Challenging the challenge: A randomized controlled trial evaluating the inflammatory response and pain perception of healthy volunteers after single-dose LPS administration, as a potential model for inflammatory pain in early-phase drug development.

BACKGROUND AND AIMS: Following an infection, cytokines not only regulate the acute immune response, but also contribute to symptoms such as inflammatory hyperalgesia. We aimed to characterize the acute inflammatory response induced by a human endotoxemia model, and its effect on pain perception using evoked pain tests in two different dose levels. We also attempted to determine whether combining a human endotoxemia challenge with measurement of pain thresholds in healthy subjects could serve as a model to study drug effects on inflammatory pain. METHODS AND RESULTS: This was a placebo-controlled, randomized, cross-over study in 24 healthy males. Twelve subjects were administered a bolus of 1 ng/kg LPS intravenously, and twelve 2 ng/kg LPS. Before days of placebo/LPS administration, subjects completed a full study day without study drug administration, but with identical pain threshold testing. Blood sampling and evoked pain tests (electrical burst and -stair, heat, pressure, and cold pressor test) were performed pre-dose and at frequent intervals up to 10hr post-dose. Data were analysed with a repeated-measures ANCOVA. For both dose levels, LPS induced an evident acute inflammatory response, but did not significantly affect any of the pain modalities. In a post-hoc analysis, lowering of pain thresholds was observed in the first 3 h after dosing, corresponding with the peak of the acute inflammatory response around 1-3 h post-dose. CONCLUSION: Mild acute systemic inflammation, as induced by 1 ng/kg and 2 ng/kg LPS intravenous administration, did not significantly change pain thresholds in this study. The endotoxemia model in combination with evoked pain tests is not suitable to study acute inflammatory hyperalgesia in healthy males.

Retinal oximetry and fractal analysis of capillary maps in sickle cell disease patients and matched healthy volunteers.

PURPOSE: Fractal analysis can be used to quantitatively analyze the retinal microvasculature and might be a suitable method to quantify retinal capillary changes in sickle cell disease (SCD) patients. Retinal oximetry measurements might function as a proxy for the pathophysiology of cerebrovascular diseases. Moreover, hypoxia has an important role in the pathophysiology of diabetic and other retinopathies. However, little is known about the oximetry around the macula in SCD patients. With this study, we explored the feasibility to perform these quantified measurements in SCD patients. METHODS: Retinal microvascular and oximetry measurements were performed in eight SCD patients and eight healthy matched controls. Oximetry pictures and non-invasive capillary perfusion maps (nCPM) were obtained by the retinal function imager. Measurements were conducted twice on two different study days. Measured variables included monofractal dimension (Dbox), relative saturation, deoxygenated hemoglobin (deoxyHb), and oxygenated hemoglobin (oxyHb) concentration. RESULTS: No statistically significant differences in vessel density were found in the different annular zones (large vessels, p = 0.66; small vessels, p = 0.66) and anatomical quadrants (large vessels, p = 0.74; small vessels, p = 0.72). Furthermore, no significant between-group differences were found in the other different anatomical quadrants and annular zones around the fovea for relative saturation levels and deoxygenated Hb. However, the oxyHb levels were significantly lower in SCD patients, compared with those in matched controls in the temporal quadrants (p = 0.04; p = 0.02) and the superior nasal quadrant (p = 0.05). CONCLUSIONS: Our study demonstrated the feasibility of multispectral imaging to measure retinal changes in oxygenation in both SCD patients and matched volunteers. The results suggest that in SCD patients before any structural microvascular changes in the central retina are present, functional abnormalities can be observed with abnormal oximetry measurements.

Correction to: Retinal oximetry and fractal analysis of capillary maps in sickle cell disease patients and matched healthy volunteers.

In the published online PDF version, Figure 3 was incorrectly captured the same as Figure 1.

Effect profile of paracetamol, Δ9-THC and promethazine using an evoked pain test battery in healthy subjects.

