[ENT surgery in anticoagulate patients]. / HNO-Chirurgie bei Patienten unter oraler Antikoagulation und Plättchenhemmer-Therapie.

BACKGROUND: In elective ENT surgery, one frequently sees -patients on oral anticoagulants and platelet inhibitors. While continuation of these therapies increases the risk of bleeding complications, indiscriminate discontinuation can have severe thromboembolic consequences. Furthermore, the number of -anticoagulants and platelet inhibitors in use has increased. The ENT-specialist is regulary confronted with the question of continuation, discontinuation, or bridging of this therapy. METHODS: Review of the available literature on bleeding complications associated with ENT interventions performed with and without anticoagulants. Overview of the indications for anticoagulants and the different mechansims of action and properties of the different agents. Development of protocols for risk stratification and for perioperative management. CONCLUSIONS: Patients on oral anticoagulants and platelet inhibitors have significant morbidity and mortality not only due to the underlying diseases, but also due to the perioperative management of these therapies. Perioperative management should be based on well-established treatment guidelines or, in high-risk patients, on multidisciplinary consultation. Even though the recommendations here are evidence-based and cover a multitude of clinical contingencies, they cannot replace clinical decision making, which must consider the specific characteristics and circumstances of the patient, the planned intervention, and the surgical environment.

Elevated brain cannabinoid CB1 receptor availability in post-traumatic stress disorder: a positron emission tomography study.

Endocannabinoids and their attending cannabinoid type 1 (CB1) receptor have been implicated in animal models of post-traumatic stress disorder (PTSD). However, their specific role has not been studied in people with PTSD. Herein, we present an in vivo imaging study using positron emission tomography (PET) and the CB1-selective radioligand [(11)C]OMAR in individuals with PTSD, and healthy controls with lifetime histories of trauma (trauma-exposed controls (TC)) and those without such histories (healthy controls (HC)). Untreated individuals with PTSD (N=25) with non-combat trauma histories, and TC (N=12) and HC (N=23) participated in a magnetic resonance imaging scan and a resting PET scan with the CB1 receptor antagonist radiotracer [(11)C]OMAR, which measures the volume of distribution (VT) linearly related to CB1 receptor availability. Peripheral levels of anandamide, 2-arachidonoylglycerol, oleoylethanolamide, palmitoylethanolamide and cortisol were also assessed. In the PTSD group, relative to the HC and TC groups, we found elevated brain-wide [(11)C]OMAR VT values (F(2,53)=7.96, P=0.001; 19.5% and 14.5% higher, respectively), which were most pronounced in women (F(1,53)=5.52, P=0.023). Anandamide concentrations were reduced in the PTSD relative to the TC (53.1% lower) and HC (58.2% lower) groups. Cortisol levels were lower in the PTSD and TC groups relative to the HC group. Three biomarkers examined collectively--OMAR VT, anandamide and cortisol--correctly classified nearly 85% of PTSD cases. These results suggest that abnormal CB1 receptor-mediated anandamide signaling is implicated in the etiology of PTSD, and provide a promising neurobiological model to develop novel, evidence-based pharmacotherapies for this disorder.

Stenting of stenotic mesenteric arteries for symptomatic chronic mesenteric ischemia.

