicate the viral infection.

Proposal for a new therapeutic high dosage of Pidotimod in children with periodic fever, aphthous stomatitis, pharyngitis, adenitis (PFAPA) syndrome: a randomized controlled study.

BACKGROUND: Despite to PFAPA syndrome is considered a benign and self-limited condition in childhood its impact on patients and families can be remarkable in many cases. Currently, the therapeutic options for managing are non-specific and no consensus exists about the best treatment to use. Pidotimod has been suggested as a new potential treatment in PFAPA syndrome for its immunodulatory effects. We conducted a preliminary, prospective, controlled, open, cross-over trial to assess the efficacy and the safety of Pidotimod in the treatment of children with PFAPA syndrome. METHODS: 22 children with PFAPA syndrome were randomly allocated to treatment with pidotimod (with 2 vials of 400 mg daily) in combination with betamethasone 0.5-1 mg on need, based on parents/caregivers' decision (group A) or betamethasone 0.5-1 mg on need, based on parents/caregivers' decision (group B). Each treatment period was for 3 months (Phase 1), after that patients were switched to the other arm for other 3 months (Phase 2). Efficacy was expressed in terms of number of episodes of fever, pharyngitis, or aphthous stomatitis, as well as the additional use of betamethasone on need. Safety and tolerability of the Pidotimod were evaluated on the basis of the number and type of adverse events (AEs) recorded during the treatment. RESULTS: Patients receiving Pidotimod and use betametasone showed a significant decrease in frequency of fevers (p = 0.002); number of episodes of pharyngitis (p = 0.049); aphthous stomatitis (p = 0.036) as well as the betamethasone use on need (p = 0.007). Overall, 19/22 (86.4%) showed benefits from Pidotimod administration. The safety profile of Pidotimod was excellent as no serious adverse events have been reported in the treated groups. CONCLUSIONS: We firstly showed that high dosage of Pidotimod could be an effective and safe to reduce the PFAPA attacks in children.

Rhythmic change of adipokinetic hormones diurnally regulates locust vitellogenesis and egg development.

Adipokinetic hormones (AKHs), the neurohormones synthesized in the insect corpora cardiaca are known to mobilize lipids and carbohydrates for energy-consuming activities including reproduction. However, both inhibitory and stimulatory effects of AKHs on insect reproduction have been reported, and the underlying mechanisms remain elusive. Using the migratory locust, Locusta migratoria, as a model system, we report here that AKHs are expressed in response to rhythmic diel change, and AKH III expression increases markedly at photophase. Diurnal injection of AKH III but not AKH I or AKH II in adult females stimulates vitellogenesis and egg development. In contrast, AKH treatment at scotophase represses female reproduction. RNA interference-mediated knockdown of AKH receptor (AKHR) results in significantly reduced vitellogenin (Vg) expression in the fat body at photophase along with reduced Vg deposition in the ovary. AKHR knockdown also leads to decreased expression of Brummer, triacylglycerol lipase and trehalose transporter, accompanied by suppressed mobilization of triacylglycerol and trehalose. We propose that in addition to stimulating Vg expression at photophase, AKH/AKHR signalling is likely to regulate ovarian uptake of Vg via triacylglycerol mobilization and trehalose homeostasis. This study provides new insights into the understanding of AKH/AKHR signalling in the regulation of insect reproduction.

Therapeutic Role of a Cysteine Precursor, OTC, in Ischemic Stroke Is Mediated by Improved Proteostasis in Mice.

