HbA1c determination from HemaSpot™ blood collection devices: comparison of home prepared dried blood spots with standard venous blood analysis.

AIM: To assess the clinical performance and patient acceptance of HemaSpot™ blood collection devices as an alternative blood collection method. METHODS: Adult men and women with any type of diabetes, routinely carrying out self-monitoring of blood glucose were recruited (n = 128). Participants provided a venous blood sample and prepared two HemaSpot dried blood spots, one at clinics and one at home. HbA1c analysis was by Tosoh G8 high-performance liquid chromatography. Participants also completed a questionnaire. RESULTS: Strong linear relationships been HbA1c levels in dried blood spots and venous blood were observed and a linear model was fitted to the data. Time between dried blood spot preparation and testing did not impact the model. Participants were accepting of the approach: 69.2% would use this system if available and 60.7% would be more likely to use this system than going to their general practitioner. CONCLUSIONS: The combination of a robust desiccating dried blood spot device, home sample preparation and return by post produces HbA1c data that support the use of a time-independent linear calibration of dried blood spot to venous blood HbA1c . A robust remote sample collection service would be valuable to people living with diabetes in urban areas who are working or house-bound as well as those living in remote or rural locations.

The selective 5-HT6 receptor antagonist SLV has putative cognitive- and social interaction enhancing properties in rodent models of cognitive impairment.

In the present study, our aim was to investigate whether the novel highly selective 5-hydroxytryptamine6 (5-HT6) receptor antagonist SLV can ameliorate impairments in cognition and social interaction with potential relevance for both schizophrenia and Alzheimer's disease (AD). SLV sub-chronically - treated Wistar rats reared in isolation showed significantly enhanced prepulse inhibition (PPI) and object recognition performance when compared to vehicle - treated rats. In the isolated rats, also a significant reduction in expression of hippocampal neural cell adhesion molecule polysialylation (NCAM-PSA) was found which was ameliorated following treatment with SLV (30mg/kg). The social engagement deficit in rats exposed in utero (on gestational day 12.5) to valproic acid (VPA) was reversed by treatment with SLV (30mg/kg). SLV (20 and 30mg/kg, p.o.) fully reversed MK-801 - induced deficits in the ORT and also scopolamine - induced deficits in both the Object Recognition Task (ORT) and Object Location Task (OLT) in Wistar rats. In addition, a combination of sub-optimal doses of SLV and donepezil attenuated scopolamine-induced ORT deficits. Furthermore, SLV (10mg/kg, p.o.) reversed spontaneous alternation deficits in the T-maze induced by MK-801 administration in Swiss mice and in aged C57Bl/6J mice. SLV additionally improved T-Maze spatial learning and passive avoidance learning in Sprague-Dawley rats with amyoid-beta (Aß) injections into the hippocampus. In contrast, no benefits were found with SLV or the tested reference compounds (donepezil and RVT-101) on cognitive performance of 12months old Tg2576 mice. Also, in the social recognition task, an absence of cognitive enhancing properties was observed with SLV on "normal forgetting" in Wistar rats. Finally, analysis of spontaneous inhibitory postsynaptic currents (sIPSCs) frequency recorded from pyramidal cells revealed a reduction in the presence of 1µM of SLV. In conclusion, SLV was investigated in several rodent animal models and found to be effective at a least effective dose (LED) of 20mg/kg and 10mg/kg (p.o.) in the rat and the mouse, respectively.

Effects of risperidone, clozapine and the 5-HT6 antagonist GSK-742457 on PCP-induced deficits in reversal learning in the two-lever operant task in male Sprague Dawley rats.

