Study of antinociceptive effect of paroxetine in acute pain in albino rats

Background: Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage. In spite of having a number of drugs like NSAIDS and opioids for the management of pain, there is still need for an ideal analgesic agent with favourable safety profile. Many studies have shown that antidepressant drugs also have analgesic activity and particularly, selective serotonin reuptake inhibitors (SSRI) are effective in mixed and chronic pain. This study was done to evaluate antinociceptive effect of Paroxetine in albino rat and to compare antinociceptive effect of Paroxetine with the standard drug pentazocine in albino rat.Methods: Animals were divided into five groups of six each, group I as control, group II as standard whereas groups III, IV and V as test groups (three doses). Antinociceptive effect of group II pentazocine (10 mg/kg intraperitoneal) and group III, IV and V received paroxetine (2.5 mg/kg, 5 mg/kg, and 10 mg/kg bodyweight intraperitoneally respectively) was evaluated in adult albino rats by Tail flick method.Results: Mean RT after 120 minutes of injection of Paroxetine (10 mg) was higher than baseline value of 3.42 second with, mean difference 9.55±0.45 and is significant when compared to control. No significant difference in RT was found between paroxetine 10 mg and pentazocine 10 mg. No significant difference found when baseline reading was compared with 120 minutes readings of paroxetine 2.5 group.Conclusions: Paroxetine, a SSRI antidepressant, has a clear antinociceptive activity

Collision and symmetry-breaking in the transition to strange nonchaotic attractors

Strange nonchaotic attractors (SNAs) can be created due to the collision of an invariant curve with itself. This novel ``homoclinic'' transition to SNAs occurs in quasiperiodically driven maps which derive from the discrete Schr\"odinger equation for a particle in a quasiperiodic potential. In the classical dynamics, there is a transition from torus attractors to SNAs, which, in the quantum system is manifest as the localization transition. This equivalence provides new insights into a variety of properties of SNAs, including its fractal measure. Further, there is a {\it symmetry breaking} associated with the creation of SNAs which rigorously shows that the Lyapunov exponent is nonpositive. By considering other related driven iterative mappings, we show that these characteristics associated with the the appearance of SNA are robust and occur in a large class of systems.Comment: To be appear in Physical Review Letter

Dimer Decimation and Intricately Nested Localized-Ballistic Phases of Kicked Harper

Dimer decimation scheme is introduced in order to study the kicked quantum systems exhibiting localization transition. The tight-binding representation of the model is mapped to a vectorized dimer where an asymptotic dissociation of the dimer is shown to correspond to the vanishing of the transmission coefficient thru the system. The method unveils an intricate nesting of extended and localized phases in two-dimensional parameter space. In addition to computing transport characteristics with extremely high precision, the renormalization tools also provide a new method to compute quasienergy spectrum.Comment: There are five postscript figures. Only half of the figure (3) is shown to reduce file size. However, missing part is the mirror image of the part show

Validation of verbal autopsy tool for ascertaining the causes of stillbirth

Objective: To assess performance of the WHO revised verbal autopsy tool for ascertaining the causes of still birth in comparison with reference standard cause of death ascertained by standardized clinical and supportive data.Methods: All stillbirths at a tertiary hospital in Karachi, Pakistan were prospectively recruited into study from August 2006- February 2008. The reference standard cause of death was established by two senior obstetricians within 48 hours using the ICD coding system. Verbal autopsy interviews using modified WHO tool were conducted by trained health workers within 2- 6 weeks of still birth and the cause of death was assigned by second panel of obstetricians. The performance was assessed in terms of sensitivity, specificity and Kappa.Results: There were 204 still births. Of these, 80.8% of antepartum and 50.5% of intrapartum deaths were correctly diagnosed by verbal autopsy. Sensitivity of verbal autopsy was highest 68.4%, (95%CI: 46-84.6) for congenital malformation followed by obstetric complication 57.6%, (95%CI: 25-84.2). The specificity for all major causes was greater than 90%. The level of agreement was high (kappa=0.72) for anomalies and moderate (k=0.4) for all major causes of still birth, except asphyxia.Conclusion: Our results suggest that verbal autopsy has reasonable validity in identifying and discriminating between causes of stillbirth in Pakistan. On the basis of these findings, we feel it has a place in resource constrained areas to inform strategic planning and mobilization of resources to attain Millennium Development Goal

Free radical scavenging activity of Lantana aculeata root extract in hyperlipidemic rats.

Abstract: Lantana aculeata is a common weed that grows abundantly in many parts of India. The aerial part of the plant is reported to be toxic while the roots were found to be non-toxic when tested in albino rats. The alcoholic extract of the roots showed a significant hypolipidemic activity in normal rats. Hence the roots were studied for their free radical scavenging potential in hyperlipidemic animals by administering the alcoholic extract (LAR) in doses of 25, 50 and 100 mg/kg for 30 days. The levels of LPO, non-enzymatic antioxidant (TRG) and enzymatic antioxidants viz. SOD, CAT and GPx that showed changes in diseased condition were reverted back to near normal values by LAR extract treatment of plasma, liver and heart tissues. The presence of flavonoids besides oleanolic acid in large amounts might have caused the observed effect

Loneliness, social support and cardiovascular reactivity to laboratory stress

Self-reported or explicit loneliness and social support have been inconsistently associated with cardiovascular reactivity (CVR) to stress. The present study aimed to adapt an implicit measure of loneliness, and use it alongside the measures of explicit loneliness and social support, to investigate their correlations with CVR to laboratory stress. Twenty-five female volunteers aged between 18 and 39 years completed self-reported measures of loneliness and social support, and an Implicit Association Test (IAT) of loneliness. The systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) reactivity indices were measured in response to psychosocial stress induced in the laboratory. Functional support indices of social support were significantly correlated with CVR reactivity to stress. Interestingly, implicit, but not explicit, loneliness was significantly correlated with DBP reactivity after one of the stressors. No associations were found between structural support and CVR indices. Results are discussed in terms of validity of implicit versus explicit measures and possible factors that affect physiological outcomes

Do positive or negative experiences of social support relate to current and future health? Results from the Doetinchem Cohort Study

Cross-sectional studies have reported associations between social support and health, but prospective evidence is less conclusive. This study aims to investigate the associations of positive and negative experiences of social support with current and future lifestyle factors, biological risk factors, self-perceived health and mental health over a 10-year period