BACKGROUND: A battery of evoked pain tasks (PainCart) was developed to investigate the pharmacodynamic properties of novel analgesics in early-phase clinical research. As part of its clinical validation, compounds with different pharmacological mechanisms of actions are investigated. The aim was to investigate the analgesic effects of classic and nonclassic analgesics compared to a sedating negative control in a randomized placebo-controlled crossover study in 24 healthy volunteers using the PainCart. METHODS: The PainCart consisted of pain tasks eliciting electrical, pressure, heat, cold and inflammatory pain. Subjective scales for cognitive functioning and psychotomimetic effects were included. Subjects were administered each of the following oral treatments: paracetamol (1000 mg), Δ9-THC (10 mg), promethazine (50 mg) or matching placebo. Pharmacodynamic measurements were performed at baseline and repeated up to 10 h postdose. RESULTS: Paracetamol did not show a significant reduction in pain sensation or subjective cognitive functioning compared to placebo. Promethazine induced a statistically significant reduction in PTT for cold pressor and pressure stimulation. Furthermore, reduced subjective alertness was observed. Δ9-THC showed a statistically significant decrease in PTT for electrical and pressure stimulation. Δ9-THC also demonstrated subjective effects, including changes in alertness and calmness, as well as feeling high and psychotomimetic effects. CONCLUSIONS: This study found a decreased pain tolerance due to Δ9-THC and promethazine, or lack thereof, using an evoked pain task battery. Pain thresholds following paracetamol administration remained unchanged, which may be due to insufficient statistical power. We showed that pain thresholds determined using this pain test battery are not driven by sedation. SIGNIFICANCE: The multimodal battery of evoked pain tasks utilized in this study may play an important role in early-phase clinical drug development. This battery of pain tasks is not sensitive to the effects of sedation alone, and thus suitable to investigate the analgesic potential of novel analgesic compounds.

Impact of (chemo)radiotherapy on immune cell composition and function in cervical cancer patients.

New treatments based on combinations of standard therapeutic modalities and immunotherapy are of potential use, but require a profound understanding of immune modulatory properties of standard therapies. Here, the impact of standard (chemo)radiotherapy on the immune system of cervical cancer patients was evaluated. Thirty patients with cervical cancer were treated with external beam radiation therapy (EBRT), using conventional three-dimensional or intensity modulated radiation therapy without constraints for bone marrow sparing. Serial blood sampling for immunomonitoring was performed before, midway and at 3, 6 and 9 weeks after EBRT to analyze the composition of lymphocyte and myeloid-cell populations, the expression of co-stimulatory molecules, T-cell reactivity and antigen presenting cell (APC) function. Therapy significantly decreased the absolute numbers of circulating leukocytes and lymphocytes. Furthermore, the capacity of the remaining T cells to respond to antigenic or mitogenic stimulation was impaired. During treatment the frequency of both CD4+ and CD8+ T cells dropped and CD4+ T cells displayed an increased expression of programmed cell death-1 (PD-1). In vitro blocking of PD-1 successfully increased T-cell reactivity in all five samples isolated before radiotherapy but was less successful in restoring reactivity in samples isolated at later time points. Moreover, (chemo)radiotherapy was associated with an increase in both circulating monocytes and myeloid-derived suppressor cells (MDSCs) and an impaired capacity of APCs to stimulate allogeneic T cells. T-cell reactivity was slowly restored at 6-9 weeks after cessation of therapy. We conclude that conventional (chemo)radiotherapy profoundly suppresses the immune system in cervical cancer patients, and may restrict its combination with immunotherapy.

The identification of patients at high risk for recurrent disease after treatment for early-stage cervical cancer.