BACKGROUND: We report the results of our single center series of patients with chronic mesenteric ischemia (CMI) to determine the role of stenting in the management of patients. PATIENTS AND METHODS: We retrospectively reviewed all patients with CMI treated endovascularly with stent revascularisation from January 2008 to January 2011.CMI diagnosis was made according to clinical symptoms, including postprandial abdominal pain, food fear, and weight loss. Additionally, the diagnosis was confirmed by duplex ultrasonography and/or computed tomography angiography and/or contrast-enhanced magnetic resonance angiography. RESULTS: All 45 patients presented with typical CMI symptoms: 45/45 (100 %) had postprandial pain, 31/45 (68.8 %) had a weight loss of more than 10 kilograms, and 11/45 (24.4 %) suffered from ischemic colitis combined with lower gastrointestinal bleeding. In three patients occlusion could not be crossed, therefore considered as technical failure. A total of 55 arteries were stented in the remaining 42 patients. Nineteen patients underwent SMA stenting alone, eight underwent celiac stenting, alone and three patients underwent stenting of inferior mesenteric artery (IMA) alone. We performed combined stenting of the celiac artery and superior mesenteric artery in ten patients, and one patient underwent a combined stenting of the celiac artery and the IMA. All three mesenteric arteries were stented in only one patient. Primary technical success was achieved in 42/45 (94.8 %) patients. Clinical symptom relief was achieved in 39/45 (86.6 %) patients with abdominal pain. Increased body weight was observed in 28/31 (90.3 %) patients with an average weight gain of 8.8 kilograms (5 - 12 kilograms), and 10/11 (90.9 %) patients recovered from ischaemic colitis/lower gastrointestinal bleeding. CONCLUSIONS: Stent revascularisation can be considered as the first-line therapy for patients with chronic mesenteric ischemia.

Effects of duloxetine in treatment-refractory men with posttraumatic stress disorder.

INTRODUCTION: Although there is evidence that selective serotonin reuptake inhibitors provide some benefit in the treatment of post-traumatic stress disorder (PTSD), most meta-analytical reviews have concluded that effect sizes are small and, moreover, that there may be relatively little benefit for some populations (e. g., combat veterans with co-morbid major depression, MDD). This study aimed to evaluate the effectiveness and tolerability of the dual reuptake inhibitor duloxetine in the treatment of PTSD and co-morbid MDD. METHODS: Twenty-one treatment refractory, male, combat-related patients with PTSD and co-morbid MDD were enrolled in a naturalistic study and twenty completed the trial. Duloxetine was given between 60 and 120 mg daily over 8 weeks. RESULTS: Duloxetine led to a significant improvement of PTSD-characteristic symptoms as well as co-morbid MDD. Duloxetine effectively reduced nightmares, which is important because decreasing nightmares has been associated with improved sleep in PTSD. DISCUSSION: The results of this naturalistic study suggest that duloxetine is an effective and well-tolerated treatment for patients with PTSD and co-morbid MDD. These initial results need to be extended to the study of women with PTSD.

The MCP-4/MCP-1 ratio in plasma is a candidate circadian biomarker for chronic post-traumatic stress disorder.

Post-traumatic stress disorder (PTSD) is psychiatric disease, which can occur following exposure to traumatic events. PTSD may be acute or chronic, and can have a waxing and waning course of symptoms. It has been hypothesized that proinflammatory cytokines and chemokines in the cerebrospinal fluid (CSF) or plasma might be mediators of the psychophysiological mechanisms relating a history of trauma exposure to changes in behavior and mental health disorders, and medical morbidity. Here we test the cytokine/chemokine hypothesis for PTSD by examining levels of 17 classical cytokines and chemokines in CSF, sampled at 0900 hours, and in plasma sampled hourly for 24 h. The PTSD and healthy control patients are from the NIMH Chronic PTSD and healthy control cohort, initially described by Bonne et al. (2011), in which the PTSD patients have relatively low comorbidity for major depressive disorder (MDD), drug or alcohol use. We find that in plasma, but not CSF, the bivariate MCP4 (CCL13)/ MCP1(CCL2) ratio is ca. twofold elevated in PTSD patients compared with healthy controls. The MCP-4/MCP-1 ratio is invariant over circadian time, and is independent of gender, body mass index or the age at which the trauma was suffered. By contrast, MIP-1ß is a candidate biomarker for PTSD only in females, whereas TARC is a candidate biomarker for PTSD only in males. It remains to be discovered whether these disease-specific differences in circadian expression for these specific immune signaling molecules are biomarkers, surrogates, or drivers for PTSD, or whether any of these analytes could contribute to therapy.