Oxidative stress aggravates brain injury following ischemia/reperfusion (I/R). We previously showed that ubiquilin-1 (Ubqln1), a ubiquitin-like protein, improves proteostasis and protects brains against oxidative stress and I/R-induced brain injury. Here, we demonstrate that a small molecule compound, L-2-oxothiazolidine-4-carboxylic acid (OTC) that functions as a precursor of cysteine, upregulated Ubqln1 and protected cells against oxygen-glucose deprivation-induced cell death in neuronal cultures. Further, the administration of OTC either at 1 h prior to ischemia or 3 h after the reperfusion significantly reduced brain infarct injury and improved behavioral outcomes in a stroke model. Administration of OTC also increased glutathione (GSH) level and decreased superoxide production, oxidized protein, and neuroinflammation levels in the penumbral cortex after I/R in the stroke mice. Furthermore, I/R reduced both Ubqln1 and the glutathione S-transferase protein levels, whereas OTC treatment restored both protein levels, which was associated with reduced ubiquitin-conjugated protein level. Interestingly, in the Ubqln1 knockout (KO) mice, OTC treatment showed reduced neuroprotection and increased ubiquitin-conjugated protein level when compared to the similarly treated non-KO mice following I/R, suggesting that OTC-medicated neuroprotection is, at least partially, Ubqln1-dependent. Thus, OTC is a potential therapeutic agent for stroke and possibly for other neurological disorders and its neuroprotection involves enhanced proteostasis.

Pidotimod: a review of its pharmacological features and clinical effectiveness in respiratory tract infections.

Introduction: The majority of acute respiratory tract infections (RTIs) are caused by viruses and the overzealous use of antibacterial drugs, when not really required, is a cause for concern. This has led to evaluation of alternative approaches such as boosting the immune response in individuals who are most vulnerable to develop RTIs such as the very young and the elderly. Areas covered: This article overviews the immunostimulant activity and pharmacokinetic properties of pidotimod, and focuses on assessing its role in the treatment and prevention of acute RTIs through evaluation of clinical trials and real-world evidence. Articles were obtained from a full search of Medline, and this was augmented by published clinical studies known to the authors and manufacturer. Expert opinion: Pidotimod's activity was shown to be mediated via multiple pathways of the immune system. Comparison with placebo demonstrated significant advantages for pidotimod in terms of reduced reinfection rates [OR 0.20, 95% CI 0.12 to 0.33; p < 0.00001], a lesser need for antibiotics [mean difference -2.65, 95% CI -3.68 to -1.62; p < 0.00001] and rescue medications, and decreased absenteeism [mean difference-2.99, 95% CI -4.03 to -1.95; p < 0.00001]. No safety concerns were raised in these studies.

Pirometaxine™ (Narlisim™) in pediatric nasal congestion: a retrospective study.

BACKGROUND: Nasal congestion represents a troublesome health issue which is especially and invalidating in children. Effective nasal drugs, such as sympathomimetic drugs, are usually forbidden in children under 12 years of age because of their potential systemic adverse effects. Hypertonic nasal physiological solutions have recently been successfully used to decongest nasal mucosa in children: its mechanical activity has been universally recognized as safe and effective and it represents a well-established, useful treatment in children. METHODS: We have retrospectively analyzed a case series of 40 children treated for 4 days (96 hours) with a new class 1s medical device nasal hypertonic spray containing Pirometaxine™ (Narlisim™) in outpatient affected by nasal congestion due to common cold. Every child was evaluated on a 3-point symptom assessment scale (0: no symptom; 1: mild symptom; 2: moderate symptom; 3: severe symptom) at the beginning of the trial (T0) and after 48 (T1) and 96 hours (T2). The symptoms assessed were nasal obstruction, nasal secretion, headache, flash of cold, pharyngodynia, cough, and sneeze. RESULTS: The results, in terms of short-term efficacy to control nasal obstruction (T1 vs. T0: P<0.0001; T2 vs. T0: P<0.0001), nasal secretion (T1 vs. T0: P<0.0001; T2 vs. T0: P<0.0001) and all the symptoms related to common cold have supported the efficacy of this hypertonic nasal solution. No adverse events have been pointed out during the trial supporting the safety of this new nasal hypertonic approach. CONCLUSIONS: The absence of adverse events after 48-96 hours along with the short-term effectiveness of this new treatment seems to represent a new, safe option to treat children affected by nasal congestion secondary to common cold. Considering the current lack of safe treatments for children under 12 years of age, Narlisim™ can be considered as a useful short-term option to control nasal congestion in children.