OBJECTIVE: To investigate prognostic factors in patients with recurrent cervical cancer after treatment of early-stage disease in order to identify high-risk patients who might benefit from alternative treatment strategies. STUDY DESIGN: The authors retrospectively analyzed clinical and pathology data from 130 recurrent cervical cancer patients after surgical treatment for early-stage disease. Patients were compared with a recurrence-free control group matched for age, FIGO Stage, and adjuvant treatment. Univariate and multivariate Cox regression analyses were performed to determine prognostic factors for recurrence and survival. RESULTS: Of 889 patients, 130 (14.6%) developed recurrent disease after primary treatment for early-stage cervical cancer. Local or loco-regional metastasis was observed in 45%, distant metastasis in 31%, and combined pelvic and distant metastasis in 24%. Median survival after recurrence was 12 months (range 1-107 months). Median five-year survival was 96% in the control group and 29% in the recurrence group. Tumor size ≥ 40 mm and lymph node metastasis were independent unfavorable prognostic factors for overall survival (OS) and disease-free survival (DFS). The number of positive lymph nodes (≥ one) and bilateral occurrence of pelvic lymph node metastasis were associated with adverse clinical outcome. CONCLUSIONS: Tumor size ≥ 40 mm and lymph node metastasis were independent unfavorable prognostic factors in surgically treated, early-stage cervical cancer patients. The combination of these factors was particularly associated with recurrence. Future trials should focus on the role of alternative adjuvant treatment strategies in patients at high risk of recurrent disease (e.g., by chemotherapy, immunotherapy or combinations thereof).

No evidence of potentiation of buprenorphine by milnacipran in healthy subjects using a nociceptive test battery.

BACKGROUND: Serotonin-norepinephrine reuptake inhibitors inhibit the reuptake of serotonin and noradrenalin and are used in the treatment of neuropathic pain. Animal studies suggest that milnacipran co-administered with opioids may potentiate the analgesic effect of µ-opioid receptor agonists. This study hypothesized that co-administration of milnacipran and buprenorphine would have a synergistic effect in evoked pain models in healthy subjects. METHODS: This was a randomized double-blinded, placebo-controlled, four-way cross-over, multiple dose clinical trial to investigate the analgesic effects of buprenorphine (placebo, 0.5, 1 and 3 µg/kg) in combination with milnacipran (placebo, 25 and 50 mg) in healthy subjects. RESULTS: 11 healthy men were enrolled in the study. Buprenorphine alone showed a dose-response relationship indicative of anti-nociception in the pain tests. Following milnacipran administration, no changes were seen in the pharmacodynamic measurements for pain, psychomotor function, body stability or eye movements. For the electrical tests, cold pressor test and pressure pain test, buprenorphine alone was superior when compared with buprenorphine plus milnacipran. No differences in pharmacodynamic variables, besides an increase in pupil/iris ratio, were observed after repeated administration of milnacipran 50 mg. Single and multiple doses of 25 or 50 mg milnacipran did not further potentiate the anti-nociceptive effects of buprenorphine. CONCLUSIONS: Buprenorphine showed dose-dependent effects consistent with its pharmacological profile. Milnacipran alone did not affect any of the pain variables. The combination of both buprenorphine and milnacipran did not potentiate or show a synergistic effect on the pain models used in this study. SIGNIFICANCE: Buprenorphine is known to be a potent opioid agonist. Animal studies suggest that milnacipran co-administered with opioids may potentiate the analgesic effect of µ-opioid receptor agonists. Here, we found that buprenorphine showed a dose-dependent analgesic effect, but that no potentiation or synergy on a battery of evoked pain tasks could be observed after co-administration of both milnacipran and buprenorphine.

Changes in bone mineral density in newly diagnosed testicular cancer patients after anticancer treatment.

CONTEXT: Patients with germ cell tumors (GCTs) have an excellent prognosis but are at risk for silent fractures. Data on bone mineral density (BMD) after anticancer treatment are scarce. OBJECTIVE: The objective of the study was BMD monitoring in GCT patients treated with or without chemotherapy. DESIGN: We prospectively studied 63 newly diagnosed GCT patients with a median age of 33 years (range 16-70 y) within 3 months of unilateral orchidectomy. Twenty-seven patients (42.9%) had no metastases. Thirty-six patients (57.1%) with metastatic disease received combination chemotherapy. SETTING: This study was conducted at the outpatient clinic of a single academic institution. INTERVENTIONS: We performed dual-energy X-ray absorptiometry scans and collected blood samples on a yearly basis, before and up to 5 years after anticancer treatment. MAIN OUTCOME MEASURES: Changes in total hip and lumbar spine BMD, serum concentrations of gonadal hormones, and bone turnover markers were measured. RESULTS: BMD remained normal in stage I patients. In patients with metastatic disease, a significant decrease in lumbar spine BMD (-1.52%; P = .004) and total hip BMD (-2.05%; P < .0001) was observed 1 year after chemotherapy and remained stable thereafter for up to 5 years. There was no significant relationship between the observed decrease in BMD and gonadal status, vitamin D status, or cumulative dose of cisplatin or (antiemetic) corticosteroids. CONCLUSIONS: Metastatic GCT survivors demonstrate significant bone loss within the first year after curative combination chemotherapy, with no recovery up to 5 years after anticancer treatment. Whether this bone loss is associated with increased fracture risk and whether this could be prevented by bone modifying treatment remains to be established.