Reasoning and problem solving deficits have been reported in schizophrenic patients. In the present study, we have tested rats in a two-lever reversal learning task in a Skinner box to model these deficits. In other studies using the Skinner box, atypical antipsychotics fully reversed phencyclidine (PCP)-induced impairments in reversal learning which is in contrast to clinical observations where antipsychotics lack the ability to fully reverse cognitive deficits in schizophrenia. Therefore, it can be argued that the outcome of these tests may lack predictive value. In the present study, after training on a spatial discrimination between two levers, rats were exposed to a reversal of the previously learned stimulus-response contingency during 5 days. We first investigated the effects of sub-chronic treatment with the non-competitive N-methyl-d-aspartate (NMDA) antagonists dizocilpine (MK-801) and PCP on reversal learning and extinction in male Sprague Dawley rats. Subsequently, we studied the effects of different PCP treatment regimes. Then, we investigated whether the atypical antipsychotics risperidone and clozapine and the 5-hydroxytryptamine6 (5-HT6) antagonist GSK-742457 could reverse the PCP-induced deficits. All drugs were administered subcutaneously (s.c.). MK-801 did not impair reversal learning, while PCP (1.0 and 2.0 mg/kg) induced a clear deficit in reversal learning. Both compounds, however, disrupted extinction at all tested doses. Risperidone and clozapine were both ineffective in significantly ameliorating the PCP-induced deficit in reversal learning which fits well with the clinical observations. The lowest dose of clozapine (1.25 mg/kg) had an intermediate effect in ameliorating the deficit in reversal learning induced by PCP (not different from control or PCP-treated rats). The lowest dose of GSK-742457 (0.63 mg/kg) fully reversed the PCP-induced deficits while the higher dose (5.0 mg/kg) had an intermediate effect.

A novel highly selective 5-HT6 receptor antagonist attenuates ethanol and nicotine seeking but does not affect inhibitory response control in Wistar rats.

Recent studies suggest a potential role for 5-hydroxytryptamine(6) (5-HT(6)) receptors in the regulation of addictive behavior. In the present study, our aim was to investigate whether the novel highly selective 5-HT(6) receptor antagonist compound (CMP) 42 affected nicotine and ethanol seeking behavior in Wistar rats. We have also studied whether CMP 42 had beneficial effects in a model of impulse control, as measured in the 5-choice serial reaction time task (5-CSRTT). Rats were trained to nose poke to receive intravenous infusions of nicotine or an ethanol drop. CMP 42 (3-30 mg/kg intraperitoneally, i.p.) was administered to investigate the effects on nicotine self-administration. Rats were also tested for cue-induced reinstatement of nicotine and ethanol seeking. In addition, the effects of CMP 42 were studied on the number of anticipatory responses in the 5-CSRTT. CMP 42 was effective in reducing nicotine self-administration and reinstatement of nicotine seeking at a dose of 30 mg/kg (i.p.). CMP 42 was also effective in reducing reinstatement of ethanol seeking (30 mg/kg i.p.). In contrast, CMP 42 did not affect anticipatory responding at doses tested, indicating no effects on impulse control. These results add to a body of evidence implicating the 5-HT(6) receptor as a viable target for the control of drug abuse. Specifically, we demonstrated for the first time effects on nicotine self-administration and on nicotine and ethanol reinstatement. Further, these effects are probably not mediated by effects on impulse control.

SLV330, a cannabinoid CB(1) receptor antagonist, attenuates ethanol and nicotine seeking and improves inhibitory response control in rats.

Cannabinoid CB(1) receptor (CB(1)R) signaling has been shown to play a role in the regulation of addictive behavior. In the present study, our aim was to investigate whether the CB(1)R antagonist SLV330 could reduce ethanol and nicotine self-administration and cue-induced reinstatement of ethanol and nicotine seeking behavior in Wistar rats. In operant chambers, rats were learned to emit a specific response (nose poke) in order to receive an ethanol solution or intravenous injections of nicotine. Discrete light and tone cues were presented during ethanol and nicotine delivery. These cues are particularly important for drug self-administration behavior and, through Pavlovian conditioning, acquire conditioned reinforcing and motivational properties and are therefore able to generate and maintain drug-seeking behavior. Subsequently, the CB(1)R antagonist SLV330 (doses ranging from 1 to 10mg/kg, given orally, p.o.) was administered to investigate the effects on drug self-administration. In addition, responding for ethanol and nicotine was extinguished. Then, the animals were tested for cue-induced reinstatement of ethanol and nicotine seeking and treated with vehicle or SLV330. Finally, the effects of SLV330 were studied on the number of anticipatory responses in the 5-choice serial reaction time task (5-CSRTT) in order to determine whether this compound could also increase impulse control in Wistar rats. The CB(1) antagonist SLV330 was effective in reducing ethanol self-administration at a lowest effective dose (LED) of 10mg/kg (p.o.) and reinstatement of ethanol seeking at a LED of 3mg/kg (p.o.). SLV330 was also effective in reducing nicotine self-administration and reinstatement of nicotine seeking, although at a LED of 10mg/kg (p.o.). Finally, SLV330 decreased time delay-dependent anticipatory responding (LED of 3.0mg/kg, p.o.), indicating an increased inhibitory control. These findings are in agreement with results reported with other CB(1) antagonists. The combined action of reducing the reinforcing and motivational properties of nicotine and alcohol and the improvement of impulse control supports the idea that the cannabinoid system is a promising target for anti-relapse medication.