Graded Transmission without Action Potentials Sustains Rhythmic Activity in Some But Not All Modulators That Activate the Same Current.

Neurons in the central pattern-generating circuits in the crustacean stomatogastric ganglion (STG) release neurotransmitter both as a graded function of presynaptic membrane potential that persists in TTX and in response to action potentials. In the STG of the male crab Cancer borealis, the modulators oxotremorine, C. borealis tachykinin-related peptide Ia (CabTRP1a), red pigment concentrating hormone (RPCH), proctolin, TNRNFLRFamide, and crustacean cardioactive peptide (CCAP) produce and sustain robust pyloric rhythms by activating the same modulatory current (IMI), albeit on different subsets of pyloric network targets. The muscarinic agonist oxotremorine, and the peptides CabTRP1a and RPCH elicited rhythmic triphasic intracellular alternating fluctuations of activity in the presence of TTX. Intracellular waveforms of pyloric neurons in oxotremorine and CabTRP1a in TTX were similar to those in the intact rhythm, and phase relationships among neurons were conserved. Although cycle frequency was conserved in oxotremorine and TTX, it was altered in CabTRP1a in the presence of TTX. Both rhythms were primarily driven by the pacemaker kernel consisting of the Anterior Burster and Pyloric Dilator neurons. In contrast, in TTX the circuit remained silent in proctolin, TNRNFLRFamide, and CCAP. These experiments show that graded synaptic transmission in the absence of voltage-gated Na+ current is sufficient to sustain rhythmic motor activity in some, but not other, modulatory conditions, even when each modulator activates the same ionic current. This further demonstrates that similar rhythmic motor patterns can be produced by qualitatively different mechanisms, one that depends on the activity of voltage-gated Na+ channels, and one that can persist in their absence.SIGNIFICANCE STATEMENT The pyloric rhythm of the crab stomatogastric ganglion depends both on spike-mediated and graded synaptic transmission. We activate the pyloric rhythm with a wide variety of different neuromodulators, all of which converge on the same voltage-dependent inward current. Interestingly, when action potentials and spike-mediated transmission are blocked using TTX, we find that the muscarinic agonist oxotremorine and the neuropeptide CabTRP1a sustain rhythmic alternations and appropriate phases of activity in the absence of action potentials. In contrast, TTX blocks rhythmic activity in the presence of other modulators. This demonstrates fundamental differences in the burst-generation mechanisms in different modulators that would not be suspected on the basis of their cellular actions at the level of the targeted current.

[Clinical effect of pidotimod oral liquid as adjuvant therapy for infectious mononucleosis].

OBJECTIVE: To study the clinical effect of pidotimod oral liquid as adjuvant therapy for infectious mononucleosis and its effect on T lymphocyte subsets. METHODS: A total of 76 children with infectious mononucleosis, who were admitted to the hospital between July 2016 and June 2017, were enrolled and randomly divided into two groups: conventional treatment and pidotimod treatment (n=38 each). The children in the conventional treatment group were given antiviral therapy with ganciclovir for injection and symptomatic treatment. Those in the pidotimod treatment group were given pidotimod oral liquid in addition to the treatment in the conventional treatment group. The course of treatment was two weeks for both groups. The two groups were compared in terms of the recovery of clinical indices and the changes in peripheral blood T lymphocyte subsets. RESULTS: Compared with the conventional treatment group, the pidotimod treatment group had significantly shorter fever clearance time, time to the disappearance of isthmopyra, time to the relief of lymph node enlargement, time to the relief of hepatosplenomegaly, and length of hospital stay (P<0.05). After treatment, the pidotimod treatment group had significant reductions in the percentages of CD3+ and CD8+ T cells and had significantly lower percentages of CD3+ and CD8+ T cells than the conventional treatment group (P<0.001). The pidotimod treatment group had significant increases in the percentage of CD4+ T cells and CD4+/CD8+ ratio after treatment, which was significantly higher than those in the conventional treatment group (P<0.001). The conventional treatment group had no significant changes in T lymphocyte subsets after treatment (P>0.05). CONCLUSIONS: Pidotimod oral liquid has a good clinical effect as the adjuvant therapy for infectious mononucleosis and can improve cellular immune function, so it holds promise for clinical application.