Characterization of a standardized glucagon challenge test as a pharmacodynamic tool in pharmacological research.

The aim of this study was to characterize a glucagon challenge test as a tool in diabetes research by assessing the inter- and intra-individual variability, and investigating the activity of the autonomic nervous system (ANS) during the challenge, as this might have an indirect impact on glucose homeostasis. The study was performed in 24 healthy volunteers separated in 2 groups. The first group of 12 volunteers underwent a 5-h glucagon challenge during a pancreatic clamp procedure with infusion of [6,6-2H2]-glucose infusion in combination with heart rate variability measurements. In the second group, 12 other healthy volunteers underwent two 6-h glucagon challenges separated by 6 weeks, and fat biopsies were taken for analysis of glucagon receptor expression. Serum glucose rose rapidly after glucagon infusion, and reached a plateau at 90 min. The time profiles suggested rapid development of tolerance for glucagon-induced hyperglycemia. During the glucagon challenge intra- and inter-individual variabilities for hepatic glucose production, the rate of disappearance of glucose, and plasma glucose were approximately 10-15% for all variables. Hyperglucagonemia did not affect heart rate variability. Human adipose tissue had a low, but variable, expression of glucagon receptor mRNA. This standardized glucagon challenge test has a good reproducibility with only limited variability over 6 weeks. It is a robust tool to explore in detail the contribution of glucagon in normal and altered glucose homeostasis and can also be used to evaluate the effects of drugs antagonizing glucagon action in humans without confounding changes in ANS tone.

Desmopressin as a pharmacological tool in vasopressinergic hypothalamus-pituitary-adrenal axis modulation: neuroendocrine, cardiovascular and coagulatory effects.

Arginine-vasopressin (AVP) is a physiological co-activator of the hypothalamus-pituitary-adrenal (HPA) axis, together with corticotrophin releasing hormone (CRH). A synthetic analogue of AVP, desmopressin (dDAVP), is often used as a pharmacological tool to assess co-activation in health and disease. The relation between dDAVP's neuroendocrine, cardiovascular, pro-coagulatory, anti-diuretic and non-specific stress effects has not been studied. A randomized, double-blind, placebo-controlled, three-way crossover study was performed in 12 healthy male and female volunteers (6 : 6). dDAVP was administered intravenously as a 10 µg bolus (over 1 min) or a 30 µg incremental infusion (over 60 min). Neuroendocrine, cardiovascular, pro-coagulatory, anti-diuretic effects and adverse events (AEs) were recorded, and autonomic nervous system (ANS) activation evaluated. The incremental infusion reached 1.8-fold higher dDAVP concentrations than the bolus. Neuroendocrine effects were similar for the 10 µg dDAVP bolus and the 30 µg incremental infusion, while cardiovascular and coagulatory effects were greater with the 30 µg dose. Osmolality and ANS activity remained uninfluenced. AEs corresponded to dDAVP's side-effect profile. In conclusion, the neuroendocrine effects of a 10 µg dDAVP bolus administered over 1 min are similar to those of a 30 µg incremental infusion administered over one hour, despite higher dDAVP concentrations after the infusion. Cardiovascular and coagulatory effects showed clear dose-related responses. A 10 µg dDAVP bolus is considered a safe vasopressinergic function test at which no confounding effects of systemic or autonomic stress were seen.

A pharmacological tool to assess vasopressinergic co-activation of the hypothalamus-pituitary-adrenal axis more integrally in healthy volunteers.

