Galanin-like peptide stimulates feeding and sexual behavior via dopaminergic fibers within the medial preoptic area of adult male rats

Galanin-like peptide (GALP) is located in the arcuate nucleus (Arc) of the hypothalamus and is known to regulate both food intake and sexual behaviors in adult male rats. We have previously demonstrated that ICV GALP administration elicits a significant fos response within the medial preoptic area (mPOA). GALP is known to stimulate both food intake and male-typical sex behavior, presumably by direct actions within the mPOA. Recent data from our and other labs have led us to suspect that GALP effects on sex behaviors are due to activation of incertohypothalamic dopaminergic neurons that terminate within the mPOA. To test the hypothesis that GALP activates mPOA dopaminergic systems, we utilized an immunolesion technique to eliminate dopaminergic fiber input to the mPOA via a dopamine transporter-specific toxin (DATSAP, n = 8) and compared to control injections (SAP, n = 8). All animals were sexually experienced adult male Long-Evans rats. DATSAP-treated male rats showed a significant (p < 0.001) reduction in male sexual behaviors compared to SAP controls. We found that elimination of dopaminergic fibers within the mPOA significantly (p < 0.001) eliminated all aspects of male sexual behavior under normal mating paradigms. Injections of GALP (5.0 nmol) significantly increased (p < 0.01) male sex behavior and food intake in SAP control male rats but GALP did not stimulate the expression of these behaviors in DATSAP-treated rats. The orexigenic and anorexigenic effects of GALP were significantly (p < 0.001) attenuated in DATSAP-treated male rats compared to SAP controls; however, ICV GALP was still able to significantly (p < 0.05) reduce 24 h body weight in both DATSAP and SAP rats. ICV GALP significantly (p < 0.05) stimulated fos within the mPOA of SAP rats but not in DATSAP-treated male rats. These data suggest that GALP activates feeding and sexual behaviors in male rats by stimulating dopaminergic neurons that terminate within the mPOA.     

Characterization of spinal amino acid release and touch-evoked allodynia produced by spinal glycine or GABAA receptor antagonist

Intrathecal strychnine (glycine antagonist) or bicuculline (GABA_A antagonist) yields a touch-evoked agitation that is blocked by N-methyl-d-aspartate receptor antagonism. We examined the effects of intrathecal strychnine and bicuculline on touch-evoked agitation and the spinal release of amino acids. Fifty-two Sprague–Dawley rats were prepared under halothane anesthesia with a lumbar intrathecal catheter and a loop dialysis catheter. Four days after implantation, rats were randomized to receive an intrathecal injection of N-methyl-d-aspartate (3 μg), strychnine (3 μg) or bicuculline (10 μg), or a combination of N-methyl-d-aspartate with bicuculline or strychnine. The agitation produced by brief light tactile stroking of the flank (tactile allodynia), and the spontaneous spinal release of glutamate, taurine and serine was measured. Intrathecal N-methyl-d-aspartate, strychnine and bicuculline produced similar touch-evoked allodynia. Intrathecal bicuculline and N-methyl-d-aspartate alone evoked a transient spinal release of glutamate and taurine, but not serine, in the 0–10 min sample, while strychnine did not affect spinal transmitter release at any time.As GABA_A but not glycine receptor inhibition at equi-allodynic doses increases glutamate release, while the allodynia of both is blocked by N-methyl-d-aspartate receptor antagonism, we hypothesize that GABA_A sites regulate presynaptic glutamate release, while glycine regulates the excitability of neurons postsynaptic to glutamatergic terminals.     