Pharmacokinetics of pidotimod in broiler chickens by UHPLC-MS/MS after oral and intravenous administration.

Pidotimod is widely used in children as an immune promoter but it has not been fully evaluated in animals. The pharmacokinetics of pidotimod and its oral bioavailability have not been described in broiler chickens. We developed a simple and sensitive UHPLC-MS/MS assay for rapid determination of pidotimod levels in chicken blood. Recoveries were nearly 100% and the coefficients of accuracy and precision were minimal. Healthy broiler chickens were given 10 mg/kg pidotimod either orally or intravenously. The oral pidotimod was rapidly absorbed (time to reach maximum concentration, 1.25 h) and rapidly eliminated (the mean residence time was 3.2 h). A noncompartmental analysis of the intravenous route indicated a mean plasma clearance of 2.2 L (h kg)-1 with an estimated mean volume of distribution at steady state of 12.69 L/kg. The bioavailability of pidotimod after oral dosing was 27%.

Abdominal surgery induced gastric ileus and activation of M1-like macrophages in the gastric myenteric plexus: prevention by central vagal activation in rats.

Inflammation plays a role in abdominal surgery (AS)-induced intestinal ileus that is alleviated by electrical vagal stimulation. Intracisternal injection of RX-77368, the stable thyrotropin-releasing hormone agonist, activates dorsal motor nucleus neurons and gastric vagal efferent discharges. We investigated the gastric inflammation induced by AS and the modulation by intracisternal RX-77368 in rats. RX-77368 (50 ng/rat) or saline was injected followed, 1 h later, by laparotomy and small intestinal/cecal manipulation. The sham group had anesthesia alone. After 6 h, gastric emptying (GE) and the inflammation in gastric corpus were determined. AS inhibited GE by 72% vs. control and doubled the number of M1-like macrophage immunoreactive for major histocompatibility complex class II (MHCII; M1 marker) but not for cluster of differentiation 206 (CD206; M2 marker) (MHCII+/CD206-) while there was no change in M2-like macrophages (MHCII-/CD206+). AS increased mRNA levels of interleukin-1ß (IL-1ß) and tumor necrosis factor α (TNF-α) by 1.7- and 1.5-fold, respectively, in the gastric submucosa plus muscle layers and the infiltration of neutrophils labeled by myeloperoxidase by 9.5-fold in the muscularis externa. RX-77368 inhibited AS-related gastric changes while not altering these parameters in the sham group. There was a significant negative correlation between GE and IL-1ß (r = -0.46), TNF-α (r = -0.44), M1 macrophage (r = -0.82), and neutrophils (r = -0.91). The M2-like macrophages and IL-10 expression were unchanged by AS with intracisternal saline or RX-77368. These data indicate that AS activates gastric M1 macrophages and increases proinflammatory cytokines expression, which are prevented by central vagal activation and may contribute to the correlated dampening of postoperative gastric ileus.NEW & NOTEWORTHY MHCII+/CD206- (M1) and MHCII-/CD206+ (M2) constitute two distinct populations of macrophages that are in close apposition to the cholinergic neurons in the rat gastric myenteric plexus (MP). Abdominal surgery (6 h) activates M1 macrophage leading to inflammation in the gastric MP correlated with the delayed gastric emptying, which was abolished by central vagal stimulation via intracisternal injection of RX-77368. Vagal stimulation linked with the cephalic phase may have potential beneficial effects to curtail postoperative gastric ileus.

Effects of Acute Administration of Adipokinetic Hormone on Depression, Anxiety, Pain, Locomotion and Memory in Mice.

