Idiosyncratic shocks, risk management and welfare dynamics in rural Ghana

International Development, Risk and Uncertainty,

Striatal dopamine D-2 receptors attenuate neuropathic hypersensitivity in the rat

Earlier studies indicate that striatal dopamine D-2 receptors are involved in pain regulation in non-neuropathic conditions. We assessed whether striatal dopamine D-2 receptors contribute to pain regulation also in neuropathic conditions. The spared nerve injury model of neuropathy was induced by unilateral ligation of the tibial and common peroneal nerves in the rat. In awake nerve-injured animals, pain-related withdrawal responses to calibrated monofilaments or noxious heating were attenuated following striatal administration of a dopamine D-2 receptor agonist quinpirole. Pain-related responses were attenuated only in the nerve-injured limb ipsilateral to the injection and in the midline (tail). In unoperated controls, striatal administration of quinpirole at an antihypersensitive dose did not influence withdrawal responses to mechanical stimulation. Attenuation of pain-related responses induced by striatal administration of quinpirole was reversed by intrathecal administration of a dopamine D-2 receptor antagonist (eticlopride) or a non-selective 5-HT receptor antagonist (methysergide), but not by an alpha(2)-adrenoceptor antagonist (atipamezole). In the rostroventromedial medulla of lightly anesthetized neuropathic animals, striatal administration of quinpirole significantly decreased the activity of presumably pronociceptive cells that are activated by noxious stimulation. The innocuous H-reflex in lightly anesthetized control animals was not suppressed by striatal administration of quinpirole at an antihypersensitive dose. The results indicate that striatal dopamine D-2 receptors attenuate neuropathic hypersensitivity. The antihypersensitive effect induced by striatal dopamine D-2 receptors in peripheral neuropathy involves suppression of impulse discharge of presumably pronociceptive neurons in the rostroventromedial medulla, and a descending influence acting on spinal 5-HT and dopamine D-2 receptors.This study was supported by the Academy of Finland and the Sigrid Jusélius Foundation, Helsinki, Finlandinfo:eu-repo/semantics/publishedVersio

Influence of arthritis on descending modulation of nociception from the paraventricular nucleus of the hypothalamus

We studied the influence of arthritis on descending modulation of nociception from the hypothalamic paraventricular nucleus (PVN) in the rat. Spinal nociception was assessed by the heat-evoked limb withdrawal in awake animals while neuronal responses were recorded in a potential brainstem relay, the rostroventromedial medulla (RVM), under pentobarbitone anesthesia. Following injection into the PVN, glutamate attenuated and lidocaine enhanced nociceptive spinal reflex responses in arthritic and control animals. In controls, PVN-induced antinociception was reversed by spinal administration of a 5-HT1A receptor or an α2-adrenoceptor antagonist but not by an opioid receptor antagonist. In arthritic animals, PVN-induced antinociception was not reversed by a 5-HT1A receptor antagonist, while the roles of α2-adrenoceptors or opioid receptors could not be assessed due to significant actions of antagonists alone. The spontaneous activity of presumably pronociceptive ON-cells of the RVM and that of antinociceptive OFF-cells was increased in arthritis. Lidocaine in the PVN increased ON-cell firing in control animals and decreased OFF-cell firing in arthritic animals, while glutamate failed to affect activity of RVM cells. The results indicate that the PVN influences phasic and tonic descending antinociception in arthritic as well as control conditions, and the RVM may contribute to the relay of this influence. In arthritis, the neurochemistry of descending antinociception differs at least partly from that in controls. Arthritis has a dual influence on the PVN-induced drive of relay cells in the RVM which reduces the arthritis-induced net change in the descending antinociceptive influence from the PVN.Grünenthal FoundationCalouste Gulbenkian FoundationCentre for International Mobility (CIMO)Sigrid Jusélius FoundationAcademy of Finlan