Pharmacological function tests consisting of 100 µg hCRH (corticorelin) and 10 µg dDAVP (desmopressin) mimic endogenous hypothalamus-pituitary-adrenal (HPA) axis activation. However, physiological CRH concentrations preclude informative vasopressinergic co-activation (using dDAVP) and independent quantification of both corticotrophinergic (using hCRH) and vasopressinergic (using dDAVP) activation is limited due to administration on separate occasions. This randomized, double-blind, placebo-controlled, partial five-way crossover study in healthy males and females (six : six) examined whether (1) concomitant administration of dDAVP and hCRH provides more informative vasopressinergic co-activation than dDAVP alone; and (2) whether the administration of dDAVP followed two hours later by hCRH can quantify both vasopressinergic and corticotrophinergic activation on a single test day. Combining 10 µg dDAVP with 10 µg and 30 µg hCRH caused dose-related ACTH and cortisol release which was larger than with 10 µg dDAVP alone and respectively comparable to and greater than that induced by 100 µg hCRH. Using 10 µg dDAVP alone demonstrated limited ACTH release while the effects of 100 µg hCRH two hours later were three times as large. ACTH and cortisol released by 10 µg dDAVP returned to baseline prior to 100 µg hCRH administration and dDAVP did not influence the response to subsequent hCRH administration. Dose-related vasopressinergic co-activation of the HPA axis was induced by combining 10 µg dDAVP with 10 µg and 30 µg hCRH. Combining 10 µg dDAVP with 10 µg hCRH induced the potentially most informative vasopressinergic co-activation since it is not restricted by ceiling or flooring effects. The hCRH response was not affected by prior dDAVP, allowing for a practical function test examining both HPA activation routes on the same day.

Metoclopramide as pharmacological tool to assess vasopressinergic co-activation of the hypothalamus-pituitary-adrenal (HPA) axis: a study in healthy volunteers.

The synthetic vasopressin (AVP) analogue desmopressin (dDAVP) has been used as pharmacological function test to quantify vasopressinergic co-activation of the hypothalamus-pituitary-adrenal (HPA) axis in the past. Such exogenous vasopressinergic stimulation may induce confounding cardiovascular, pro-coagulatory and anti-diuretic effects and low endogenous corticotrophin-releasing-hormone (CRH) levels may limit its potential to reliably assess co-activation. Alternatively, the dopamine-2-(D2)-antagonist metoclopramide is believed to induce co-activation indirectly by releasing endogenous AVP. We investigated this indirect co-activation with metoclopramide under conditions of low and enhanced endogenous CRH release in healthy volunteers. A randomized, double-blind, placebo-controlled, four-way crossover study was performed in 12 healthy males. CRH release was induced by administering an oral 5-hydroxytryptophan (5-HTP) 200 mg function test. Co-activation was investigated by administering metoclopramide 10mg intravenously around the expected maximal effect of 5-HTP. The neuroendocrine effects were compared to those of metoclopramide alone, the 5-HTP test alone and matching placebo. Metoclopramide safely induced HPA-axis activation by itself, and potently synergized 5-HTP-induced corticotrophinergic activation of the HPA axis. These findings are indicative of vasopressinergic co-activation and suggest a role for metoclopramide as a practical function test for co-activation of the HPA axis. However, its application will be hampered pending clarification of the exact pharmacological mechanism by which metoclopramide induces co-activation of the HPA axis.

Hypothalamic glutamate levels following serotonergic stimulation: a pilot study using 7-Tesla magnetic resonance spectroscopy in healthy volunteers.

