Home About us Contact
|
Home About us Contact | ||
|
|
||
Thermal Thresholds (thermal + threshold)
Selected AbstractsBeneficial effects of C-peptide on incipient nephropathy and neuropathy in patients with Type 1 diabetes mellitusDIABETIC MEDICINE, Issue 3 2000B. -L. Summary Aims Recent studies have indicated that proinsulin C-peptide shows specific binding to cell membrane binding sites and may exert biological effects when administered to patients with Type 1 diabetes mellitus. This study was undertaken to determine if combined treatment with C-peptide and insulin might reduce the level of microalbuminuria in patients with Type 1 diabetes and incipient nephropathy. Methods Twenty-one normotensive patients with microalbuminuria were studied for 6 months in a double-blind, randomized, cross-over design. The patients received s.c. injections of either human C-peptide (600 nmol/24 h) or placebo plus their regular insulin regimen for 3 months. Results Glycaemic control improved slightly during the study and to a similar extent in both treatment groups. Blood pressure was unaltered throughout the study. During the C-peptide treatment period, urinary albumin excretion decreased progressively on average from 58 ,g/min (basal) to 34 ,g/min (3 months, P < 0.01) and it tended to increase, but not significantly so, during the placebo period. The difference between the two treatment periods was statistically significant (P < 0.01). In the 12 patients with signs of autonomic neuropathy prior to the study, respiratory heart rate variability increased by 21 ± 9% (P < 0.05) during treatment with C-peptide but was unaltered during placebo. Thermal thresholds were significantly improved during C-peptide treatment in comparison to placebo (n = 6, P < 0.05). Conclusion These results indicate that combined treatment with C-peptide and insulin for 3 months may improve renal function by diminishing urinary albumin excretion and ameliorate autonomic and sensory nerve dysfunction in patients with Type 1 diabetes mellitus. [source] Sensory function and pain in a population of patients treated for breast cancerACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2009O. J. VILHOLM Background: Chronic pain is often reported after surgery for breast cancer. This study examined pain and sensory abnormalities in women following breast cancer surgery. Methods: Sensory tests were carried out on the operated and contra-lateral side in 55 women with chronic pain after breast cancer treatment and in a reference group of 27 pain-free women, who had also undergone treatment for breast cancer. Testing included a numeric rating score of spontaneous pain, detection and pain threshold to thermal and dynamic mechanical stimuli and temporal summation to repetitive pinprick stimulation. The neuropathic pain symptom inventory was applied for participants with chronic pain. Results: The mean age was 58.6 years for the pain patients and 60.6 years for the pain-free patients. Thermal thresholds were significantly higher on the operated side than on the contra-lateral side in both groups and side difference in warmth detection threshold was significantly higher in the pain group than in the pain-free group (mean 3.8 °C vs. 1.1 °C, P=0.01). The frequency of cold allodynia was higher in participants with pain than in pain-free participants (15/53 vs. 1/25, P=0.01), and the frequency of temporal summation evoked by repetitive pinprick was higher in participants with pain than in pain-free participants (23/53 vs. 2/25, P=0.0009). The frequency of dynamic mechanical allodynia did not differ significantly between the two groups. Conclusion: These findings suggest that chronic pain after surgery for breast cancer is associated with sensory hyperexcitability and is a neuropathic pain condition. [source] Relationship between plasma concentrations and analgesia after intravenous fentanyl and disposition after other routes of administration in cats,JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2005S. A. ROBERTSON Data allowing rational use of analgesics in cats are limited. Pharmacokinetics and pharmacodynamics of fentanyl were studied in cats. Plasma fentanyl concentrations were measured using radioimmunoassay in a crossover study in six cats after 10 ,g/kg (i.v.) or by application of fentanyl in pluronic lecithin organogel (PLO) to the inner ear pinna. On a separate occasion thermal thresholds were measured after i.v. fentanyl (10 ,g/kg) or saline. Plasma fentanyl concentrations reached 4.7,8.31 ng/mL 2 min after i.v. administration and were undetectable after 95 min. Fentanyl was not detected in plasma at any time after PLO use. Thermal thresholds did not change following saline administration but were increased above baseline from 5 to 110 min after i.v. fentanyl. In this model a plasma concentration of >1.07 ng/mL was required to provide analgesia. Plasma concentrations were measured in additional cats after intranasal or