[Interventional revascularization for severe mesenteric ischemia in contribution with venal artery angioplasty]. / Interventionelle Revaskularisation bei schwerer mesenterialer Ischämie kombiniert mit einer Angioplastie einer Nierenarterie.

A 82 year old lady presented with haemorraghic erosive gastritis, progressing lost of weight, hypertension, diabetes mellitus and renal dysfunction. Colour flow duplex scanning and MRA revealed subtotal stenosis of the celiac artery and the right renal artery, proximal occlusion of the superior mesenteric artery and complete occlusion of the inferior mesenteric artery. There were also stenoses in the left renal artery. The patient was accessed via the left brachial artery, because of the relatively unfavourable angle of the mesenteric arteries. The procedures were done using F8-sheath-, F7-guiding catheter and vertebral shaped F5-diagonstic catheter. The celiac trunk und the right renal artery were initially treated with 7 x 12 and 5 x 17 mm balloon-expanding Stents. 7 x 40 mm self-expanding stent (Carotid wallstent) was inserted in the superior mesenteric artery following balloon dilatation with 5-mm-PTA-ballon. Dilatation of the superior mesenteric artery was done also after placement of the stent with 7-mm-PTA-ballon. One stage successful endovascular treatment was performed in the three vascular territories. A follow-up of 3 months period with colour duplex sonography revealed the stent to be patent with normal flow, better control of the hypertension and improvement of the renal function.

Effects of tryptophan depletion on drug-free patients with seasonal affective disorder during a stable response to bright light therapy.

BACKGROUND: A dysfunction of the serotonin system may play a major role in the pathogenesis of seasonal affective disorder. Bright light therapy has been shown to be effective in the treatment of winter depression in patients with seasonal affective disorder. Light therapy-induced remission from depression may be associated with changes in brain serotonin function. METHODS: After at least 2 weeks of clinical remission, 12 drug-free patients who had had depression with seasonal affective disorder underwent tryptophan depletion in a double-blind, placebo-controlled, balanced cross-over design study. RESULTS: Short-term tryptophan depletion induced a significant decrease in plasma free and total tryptophan levels (P < .001 for both, repeated measures analysis of variance), with peak effects occurring 5 hours after ingestion of a tryptophan-free amino acid drink. It emerged that tryptophan depletion leads to a transient depressive relapse, which was most pronounced on the day after the tryptophan-depletion testing. No clinically relevant mood changes were observed in the control testing. CONCLUSIONS: The maintenance of light therapy-induced remission from depression in patients with seasonal mood cycles seems to depend on the functional integrity of the brain serotonin system. Our results suggest that the serotonin system might be involved in the mechanism of action of light therapy.

Effects of tryptophan depletion in drug-free depressed patients who responded to total sleep deprivation.

BACKGROUND: There is some evidence that sleep deprivation (SD) might exert its antidepressant properties by involving serotonergic mechanisms. We investigated the effects of short-term tryptophan depletion (TD) on depressed patients who responded to a single night of total SD. METHODS: Drug-free depressed inpatients (n = 30) were randomly assigned to either TD or sham depletion. Tryptophan depletion was induced by a 24-hour low-tryptophan diet (day 1) followed the next morning by ingestion of a tryptophan-free amino acid mixture (day 2). During sham depletion, the diet and the amino acid beverage were supplemented with tryptophan. Sleep deprivation was performed from day 1 until day 2. Only SD responders received the amino acid beverage the morning after SD. Behavioral ratings and total and free plasma tryptophan levels were obtained before and after the test sessions. RESULTS: Twenty-two of 30 patients showed a favorable outcome after SD. As predicted, TD significantly lowered total and free plasma tryptophan levels, whereas both levels increased during sham depletion. No acute effects on mood were observed during the day after SD in either treatment group. Unexpectedly, TD, but not control testing, prevented the depressive relapse after the recovery night in most of the patients. CONCLUSIONS: Tryptophan depletion did not reverse the antidepressant effects of SD, but it prevented the relapse beyond a night of recovery sleep. These findings suggest that SD does not act via a single monoamine-related mechanism, but they allow the assumption that TD may induce neurochemical alterations that transiently improve depression.