SLV330, a cannabinoid CB1 receptor antagonist, ameliorates deficits in the T-maze, object recognition and Social Recognition Tasks in rodents.

Cannabinoid CB(1) receptor (CB(1)R) signaling has been suggested to play an important role in the regulation of memory and cognition. In the present study, our aim was to investigate whether the CB(1)R antagonist SLV330 (doses ranging from 0.3 to 10mg/kg, given orally, p.o.) could ameliorate impairments in distinct aspects of cognition using different disruption models in both mice and rats. Effects of SLV330 were tested on working memory deficits in the T-maze Continuous Alternation Task (T-CAT) in mice; episodic memory deficits in the Object Recognition Task (ORT) and Social Recognition Task (SRT) in rats. The acetylcholinesterase inhibitor (AChEI) donepezil (Aricept, approved for symptomatic treatment of Alzheimer's disease) and nicotine were used as reference compounds. SLV330 markedly improved aging and scopolamine-induced memory deficits in the T-CAT in mice with a lowest effective dose (LED) of 1mg/kg p.o., while reversing the cognitive dysfunction induced by the N-methyl-D-aspartate (NMDA) antagonist dizocilpine (MK-801) only at the middle dose of 3mg/kg. In the ORT, we have found that combined administration of subthreshold doses of SLV330 (1mg/kg, p.o.) and the AChEI donepezil (0.1mg/kg, p.o.), that had no discernable effects on performance when given alone, enhanced memory performance in Wistar rats with deficits induced by the muscarinic antagonist scopolamine, suggestive of additive synergistic effects of SLV330 and donepezil on cognitive impairment. Finally, SLV330 was found to have cognition enhancing properties in a time delay paradigm in the SRT at a LED dose of 3mg/kg (p.o.). In conclusion, the CB(1)R antagonist SLV330 was found to clearly improve memory in several preclinical models for cognitive impairment.

The 5-HT1A receptor agonist flesinoxan shares discriminative stimulus properties with some 5-HT2 receptor antagonists.

Ten homing pigeons were trained to discriminate the selective 5-HT1A receptor agonist flesinoxan (0.25 mg/kg p.o.) from its vehicle in a fixed-ratio (FR) 30 two-key operant drug discrimination procedure. The 5-HT2 receptor antagonist mianserin (ED50 = 4.8 mg/kg) fully substituted for flesinoxan, whereas ketanserin, ritanserin, mesulergine, and SB200646A substituted only partially, suggesting an interaction between 5-HT1A and 5-HT2 receptors. However, the 5-HT2 receptor agonists [DOI (0.6 mg/kg), TFMPP (10 mg/kg), mCPP (4 mg/kg)] were unable to antagonize the flesinoxan cue. The 5-HT1A receptor antagonists DU125530 (0.5-13 mg/kg) and WAY100,635 (0.1-1 mg/kg) partially antagonized the generalization of mianserin to flesinoxan. Taken together, these results are in accordance with the hypothesis that 5-HT1A receptor activation exerts an inhibitory effect on activation of 5-HT2 receptors. These results are in broad agreement with existing theories on 5-HT1A and 5-HT2 receptor interaction. Furthermore, it is argued that the discriminative stimulus properties of a drug may undergo qualitative changes with prolonged training.

Discriminative stimulus properties of eltoprazine in the pigeon.

