Surveying heterocycles as amide bioisosteres within a series of mGlu7 NAMs: Discovery of VU6019278

This letter describes a diversity-oriented library approach to rapidly assess diverse heterocycles as bioisosteric replacements for a metabolically labile amide moiety within a series of mGlu₇ negative allosteric modulators (NAMs). SAR rapidly honed in on either a 1,2,4- or 1,3,4-oxadizaole ring system as an effective bioisostere for the amide. Further optimization of the southern region of the mGlu₇ NAM chemotype led to the discovery of VU6019278, a potent mGlu₇ NAM (IC₅₀?=?501?nM, 6.3% L-AP₄ Min) with favorable plasma protein binding (rat f_u?=?0.10), low predicted hepatic clearance (rat CL_hep?=?27.7?mL/min/kg) and high CNS penetration (rat K_p?=?4.9, K_p,uu?=?0.65).     

The decay of genetic variability in geographically structured populations. II

The ultimate rate of approach to equilibrium in the infinite stepping-stone model is calculated. The analysis is restricted to a single locus in the absence of selection, and every mutant is assumed to be new to the population. Let f(t, x) be the probability that two homologous genes separated by the vector x in generation t are the same allele. It is supposed that $\text{f(}\text{0, x}\text{) = O(x}{}^{\mathrm{?2?\eta }}\text{), η > 0,}\text{as}\text{x ≡ ¦}\text{x}\text{¦ → ∞}$. In the absence of mutation, f(t, x) tends to unity at the rate $\text{t}{}^{\mathrm{<mtext>?1</mtext><mtext>2</mtext>}}$ in one dimension and (ln t)^?1 in two dimensions. Thus, the loss of genetic variability in two dimensions is so slow that evolutionary forces not considered in this model would supervene long before a two-dimensional natural population became completely homogeneous. If the mutation rate, u, is not zero f(t, x) asymptotically approaches equilibrium at the rate $\text{(1 ? u)}{}^{\mathrm{2t}}\text{t}{}^{\mathrm{<mtext>?3</mtext><mtext>2</mtext>}}$ in one dimension and (1 ? u)^2tt^?1(lnt)^?2 in two dimensions. Integral formulas are presented for the spatial dependence of the deviation of f(t, x) from its stationary value as t → ∞, and for large separations this dependence is shown to be (const + x) in one dimension and (const + ln x) in two dimensions. All the results are the same for the Malécot model of a continuously distributed population provided the number of individuals per colony is replaced by the population density. The relatively slow algebraic and logarithmic rates of convergence for the infinite habitat contrast sharply with the exponential one for a finite habitat.     

Energetics of Contraction in Phasic and Tonic Skeletal Muscles of the Chicken

Comparative energetics of chicken latissimus dorsi muscles, tonic anterior (ALD) and phasic posterior (PLD), were investigated by measuring initial heat production. Heat components were analyzed in terms of the equation: E = A + W + α_F(L) + f(P, t) As the muscles were stretched by increments, heat produced in isometric twitches and tetani decreased in a linear fashion. Two processes are involved: one tension independent, the activation heat, or A; and the other tension dependent, W_i + α_F(L) + f(P, t). In twitches, A, per unit tension, is equivalent in the PLD and ALD. Tension-dependent heat, per unit tension, is greater in the PLD due to W_i; but tension-time-related heat, f(P, t), per unit tension, is similar in both muscles. In tetanic contractions, differences in A and f(P, t), per unit tension, are attributed to the greater V_max in the PLD. The differences in the energetics of isometric contractions in the PLD and ALD, therefore, can be explained by inherent differences in tension development, compliance, and myosin and reticular ATPase activities. Data from isotonic twitches were quantified by means of the equivalent tension technique. Both muscles exhibited an extra heat associated with shortening, α_F(L). In the PLD, the ratio α_F/P_ot is greater; it is load independent and ½ the value of a/P_o in both muscles. Enthalpy efficiency, W_e + W_i/E, is comparable in both muscles. A Fenn effect is observed only when isotonic energy liberation is compared to a decreasing isometric energy expenditure base line.     