Role of α2-adrenoceptors in the lateral parabrachial nucleus in the control of body fluid homeostasis

Central α₂-adrenoceptors and the pontine lateral parabrachial nucleus (LPBN) are involved in the control of sodium and water intake. Bilateral injections of moxonidine (α₂-adrenergic/imidazoline receptor agonist) or noradrenaline into the LPBN strongly increases 0.3 M NaCl intake induced by a combined treatment of furosemide plus captopril. Injection of moxonidine into the LPBN also increases hypertonic NaCl and water intake and reduces oxytocin secretion, urinary sodium, and water excreted by cell-dehydrated rats, causing a positive sodium and water balance, which suggests that moxonidine injected into the LPBN deactivates mechanisms that restrain body fluid volume expansion. Pretreatment with specific α₂-adrenoceptor antagonists injected into the LPBN abolishes the behavioral and renal effects of moxonidine or noradrenaline injected into the same area, suggesting that these effects depend on activation of LPBN α₂-adrenoceptors. In fluid-depleted rats, the palatability of sodium is reduced by ingestion of hypertonic NaCl, limiting intake. However, in rats treated with moxonidine injected into the LPBN, the NaCl palatability remains high, even after ingestion of significant amounts of 0.3 M NaCl. The changes in behavioral and renal responses produced by activation of α₂-adrenoceptors in the LPBN are probably a consequence of reduction of oxytocin secretion and blockade of inhibitory signals that affect sodium palatability. In this review, a model is proposed to show how activation of α₂-adrenoceptors in the LPBN may affect palatability and, consequently, ingestion of sodium as well as renal sodium excretion.     

Vasopressin and sympathetic systems mediate the cardiovascular effects of the GABAergic system in the bed nucleus of the stria terminalis

The bed nucleus of the stria terminalis (BST) is an important part of the limbic system. It has been shown that chemical stimulation of the BST elicited cardiovascular depressive and bradycardic responses. It was also demonstrated that GABA is present in the BST, though its role in cardiovascular control is not yet understood. This study was performed to find the effects of GABA receptor subtypes in the BST on cardiovascular responses and to find the possible mechanisms that mediate these responses in urethane-anesthetized rats. Microinjection of muscimol (500 pmol/100 nl), a GABA_A agonist, into the BST produced a weak unsignificant decrease in the mean arterial pressure (MAP) and heart rate (HR). Injection of bicuculline methiodide (BMI, 100 pmol/100 nl), a GABA_A antagonist, caused a significant increase in the MAP (41.3 ± 5.1 mmHg) as well as in the HR (33.2 ± 5.6 beats/min). Injection of two doses (500 and 1000 pmol/100 nl) of phaclofen, a GABA_B antagonist, produced no significant change in either MAP or HR. Administration (i.v.) of the muscarinic receptor blocker, homatropine methyl bromide had no effect on the magnitude of mean arterial pressure or heart rate responses to BMI. This suggests that the parasympathetic system is not involved in these responses. However, administration (i.v.) of the nicotinic receptor blocker, hexamethonium bromide had no effect on the magnitude of mean arterial pressure response but abolished heart rate response to BMI. This suggests that the sympathetic system is involved in the bradycardic effect of GABA. On the other hand, administration (i.v.) of a selective vasopressin V₁ receptor antagonist abolished the pressor effect of BMI, which indicates that the GABAergic system of the BST decreases the arterial pressure via tonic inhibition of vasopressin release. In summary, we demonstrated, for the first time, that GABA exerts its influence in the BST through the activation of GABA_A, but not GABA_B, receptors that, in turn, tonically inhibit vasopressin release and sympathetic outflow to the heart.     

Opioid activation in the lateral parabrachial nucleus induces hypertonic sodium intake