Twelve pigeons were successfully (ED50 = 2.4 mg/kg p.o.) trained to discriminate the 5-HT(1A/B) receptor agonist eltoprazine (5.0 mg/kg p.o.) from its vehicle in a fixed-ratio (FR)30 two-key operant drug discrimination procedure. Tests for generalization and antagonism showed that 5-HT1A receptor agonists, such as 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin) (66.7%), flesinoxan (72.7%), buspirone (58.3%), and ipsapirone (36.4%) only partially substituted for the eltoprazine cue. Compounds with mixed agonistic action at 5-HT1 receptors, completely (> or = 80%) [(eltoprazine; TFMPP (1-(3-trifluoromethylphenyl) piperazine (ED50 = 7.68 mg/kg) and RU 24969 (5-methoxy-3-(1,2,3,6-tetrahydropyridin-4-yl-1H-indole) (ED50 = 15.8 mg/kg)] substituted for eltoprazine; whereas m-CPP (1-(3-chlorophenyl)piperazine) did not. The selective 5-HT reuptake inhibitor fluvoxamine partially (44%) substituted for the eltoprazine cue. The 5-HT1A receptor antagonist NAN-190 (1-(2-methoxyphenyl)-4-[4-(2-phtalimido)butyl]piperazine) fully blocked the eltoprazine cue. Both (+/-)-pindolol and (+/-)-propranolol showed partial antagonism of the eltoprazine cue (66.7 and 50.0%, respectively). (+/-)-Pindolol also showed partial substitution (50%) for the eltoprazine cue, but NAN-190 and (+/-)propranolol did not. It is concluded that the discriminatory stimulus properties of eltoprazine in the pigeon are mediated by 5-HT1A and 5-HT1B receptors.

The putative 5-HT1A receptor antagonist DU125530 blocks the discriminative stimulus of the 5-HT1A receptor agonist flesinoxan in pigeons.

Twelve homing pigeons were trained to discriminate the 5-HT1A receptor agonist flesinoxan (0.25 mg/kg p.o.) from its vehicle in a fixed ratio (FR) 30 two-key operant drug discrimination procedure. Tests for generalization and antagonism showed that compounds with agonistic action at the 5-HT1A receptor, such as 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin), buspirone and ipsapirone all substituted for the flesinoxan cue. Compounds with mixed agonistic action at the 5-HT(1A/1B) receptor fully (eltoprazine) or partially (RU24969 (5-methoxy-3-(1,2,3,6-tetrahydropyridin-4-yl-1H-indole)) substituted for flesinoxan. TFMPP (1-(3-trifluoromethylphenyl)piperazine) and mCPP (1-(3-chlorophenyl)piperazine), both acting at the 5-HT(1B/2C) receptor, did not substitute for flesinoxan, neither did the selective 5-HT re-uptake inhibitor fluvoxamine. The results of the antagonism tests showed that the 5-HT1A receptor antagonists NAN-190 (1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine), WAY 100635 ((N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclo-he xane-carboxamide) and the newly developed DU125530 (2-[4-[4-(7-chloro-2,3-dihydro-1,4-benzodioxin-5-yl)-1-piperazinyl ]butyl]-1,2-benzisothiazol-3(2H)-one-1,1-dioxide) fully (more than 80%) blocked the flesinoxan cue without having substantial effects when given alone. WAY100135 (N-tert-butyl-3-(4-(2-methoxyphenyl)piperazine-1-yl)-2-phenylpropanamide ), (+/-)-pindolol and (S)-UH-301 ((S)-5-fluoro-8-hydroxy-2-(dipropylamino)-tetralin) all partially antagonized the flesinoxan cue. However, both WAY100135 as well as (+/-)-pindolol also partially substituted for flesinoxan in generalization tests. NAN190, (S)-UH-301, WAY100635 and DU125530 were without any activity in the generalization test at the doses tested. The putative 5-HT1A receptor antagonist S15535 (4-benzodioxan-5-yl) 1-(indan-2-yl)piperazine) was identified as a full agonist in the present procedure. Taken together these results suggest that the flesinoxan cue in pigeons is mediated by the 5-HT1A receptor and that DU125530 acts as a full antagonist on the 5-HT1A receptor.

