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Biomedical subjects

Hans G Kress

Publications and source records attributed to Hans G Kress.

8 recordsLinked to original sources
PubMed2005

Indirect CB2 receptor and mediator-dependent stimulation of human whole-blood neutrophils by exogenous and endogenous cannabinoids.

Immunomodulatory effects of endogenous and exogenous cannabinoids have been investigated in numerous studies, mostly performed with isolated cells or transformed cell lines, but only sparse data exist on human polymorphonuclear neutrophils (PMNs). We therefore investigated the respiratory burst reaction of human whole-blood PMNs under the influence of cannabinoids using flow cytometry. In their natural whole-blood milieu, a CB(2) receptor-dependent stimulation of the PMN respiratory burst was found at nanomolar concentrations of CP55 940 [(-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol] and methanandamide after a 3-h incubation period, whereas the short-living and rapidly hydrolyzed endogenous ligand anandamide did not alter the burst reaction of whole-blood PMNs under the same experimental conditions. The stimulatory cannabinoid effect was totally absent in isolated PMNs but could be transferred onto isolated PMNs by adding the cell-free low-molecular mass plasma fraction (<5000 Da) of cannabinoid-incubated blood, indicating an indirect mechanism depending on humoral products or mediators. Results of our further experiments suggest that products of the arachidonic acid metabolism are mediators of the cannabinoid-induced enhancement of the respiratory burst reaction of whole-blood PMNs.

Arachidonic Acids↗
PubMed2005

Opioid medication and driving ability.

In many European countries the use of opioids for long-term treatment of nonmalignant pain has dramatically increased during the last decade in order to improve the patient's quality of life, to allow an active social life and the return to work. In modern society, driving is regarded as an essential activity of daily living. Since opioids are centrally acting drugs that may interfere with the ability of safely driving a motor vehicle, the question arises of whether or not and on which conditions patients under continuous opioid medication may be considered fit to drive. In this article the evidence from recent studies of opioid effects on driving ability of patients is reviewed. Based on these data, the prerequisites and restrictions for driving under chronic opioid medication are outlined and practical guidelines are proposed.

Analgesics, Opioid↗
PubMed2004

Cannabinoid receptor-independent suppression of the superoxide generation of human neutrophils (PMN) by CP55 940, but not by anandamide.

Cannabinoids have been shown to affect various immune functions. To date, almost no data exist on PMN, which provide the first line antimicrobial defense. The objective of the present study was to investigate the effects of the synthetic dibenzopyrane ligand CP55 940, the endogenous cannabinoid anandamide and methanandamide on the "respiratory burst" of isolated human PMN in vitro. After preincubation with high micromolar concentrations of CP55 940, fMLP-stimulated PMN showed a reduction in superoxide production, whereas the spontaneous burst activity of resting PMN remained unaffected. This inhibitory effect of CP55 940 was not CB-receptor-mediated. In contrast, anandamide and methanandamide did not alter the oxidative microbicidal PMN function.

Adult↗
PubMed2004

The sunburn pain model: the stability of primary and secondary hyperalgesia over 10 hours in a crossover setting.

UNLABELLED: It was our aim to study the within-day stability and between-day repeatability of ultraviolet B (UVB) light-induced primary and secondary hyperalgesia over 10 h. Twenty hours after UVB irradiation of a skin spot (r = 2.5 cm) on the upper leg of 8 healthy volunteers the areas of secondary hyperalgesia to pinprick and pain tolerance thresholds to heat (HPTT) and electrical stimuli (5 and 250 Hz, electrical pain tolerance thresholds [EPTT]) were assessed. Measurements were repeated for 10 h at 2-h intervals and in 2 different sessions. Large areas of secondary hyperalgesia to pin prick were observed (5995 mm(2); SD, 1645). Primary hyperalgesia was evidenced by significant decreases of HPTT (mean difference, 6.5 degrees C; 95% confidence interval, 6.1-6.8; P < 0.001) and EPTT at 250 Hz (mean difference, 0.45 mA; 95% confidence interval, 0.13-0.78; P < 0.05) compared to normal skin. There was no trend within one session of either primary (P = 0.14 for HPTT) or secondary hyperalgesia (P = 0.95) and no difference between the two sessions (primary hyperalgesia, P = 0.28; secondary hyperalgesia, P = 0.07). The sunburn pain model provides a long time course of stable hyperalgesia with a high within-day stability and between-day repeatability for primary and secondary hyperalgesia. IMPLICATIONS: The sunburn pain model provides a long time course of stable hyperalgesia with a high within-day stability and between-day repeatability for primary and secondary hyperalgesia.

Adult↗
PubMed2004

The effects of remifentanil and gabapentin on hyperalgesia in a new extended inflammatory skin pain model in healthy volunteers.