Opioid mechanisms are involved in the control of water and NaCl intake and opioid receptors are present in the lateral parabrachial nucleus (LPBN), a site of important inhibitory mechanisms related to the control of sodium appetite. Therefore, in the present study we investigated the effects of opioid receptor activation in the LPBN on 0.3 M NaCl and water intake in rats. Male Holtzman rats with stainless steel cannulas implanted bilaterally in the LPBN were used. In normohydrated and satiated rats, bilateral injections of the opioid receptor agonist beta-endorphin (2 nmol/0.2 mul) into the LPBN induced 0.3 M NaCl (17.8+/-5.9 vs. saline: 0.9+/-0.5 ml/240 min) and water intake (11.4+/-3.0 vs. saline: 1.0+/-0.4 ml/240 min) in a two-bottle test. Bilateral injections of the opioid antagonist naloxone (100 nmol/0.2 mul) into the LPBN abolished sodium and water intake induced by beta-endorphin into the LPBN and also reduced 0.3 M NaCl intake (12.8+/-1.5 vs. vehicle: 22.4+/-3.1 ml/180 min) induced by 24 h of sodium depletion (produced by the treatment with the diuretic furosemide s.c.+sodium deficient food for 24 h). Bilateral injections of beta-endorphin into the LPBN in satiated rats produced no effect on water or 2% sucrose intake when water alone or simultaneously with 2% sucrose was offered to the animals. The results show that opioid receptor activation in the LPBN induces hypertonic sodium intake in satiated and normohydrated rats, an effect not due to general ingestive behavior facilitation. In addition, sodium depletion induced 0.3 M NaCl intake also partially depends on opioid receptor activation in the LPBN. The results suggest that deactivation of inhibitory mechanisms by opioid receptor activation in the LPBN releases sodium intake if excitatory signals were activated (sodium depletion) or not.     

Nintendo® Wii Fit based sleepiness tester detects impairment of postural steadiness due to 24 h of wakefulness

A field-usable sleepiness tester could reduce sleepiness related accidents. 15 subjects’ postural steadiness was measured with a Nintendo^® Wii Fit balance board every hour for 24 h. Body sway was quantified with complexity index, C_I, and the correlation between C_I and alertness predicted by a three-process model of sleepiness was calculated. The C_I group average was 8.9 ± 1.3 for alert and 7.9 ± 1.4 for sleep deprived subjects (p < 0.001, ρ = 0.94). The Wii Fit board detects the impairment of postural steadiness. This may allow large scale sleepiness testing outside the laboratory setting.     

A critical analysis of whole body bioimpedance spectroscopy (BIS) for the estimation of body compartments in health and disease

Aim of the study was to assess the accuracy and precision of a BIS device and the relative contribution of BIS beyond the anthropometric parameters. The output of the Impedimed device (SFB7) and the relative contribution of height, weight, age, sex and resistance values at zero and infinite frequency (R_zero and R_inf respectively) to the prediction of total body water (TBW_d, deuterium space), of extracellular fluid (ECF_br, sodium bromide space) and of fat mass (FM_DXA) were assessed in 116 subjects (32 healthy subjects and 84 patients with disorders of body composition). Using a repeated randomization procedure, new equations for TBW, ECF and FM were derived.The SFB7 gave measures of determination similar to those obtained with equations that included only anthropometric data. The SFB7, but not the newly derived regression equations, underestimated TBW and ECF by 3.82 ± 3.37 (mean ± SD) and by 0.93 ± 2.62 l and overestimated FM by 6.55 ± 3.86 kg. Nine of 16 patients with ECF overload as detected by ECF_br were also detected by BIS. BIS measurements contribute marginally but not significantly beyond anthropometric data to the prediction of TBW, ECF and FM, either in healthy subjects or in patients with disturbed body composition.     

Assessment of cortical bone elasticity and strength: Mechanical testing and ultrasound provide complementary data

Cortical bone is a compact tissue with anisotropic macroscopic mechanical properties determined by a microstructure and the quality of a mineralised collagen matrix. Anisotropic elastic properties and strength are usually measured on different groups of sample which can hardly be pooled; as a consequence little is known on the relationships between strength and elasticity in the different anatomical directions. A method is presented to measure on a same cortical bone sample: (1) Young's modulus and strength (σ_max) in the longitudinal direction; (2) stiffness (C₁₁) in the transverse direction. Longitudinal and transverse direction are taken along and perpendicular to the diaphysis axis, respectively. Ultrasonic techniques yield Young's modulus (E_a) and C₁₁; three-point bending tests yield Young's modulus (E) and σ_max. The relationships between strength, elasticity and density and their anatomical distributions were investigated for 36 human femur samples. (i) A marginal negative correlation was obtained for E_a and C₁₁ (R = ?0.21; p = 0.08); (ii) σ_max was significantly correlated to E and E_a (R ～ 0.5; p < 0.005) but not to C₁₁ (p > 0.2); (iii) density was not correlated with E and moderately with strength (R = 0.38; p < 0.3). Small density variability (±30 kg m^?3) may partly explain the results. The techniques presented are suited to a systematic characterization of bone samples.     