Safety of overlapping inpatient orthopaedic surgery: A multicenter study

BackgroundAlthough overlapping surgery is used to maximize efficiency, more empirical data are needed to guide patient safety. We conducted a retrospective cohort study to evaluate the safety of overlapping inpatient orthopaedic surgery, as judged by the occurrence of perioperative complications.MethodsAll inpatient orthopaedic surgical procedures performed at 5 academic institutions from January 1, 2015, to December 31, 2015, were included. Overlapping surgery was defined as 2 skin incisions open simultaneously for 1 surgeon. In comparing patients who underwent overlapping surgery with those who underwent non-overlapping surgery, the primary outcome was the occurrence of a perioperative complication within 30 days of the surgical procedure, and secondary outcomes included all-cause 30-day readmission, length of stay, and mortality. To determine if there was an association between overlapping surgery and a perioperative complication, we tested for non-inferiority of overlapping surgery, assuming a null hypothesis of an increased risk of 50%. We used an inverse probability of treatment weighted regression model adjusted for institution, procedure type, demographic characteristics (age, sex, race, comorbidities), admission type, admission severity of illness, and clustering by surgeon.ResultsAmong 14,135 cases, the frequency of overlapping surgery was 40%. The frequencies of perioperative complications were 1% in the overlapping surgery group and 2% in the non-overlapping surgery group. The overlapping surgery group was non-inferior to the non-overlapping surgery group (odds ratio [OR], 0.61 [90% confidence interval (CI), 0.45 to 0.83]; p < 0.001), with reduced odds of perioperative complications (OR, 0.61 [95% CI, 0.43 to 0.88]; p = 0.009). For secondary outcomes, there was a significantly lower chance of all-cause 30-day readmission in the overlapping surgery group (OR, 0.67 [95% CI, 0.52 to 0.87]; p = 0.003) and shorter length of stay (e, 0.94 [95% CI, 0.89 to 0.99]; p = 0.012). There was no difference in mortality.ConclusionsOur results suggest that overlapping inpatient orthopaedic surgery does not introduce additional perioperative risk for the complications that we evaluated. The suitability of this practice should be determined by individual surgeons on a case-by-case basis with appropriate informed consent.Level of evidenceTherapeutic Level III. See Instructions for Authors for a complete description of levels of evidence

Enhanced pronociception by amygdaloid group I metabotropic glutamate receptors in nerve-injured animals

Peripheral neuropathy has been associated with structural and functional changes of the amygdala, a key player in emotions. Here we study whether peripheral neuropathy influences pain regulation by the amygdala. For this purpose, we determined discharge rates of presumably pro- and antinociceptive pain-regulatory neurons in the rostral ventromedial medulla (RVM) following microinjection of various glutamatergic compounds into the central nucleus of the amygdala. RVM neurons were recorded in pentobarbitone-anesthetized rats with a peripheral nerve injury or sham-operation. In a separate behavioral experiment, we determined whether the influence of amygdaloid administration of a glutamatergic compound on affective pain-related behavior, as assessed by an aversive place-conditioning test, is changed by neuropathy. While glutamate or an NMDA receptor antagonist in the amygdala failed to induce marked changes in discharge rates of RVM cells, amygdaloid administration of DHPG, a group I metabotropic glutamate receptor (mGluR) agonist acting on mGluR1 and mGluR5, increased discharge rates of presumably pronociceptive RVM ON-cells in nerve-injured but not sham-operated animals. This pronociceptive effect of DHPG was reversed by MPEP (mGluR5 antagonist) and CPCCOEt (mGluR1 antagonist). CHPG, an mGluR5 agonist, failed to influence ONcell activity and DHPG failed to influence activity of presumably antinociceptive RVM OFF-cells. Amygdaloid administration of DHPG increased and that of CPCCOEt decreased affective pain-related behavior in nerve-injured animals. The results suggest that following nerve injury, the amygdaloid group I mGluR, particularly subtype mGluR1, has an enhanced pronociceptive effect providing a potential mechanism for emotional enhancement of pain in peripheral neuropathy.Fundação Calouste GulbenkianFundação para a Ciência e a Tecnologia (FCT