UNLABELLED: We tested the responsiveness of measures of hyperalgesia in a model of UVB-induced inflammatory hyperalgesia with remifentanil, gabapentin, and the combination of both drugs in a double-blinded, active placebo-controlled, 4-way-crossover design in 16 volunteers. A circular skin area was irradiated with UVB-light 20 h before the application of gabapentin (600 mg) and 2 h later remifentanil (0.08 microg.kg(-1).min(-1), 40 min). In the sunburn spots we observed stable decreases of the heat pain perception thresholds (HPPT, mean difference, 4.45 degrees C; 95% confidence interval [CI], 3.32 degrees -5.59 degrees ) and heat pain tolerance thresholds (HPTT; mean difference, 5.43 degrees C; 95% CI, 4.50 degrees -6.35 degrees ) compared with normal skin. Further, large areas of mechanical hyperalgesia to pinprick adjacent to the erythema spots developed in all subjects. Overall remifentanil increased the HPPT (mean increase, 2.47 degrees C; 95% CI, 1.86 degrees -3.09 degrees, P < 0.001) and HPTT (mean increase, 3.18 degrees C; 95% CI, 2.65 degrees -3.71 degrees, P < 0.001) and reduced the area of secondary hyperalgesia by 59% (mean decrease, 5326 mm(2); 95% CI, 4233-6419 mm(2), P < 0.001) compared with placebo. In the sunburn remifentanil markedly increased the HPTT by 86% compared with normal skin (additional increase, 2.57 degrees C; 95% CI, 1.71 degrees -3.43 degrees). This different effect was not seen in the HPPT. With the exception of a small increase of HPTT in the sunburn (P = 0.02) gabapentin had no noticeable effect on either hyperalgesia. In conclusion, opioid analgesia was reliably demonstrated in this new extended pain model. IMPLICATIONS: Opioid analgesia was reliably demonstrated in a new inflammatory model of primary and secondary hyperalgesia. Gabapentin showed no antihyperalgesic and no opioid-enhancing effect in this model.

Acetates↗
PubMed2004

4-chloro-m-cresol cannot detect malignant hyperthermia equivocal cells in an alternative minimally invasive diagnostic test of malignant hyperthermia susceptibility.

Malignant hyperthermia (MH) is an inherited skeletal muscle disorder triggered by commonly used anesthetics. Mutated ryanodine receptors have been identified as molecular targets. The sensitivity of myotubes from individuals classified by the in vitro contracture test as MH susceptible (MHS), normal (MHN), and equivocal (MHEH) was assessed for the Ca2+-releasing activity of 4-chloro-m-cresol (4-CmC) and caffeine. In this study, we sought to determine whether 4-CmC can differentiate the MH status of an individual on the basis of the release of intracellular Ca2+, particularly in regard to MHEH diagnosis. Intracellular Ca2+ concentration was determined photometrically with Fura2. Regions of the ryanodine receptor 1 harboring most of the described MH mutations were sequenced from MHS and MHEH cells. One MH mutation (Gly2434Arg) was found in one MHS individual. Results of the caffeine-induced Ca2+ release in MHS and MHN cells correlated well with the in vitro contracture test results. MHS cells showed a higher sensitivity against caffeine and, to a lesser extent, against 4-CmC. Cells of MHEH individuals showed low sensitivities against both caffeine and 4-CmC, comparable to those of the MHN group. Therefore, with myotubes, caffeine was able to discriminate between MHS and MHN cells, but both caffeine and 4-CmC failed to detect MHEH cells.

Caffeine↗
PubMed2002

The absence of acute tolerance during remifentanil infusion in volunteers.

UNLABELLED: The development of acute opioid tolerance in humans remains controversial. We tested the hypothesis that continuous remifentanil infusion leads to rapid development of opioid tolerance. Twenty healthy male volunteers were enrolled onto a randomized, placebo-controlled, double-blinded, cross-over design study to receive a 3 h continuous infusion of remifentanil (0.08 microg x kg(-1) x min(-1)) or saline. Test procedures included determination of pain perception thresholds and pain tolerance thresholds to heat and cold and neuroselective sine wave constant current at 5 Hz and 250 Hz. Test procedures were performed at baseline and then repeated at 25, 55, 85, 115, and 160 min (heat/cold) and at 35, 65, 95, 125, and 170 min (electrical current) during infusion. No significant decrease of the pain threshold devolutions between 55 and 180 min after the start of infusion of remifentanil could be detected. In conclusion, no development of acute opioid tolerance was observed during constant remifentanil infusion of 3 h in volunteers. IMPLICATIONS: The opioid remifentanil was applied to 20 volunteers at a constant concentration for 3 h while pain thresholds to temperature and current were repeatedly assessed. Our aim was to study whether thresholds decrease over time because of the rapid development of opioid tolerance. No development of rapid opioid tolerance was observed.

Adult↗