Loss of motoneurons in the ventral compartment of the rat hypoglossal nucleus following early postnatal exposure to alcohol

Perinatal alcohol exposure (AE) has multiple detrimental effects on cognitive and various behavioral outcomes, but little is known about its impact on the autonomic functions. In a rat model of fetal alcohol spectrum disorders (FASD), we investigated neurochemical and neuroanatomical alterations in two brainstem nuclei, the hypoglossal nucleus (XIIn) and the dorsal nucleus of the vagus nerve (Xdn).One group of male Sprague–Dawley rats (n = 6) received 2.625 g/kg ethanol intragastrically twice daily on postnatal days (PD) 4–9, a period equivalent to the third trimester of human pregnancy, and another group (n = 6) was sham-intubated. On PD 18–19, the rats were perfused and medullary sections were immunohistochemically processed for choline acetyltransferase (ChAT) or two aminergic receptors that mediate excitatory drive to motoneurons, α₁-adrenergic (α₁-R) and serotonin 2A (5-HT_2A-R), and c-Fos.Based on ChAT labeling, AE rats had reduced numbers of motoneurons in the ventral XIIn (XIIn-v; 35.4 ± 1.3 motoneurons per side and section vs. 40.0 ± 1.2, p = 0.022), but not in the dorsal XIIn or Xdn. Consistent with ChAT data, both the numbers of α₁-R-labeled motoneurons in the XIIn-v and the area of the XIIn-v measured using 5-HT_2A-R staining were significantly smaller in AE rats (19.7 ± 1.5 vs. 25.0 ± 1.4, p = 0.031 and 0.063 mm² ±0.002 vs. 0.074 ± 0.002, p = 0.002, respectively). Concurrently, both 5-HT_2A-R and c-Fos staining tended to be higher in AE rats, suggesting an increased activation.Thus, postnatal AE causes motoneuronal loss in the XIIn-v. This may compromise upper airway control and contribute to increased risk of upper airway obstructions and sudden infant death in FASD victims.     

Preventive effect of a galactoglucomannan (GGM) from Dendrobium huoshanense on selenium-induced liver injury and fibrosis in rats

This study was carried out to investigate the preventive effects of galactoglucomannan (GGM), a homogeneous polysaccharide from Dendrobium huoshanense, on liver injury and fibrosis induced by sodium selenite. Sprague–Dawley rats injected subcutaneously with sodium selenite at the dosage of 3.28 mg kg^?1 b. wt. were set as the model groups. Rats treated with sodium selenite at the dosage of 3.28 mg kg^?1 b. wt. and GGM at 50–200 mg kg^?1 b. wt. were set as the prevention groups. Biochemical and histological analysis showed that GGM significantly ameliorated selenite-induced liver injury and fibrosis in rats. Oral administration of GGM effectively attenuated the toxicity of selenite to liver tissue, which was judged both by the decreased activities of serum hepatic enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), and by liver histopathological examination. Meanwhile, GGM also reduced the levels of H₂O₂ and malondialdehyde (MDA), elevated the levels of GSH, restored the fluidity of hepatic plasma membrane, and retained the activities of endogenous enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST). The prevention of selenite-induced liver injury and fibrosis by GGM was further supported by the reduced expression of transforming growth factor-β1 (TGF-β1) and type I collagen. These results suggested that GGM may be developed into a novel antifibrotic agent for the prevention of liver injury and fibrosis.     