Manganese Alters Rat Brain Amino Acids Levels

Manganese (Mn) is an essential element and it acts as a cofactor for a number of enzymatic reactions, including those involved in amino acid, lipid, protein, and carbohydrate metabolism. Excessive exposure to Mn can lead to poisoning, characterized by psychiatric disturbances and an extrapyramidal disorder. Mn-induced neuronal degeneration is associated with alterations in amino acids metabolism. In the present study, we analyzed whole rat brain amino acid content subsequent to four or eight intraperitoneal injections, with 25?mg MnCl₂/kg/day, at 48-h intervals. We noted a significant increase in glycine brain levels after four or eight Mn injections (p?<?0.05 and p?<?0.01, respectively) and arginine also after four or eight injections (p?<?0.001). Significant increases were also noted in brain proline (p?<?0.01), cysteine (p?<?0.05), phenylalanine (p?<?0.01), and tyrosine (p?<?0.01) levels after eight Mn injections vs. the control group. These findings suggest that Mn-induced alterations in amino acid levels secondary to Mn affect the neurochemical milieu.     

Skeletal muscle post-conditioning by diazoxide, anti-oxidative and anti-apoptotic mechanisms

Pretreatment with diazoxide, K_ATP channel opener, increases tissue tolerance against ischemia reperfusion (IR) injury. In clinical settings pretreatment is rarely an option therefore we evaluated the effect of post-ischemic treatment with diazoxide on skeletal muscle IR injury. Rats were treated with either saline, diazoxide (K_ATP opener; 40?mg/kg) or 5-hydroxydecanoate (5-HD; mitochondrial K_ATP inhibitor; 40?mg/kg) after skeletal muscle ischemia (3?h) and reperfusion (6, 24 or 48?h). Tissue contents of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activities, Bax and Bcl-2 protein expression and muscle histology were determined. Apoptosis was examined (24 and 48?h) after ischemia. IR induced severe histological damage, increased MDA content and Bax expression (24 and 48?h; p?<?0.01) and decreased CAT and SOD activities (6 and 24?h, p?<?0.01 and 48?h, p?<?0.05), with no significant effect on Bcl-2 expression. Diazoxide reversed IR effects on MDA (6 and 24?h; p?<?0.05), SOD (6 and 24?h; p?<?0.01) and CAT (6 and 48?h, p?<?0.05 and 24?h p?<?0.01) and tissue damage. Diazoxide also decreased Bax (24 and 48?h; p?<?0.05) and increased Bcl-2 protein expression (24 and 48?h; p?<?0.01). Post-ischemic treatment with 5-HD had no significant effect on IR injury. Number of apoptotic nuclei in IR and 5-HD treated groups significantly increased (p?<?0.001) while diazoxide decreased apoptosis (p?<?0.01). The results suggested that post-ischemic treatment with diazoxide decrease oxidative stress in acute phase which modulates expression of apoptotic proteins in the late phase of reperfusion injury. Involvement of KATP channels in this effect require further evaluations.     

Identity Coefficients in Finite Populations. I. Evolution of Identity Coefficients in a Random Mating Diploid Dioecious Population

Properties of identity relation between genes are discussed, and a derivation of recurrent equations of identity coefficients in a random mating, diploid dioecious population is presented. Computations are run by repeated matrix multiplication. Results show that for effective population size (N_e) larger than 16 and no mutation, a given identity coefficient at any time t can be expressed approximately as a function of (1—f), (1—f)³ and (1— f)⁶, where f is the mean inbreeding coefficient at time t. Tables are presented, for small N_e values and extreme sex ratios, showing the pattern of change in the identity coefficients over time. The pattern of evolution of identity coefficients is also presented and discussed with respect to N _eu, where u is the mutation rate. Applications of these results to the evolution of genetic variability within and between inbred lines are discussed.     