oral dosing (2 ,g/kg) and after 30 ,g/kg in PLO gel. After oral and nasal dosing, Cmax values were 0.96 and 1.48 ng/mL at 5 and 2 min, respectively. Plasma fentanyl was not detected after application of the higher dose of fentanyl in PLO. [source] Control of summer and winter diapause in the leaf-mining fly Pegomyia bicolor Wiedemann (Dipt., Anthomyiidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 4 2001Effects of photoperiod and temperature on diapause induction and termination were investigated in both aestival and hibernal pupae of Pegomyia bicolor Wiedemann under field and laboratory conditions. In the field, summer diapause had occurred already in part of the first pupal population; the proportion of diapause gradually rose as the day length and temperature increased. This fly is a short-day species with a pupal summer and winter diapause. Summer diapause was induced by both long day-lengths and mild temperatures. The whole larval life is sensitive to photoperiod. Winter diapause was induced mainly by low temperatures, especially in the first 10 days after pupation. High temperatures strongly enhanced summer diapause induction regardless of photoperiod. The diapause-averting influence of short photoperiods was fully expressed only at moderately low temperatures. High temperatures delayed diapause development, resulting in a rather long summer diapause; whereas low temperatures hastened it, leading to a short winter diapause and showing a low thermal threshold for diapause development. In the field, the post-diapause development started in January, the coldest month, suggesting that the thermal requirements for post-diapause development is also low. [source] A world-wide study of high altitude treeline temperaturesJOURNAL OF BIOGEOGRAPHY, Issue 5 2004Christian Körner Abstract Aim, At a coarse scale, the treelines of the world's mountains seem to follow a common isotherm, but the evidence for this has been indirect so far. Here we aim at underpinning this with facts. Location, We present the results of a data-logging campaign at 46 treeline sites between 68° N and 42° S. Methods, We measured root-zone temperatures with an hourly resolution over 1,3 years per site between 1996 and 2003. Results, Disregarding taxon-, landuse- or fire-driven tree limits, high altitude climatic treelines are associated with a seasonal mean ground temperature of 6.7 °C (±0.8 SD; 2.2 K amplitude of means for different climatic zones), a surprisingly narrow range. Temperatures are higher (7,8 °C) in the temperate and Mediterranean zone treelines, and are lower in equatorial treelines (5,6 °C) and in the subarctic and boreal zone (6,7 °C). While air temperatures are higher than soil temperatures in warm periods, and are lower than soil temperatures in cold periods, daily means of air and soil temperature are almost the same at 6,7 °C, a physics driven coincidence with the global mean temperature at treeline. The length of the growing season, thermal extremes or thermal sums have no predictive value for treeline altitude on a global scale. Some Mediterranean (Fagus spp.) and temperate South Hemisphere treelines (Nothofagus spp.) and the native treeline in Hawaii (Metrosideros) are located at substantially higher isotherms and represent genus-specific boundaries rather than boundaries of the life-form tree. In seasonal climates, ground temperatures in winter (absolute minima) reflect local snow pack and seem uncritical. Main conclusions, The data support the hypothesis of a common thermal threshold for forest growth at high elevation, but also reflect a moderate region and substantial taxonomic influence. [source] Effect of temperature changes on the reproductive cycle of roach in Lake Geneva from 1983 to 2001JOURNAL OF FISH BIOLOGY, Issue 2 2006C. Gillet In Lake Geneva, the surface water temperature has increased by 1° C over 20 years probably as a result of climate change. The effects of changes in temperature on the reproductive cycle of the roach Rutilus rutilus were assessed in a 19 year survey. Over time, spawning tended to begin earlier. The consequences of temperature changes were assessed on two different stages of the female reproductive cycle: the development of the ovaries from the beginning of autumn to ovulation, and the onset of the spawning period. The development of the ovaries was studied for 7 consecutive years from October to June. From 1 October to the onset of spawning, it was possible to assess the gonado-somatic index (IG) of females in terms of time expressed as a sum of degree-days. The correlation between IG and the sum of degree-days was +0·97. The onset of the roach spawning period in Lake Geneva was triggered by a thermal threshold (median and range 190 ± 10 degree-days for the 15 previous days). From October to April, climate warming accelerated the development of gonads, then in May, a thermal threshold that triggered the onset of roach spawning occurred