[Telemedicine in stroke-pertinent to stroke care in Germany]. / Telemedizin in der Schlaganfallversorgung ­ versorgungsrelevant für Deutschland.

BACKGROUND AND OBJECTIVE: Telemedical stroke networks improve stroke care and provide access to time-dependent acute stroke treatment in predominantly rural regions. The aim is a presentation of data on its utility and regional distribution. METHODS: The working group on telemedical stroke care of the German Stroke Society performed a survey study among all telestroke networks. RESULTS: Currently, 22 telemedical stroke networks including 43 centers (per network: median 1.5, interquartile range, IQR, 1-3) as well as 225 cooperating hospitals (per network: median 9, IQR 4-17) operate in Germany and contribute to acute stroke care delivery to 48 million people. In 2018, 38,211 teleconsultations (per network: median 1340, IQR 319-2758) were performed. The thrombolysis rate was 14.1% (95% confidence interval 13.6-14.7%) and transfer for thrombectomy was initiated in 7.9% (95% confidence interval 7.5-8.4%) of ischemic stroke patients. Financial reimbursement differs regionally with compensation for telemedical stroke care in only three federal states. CONCLUSION: Telemedical stroke care is utilized in about 1 out of 10 stroke patients in Germany. Telemedical stroke networks achieve similar rates of thrombolysis and transfer for thrombectomy compared with neurological stroke units and contribute to stroke care in rural regions. Standardization of network structures, financial assurance and uniform quality measurements may further strengthen the importance of telestroke networks in the future.

The Double Burden of COVID-19 and Dengue in Nepal: The challenges ahead.

Coronavirus disease 2019 (COVID-19) pandemic has caused significant impact on the health care system. As a consequence, diagnosis and treatment of vector borne diseases including dengue has been equally affected. Nepal is no exception to this, where COVID-19 cases is exponentially increased and all resources are concentrated on its prevention, control and management. Dengue, one of the major vector-borne diseases in Nepal, is apparently overlooked despite approaching the peak season of the disease. The aim of this paper is to describe the double burden of COVID-19 and dengue in Nepal, particularly highlighting the co-circulation and possible coinfections. This has posed higher risk of increased severity, more severe cases and deaths in Nepal. Moreover, potential misdiagnosis of these viral diseases may lead to delayed or, inappropriate treatment and poor allocation of resources.

Negative Refraction in Time-Varying Strongly Coupled Plasmonic-Antenna-Epsilon-Near-Zero Systems.

Time-varying metasurfaces are emerging as a powerful instrument for the dynamical control of the electromagnetic properties of a propagating wave. Here we demonstrate an efficient time-varying metasurface based on plasmonic nano-antennas strongly coupled to an epsilon-near-zero (ENZ) deeply subwavelength film. The plasmonic resonance of the metal resonators strongly interacts with the optical ENZ modes, providing a Rabi level spitting of ∼30%. Optical pumping at frequency ω induces a nonlinear polarization oscillating at 2ω responsible for an efficient generation of a phase conjugate and a negative refracted beam with a conversion efficiency that is more than 4 orders of magnitude greater compared to the bare ENZ film. The introduction of a strongly coupled plasmonic system therefore provides a simple and effective route towards the implementation of ENZ physics at the nanoscale.

[The effectiveness of pancreatic enzyme replacement therapy using microencapsulated pancreatin preparations in the correction of nutritional status in patients with chronic pancreatitis: a prospective observational study].