Discovery of furan and dihydrofuran-fused tricyclic benzo[d]imidazole derivatives as potent and orally efficacious microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors: Part-1

This letter describes the synthesis and biological evaluation of furan and dihydrofuran-fused tricyclic benzo[d]imidazole derivatives as novel mPGES-1 inhibitors, capable of inhibiting an increased PGE₂ production in the disease state. Structure-activity optimization afforded many potent mPGES-1 inhibitors having <50?nM potencies in the A549 cellular assay and adequate metabolic stability in liver microsomes. Lead compounds 8l and 8m demonstrated reasonable in vitro pharmacology and pharmacokinetic properties over other compounds. In particular, 8m revealed satisfactory oral pharmacokinetics and bioavailability in multiple species like rat, guinea pig, dog and cynomolgus monkey. In addition, the representative compound 8m showed in vivo efficacy by inhibiting LPS-induced thermal hyperalgesia with an ED₅₀ of 14.3?mg/kg in guinea pig.     

In vitro and in vivo effects of some benzodiazepine drugs on human and rabbit erythrocyte carbonic anhydrase enzymes

Carbonic anhydrase inhibitors (CAIs) are a class of pharmaceuticals used as antiglaucoma agents, diuretics and antiepileptics. Thus, discovery of novel CAIs has become of great importance in the recent years. In the current study, in vitro and in vivo inhibition effects of benzodiazepine drugs, diazepam and midazolam, on human erythrocytes carbonic anhydrase I and II isozymes were investigated. After purification of the isoenzymes, in vitro inhibition assays were performed and K_i values were determined to be of 141.5 μM and 40.7 μM for hCA I and of 5.11 μM and 0.58 μM against hCA II by the esterase activity assay, respectively. The drugs showed strong inhibitory effects on hCA II, in the same range as the clinically used sulphonamide acetazolamide. For in vivo studies, five adult male New Zealand White rabbits (3–4.2?kg) were selected for intravenous administrations of the drugs (2?mg/kg and 0.2?mg/kg body weight, respectively). The enzyme was significantly inhibited by 2?mg/kg diazepam (p?<?0.05), and 0.2?mg/kg midazolam (p?<?0.05) for up to 30?min following intravenous administration.     

Design and Evaluation of a Novel Felbinac Transdermal Patch: Combining Ion-Pair and Chemical Enhancer Strategy

The aim of this study was to design a novel felbinac (FEL) patch with significantly higher (P?<?0.05) skin permeation amount than the commercial product SELTOUCH® using ion-pair and chemical enhancer strategy, overcoming the disadvantage of the large application area of SELTOUCH®. Six complexes of FEL with organic amines diethylamine (DEA), triethylamine (TEA), N-(2′-hydroxy-ethanol)-piperdine (HEPP), monoethanolamine (MEtA), diethanolamine (DEtA), and triethanolamine (TEtA) were prepared by ion-pair interaction, and their formation were confirmed by differential scanning calorimetry (DSC), powder X-ray diffraction (pXRD), infared spectroscopy (IR), and proton nuclear magnetic resonance spectroscopy (¹H-NMR). Subsequently, the effect of ion-pair complexes and chemical enhancers were investigated through in vitro and in vivo experiments using rabbit abdominal skin. Results showed that FEL-TEA was the most potential candidate both in isopropyl palmitate (IPP) solution and transdermal patches. Combining use of 10% N-dodecylazepan-2-one (Azone), the optimized FEL-TEA patch achieved a flux of 18.29?±?2.59 μg/cm²/h, which was twice the amount of the product SELTOUCH® (J?=?9.18?±?1.26 μg/cm²/h). Similarly, the area under the concentration curve from time 0 to time t (AUC_0-t ) in FEL-TEA patch group (15.94?±?3.58 h.μg/mL) was also twice as that in SELTOUCH® group (7.31?±?1.16 h.μg/mL). Furthermore, the in vitro skin permeation results of FEL-TEA patch was found to have a good correlation with the in vivo absorption results in rabbit. These findings indicated that a combination of ion-pair and chemical enhancer strategy could be useful in developing a novel transdermal patch of FEL.     