earlier. [source] Intraepidermal nerve fibre density, quantitative sensory testing and nerve conduction studies in a patient material with symptoms and signs of sensory polyneuropathyEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2006S. Løseth Small diameter nerve fibre (SDNF) neuropathy is an axonal sensory neuropathy affecting unmyelinated (C) and thin myelinated (A-delta) fibres. We have evaluated 75 patients with symptoms and signs suggesting SDNF dysfunction with or without symptoms and signs of co-existing large diameter nerve fibre involvement. The patients were examined clinically and underwent skin biopsy, quantitative sensory testing (QST) and nerve conduction studies (NCS). The purpose of this study was to compare the relationship between the different methods and in particular measurements of thermal thresholds and intraepidermal nerve fibre (IENF) density in the same site of the distal leg. The main subdivision of the patient material was made according to the overall NCS pattern. Patients with normal NCS (38) had 6.4 ± 3.8 and patients with abnormal NCS (37) had 4.4 ± 3.4 IENF per mm (P = 0.02). Limen (difference between warm and cold perception thresholds) was significantly higher (more abnormal) in those with abnormal than in those with normal NCS (22.1 ± 9.1 vs. 13.4 ± 5.6, P < 0.0001). Cold perception threshold was more abnormal (P < 0.0001) than warm perception threshold (P = 0.002). Correlation between IENF and QST was statistically significant only when NCS was abnormal, and thus dependent of a more severe neuropathic process in SDNFs. [source] The effects of local perfusion of DAMGO on extracellular GABA and glutamate concentrations in the rostral ventromedial medullaJOURNAL OF NEUROCHEMISTRY, Issue 3 2008Raf Jan-Filip Schepers Abstract Electrophysiological data suggest an involvement of rostral ventromedial medulla (RVM) GABA and glutamate (GLU) neurons in morphine analgesia. Direct evidence that extracellular concentrations of GABA or GLU are altered in response to mu opioid receptor (MOP-R) activation is, however, lacking. We used in vivo microdialysis to investigate this issue. Basal GABA overflow increased in response to intra-RVM perfusion of KCl (60 mmol/L). Reverse microdialysis of the MOP-R agonist d -Ala(2),NMePhe(4),Gly-ol(5)]enkephalin (DAMGO) (20,500 ,mol/L) produced a concentration-dependent decrease of RVM GABA overflow. Behavioral testing revealed that concentrations that decreased GABA levels increased thermal withdrawal thresholds. A lower agonist concentration that did not increase GABA failed to alter thermal thresholds. DAMGO did not alter GLU concentrations. However, KCl also failed to modify GLU release. Since rapid, transporter-mediated uptake may mask the detection of changes in GLU release, the selective excitatory amino acid transporter inhibitor pyrrolidine-2,4-dicarboxylic acid (tPDC, 0.6 mmol/L) was added to the perfusion medium for subsequent studies. tPDC increased GLU concentrations, confirming transport inhibition. KCl increased GLU dialysate levels in the presence of tPDC, demonstrating that transport inhibition permits detection of depolarization-evoked GLU overflow. In the presence of tPDC, DAMGO increased GLU overflow in a concentration-dependent manner. These data demonstrate that MOP-R activation decreases GABA and increases GLU release in the RVM. We hypothesize that the opposing effects of MOP-R on GLU and GABA transmission contribute to opiate antinociception. [source] QUANTITATIVE SENSORY TESTING AND SWEAT FUNCTION IN FRIEDREICH'S ATAXIA.JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000CORRELATION WITH CUTANEOUS INNERVATION To evaluate small fiber function in Friedreich's Ataxia (FA), we performed in 7 patients pin-prick, thermal thresholds, and sweat test. All tests were performed in four different sites: hand dorsum, anterior thigh, lateral distal leg, and foot dorsum. The same subjects underwent 3 mm punch skin biopsy from fingertip, anterior thigh, and lateral distal leg. We used a thin needle mounted on a calibrated nylon wire for the pin-prick test, and a Medoc 2001 TSA system for thermal threshold assessment. Sweat test was performed using a silicon mold after stimulation with pilocarpine by iontophoresis. Skin specimens, cut into 100-,m-thick sections, were double-stained using primary antibodies specific for collagen and nervous fibers and secondary antibodies labeled with Cy3 and Cy5 fluorophores. Tridimensional digitized images were obtained from z-series of 2-,m-thick optical sections acquired with a confocal microscope. We found in all patients in the more distal sites definite signs of functional impairment of the small fibers. These data correlated with the skin innervation morphological findings that showed, in the same sites, a sensible loss of small fibers regarding both the epidermal free endings and the subepidermal neural plexus. Less severe morphological abnormalities were found in