Effects of tryptophan depletion vs catecholamine depletion in patients with seasonal affective disorder in remission with light therapy.

BACKGROUND: Although hypotheses about the therapeutic mechanism of action of light therapy have focused on serotonergic mechanisms, the potential role, if any, of catecholaminergic pathways has not been fully explored. METHODS: Sixteen patients with seasonal affective disorder who had responded to a standard regimen of daily 10000-lux light therapy were enrolled in a double-blind, placebo-controlled, randomized crossover study. We compared the effects of tryptophan depletion with catecholamine depletion and sham depletion. Ingestion of a tryptophan-free amino acid beverage plus amino acid capsules was used to deplete tryptophan. Administration of the tyrosine hydroxylase inhibitor alpha-methyl-paratyrosine was used to deplete catecholamines. Diphenhydramine hydrochloride was used as an active placebo during sham depletion. The effects of these interventions were evaluated with measures of depression, plasma tryptophan levels, and plasma catecholamine metabolites. RESULTS: Tryptophan depletion significantly decreased plasma total and free tryptophan levels. Catecholamine depletion significantly decreased plasma 3-methoxy-4-hydroxyphenylethyleneglycol and homovanillic acid levels. Both tryptophan depletion and catecholamine depletion, compared with sham depletion, induced a robust increase (P<.001, repeated-measures analysis of variance) in depressive symptoms as measured with the Hamilton Depression Rating Scale, Seasonal Affective Disorder Version. CONCLUSIONS: The beneficial effects of light therapy in the treatment of seasonal affective disorder are reversed by both tryptophan depletion and catecholamine depletion. These findings confirm previous work showing that serotonin plays an important role in the mechanism of action of light therapy and provide new evidence that brain catecholaminergic systems may also be involved.

Anxiety disorders: noradrenergic neurotransmission.

The past decade has seen a rapid progression in our knowledge of the neurobiological basis of fear and anxiety. Specific neurochemical and neuropeptide systems have been demonstrated to play important roles in the behaviors associated with fear and anxiety-producing stimuli. Long-term dysregulation of these systems appears to contribute to the development of anxiety disorders, including panic disorder, posttraumatic stress disorder (PTSD), and social anxiety disorder. These neurochemical and neuropeptide systems have been shown to have effects on distinct cortical and subcortical brain areas that are relevant to the mediation of the symptoms associated with anxiety disorders. Moreover, advances in molecular genetics portend the identification of the genes that underlie the neurobiological disturbances that increase the vulnerability to anxiety disorders. This chapter reviews clinical research pertinent to the neurobiological basis of anxiety disorders. The implications of this synthesis for the discovery of anxiety disorder vulnerability genes and novel psychopharmacological approaches will also be discussed.

Serotonin versus catecholamine deficiency: behavioral and neural effects of experimental depletion in remitted depression.

Despite immense efforts into development of new antidepressant drugs, the increases of serotoninergic and catecholaminergic neurotransmission have remained the two major pharmacodynamic principles of current drug treatments for depression. Consequently, psychopathological or biological markers that predict response to drugs that selectively increase serotonin and/or catecholamine neurotransmission hold the potential to optimize the prescriber's selection among currently available treatment options. The aim of this study was to elucidate the differential symptomatology and neurophysiology in response to reductions in serotonergic versus catecholaminergic neurotransmission in subjects at high risk of depression recurrence. Using identical neuroimaging procedures with [(18)F] fluorodeoxyglucose positron emission tomography after tryptophan depletion (TD) and catecholamine depletion (CD), subjects with remitted depression were compared with healthy controls in a double-blind, randomized, crossover design. Although TD induced significantly more depressed mood, sadness and hopelessness than CD, CD induced more inactivity, concentration difficulties, lassitude and somatic anxiety than TD. CD specifically increased glucose metabolism in the bilateral ventral striatum and decreased glucose metabolism in the bilateral orbitofrontal cortex, whereas TD specifically increased metabolism in the right prefrontal cortex and the posterior cingulate cortex. Although we found direct associations between changes in brain metabolism and induced depressive symptoms following CD, the relationship between neural activity and symptoms was less clear after TD. In conclusion, this study showed that serotonin and catecholamines have common and differential roles in the pathophysiology of depression.