Effects of Selenium and L-Carnitine on Oxidative Stress in Blood of Rat Induced by 2.45-GHz Radiation from Wireless Devices

The levels of blood lipid peroxidation, glutathione peroxidase, reduced glutathione, and vitamin C were used to follow the level of oxidative damage caused by 2.45 GHz electromagnetic radiation in rats. The possible protective effects of selenium and L-carnitine were also tested and compared to untreated controls. Thirty male Wistar Albino rats were equally divided into five groups, namely Groups A₁ and A₂: controls and sham controls, respectively; Group B: EMR; Group C: EMR + selenium, Group D: EMR + L-carnitine. Groups B–D were exposed to 2.45 GHz electromagnetic radiation during 60 min/day for 28 days. The lipid peroxidation levels in plasma and erythrocytes were significantly higher in group B than in groups A₁ and A₂ (p?<?0.05), although the reduced glutathione and glutathione peroxidase values were slightly lower in erythrocytes of group B compared to groups A₁ and A₂. The plasma lipid peroxidation level in group A₂ was significantly lower than in group B (p?<?0.05). Erythrocyte reduced glutathione levels (p?<?0.01) in group B; erythrocyte glutathione peroxidase activity in group A₂ (p?<?0.05), group B (p?<?0.001), and group C (p?<?0.05) were found to be lower than in group D. In conclusion, 2.45 GHz electromagnetic radiation caused oxidative stress in blood of rat. L-carnitine seems to have protective effects on the 2.45-GHz-induced blood toxicity by inhibiting free radical supporting antioxidant redox system although selenium has no effect on the investigated values.     

Relation between mechanical foam-breaking difficulty and the foaming characteristics of solutions

Using a small foaming apparatus, liquid foaming characteristics such as liquid holdup in foamate flow (φ_t), rate of liquid drainage from foam (ν), foam velocity (u_f) and foam size (d_f) were examined for various liquids. A parameter φ_f, incorporating φ_t, ν and u_f, was obtained. The relationship among φ_f, d_f and the liquid holdup in foam, φ_b, in the actual gas-bubbling systems under foam control was expressed in the form of φ_b ∞ φ_fd_f^1.83, regardless of the type of foaming liquid or its concentration. This relationship was useful for the prediction of φ_b as related to mechanical foam-breaking difficulty.     

Effects of Selenium Source and Level on Growth Performance, Tissue Selenium Concentrations, Antioxidation, and Immune Functions of Heat-Stressed Broilers

An experiment is conducted to investigate the effects of selenium (Se) source and level on growth performance, tissue Se concentrations, antioxidation, and immune functions of heat-stressed broilers from 22 to 42?days of age. A total of 210 22-day-old Arbor Acres commercial male chicks were assigned by body weight to one of seven treatments with six replicates of five birds each in a completely randomized design involving a 3?×?2 factorial arrangement plus one Se-unsupplemented basal diet control (containing 0.027?mg of Se/kg). The three Se sources were sodium selenite (Na₂SeO₃), Se yeast, and AMMS Se (Se protein), and the two supplemental Se levels were 0.15 or 0.30?mg Se/kg. All birds were reared under heat-stressed condition (33?±?1?°C during 0900?C1700?hours and 27?±?1?°C during 1900?C0700?hours with a relative humidity of 60?C80?%). The results showed that heat-stressed chicks fed Se-supplemented diets had higher (P?<?0.10) average daily feed intake, Se concentrations in liver and breast muscle, liver glutathione peroxidase (GSH-Px) activity, serum antibody titers against H5N1(Re-4 strain), H5N1(Re-5 strain) and lower (P?<?0.01) mortality compared with the control. Chicks fed the diets supplemented with 0.30?mg/kg of Se had higher (P?<?0.05) Se concentrations in liver and breast muscle, liver GSH-Px activity, and serum antibody titer against H5N1 (Re-4 strain) than those fed the diets supplemented with 0.15?mg/kg of Se. Broilers fed the diets supplemented with Se yeast had higher (P?<?0.001) Se concentrations in liver and breast muscle than those fed the diets supplemented with Na₂SeO₃ or AMMS Se. However, broilers fed the diets supplemented with AMMS Se had higher (P?<?0.05) serum antibody titers against H5N1 (Re-4 strain) and H5N1 (Re-5 strain) than those fed the diets supplemented with Na₂SeO₃. These results indicated that Se yeast was more effective than Na₂SeO₃ or AMMS Se in increasing tissue Se retention; however, AMMS Se was more effective than Na₂SeO₃ or Se yeast in improving immune functions of heat-stressed broilers.     