Adrenergic mechanisms of the Kölliker-Fuse/A7 area on the control of water and sodium intake

The blockade of serotoninergic receptors with methysergide or the activation of α₂-adrenoceptors with moxonidine into the lateral parabrachial nucleus (LPBN) increases water and 0.3 M NaCl intake in rats treated with furosemide (FURO) combined with captopril (CAP). In the present study we investigated the effects of bilateral injections of noradrenaline (the endogenous neurotransmitter for α-adrenoceptors) alone or combined with the α₂-adrenoceptor antagonist RX 821002 into the LPBN or into the rostral portion of the Kölliker-Fuse nucleus that includes also the A7 area (KF/A7 area) on FURO+CAP-induced water and 0.3 M NaCl intake. Male Holtzman rats with bilateral stainless steel guide-cannulas implanted into KF/A7 area or LPBN were used. FURO+CAP-induced 0.3 M NaCl intake strongly increased after bilateral injections of noradrenaline (80 or 160 nmol/0.2 μl) into LPBN (26.5±5.9 and 20.7±2.0 ml/2 h versus saline: 4.4±0.9 ml/2 h) or into the KF/A7 area (31.5±6.1 and 25.9±4.7 ml/2 h versus saline: 7.2±1.6 ml/2 h). Water intake increased with noradrenaline injected in KF/A7 area, however, this treatment reduced 0.06 M sucrose intake, suggesting that the increase of water and NaCl intake is not related to non-specific effect. Bilateral injections of RX 821002 (160 nmol/0.2 μl) into LPBN or KF/A7 area abolished the effects of noradrenaline (160 nmol/0.2 μl) in the same areas on 0.3 M NaCl intake (7.5±2.5 and 9.8±4.4 ml/2 h, respectively). Moxonidine (0.5 nmol/0.2 μl) injected bilaterally into the KF/A7 area increased 0.3 M NaCl intake (39.5±6.3 ml/3 h) and water intake, while methysergide (4 μg/0.2 μl) into the KF/A7 area did not alter 0.3 M NaCl or water intake. The results suggest that α₂-adrenoceptor activation is a common mechanism in the KF/A7 area and LPBN to facilitate sodium intake. However, the serotonergic mechanism is present in LPBN, not in the KF/A7 area.     

Influence of selenium and fluoride on blood antioxidant capacity of rats

This study is to explore the effect of selenium and fluoride on blood antioxidant capacity of rats, and try to find out the optimal level of selenium in drinking water against fluorosis. Animals were divided into control group, sodium fluoride treated group (NaF, 50 mg/L) and selenium + NaF treated group (sodium selenite 0.375, 0.75, 1.5 mg/L) in water were respectively administered to male rats, which were decapitated after 6 months. Their blood was collected for GSH-Px activity, plasma SOD activity, T-AOC assay, uric acid assay, sialic acid (SA) content and MDA content, and the fluidity of erythrocyte membrane by electron spin resonance (ESR) was analyzed. The results showed that, compared with the control group, the blood antioxidant capacity of the rats exposed to fluoride was down-regulated significantly (P < 0.05, P < 0.01), MDA content increased significantly (P < 0.05), the fluidity of erythrocyte membrane decreased (P < 0.05, P < 0.01). Meanwhile, the treatments of selenium along with NaF compared with fluorosis group, SOD activity, GSH-Px activity and T-AOC assay increased respectively, MDA content decreased significantly (P < 0.05) in NaF + Se (Se 0.75, 1.5 mg/L) treated groups, uric acid level was up-regulated, but had no statistical significant difference (P > 0.05). The fluidity of erythrocyte membrane showed significant increase (P < 0.05), the content of SA was lower. Fluorosis could induce the decline of blood antioxidant capacity and the fluidity of erythrocyte membrane, as evident in this study, and Se at different levels possess some antagonistic effects on blood induced by fluoride. However, high dose of selenium (1.5 mg/L) is the optimum concentration.     