Serotonin transporter polymorphisms predict response inhibition in healthy volunteers.

Serotoninergic transmission is reliably implicated in inhibitory control processes. The aim of this study was to test the hypothesis if serotonin transporter polymorphisms mediate inhibitory control in healthy people. 141 healthy subjects, carefully screened for previous and current psychopathology, were genotyped for the 5-HTTLPR and rs25531 polymorphisms. Inhibitory control was ascertained with the Stop Signal Task (SST) from the Cambridge Neuropsychological Test Automated Battery (CANTAB). The triallelic gene model, reclassified and presented in a biallelic functional model, revealed a dose-dependent gene effect on SST performance with Individuals carrying the low expressive allele had inferior inhibitory control compared to high expressive carriers. This directly implicates serotonin transporter polymorphisms (5-HTTLPR plus rs25531) in response inhibition in healthy subjects.

Low frontal electroencephalographic coherence in neuroleptic-free schizophrenic patients.

BACKGROUND: Electroencephalographic (EEG) coherence analysis is a noninvasive technique for studying corticocortical associations. As there is evidence for a dysfunction of the prefrontal dorsolateral cortex in schizophrenia, we hypothesized to find lower frontal EEG coherence in schizophrenia. METHODS: EEG amplitude and coherence analysis was performed in 16 antipsychotic-free schizophrenic patients and 16 healthy controls. EEG recordings were done with 19 gold-plated electrodes placed according to the International 10/20 system against averaged signals from both earlobes. Local coherence was computed for 22 adjacent electrode pairs within the hemispheres and interhemispheric coherence for eight corresponding electrode pairs of both hemispheres in the delta, theta, alpha, and beta-I band. RESULTS: Amplitude and interhemispheric coherence analysis revealed no differences. Local EEG coherence was significantly lower in schizophrenic patients for Fpl-F7 in the delta (p = .001) and the theta band (p = .002), and at F7-F3 in the alpha band (p = .002). In the delta band coherence of Fpl-F7 was inversely correlated to the Positive and Negative Syndrome Scale positive symptoms subscore (R = -.74, p = .014). CONCLUSIONS: Assuming that EEG coherence can be used to index functional coupling between brain areas under the electrodes, the low EEG coherence in Fpl-F7 and F7-F3 in schizophrenic patients might reflect impaired information processing in the left dorsolateral prefrontal cortex.

Seasonal variation of availability of serotonin transporter binding sites in healthy female subjects as measured by [123I]-2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane and single photon emission computed tomography.

BACKGROUND: Previous studies have indicated annual variations in central and peripheral serotonergic activity. In the present study we studied five women in summer and six women in winter and evaluated possible differences in availability of brain serotonin transporters between summer and winter. METHODS: We employed the single photon emission computed tomography ligand [123I]-2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane ([123I] beta-CIT) to visualize binding to the serotonin transporter site in the human thalamus/hypothalamus midbrain area in vivo. Brain imaging studies were performed in one group between May and August and in the other between November and December. RESULTS: We found significant differences in displaceable [123I] beta-CIT binding in the region corresponding to thalamus/hypothalamus between the summer group and the winter group (1.9 +/- 0.3 vs. 1.4 +/- 0.2, respectively; p < .01). CONCLUSIONS: The results of the present study suggest reduced brain serotonin transporter availability in winter. This finding further substantiates evidence of seasonal variations in brain serotonergic function.