Cross-Correlation Functions for a Neuronal Model

Cross-correlation functions, R_XY(t,τ), are obtained for a neuron model which is characterized by constant threshold θ, by resetting to resting level after an output, and by membrane potential U(t) which results from linear summation of excitatory postsynaptic potentials h(t). The results show that: (1) Near time lag τ = 0, R_XY(t,τ) = f_U [θ-h(τ), t + τ] {h′(τ) + E_U [u′(t + τ)]} for positive values of this quantity, where f_U(u,t) is the probability density function of U(t) and E_U [u′(t + τ)] is the mean value function of U′(t + τ). (2) Minima may appear in R_XY(t,τ) for a neuron subjected only to excitation. (3) For large τ, R_XY(t,τ) is given approximately by the convolution of the input autocorrelation function with the functional of point (1). (4) R_XY(t,τ) is a biased estimator of the shape of h(t), generally over-estimating both its time to peak and its rise time.     

Synthesis and biological evaluation of novel analogues of Gly-l-Pro-l-Glu (GPE) as neuroprotective agents

This study investigated the anti-inflammatory effects of novel pseudotripeptides (GPE 1–3) as potential candidates to counteract neuroinflammation processes in Alzheimer’s disease.GPE 1–3 pseudotripeptides are synthetic derivatives of Gly-l-Pro-l-Glu (GPE), the N-terminal tripeptide of IGF-1, obtained through the introduction of isosteres of the amidic bond (aminomethylene unit) to increase the metabolic stability of the native tripeptide. The results showed that all synthetic derivatives possessed higher half-lives (t_1/2?>?4?h) than GPE (t_1/2?=?30?min) in human plasma and had good water solubility. The biological results demonstrated that GPE 1–3 had protective properties in several experimental models of treated THP-1 cells. Notably, the novel pseudotripeptides influenced inflammatory cytokine expression (IL-1β, IL-18, and TNF-α) in Aβ_25–35-, PMA-, and LPS-treated THP-1 cells. In PMA-differentiated THP-1 macrophages, both GPE 1 and GPE 3 reduced the expression levels of all selected cyto-chemokines, even though GPE 3 showed the best neuroprotective properties.     

The Molecular Basis of Leukocyte Adhesion Involving Phosphatidic Acid and Phospholipase D

Defining how leukocytes adhere to solid surfaces, such as capillary beds, and the subsequent migration through the extracellular matrix, is a central biological issue. We show here that phospholipase D (PLD) and its enzymatic reaction product, phosphatidic acid (PA), regulate cell adhesion of immune cells (macrophages and neutrophils) to collagen and have defined the underlying molecular mechanism in a spatio-temporal manner that coincides with PLD activity timing. A rapid (t_½ = 4 min) and transient activation of the PLD1 isoform occurs upon adhesion, and a slower (t_½ = 7.5 min) but prolonged (>30 min) activation occurs for PLD2. Importantly, PA directly binds to actin-related protein 3 (Arp3) at EC₅₀ = 22 nm, whereas control phosphatidylcholine did not bind. PA-activated Arp3 hastens actin nucleation with a kinetics of t_½ = 3 min at 300 nm (compared with controls of no PA, t_½ = 5 min). Thus, PLD and PA are intrinsic components of cell adhesion, which reinforce each other in a positive feedback loop and react from cues from their respective solid substrates. In nascent adhesion, PLD1 is key, whereas a sustained adhesion in mature or established focal points is dependent upon PLD2, PA, and Arp3. A prolonged adhesion could effectively counteract the reversible intrinsic nature of this cellular process and constitute a key player in chronic inflammation.     