Lateral parabrachial nucleus and central amygdala in the control of sodium intake

The lateral parabrachial nucleus (LPBN) and the central nucleus of the amygdala (CeA) are important areas for the control of sodium appetite. In the present study we investigated the effects of bilateral lesions of the CeA on the facilitation of water and 0.3 M NaCl intake produced by the blockade of serotonergic mechanisms or activation of α₂-adrenoceptors with bilateral injections of methysergide or moxonidine, respectively, into the LPBN. Male Holtzman rats (n=5–8) with bilateral sham or electrolytic lesions of the CeA (2 mA; 10 s) and stainless steel cannulas implanted bilaterally in the LPBN were used. In sham rats treated with the diuretic furosemide (10 mg/kg b.w.) combined with the angiotensin converting enzyme inhibitor captopril (5 mg/kg b.w) subcutaneously, bilateral injections of moxonidine (0.5 nmol) or methysergide (4 μg) into the LPBN increased 0.3 M NaCl intake (29.8±5.1 and 19.5±3.7 ml/2 h, respectively, versus vehicle: 8.3±1.4 ml/2 h) and water intake (17.9±3.7 and 23.3±2.8 ml/2 h, respectively, versus vehicle: 11.5±1.6 ml/2 h). Lesions of the CeA (5–18 days) abolished the increase in 0.3 M NaCl and water intake produced by bilateral injections of moxonidine (10.3±2.8 and 6.8±2.3 ml/2 h, respectively) and reduced the increase produced by methysergide (13.6±2.5 and 14.5±3.2 ml/2 h, respectively) into the LPBN. The present results show that the increase in water and 0.3 M NaCl intake produced by serotonergic blockade and α₂-adrenergic activation in the LPBN depends on the integrity of the CeA, suggesting that facilitatory mechanisms present in the CeA are essential for the increase of water and hypertonic NaCl intake produced by the blockade of the inhibitory mechanisms of the LPBN.     

Receptor changes in brain tissue of rats treated as neonates with capsaicin

Capsaicin, the hot chemical in chillies, administered to neonatal rats, causes destruction of polymodal nociceptive primary afferent neurons by acting on TRPV1 receptors causing intrinsic somatosensory deprivation. Although the effects of neonatal capsaicin treatment in the periphery have been extensively investigated, less is known about the brain networks to which the capsaicin sensory neurons are relayed. In the present study the effect of neonatal capsaicin treatment on brain receptors that have been shown to interact with TRPV1 was examined. Wistar rats were treated on neonatal day 2 with capsaicin and at 15–16 weeks of age, brains were processed to measure levels of muscarinic M₁/M₂ and M₂/M₄, serotonin 5HT_2A, cannabinoid CB₁, dopamine D₁, D₂ receptors and dopamine transporter. Overall increases in levels of muscarinic M₁/M₄ (F = 8.219, df = 1, p = 0.005), muscarinic M₂/M₄ (F = 99.759, df = 1, p < 0.0001), serotonin 5HT_2A (F = 28.892, df = 1, p < 0.0001), dopamine D₁ (F = 8.726, df = 1, p = 0.008) and cannabinoid CB₁ (F = 25.084, df = 1, p < 0.0001) receptors were found in the brains of capsaicin-treated rats, although significant regional changes occurred only in muscarinic M₂/M₄ and serotonin 5HT_2A receptors. The results of the present study suggest that neonatal intrinsic somatosensory deprivation may have a significant impact on substrates at the central nervous system that manifest as changes in central cholinergic, monaminergic and cannabinoid systems in the adult animal.     