Bright light therapy stabilizes the antidepressant effect of partial sleep deprivation.

Partial sleep deprivation (PSD) results in a pronounced decrease of depressive symptoms in the majority of patients with major depressive disorder. Generally this acute antidepressant effect is not stable, relapse usually occurs after one night of recovery sleep. We therefore studied whether light therapy, beginning in the morning after PSD, is able to prevent the relapse after sleep deprivation, using a controlled, balanced, parallel design. All patients received an antidepressant medication, which was kept constant before and during the study period. Fourteen of 20 patients (70%) showed a reduction of at least 40% in the Hamilton Depression Rating Scale (HDRS) in the morning after PSD and were classified as PSD responders. Responders as well as nonresponders were randomly assigned to receive either bright light (BL/3000 lux) or dim light (DL/100 lux) therapy during the following 6 days after PSD. In the responder group BL therapy prevented significantly (p = 0.005) the relapse after the next night of sleep and prolonged significantly (p = 0.011) the antidepressant effects of PSD up to 7 days. In contrast, patients in the DL condition relapsed after the recovery night and showed no further improvement of the depressive syndrome after 1 week of DL therapy. PSD nonresponders did not benefit from light treatment. These findings indicate that BL therapy might be efficacious to prevent relapse after PSD.

The effects of light therapy on mini-mental state examination scores in demented patients.

BACKGROUND: Preliminary evidence suggests that demented patients may experience beneficial effects of light therapy. The authors tested whether bright light therapy (BLT) is capable of improving cognitive functions in patients with Alzheimer-type dementia (AD) or vascular dementia (VD). METHODS: Twenty-three patients with AD or VD were randomly assigned to either evening BLT or dim light therapy (DLT). Effects of light therapy on cognitive functions were assessed before and after light therapy using Mini-Mental State Examination (MMSE) scores. Body temperature rhythm (BTR) was additionally recorded pre- and posttreatment. RESULTS: Irrespective of their diagnosis, patients treated with BLT (p =.0012) but not with DLT (p =.73) showed a statistically significant increase in MMSE total scores after light therapy. Evening BLT simultaneously induced a significant phase delay of 56 min on BTR (p =.025). CONCLUSION: Our preliminary results suggest that short-term evening BLT may exert beneficial effects on cognitive functioning in patients with dementia.

[123I]-beta-CIT SPECT imaging shows reduced brain serotonin transporter availability in drug-free depressed patients with seasonal affective disorder.

BACKGROUND: Numerous findings indicate alterations in brain serotonin systems in seasonal affective disorder (SAD). [(123)I]-2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane ([(123)I]-beta-CIT) labels serotonin transporters (5-HTTs) in the midbrain. We performed a [(123)I]-beta-CIT single photon emission computer tomography (SPECT) study under the hypothesis of lower [(123)I]-beta-CIT binding reflecting reduced central 5-HTT availability in depressed SAD patients. METHODS: Depressed SAD patients and healthy control subjects were investigated using [(123)I]-beta-CIT SPECT 4 hours and again 24 hours after tracer injection. Subjects had either never used psychotropic medication or had been drug-free for at least 6 months prior to the investigation. Specific-to-nondisplaceable partition coefficient (V(3)") was calculated for the thalamus-hypothalamus and the midbrain-pons; the cerebellum served as a reference region. RESULTS: Patients showed a reduction in V(3)" in thalamus-hypothalamus (2.41+/-0.3 vs. 2.84+/-0.4; p = .026) 24 hours post tracer injection (p.i.). No difference between patients and control subjects was found in midbrain-pons (1.31+/-0.2 vs. 1.42+/-0.2; p = .39). No differences were detected in the SPECT acquisitions 4 hours p.i. CONCLUSIONS: Depressed SAD patients showed lower specific-to-nondisplaceable [(123)I]-beta-CIT binding in the region of interest (ROI) thalamus-hypothalamus. The small size of the midbrain-pons ROI may have contributed to the failure to show a difference in this ROI as well. Similar to reduced midbrain 5-HTT availability in nonseasonal depression, depression in SAD seems to be associated with reduced 5-HTT availability to the thalamus-hypothalamus.