INTRODUCTION AND PURPOSE: Functional proton magnetic resonance spectroscopy (MRS) can be applied to measure pharmacodynamic effects of central nervous system (CNS)-active drugs. The serotonin precursor 5-hydroxytryptophan (5-HTP), administered together with carbidopa and granisetron to improve kinetics and reduce adverse effects, acutely enhances central serotonergic neurotransmission and induces hypothalamus-pituitary-adrenal-(HPA) axis activation. We studied the hypothalamic levels of glutamate/glutamine (Glx), choline (Chol), N-acetyl-aspartate (NAA) and creatine using 7-Tesla (7T) MRS, and adrenocorticotropic hormone (ACTH) and cortisol in peripheral blood, after the administration of the 5-HTP function test in healthy volunteers. METHODS: A randomized, double blind, placebo-controlled, two-way cross-over study was performed in 12 healthy males with a 7day wash-out period. After administration of the oral 5-HTP function test, ACTH and cortisol were measured over 4h and MRS scans at 7T were performed every 30min over 3h measuring Glx:Creatine, Chol:Creatine and NAA:Creatine ratios. RESULTS: In the hypothalamus, the administration of 5-HTP had no effect on the average Glx, Chol or NAA levels over 180min but induced a significant decrease of Glx at 60min on post-hoc analysis. 5-HTP-induced significant ACTH release reaching an E(max) of 60.2ng/L at 80min followed by cortisol with an E(max) of 246.4ng/mL at 110min. CONCLUSIONS: The reduction in hypothalamic Glx levels after serotonergic stimulation is compatible with activation of excitatory neurons in this region, which is expected to cause depletion of local glutamate stores. The hypothalamic MRS-response reached its maximum prior to subsequent increases of ACTH and cortisol, which support the functional relevance of hypothalamic Glx-depletion for activation of the HPA-axis. This exploratory study shows that MRS is capable of detecting neuronal activation following functional stimulation of a targeted brain area.

The effects of the glycine reuptake inhibitor R213129 on the central nervous system and on scopolamine-induced impairments in psychomotor and cognitive function in healthy subjects.

In this study the effects of R213129, a selective glycine transporter 1 inhibitor, on central nervous system function were investigated in healthy males in the absence and presence of scopolamine. This was a double-blind, placebo-controlled, 4-period crossover ascending dose study evaluating the following endpoints: body sway, saccadic and smooth pursuit eye movements, pupillometry, electroencephalography, visual analogue scales for alertness, mood, calmness and psychedelic effects, adaptive tracking, finger tapping, Visual and Verbal Learning Task, Stroop test, hormone levels and pharmacokinetics. R213129 dose levels were selected based on exposure levels that blocked the GlyT1 sites >50% in preclinical experiments. Forty-three of the 45 included subjects completed the study. Scopolamine significantly affected almost every central nervous system parameter measured in this study. R213129 alone compared with placebo did not elicit pharmacodynamic changes. R213129 had some small effects on scopolamine-induced central nervous system impairments. Scopolamine-induced finger tapping impairment was further enhanced by 3 mg R213129 with 2.0 taps/10 seconds (95% CI -4.0, -0.1), electroencephalography alpha power was increased by 10 mg R213129 with respectively 12.9% (0.7, 26.6%), scopolamine-induced impairment of the Stroop test was partly reversed by 10 mg R213129 with 59 milliseconds (-110, -7). Scopolamine produced robust and consistent effects in psychomotor and cognitive function in healthy volunteers. The most logical reason for the lack of R213129 effects seems to be that the central nervous system concentrations were too low. The effects of higher doses in healthy volunteers and the clinical efficacy in patients remain to be established.

The effects of a glycine reuptake inhibitor R231857 on the central nervous system and on scopolamine-induced impairments in cognitive and psychomotor function in healthy subjects.

The effects of the selective inhibitor of the glycine transporter 1, R231857, in development for schizophrenia, on the central nervous system (CNS) were investigated in healthy males in the absence and presence of scopolamine. This was a double-blind, placebo-controlled, four-period crossover ascending dose study. Pharmacokinetics, body sway, saccadic and smooth pursuit eye movements, pupillometry, pharmacoelectroencephalogram (EEG), Visual Analogue Scales (VAS) for alertness, mood, calmness and psychedelic effects, adaptive tracking, finger tapping, Stroop test, Visual and Verbal Learning Task (VVLT) and hormone levels were assessed. R231857 was administered alone and together with scopolamine to investigate the potential reversal of anticholinergic CNS impairment by the glycine reuptake inhibitor. Forty-two of the 45 included subjects completed the study. Scopolamine significantly affected almost every CNS parameter measured in this study. R231857 alone showed some pharmacodynamic changes compared with placebo. Although these effects might be an indication that R231857 penetrated the CNS, they were not consistent or dose-related. R231857 had some small effects on scopolamine-induced CNS-impairment, which were also not clearly dependent on dose. Scopolamine proved to be an accurate, reproducible and safe model to induce CNS impairment by an anticholinergic mechanism. R231857 lacked consistent dose-related effects in this study, probably because CNS concentrations were too low to produce significant/ reproducible CNS-effects or to affect the scopolamine challenge in healthy volunteers. The effects of higher doses in healthy volunteers and the clinical efficacy in patients remain to be established.