Combined Impact of Exercise and Temperature in Learning and Memory Performance of Fluoride Toxicated Rats

In previous studies, we investigated a link between high fluoride exposure and functional IQ deficits in rats. This study is an extension conducted to explore the combined influence of physical exercise and temperature stress on the learning ability and memory in rats and to assess whether any positive modulation could be attenuated due to exercise regimen subjected to F-toxicated animals at different temperatures. Accumulation of ingested fluoride resulted significant inhibition in acetylcholinesterase activity (P?<?0.05), plasma cortisol levels (P?<?0.05), and impaired the acquisition, performance, latency time, and retention in fluoride-exposed animals. Fluoride-toxicated rats took more number of sessions during the learning phase [F _{5, 35}?=?19.065; P?<?0.05] and post hoc analysis on the number of correct choices revealed that there was a significant effect of treatments [F _{5, 30}?=?15.763; P?<?0.05]; sessions [F _{8, 240}?=?58.698; P?<?0.05]; and also significant difference in the interactions [F _{40, 240}?=?1.583; P?<?0.05]. The latency data also revealed a significant difference between groups [F _{5, 30}?=?28.085; P?<?0.05]; time?=?[F _{8, 240}?=?136.314; P?<?0.05]; and there was a significant difference in the interactions [F _{40, 240}?=?2.090; P?<?0.05]. In order to ascertain if interdependence between fluoride concentrations and the foregoing free radical parameters, respective correlation coefficients were calculated and results clearly emphasize the positive role of exercise in the promotion of cognitive functions by decreasing fluoride levels in rat hippocampus. A significant recovery in cognitive function was noticed in all the exercised animals due to reduced burden of brain oxidative stress. In comparison to exercise regimens performed at different temperatures, high (35?°C) and low temperatures (20?°C) led to a slower acquisition and poor retention of the task when compared to thermo neutral temperatures (25 and 30?°C). Thus exercise up-regulate antioxidant defenses and promote learning abilities in fluorotic population.     

Changes in fucosylation of human seminal IgG and secretory component of IgA in leukocytospermic patients

Our study compares the status of human seminal plasma immunoglobulin G (IgG) and IgA secretory component (SC) fucosylation between infertile leukocytospermic and normal, fertile normozoospermic patients. The seminal IgG and SC are decorated with AAL-reactive core fucose, and antennary UEA- and LTA-reactive fucose of Lewis^y and Lewis^x structures, respectively. However, a correlation between IgG core fucosylation and IgG concentration (r?=??0.52; p?<?0.0003) was observed. The IgG present in leukocytospermic samples is characterized by lower expression of core fucose than in the normal group (0.82?±?0.3 AU and 1.2?±?0.3 AU, respectively; p?<?0.002). In seminal plasma the SC is present in two forms: 78-kDa and 63-kDa. The present study has also shown a higher AAL and LTA specific reactivity of glycans expressed in 63-kDa SC, in comparison to 78-kDa SC, in the normal group. In leukocytospermia, the values of specific lectin reactivity for core fucose, fucose α(1-2)- and α(1-3)- linked, were similar for both SC bands. Moreover, the present study has shown that in leukocytospermic samples the mean concentrations of IgG and S-IgA are twice as high (131.68?±?102.6 mg/l and 36?±?27 mg/l, respectively) as in the normal group (67.68?±?29.2 mg/l; p?<?0.02, and 19?±?18 mg/l, p?<?0.019, respectively). The analysis of IgG and SC fucosylation status and the determination of IgG and S-IgA concentrations in seminal plasma might constitute a valuable diagnosis tools for the evaluation of male infertility associated with leukocytospermia with accompanying inflammation.