The neurosecretory cells in the corpus cardiacum of insects synthesize a set of hormones that are called adipokinetic, hypertrehalosemic or hyperprolinemic depending on the insect in question. They are the Adipokinetic Hormone/Red Pigment-Concentrating Hormone (AKH/RPCH) family of peptides. The present study investigated the effects of acute administration of Locusta Migratoria (Locmi-AKHII) and Anax Imperator (Anaim-AKH) on depression, anxiety, pain (analgesy), locomotion and memory in mice in forced swimming (FST), elevated plus maze (EPM), hot plate, locomotor activity and passive avoidance tests. Both Locmi-AKH-II (4 mg/kg) and Anaim-AKH (0.25 and 0.50 mg/kg) decreased immobility time (in sec, s) in the FST test. Anaim-AKH (0.5 and 1 mg/kg) increased the percentage of time spent in open arms/total time spent and the percentage of the number of open arm/total arm entries in the EPM test. Anaim-AKH (1 and 2 mg/kg) significantly increased latency (s) (initial time passed) for mice to lick their hind paws or jumping in the hot plate test. Anaim-AKH (4 mg/kg) significantly decreased the total distance (cm) moved, or the speed (cm/s) of movement of the animals in the locomotor activity test. Neither Locmi-AKH-II nor Anaim-AKH altered the retention latency (s) in the passive avoidance test. Both Locmi-AKH-II and Anaim-AKH exerted antidepressant effects, while only Anaim-AKH had anxiolytic and analgesic effects when administered acutely. Anaim-AKH diminished locomotion at higher doses while Locmi-AKH-II had no such effects. Neither Locmi-AKH-II nor Anaim-AKH disturbed learning and memory when acutely administered. Data of our studies suggest clinical potentials of AKH to be used in depression, anxiety and pain without disturbing memory.

Immunomodulatory effects of pidotimod in adults with community-acquired pneumonia undergoing standard antibiotic therapy.

The morbidity and mortality of community-acquired pneumonia (CAP) are still elevated and two aspects seem to contribute to a worse outcome: an uncontrolled inflammatory reaction and an inadequate immune response. Adjuvants, including corticosteroids and intravenous immunoglobulins, have been proposed to counterbalance these effects but their efficacy is only partial. We examined the immunomodulatory activity of Pidotimod (PDT), a synthetic dipeptide molecule in adult patients hospitalized for CAP. Sixteen patients with a diagnosis of CAP and a PSI score III or IV and/or a CURB-65 0-2 were randomized to receive either levofloxacin 500 mg b.i.d. alone or levofloxacin plus PDT (800mg, 2 daily doses). Blood samples were drawn at baseline (T0), before initiation of therapy, as well as 3 (T3), and 5 (T5) days after initiation of therapy. Immunologic and clinical parameters were analyzed at each time point. Supplementation of antibiotic therapy with PDT resulted in an upregulation of antimicrobial and of immunomodulatory proteins as well as in an increased percentage of Toll like receptor (TLR)2- and TLR4, and of CD80- and CD86-expressing immune cells. Notably, Pidotimod supplementation was also associated with a robust reduction of TNFα-producing immune cells. No significant differences were observed in clinical parameters. These results confirm that supplementation of antibiotic therapy with Pidotimod in patients with CAP results in a potentially beneficial modulation of innate immunity.

Proton pump inhibitors and symptomatic hypomagnesemic hypoparathyroidism.

Hypomagnesemia is a common but often overlooked problem in hospitalized patients. Unrecognized hypomagnesemia can cause serious complications. The association of hypokalemia and hypocalcemia is strongly evocative of a magnesium deficiency. Research into the causes of hypomagnesemia is imperative, as it will definitely change the approach, treatment and prognosis. We report the case of a 65-year-old man with chronic hypocalcemia and hypokalemia associated with cerebellar syndrome, a solitary seizure and cerebellar hyperintensities on magnetic resonance imaging. After the detection and treatment of hypomagnesemia with oral supplements of magnesium and the replacement of pantoprazole with ranitidine, we observed immediate relief of the symptoms. In conclusion, in clinical practice, magnesium depletion should be investigated in elderly patients with hypocalcemia treated with proton pump inhibitors for many years, in particular in the presence of neurological disorders.