Kinetics of the electrocardiographic changes after permanent coronary occlusion in rats: Relationship with infarct size

The electrocardiogram (ECG) has been a useful tool to identify ischemia in humans and laboratory animals. Previous ECG studies showed that presence of pathological Q waves in lead DI in rats submitted to ligature of the left coronary artery (LCA) is a good predictor of successful myocardial infarction (MI). This study aimed to determine the sensitivity and the specificity of these ECG findings to predict successful MI. Male Wistar rats were submitted to surgical ligature of the LCA (N = 86) or sham-operation (SO, N = 16). ECG was recorded under halothane/ether anesthesia before surgery and 1, 3, 5, 7, and 15 days later. MI was determined by the presence of a transmural fibrous scar. Sixty-nine rats survived and 60 showed fibrous scar indicating a successful production of MI (18 and 42 animals were analyzed 1 or 15 days after MI, respectively). Twenty-four hours after, Q amplitude was linearly related to infarct size (r = ?0.778; P < 0.01), but not 15 days after (r = ?0.416; P > 0.05). In 53 out of 60 rats with transmural scar, Q wave in lead DI was identified in the ECG. Absence of Q wave occurred in 7 animals. The sensitivity was 88% (CI₉₅ = 83–93%). Nine animals submitted to coronary ligature did not show infarct scar. One of these animals, however, showed Q wave in DI, indicating a specificity of 77% (CI₉₅ = 65–104%). In conclusion, ECG can be used as a reliable tool to identify MI and can be used to predict the infarct size as earlier as 1 day after LCA ligation in rats.     

Introduction of trifluoromethyl group into diphenyl diselenide molecule alters its toxicity and protective effect against damage induced by 2-nitropropane in rats

This study was undertaken to investigate if the introduction of trifluoromethyl (F₃C) group into diphenyl diselenide (PhSe)₂ molecule causes acute toxicity in rats. It was further examined if the presence of F₃C group in (PhSe)₂ molecule alters the protective effect caused by (PhSe)₂ against damage induced by 2-nitropropane (2-NP) in rats. To investigate the potential oral toxicity of (PhSe)₂ and (F₃CPhSe)₂, rats received a single oral application of (PhSe)₂ (7.8–312 mg/kg) or (F₃CPhSe)₂ (11.2–448 mg/kg). Calculated lethal dose (LD₅₀) for (PhSe)₂ and (F₃CPhSe)₂ was estimated to be 312 mg/kg (=1 mmol/kg) and 234 mg/kg (=0.52 mmol/kg), respectively. Oral administration of (PhSe)₂ in rats did not change plasma alanine and aspartate aminotransferase activities (AST and ALT) as well as urea and creatinine levels. The introduction of F₃C group into (PhSe)₂ molecule increased AST activity in plasma of rats. (PhSe)₂ (3.2 mg/kg=10 μmol/kg) and (F₃CPhSe)₂ (4.48 mg/kg=10 μmol/kg) protected ALT, AST and γ-glutamyl transferase (γ-GT) activities against the increase caused by oral administration of 2-NP (120 mg/kg) in rats. (PhSe)₂ and (F₃CPhSe)₂ ameliorated hepatic catalase activity altered by 2-NP in rats. These results indicate that the chemical alteration into (PhSe)₂ molecule introduced toxicity and altered its protective effect against damage induced by 2-NP in rats.     

Definition of a simple statistical parameter for the quantification of orientation in two dimensions: Application to cells on grooves of nanometric depths

Contact guidance is generally evaluated by measuring the orientation angle of cells. However, statistical analyses are rarely performed on these parameters. Here we propose a statistical analysis based on a new parameter σ, the orientation parameter, defined as the dispersion of the distribution of orientation angles. This parameter can be used to obtain a truncated Gaussian distribution that models the distribution of the data between ?90° and +90°. We established a threshold value of the orientation parameter below which the data can be considered to be aligned within a 95% confidence interval. Applying our orientation parameter to cells on grooves and using a modelling approach, we established the relationship σ = α_meas + (52° ? α_meas)/(1 + C_GDER) where the parameter C_GDE represents the sensitivity of cells to groove depth, and R the groove depth. The values of C_GDE obtained allowed us to compare the contact guidance of human osteoprogenitor (HOP) cells across experiments involving different groove depths, times in culture and inoculation densities. We demonstrate that HOP cells are able to identify and respond to the presence of grooves 30, 100, 200 and 500 nm deep and that the deeper the grooves, the higher the cell orientation. The evolution of the sensitivity (C_GDE) with culture time is roughly sigmoidal with an asymptote, which is a function of inoculation density. The σ parameter defined here is a universal parameter that can be applied to all orientation measurements and does not require a mathematical background or knowledge of directional statistics.     