[123I] beta-CIT and single photon emission computed tomography reveal reduced brain serotonin transporter availability in bulimia nervosa.

BACKGROUND: Impaired serotonin transmission has been implicated in the pathophysiology of eating disorders. We investigated the in vivo availability of brain serotonin transporters and dopamine transporters in bulimia nervosa patients. METHODS: Approximately 24 hours after injection of [123I]-2beta-carbomethoxy-3beta-(4-iodophenyl)tropane ([123I] beta-CIT), single photon emission computed tomography scans were performed in 10 medication-free, female bulimic patients and 10 age-matched, healthy females. For quantification of brain serotonin transporter and dopamine transporter availability, a ratio of specific to nonspecific [123I] beta-CIT brain binding was used (V(3)" = target region - cerebellum/cerebellum). RESULTS: Drug-free bulimia nervosa patients showed a 17% reduced brain serotonin transporter availability in the hypothalamus and thalamus, as compared with healthy control subjects (2.4 +/- 0.4 vs. 2.9 +/- 0.4, p =.026), and a similar reduction in striatal dopamine transporter availability. There was a negative correlation of illness duration and serotonin transporter availability (r = -.65; p =.042) and a strong positive correlation between hypothalamic/thalamic and striatal V(3)" (r =.80, p <.001). CONCLUSIONS: This first report of reduced [123I] beta-CIT binding in a relatively small group of patients with bulimia nervosa suggests a reduced hypothalamic and thalamic serotonin transporter availability in bulimia, which is more pronounced with longer duration of illness.

No evidence for in vivo regulation of midbrain serotonin transporter availability by serotonin transporter promoter gene polymorphism.

BACKGROUND: A polymorphism in the serotonin transporter promoter gene region (5-HTTLPR) has been shown to influence the quantity of serotonin transporter expressed in human cell lines: the 5-HTTLPR short allele (s) has been associated with reduced 5-HTT expression when compared to cells carrying the 5-HTTLPR long allele (l). We performed a single photon emission computed tomography (SPECT) study using the ligand [(123)I]-2-beta-carbomethoxy-3-beta-(4-iodophenyl)tropane ([(123)I]-beta-CIT) to measure 5-HTT availability in 16 healthy subjects genotyped for 5-HTTLPR. METHODS: SPECT scans were performed 24 hours after tracer injection, regions of interest anatomically corresponding to the thalamus-hypothalamus and mesencephalon-pons areas were compared to the binding in the cerebellum, representing the nondisplaceable [(123)I]-beta-CIT-binding (results expressed as target activity minus cerebellum activity/cerebellum activity). DNA from peripheral nuclear blood cells was genotyped for 5-HTTLPR using standard polymerase chain reaction methods. RESULTS: Specific binding ratios in the thalamus-hypothalamus were 2.65 +/- 0.4 in subjects with the l/l genotype (n = 3), 2.76 +/- 0.5 in subjects with the l/s genotype (n = 9), and 2.77 +/- 0.4 in subjects with the s/s genotype (n = 4). Binding ratios in the mesencephalon-pons were 1.43 +/- 0.3 (l/l; n = 3), 1.37 +/- 0.3 (l/s; n = 9), and 1.28 +/- 0.3 (s/s; n = 4). None of these differences was statistically significant. CONCLUSIONS: Our data provide no evidence for in vivo functional regulation of 5-HTT availability by 5-HTTLPR in the thalamus-hypothalamus and mesencephalon-pons of healthy subjects.