Advantage of population pharmacokinetic method for evaluating the bioequivalence and accuracy of parameter estimation of pidotimod.

OBJECTIVE: This study was aimed at exploring the accuracy of population pharmacokinetic method in evaluating the bioequivalence of pidotimod with sparse data profiles and whether this method is suitable for bioequivalence evaluation in special populations such as children with fewer samplings. Methods In this single-dose, two-period crossover study, 20 healthy male Chinese volunteers were randomized 1 : 1 to receive either the test or reference formulation, with a 1-week washout before receiving the alternative formulation. Noncompartmental and population compartmental pharmacokinetic analyses were conducted. Simulated data were analyzed to graphically evaluate the model and the pharmacokinetic characteristics of the two pidotimod formulations. Various sparse sampling scenarios were generated from the real bioequivalence clinical trial data and evaluated by population pharmacokinetic method. RESULTS: The 90% confidence intervals (CIs) for AUC0-12h, AUC0-∞, and Cmax were 97.3 - 118.7%, 96.9 - 118.7%, and 95.1 - 109.8%, respectively, within the 80 - 125% range for bioequivalence using noncompartmental analysis. The population compartmental pharmacokinetics of pidotimod were described using a one-compartment model with first-order absorption and lag time. In the comparison of estimations in different dataset, the estimation of random three- and< fixed four-point sampling strategies can provide results similar to those obtained through rich sampling. The nonlinear mixed-effects model requires fewer data points. Moreover, compared with the noncompartmental analysis method, the pharmacokinetic parameters can be more accurately estimated using nonlinear mixed-effects model. CONCLUSIONS: The population pharmacokinetic modeling method was used to assess the bioequivalence of two pidotimod formulations with relatively few sampling points and further validated the bioequivalence of the two formulations. This method may provide useful information for regulating bioequivalence evaluation in special populations.

Evidence for involvement of NK3 receptors in the anxiogenic-like effect of SP6-11(C-terminal), a metabolite of substance P, in rats evaluated in the elevated plus-maze.

INTRODUCTION: Substance P (SP) is a neuropeptide widely expressed throughout the fear-processing pathways of the brain. SP is cleaved by several proteolytic enzymes in amino (N-) and carboxy (C-) terminal sequences, which can have biological activities per se. We have previously shown that the anxiogenic-like effects elicited by SP6-11(C-terminal), a specific metabolite of SP, are mediated via NK1 and NK2 receptors. Nevertheless, there are evidences that C-terminal fragments may have a greater affinity for NK3 receptors. OBJECTIVES: The aim of the present study was to further investigate the possible involvement of NK3 receptors in the anxiogenic-like effects induced by SP6-11(C-terminal). METHODS: Adult male Wistar rats were intracerebroventricularly (i.c.v.) treated with SR142801 (NK3 receptors antagonist) or vehicle one minute to prior SP6-11(C-terminal) or vehicle. Other experimental groups received SP6-11(C-terminal) or vehicle i.c.v. one minute prior to senktide (NK3 receptors agonist) or vehicle. After five minutes, the animals were behaviorally evaluated in the elevated plus-maze test (EPM). RESULTS: SR142801 (100 pmol) or SP6-11(C-terminal) (10 pmol) reduced all the parameters of open-arms exploration and increased the number of protected stretch-attend postures in the EPM, indicating an anxiogenic-like effect. Senktide (10 pmol) promoted an opposite effect on these behavioral parameters, characterizing an anxiolytic-like profile. Pretreatment with SR142801, in an ineffective dose, potentiated the SP6-11-induced anxiety, especially in the unprotected head-dipping and protected stretch-attend postures behaviors. Moreover, the anxiolytic-like effect induced by senktide (1 pmol) was prevented by SP6-11. CONCLUSIONS: Our results give support to the involvement of NK3 receptors in the anxiogenic-like actions of SP6-11(C-terminal), where this metabolite seems to behave as an antagonist, in a way similar to SR142801.