Assessment of the Relative Suitability of Three Different Soils for Dry Season Lettuce Production in Ghana

The research was conducted at the project site of the University of Educatoion, Winneba - Mampong campus between mid - November 2007 and Mid-April 2008. The main objective of the study was to compare the relative suitability of three soils in supporting lettuce production in the dry season. The treatments were Calcic Vertisol (Akuse scries), Rodic Nitisol (Ejura sesries) and Chromic Luvisol (Bediest series). The randomized complete block design was used in a pot experience with the three treatments and each replicated three times. Plant height, fresh leaf mass, leaf dry matter yield, fresh root mass, gravimetric moisture content, total porosity, drainability and bulk density were the parameters considered. From the result Bediesi Series recorded the highest growth rate as measured by plant height (266.5mm), fresh leaf weight (30.6g), leaf dry matter weight (4.9g) at 7 weeks after transplanting as well as been the most succulent with 84% succulent. Fresh root weight however, was highest with Akuse Series followed by Bediesi Series and Ejura Series in that decreasing order. Ejura Series recorded the least value for all growth and yield parameters measured. For soil parameters, Akuse Series recorded the highest value for porosity (43.0%) and gravimetric moisture of 6.43 throughout the period of field drying for 8weeks. Ejura Series Bediesi Series also recorded the highest value for drainability after 25 minutes of drainage, followed by Bediesi Series and then Akuse Series. The result of this work indicated that the Bediesi Series is the best soil type among the soils evaluated for lettuce production in the dry season in Ghana

Response of hydro-physical properties of a Chromic Luvisol in Ghana to different methods of application of Mucuna pruriens as a soil amendments

The study assessed the response of hydro-physical properties of Chromic Luvisol to different methods of application of Mucuna pruriens as a soil amendments in two separate experiments. A Randomized Complete Block Design (RCBD) with three replications was used with the following treatments: 7.04t/ha Mucuna pruriens as green manure (GM), 7.04t/ha Mucuna pruriens as live mulch (LM), 7.04t/ha Mucuna pruriens as in-situ mulch (IM) and a control plot which had no Mucuna pruriens as soil amendment. Data were collected on gravimetric (θ_g) and volumetric moisture content ( θ_v), residual moisture storage(R), sorptivity(s), cumulative infiltration (I), bulk density (ρ_b), total porosity (f), aeration porosity (ξ_a), aggregate stability (ASt) and soil temperature, for assessment of hydro-physical properties of the soil. The results from the experiments indicated that Mucuna pruriens as live mulch used as amendment significantly reduce bulk density (ρ_b), increased total porosity (f) and aeration porosity (ξ_a) thus it gave significant improvement on those soil physical properties measured while Mucuna pruriens as in-situ mulch improved aggregate stability (ASt) and gave optimal soil temperature. In the assessment of soil volumetric moisture content ( θ_v), residual moisture storage(R), sorptivity(s), cumulative infiltration(I), the study shows that Mucuna pruriens as in-situ mulch recorded the optimal values and was closely followed by Mucuna pruriens as live mulch

Fourier Method for Approximating Eigenvalues of Indefinite Stekloff Operator

We introduce an efficient method for computing the Stekloff eigenvalues associated with the Helmholtz equation. In general, this eigenvalue problem requires solving the Helmholtz equation with Dirichlet and/or Neumann boundary condition repeatedly. We propose solving the related constant coefficient Helmholtz equation with Fast Fourier Transform (FFT) based on carefully designed extensions and restrictions of the equation. The proposed Fourier method, combined with proper eigensolver, results in an efficient and clear approach for computing the Stekloff eigenvalues.Comment: 12 pages, 4 figure