Determinants of vitamin D status in healthy men and women aged 40–80 years

ObjectivesTo determine the contribution of life style and health related factors on vitamin D status in middle-aged and older men and women.Study designA cross-sectional single-center study in 400 male subjects (40–80 years) and 402 postmenopausal female subjects (56–73 years), conducted in a University Medical Center in the central part of the Netherlands (52 degrees northern latitude).Main outcome measuresMedical history, vitamin D, calcium and alcohol intake, physical activity, Body Mass Index, Blood pressure, smoking, total fat body mass and total lean body mass were measured using DEXA. Laboratory analysis included 25-hydroxyvitamin D (25OHD) and sex hormones.ResultsThirty-six percent of men and 51% of women had 25OHD less than 50 nmol/L. In summertime men had significant higher 25OHD as compared to women (81.5 vs 53.3 nmol/L, P = .000) but this difference disappeared come winter. In a saturated model, male gender (B = .16, P = .008), and season (summer vs winter B = .30, P = .000) remained statistically significant. In men, physical activity and season explained 21% of the variance. In women, household physical activity (B = .13, P = .03), sport physical activity (B = .02, P = .02) and estradiol (B = ?.003, P = .048) remained in the model,.ConclusionIn healthy middle-aged and older men and postmenopausal women, male gender and season were important predictors of vitamin D status. In men, physically activity and season, explained 21% of the variance in vitamin D status. In women, physical activity and estradiol explained 9.3% of the variance in vitamin D.     

PLA2G2A polymorphisms are associated with metabolic syndrome and type 2 diabetes mellitus. Results from the genetics of atherosclerotic disease Mexican study

The secretory phospholipase A₂ II A (sPLA₂-IIA) encoded by PLA2G2A gene hydrolyzes phospholipids liberating free fatty acids (FFAs) and lysophospholipids. If lipolysis exceeds lipogenesis, the free fatty acids undergo a continuous release into circulation. A sustained excessive increase in this release contributes to metabolic disease. The aim of the present study was to evaluate the role of PLA2G2A gene polymorphisms as susceptibility markers for metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) in Mexican population. Three PLA2G2A gene polymorphisms (rs876018, rs3753827 and rs11573156) were genotyped by 5′ exonuclease TaqMan assays in a group of 338 patients with T2DM, 460 individuals with MetS and 366 healthy controls. Under codominant 1 (codom1), dominant (dom) and additive (add) models adjusted by age, gender, body mass index (BMI), smoking habit, and hypertension, the rs876018 T allele was associated with increased risk of MetS [Odds Ratio (OR) = 1.66, P_codom1 = 0.005; OR = 1.67, P_dom = 0.003; OR = 1.49, P_add = 0.005] as compared to controls. On the other hand, under several models adjusted by the same variables, the rs3753827 A (OR = 1.52, P_codom1 = 0.039 and OR = 1.49, P_dom = 0.039) and rs11573156C alleles (OR = 6.46, P_codom1 = 0.013; OR = 6.70, P_codom2 = 0.009; OR = 6.65, P_dom = 0.009) were associated with increased risk of T2DM when compared with controls. In addition, the rs876018 T allele was associated with hypercholesterolemia (P_dom = 0.017, P_add = 0.009) and risk of subclinical atherosclerosis (SA) (P_dom = 0.041) in MetS when compared with controls. Also, this allele was associated with SA in T2DM patients (P_dom = 0.007). The TAG haplotype was significantly associated with increased risk of MetS (OR = 1.54, P = 0.006). Results suggest that PLA2G2A polymorphisms are involved in the risk of developing MetS and T2D and are associated with SA in this group of patients.