Enhanced tolerability of the 5-hydroxytryptophane challenge test combined with granisetron.

A recently developed oral serotonergic challenge test consisting of 5-Hydroxytryptophane (5-HTP, 200 mg) combined with carbidopa (CBD, 100 mg + 50 mg) exhibited dose-related neuroendocrine responsiveness and predictable pharmacokinetics. However, its applicability is limited by nausea and vomiting. A randomized, double-blind, placebo-controlled, four-way crossover trial was performed in 12 healthy male volunteers. The 5-HTP/CBD-challenge was combined with two oral anti-emetics (granisetron, 2 mg or domperidone, 10 mg) to investigate its reliability when side-effects are suppressed. The neuroendocrine response (serum cortisol and prolactin), the side-effect profile [Visual Analogue Scale Nausea (VAS)] and vomiting subjects per treatment were the main outcome measures. Compared to 5-HTP/CBD/placebo, 5-HTP/CBD/ granisetron had no impact on cortisol [% change with 95% confidence interval: -7.1% (18.9; 6.5)] or prolactin levels [-9.6% (-25.1; 9.1)]; 5-HTP/CBD/domperidone increased cortisol [+13.0% (-4.2; 33.4)], and increased prolactin extensively [+336.8% (245.7; 451.9)]. Compared to placebo, VAS Nausea increased non-significantly with granisetron [+7.6 mm (-1.3; 16.5)], as opposed to domperidone [+16.2 mm (7.2; 25.2)] and 5-HTP/CBD/placebo [+14.7 mm (5.5; 23.8)]. No subjects vomited with granisetron, compared to two subjects treated with 5-HTP/CBD/placebo and five subjects with domperidone. Compared with 5-HTP/CBD/placebo, granisetron addition decreased C(max) of 5-HTP statistically significantly different (from 1483 to 1272 ng/ml) without influencing AUC(0- infinity). Addition of granisetron to the combined 5-HTP/CBD challenge suppresses nausea and vomiting without influencing the neuroendocrine response or pharmacokinetics, enhancing its clinical applicability in future psychiatric research and drug development.

Efficacy of 3,4-diaminopyridine and pyridostigmine in the treatment of Lambert-Eaton myasthenic syndrome: a randomized, double-blind, placebo-controlled, crossover study.

3,4-Diaminopyridine and pyridostigmine are widely used to treat Lambert-Eaton myasthenic syndrome (LEMS), either alone or in combination. 3,4-Diaminopyridine enhances the release of acetylcholine at the neuromuscular synapse, and pyridostigmine inhibits the degradation of this neurotransmitter. Although this could lead to a synergistic effect on neuromuscular transmission, no studies have compared the effects of these drugs in patients with LEMS. Therefore, we performed a placebo-controlled, double-dummy, double-blind, randomized, crossover study in nine patients with LEMS.

Pharmacodynamic and pharmacokinetic effects of the intravenously administered CB1 receptor agonist Org 28611 in healthy male volunteers.