the proximal sites. The large fiber neuropathy in FA is well documented. Our data show a length-dependent involvement of small fibers in the pathological process. [source] Relationship between plasma concentrations and analgesia after intravenous fentanyl and disposition after other routes of administration in cats,JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2005S. A. ROBERTSON Data allowing rational use of analgesics in cats are limited. Pharmacokinetics and pharmacodynamics of fentanyl were studied in cats. Plasma fentanyl concentrations were measured using radioimmunoassay in a crossover study in six cats after 10 ,g/kg (i.v.) or by application of fentanyl in pluronic lecithin organogel (PLO) to the inner ear pinna. On a separate occasion thermal thresholds were measured after i.v. fentanyl (10 ,g/kg) or saline. Plasma fentanyl concentrations reached 4.7,8.31 ng/mL 2 min after i.v. administration and were undetectable after 95 min. Fentanyl was not detected in plasma at any time after PLO use. Thermal thresholds did not change following saline administration but were increased above baseline from 5 to 110 min after i.v. fentanyl. In this model a plasma concentration of >1.07 ng/mL was required to provide analgesia. Plasma concentrations were measured in additional cats after intranasal or oral dosing (2 ,g/kg) and after 30 ,g/kg in PLO gel. After oral and nasal dosing, Cmax values were 0.96 and 1.48 ng/mL at 5 and 2 min, respectively. Plasma fentanyl was not detected after application of the higher dose of fentanyl in PLO. [source] A bilateral clinical model for the study of acute and chronic pain after breast-reduction surgeryACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2001R. F. Bell Background: There is a need for new clinical models to investigate effectively the development of pain after surgery and the effect, if any, of pre-emptive treatment. Bilateral models are of special interest, since the patient serves as his/her own control. The objective of this preliminary study was to test a clinical model for the study of acute and chronic pain after bilateral reduction mammoplasty. Methods: Eight patients participated in the study where the breasts were randomized to test and control groups. In each patient, one breast was preoperatively infiltrated with lidocaine and adrenaline and the other breast infiltrated with saline and adrenaline. Assessment included visual analogue scale (VAS) pain intensity, thermal thresholds, mapping for punctate hyperalgesia and tactile sensation. Assessments were made preoperatively, postoperatively and at 6 months after surgery. Results: With regard to acute postoperative pain intensity, the model demonstrated a clear difference between lidocaine and placebo treated breasts. There was no difference between lidocaine and placebo treated breasts with regard to chronic pain, but these results are inconclusive due to small number of patients. Conclusion: The model is sensitive and may be useful in studies of mechanisms of development and prevention of chronic pain after surgery. [source] Temperature related effects on embryonic development of the Mediterranean locust, Dociostaurus maroccanusPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2000E. Quesada-Moraga Summary Laboratory studies were conducted to assess the effect of temperature on the development of the eggs of Dociostaurus maroccanus (Thunberg) (Orthoptera, Acrididae) during anatrepsis (stages I,XIV) and during catatrepsis (stages XV,XX). The developmental rates of anatrepsis were studied at five constant temperatures ranging from 10 to 30°C. Egg development occurred over the entire range but at 10°C the embryos were unable to complete anatrepsis. The relationship between temperature and developmental times for completing anatrepsis was analysed by the non-linear Logan type III model. The optimal temperature estimated for the development of eggs during anatrepsis was 24.7°C; the lower and upper thermal thresholds were 9°C and 31°C, respectively. Once the embryos completed anatrepsis, only those incubated at 15°C continued morphogenesis beyond stage XIV (diapause stage) without a low-temperature exposure period. The developmental rate of catatrepsis was studied at four constant temperatures ranging from 15°C to 30°C after exposure to low-temperature, 10°C, for 30, 60 or 90 days. For catatrepsis, temperature and developmental time were linearly and inversely related. Linear regression was used to estimate the lower developmental threshold and the degree days requirements for catatrepsis. Both decreased with longer exposure to the low temperature; the former from 13.8°C to 10.5°C and the latter from 212.8 to 171.5 degree days, following 30 and 90 days at 10°C, respectively. Our results improve the ability of decision support systems for Mediterranean locust pest management by providing better forecasts to land managers and pest advisors. [source] | |||||||||||||