Increasing taurine intake and taurine synthesis improves skeletal muscle function in the mdx mouse model for Duchenne muscular dystrophy.

KEY POINTS: Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease associated with increased inflammation, oxidative stress and myofibre necrosis. Cysteine precursor antioxidants such as N-acetyl cysteine (NAC) and l-2-oxothiazolidine-4-carboxylate (OTC) reduce dystropathology in the mdx mouse model for DMD, and we propose this is via increased synthesis of the amino acid taurine. We compared the capacity of OTC and taurine treatment to increase taurine content of mdx muscle, as well as effects on in vivo and ex vivo muscle function, inflammation and oxidative stress. Both treatments increased taurine in muscles, and improved many aspects of muscle function and reduced inflammation. Taurine treatment also reduced protein thiol oxidation and was overall more effective, as OTC treatment reduced body and muscle weight, suggesting some adverse effects of this drug. These data suggest that increasing dietary taurine is a better candidate for a therapeutic intervention for DMD. ABSTRACT: Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease for which there is no widely available cure. Whilst the mechanism of loss of muscle function in DMD and the mdx mouse model are not fully understood, disruptions in intracellular calcium homeostasis, inflammation and oxidative stress are implicated. We have shown that protein thiol oxidation is increased in mdx muscle, and that the indirect thiol antioxidant l-2-oxothiazolidine-4-carboxylate (OTC), which increases cysteine availability, decreases pathology and increases in vivo strength. We propose that the protective effects of OTC are a consequence of conversion of cysteine to taurine, which has itself been shown to be beneficial to mdx pathology. This study compares the efficacy of taurine with OTC in decreasing dystropathology in mdx mice by measuring in vivo and ex vivo contractile function and measurements of inflammation and protein thiol oxidation. Increasing the taurine content of mdx muscle improved both in vivo and ex vivo muscle strength and function, potentially via anti-inflammatory and antioxidant effects of taurine. OTC treatment increased taurine synthesis in the liver and taurine content of mdx muscle, improved muscle function and decreased inflammation. However, OTC was less effective than taurine treatment, with OTC also decreasing body and EDL muscle weights, suggesting that OTC had some detrimental effects. These data support continued research into the use of taurine as a therapeutic intervention for DMD, and suggest that increasing dietary taurine is the better strategy for increasing taurine content and decreasing severity of dystropathology.

Promising toxicological biomarkers for the diagnosis of liver injury types: Bile acid metabolic profiles and oxidative stress marker as screening tools in drug development.

Promising biomarkers were identified in adult male Crl:CD (SD) rats for the screening of new chemical entities for their potential to cause liver injury. We examined the serum biochemistry, liver histopathology, and bile acid profiles by LC-MS/MS, and the mRNA expression of transporters and CYPs by an RT-PCR after the following treatments to male Crl:CD (SD) rats: (a) bile duct ligation (BDL); (b) a single oral dose of 150 mg/kg α-naphthylisothiocyanate (ANIT); and (c) repeated oral doses of a novel pyrrolidinecarboxylic acid derivative (abbreviated as PCA) at 30, 300, and 1000 mg/kg. The serum total bile acid levels and bilirubin concentrations were found to be elevated in all of the groups. However, the bile acid component profiles of the PCA group differed significantly from BDL and ANIT models: deoxycholic acid, lithocholic acid, and sulfated bile acids were upregulated in a dose-dependent manner only in the PCA group. In addition, the PCA group demonstrated high levels of hepatic heme oxygenase-1 expression, whereas the profiles of the mRNA levels of the hepatic transporters and CYPs of all groups were found to be similar. The histopathological findings, for both the BDL and ANIT groups, were of bile duct hyperplasia, hepatocyte degeneration and necrosis. In contrast, only bile duct hyperplasia and hepatocyte degeneration were observed in the PCA group, even at a lethal dose. These results indicated that PCA induced a cholestatic condition and the increase of oxidative stress markers implies that this will also lead hepatocellular injury. In conclusion, the serum bile acid components and sulfated bile acid levels, and the expression of oxidative stress markers could provide information that aids in the diagnosis of liver injury type and helps to elucidate the mechanisms of hepatotoxicity. These findings can be extrapolated into our clinical investigation. The analysis of these crucial biomarkers is likely to be a useful screening tool in the lead optimization phase of drug discovery.