CB1/CB2 agonists are reported to have sedative, amnestic, analgesic and anti-emetic properties, which would make them ideal drugs for outpatient treatments under conscious sedation. The main objective of this in human study was to assess the sedative properties of Org 28611, a potent water-soluble CB1 agonist. Single ascending doses were administered during a slow 25 min infusion and after a 1 min bolus administration to healthy male volunteers. In addition, the pharmacokinetics, amnestic properties, postural stability, electro-encephalography, behavioural and cardiovascular effects were studied. Midazolam 0.1 mg/kg was used as a positive control. The pharmacokinetic parameters were proportional to dose. No effects were observed after intravenous administration of doses up to Org 28611 1 microg/kg. Dose-related effects were observed at higher doses. Although subjects reported subjective sedation after administration of Org 28611 3-10 microg/kg, the observed sedation was considerably less than after midazolam. Org 28611 is, therefore, not suitable for providing sedation for outpatient surgical procedures and doses above the maximum tolerated dose of 3 microg/kg (either administered as a slow infusion or a bolus dose) can cause untoward psychotropic effects.

Comparison of exhaled nitric oxide measurements between NIOX MINO electrochemical and Ecomedics chemiluminescence analyzer.

BACKGROUND: Exhaled nitric oxide (eNO) is an established, noninvasive biomarker of active airway inflammation in (atopic) asthma. Treatment with anti-inflammatory therapy, such as inhaled corticosteroids, effectively decreases eNO levels. The NIOX MINO (MINO) is a hand-held, relatively inexpensive, electrochemical device that has been shown to yield comparable eNO measurements to the NIOX stationary unit. AIM: To compare measurements of MINO with another widely used and validated stationary chemiluminescence analyzer, the Ecomedics (ECO). METHODS: We performed subsequent eNO measurements on ECO and MINO in 50 subjects (19 healthy volunteers, 18 healthy smokers and 13 non-smoking, atopic asthmatics, not on controller therapy) on two visits 4-10 days apart. The mean of three acceptable measurements by ECO and the first acceptable measurement with the MINO were used for analysis. RESULTS: Both devices yielded reproducible eNO values for all subjects on both visits, with an overall CV of 22.7% (ECO) and 18.3% (MINO). A significant correlation was found between both devices (r=0.97, p<0.0001). Bland-Altman plots showed a high degree of agreement for the entire study population (mean difference MINO vs ECO=-10%; 95% limit of agreement were -36% and +28%) and in the three individual subgroups. CONCLUSIONS: Exhaled NO values measured with the MINO are reproducible and in agreement with the ECO. Our results add further evidence to the reliability of the MINO and warrant its applicability in research and clinical practice.

Pharmacology of rising oral doses of 5-hydroxytryptophan with carbidopa.

5-hydroxytryptophan (5-HTP) is a direct 5-hydroxytryptamine (5-HT) precursor used to assess central serotonergic function. Its use has been limited by a narrow window between neuroendocrine changes and side effects, and variable kinetics related to inconsistent administration modes. By combining 5-HTP with carbidopa (CBD), increased bioavailability for brain penetration and decreased peripheral side effects would be expected, due to reduced peripheral decarboxylation of 5-HTP to 5-HT. A double-blind, placebo-controlled, single rising dose, four-way crossover trial with placebo randomisation was performed in 15 healthy male volunteers to investigate the neuroendocrine dose-response relationship at various 5-HTP levels; the tolerability and subjective effects of oral 5-HTP at 100, 200 and 300 mg combined with CBD and the pharmacokinetic properties of the 5-HTP/CBD-challenge. Dose-dependent increases in average cortisol concentrations were observed. Mean response (area-under-the-curve) over the first 4 hours (SD): 172.0 nmol/L (22.3) for placebo, 258.3 nmol/L (72.6) for 100 mg, 328.47 nmol/L (84.6) for 200 mg and 387.3 nmol/L (82.4) for 300 mg 5-HTP. Similar dose-dependent increases for prolactin were seen while adreno-corticotrophic hormone response was more variable. 5-HTP kinetics were adequately described using a one-compartment model with first-order absorption and a lag time (mean oral clearance 28 L/h interindividual coefficient of variation 31%). Nausea and vomiting occurred dose-dependently as most frequent side effects, resulting in dose-related dropout of 6.6% at 100 mg and 45.5% at 300 mg 5-HTP. Orally administered 5-HTP combined with CBD is an effective serotonergic challenge test, exhibiting dose-related plasma concentrations and neuroendocrine responsiveness. Frequent occurrence of nausea and vomiting limits the applicability of this challenge at 5-HTP doses above 100 mg.