Flesinoxan shows antidepressant activity in a DRL 72-s screen.

Schedules which selectively reinforce low rates of responding (DRL, differential reinforcement of low rate) distinguish between antidepressants and other types of drugs. In a DRL schedule a subject is required to pause for a specified minimum period of time between two consecutive responses in order to obtain a reinforcer. The dependent variables are rate of responding and rate of reinforcement. Response patterns of rats treated with clinically effective antidepressant drugs such as imipramine (2.0-32.0 mg/kg) or fluvoxamine (4.0-32.0 mg/kg) are characterized by a decrease in response rate and an increase in reinforcement rate. Treatment with the 5-HT1A agonist flesinoxan (0.1-3.0 mg/kg) also dose-dependently decreased response rates while at the same time increasing reinforcement rates. Chlordiazepoxide (2.5-20.0 mg/kg) and diazepam (0.25-2.0 mg/kg) had no effects in the present experiment. d-Amphetamine increased response rates at low doses (0.5-2.0 mg/kg), and decreased it at the higher doses (4.0 mg/kg), but reinforcement rates were unaltered. Overall analysis of the effects of haloperidol (0.02-0.32 mg/kg) showed decreased responding and increased reinforcement rates. Post hoc analysis, however, clearly differentiated between haloperidol's profile and that of the antidepressants. As such, the results of the present experiment show that flesinoxan might possess antidepressant activity in humans.

Thyroid hormone and carrier protein interrelationships in children recovering from kwashiorkor.

We have studied 15 infants with severe protein energy malnutrition (PEM) as a model of nutritional nonthyroidal illness. Changes in circulating thyroid hormones, binding proteins, and their interrelationships were assessed before and during recovery. Serum concentrations of total thyroxine and triiodothyronine and of thyroxine-binding proteins were extremely reduced, and increased progressively during 3 wk of refeeding. The T4:TBG molar ratio was initially 0.180 +/- 0.020, and increased progressively, parallel to the increases in TT4, to 0.344 +/- 0.038 after 21 days (p less than 0.025). The changes in free T4 estimates varied according to the methods used--FTI and analogue FT4 increased, dialysis FT4 fraction decreased. Serum TSH levels increased transiently during recovery. It is concluded 1) there is reduced binding of T4 and T3 to TBG in untreated PEM which takes 2-3 wk to recover; 2) there are methodological differences in evaluating free T4 levels in PEM; 3) increased TSH secretion appears to be an integral part of the recovery from PEM.

Circulating thyroid hormones in progressive renal failure in the baboon (Papio ursinus).

In order to examine the effects of developing renal failure on circulating thyroid hormones, serum concentrations of thyroxine (T4), free T4 (FT4), triiodothyronine (T3) and reverse T3 (rT3) and TBG capacity were measured in 9 baboons before and during the progress of acute (mean survival 12 days), subacute (32 days) and chronic (120 days) renal failure following allogeneic renal transplantation. Irrespective of the rate of development of renal failure, there were significant, non linear (power functions) negative correlations between serum creatinine or urea concentrations and levels of T4, FT4 and T3; rT3 levels remained unchanged, but the T4: rT3 molar ratio fell from 236.5 +/- 61 (+/- SE) to 121.8 +/- 30.9 (p less than 0.05). T4 and T3 levels were invariably subnormal at creatinine concentrations greater than 250 mumol/l (2.8 mg/dl), but FT4 was subnormal only in chronic renal failure. Thyroxine binding globulin (TBG) capacity did not change significantly; thus the TBG: T4 ratio increased from 3.4 +/- 0.2 (basal) to 10.4 +/- 3.4 before death (p less than 0.05). In animals which survived for greater than 25 days after transplantation, a significant linear correlation between FT4 and T3 was found as uremia progressed. Polyacrylamide gel electrophoresis (pH 7.4) of (125I)-T4 labelled preoperative and uremic serum showed a consistent decline in the proportion of tracer bound to TBG, from 67.0 +/- 0.8% to 58.9 +/- 1.0% (p less than 0.001), with a 48% reduction in TBG saturation (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)