Distribution in Rats Internal Organs of Intraperitoneally Given 125I-Labeled Heptapeptide [2-8]-Leucopyrokinin ([2-8]-LPK), a Truncated Analog of Insect Neuropeptide Leucopyrokinin.

BACKGROUND: It was previously found that synthetic, insect-derived octapeptide leucopyrokinin (LPK) applied directly into the lateral brain ventricle induced a significant antinociceptive effect in rats. Its synthetic truncated analog heptapeptide [2-8]-leucopyrokinin displayed a stronger antinociceptive effect in comparison to native LPK. Moreover it was previously found a high accumulation of these both 125I-labeled peptides in adrenals, as well as in hypothalamus and in hippocampus of rats brain. OBJECTIVES: The aim of the present study was to assess the distribution of 125I-labeled [2-8]-leucopyrokinin in rats' internal organs an in several parts of the brain after peripheral - intraperitoneal (i.p.) administration. MATERIAL AND METHODS: The study was performed on male Wistar rats. A synthetic [2-8]-leucopyrokinin ([2-8]-LPK) was iodinated with Na125I. On the day of experiment a solution of 125I-[2-8]-LPK was i.p. injected and the next after 1 and 24 h animals were sacrificed by decapitation. Radioactivity levels in samples of parts of the brain and of internal organs were determined by counter Gamma Auto Count. RESULTS: A uniform, low accumulation 125I-[2-8]-LPK was found in evaluated samples of the brain and in internal organs. CONCLUSIONS: The results of the present study indicate a weak penetration into the brain and internal organs of intraperitoneally applied 125I-[2-8]-LPK in rats and correspond with previously determined weak biological effects of i.p. injected LPK and [2-8]-LPK.

GnRH suppresses excitability of visual processing neurons in the optic tectum.

Animals change their behavior in response to sensory cues in the environment as well as their physiological status. For example, it is generally accepted that their sexual behavior is modulated according to seasonal environmental changes or the individual's maturational/reproductive status, and neuropeptides have been suggested to play important roles in this process. Some behavioral modulation arises from neuropeptide modulation of sensory information processing in the central nervous system, but the neural mechanisms still remain unknown. Here we focused on the neural basis of neuropeptide modulation of visual processing in vertebrates. The terminal nerve neurons that contain gonadotropin-releasing hormone 3 (TN-GnRH3 neurons) are suggested to modulate reproductive behavior and have massive projections to the optic tectum (OT), which plays an important role in visual processing. In the present study, to examine whether GnRH3 modulates retino-tectal neurotransmission in the OT, we analyzed the effect of GnRH3 electrophysiologically and morphologically. We found that field potentials evoked by optic tract fiber stimulation, which represent retino-tectal neurotransmission, were modulated postsynaptically by GnRH3. Whole cell recording from postsynaptic neurons in the retino-tectal pathway suggested that GnRH3 activates large-conductance Ca(2+)-activated K(+) (BK) channels and thereby suppresses membrane excitability. Furthermore, our improved morphological analysis using fluorescently labeled GnRH peptides showed that GnRH receptors are localized mainly around the cell bodies of postsynaptic neurons. Our results indicate that TN-GnRH3 neurons modulate retino-tectal neurotransmission by suppressing the excitability of projection neurons in the OT, which underlies the neuromodulation of behaviorally relevant visual information processing by the neuropeptide GnRH3.