AIM: The goal is to evaluate the effectiveness of pancreatic enzyme replacement therapy (PERT) using microencapsulated pancreatin preparations for the correction of nutritional status in patients with chronic pancreatitis (CP) and associated exocrine pancreatic insufficiency (EPI). MATERIALS AND METHODS: The study included 58 patients with CP who were divided into two groups depending on the results of a laboratory assessment of indicators of nutritional status: group I (n=30) consisted of patients with CP and signs of EPI (according to low elastase test values) without deviations in nutritional status; Group II (n=28) consisted of patients with CP with a EPI and an abnormal nutritional status. In both groups, patients during the entire observation period (8-12 months) received PERT using microencapsulated pancreatin preparations at a dose adjusted for the severity of permanent residence permit. Before and after the PERT course, the dynamics of anthropometric [body weight, body mass index (BMI)] and laboratory indicators of nutritional status (total protein, albumin, vitamins D and B12, transferrin, iron and magnesium) were evaluated. RESULTS: After the completion of PERT, a significant tendency towards an increase in BMI in patients was noted in both groups. In group I, this indicator increased from 21.45 [95% confidence interval (CI) 19.80-23.92] kg/m2 to 22.15 (95% CI 20.31-23.86) kg/m2, and in II group - from 19.22 (95% CI 18.33-21.99) kg/m2 to 22.0 (95% CI 19.97-24.08) kg/m2. At the same time, the duration of PERT (months) significantly correlated with the dynamics of the patient's body weight (r=0.4679; 95% CI 0.2384-0.6479, p=0.0002). When assessing laboratory markers of nutritional status after PERT, a general tendency was found to increase the levels of total protein, albumin, vitamin D, magnesium, transferrin, and iron in both groups, however, statistically significant differences in the dynamics were observed mainly in group II patients. So, the level of total protein in group II increased from 69.05 (95% CI 65.6717-70.9000) g/l to 72.8 (95% CI 71.1358-74.9000) g/l, vitamin D - from 10.6 (95% CI 32.8397-38.9603) ng/ml to 17.1 (95% CI 12.0166-23.6232) ng/ml, magnesium - from 0.72 ( 95% CI 0.6892-0.7825) mmol/L to 0.795 (95% CI 0.7692-0.8800) mmol/L, and transferrin from 2.91 (95% CI 2.1800-3.3656 ) g/l to 2.92 (95% CI 2.4000-3.5200) g/l. CONCLUSION: A prospective observational study demonstrated the effectiveness of PERT using microencapsulated pancreatin preparations in the correction of nutritional status in patients with CP.

An OLTAM system for analysis of brown/beige fat thermogenic activity.

BACKGROUND/OBJECTIVES: Thermogenic fat is present in humans and emerging evidence indicates that increasing the content and activity of these adipocytes may lead to weight loss and improved metabolic health. Multiple reporter systems have been developed to assay thermogenic fat activity based on the transcriptional and translational activation of Ucp1, the key molecule that mediates nonshivering thermogenesis. Our study aims to develop a much-needed tool to monitor thermogenic fat activity through a mechanism independent of Ucp1 regulation, therefore effectively assaying not only canonical ß-adrenergic activation but also various non-UCP1-mediated thermogenic pathways that have been increasingly appreciated. METHODS: We detected increased luciferase activity upon thermogenic activation in interscapular brown and inguinal subcutaneous fat in ODD-Luc mice, a hypoxia reporter mouse model. We then developed an OLTAM (ODD-Luc based Thermogenic Activity Measurement) system to assay thermogenic fat cell activity. RESULTS: In both primary murine and human adipocytes and an immortalized adipose cell line that were transduced with the OLTAM system, luciferase activity can be readily measured and visualized by bioluminescence imaging in response to a variety of stimuli, including UCP1-independent thermogenic signaling. This system can offer a convenient method to assay thermogenic activity for both basic and translational research. CONCLUSIONS: The OLTAM system offers a convenient way to measure the activation of thermogenic fat and presents opportunities to discover novel signaling pathways and unknown compounds targeting metabolically active adipocytes to counteract human obesity.

Video-rate terahertz digital holographic imaging system.

Terahertz (THz) imaging has been demonstrated in numerous applications from medical to non-destructive evaluation (NDE), but current systems require expensive components, provide slow frame-rates and low resolutions. THz holography offers a potentially low-cost, high-performance alternative. Here we demonstrate the first full video-rate THz digital holography system at 2.52 THz (118.8 µm) using low-cost optical components. 2D digital reconstructions of samples are performed at frame-rates of 50 Hz - an order of magnitude higher than previous systems, whilst imaging of samples concealed in common packaging types demonstrates suitability for NDE applications. A lateral resolution of 250 µm was determined using a 1951 USAF target.

Comparing intra-articular CTXII levels assessed via magnetic capture or lavage in a rat knee osteoarthritis model.

OBJECTIVE: Parallel measures of osteoarthritis (OA) across species can help evaluate OA models relative to humans. Toward this need, our group recently developed a magnetic nanoparticle-based technology, termed magnetic capture, to analyze biomarkers within a rat knee. The objectives of this study were to directly compare magnetic capture to lavage, and assess c-telopeptide of collagen type II (CTXII) in the rat medial meniscus transection (MMT) model of knee OA. DESIGN: MMT surgery was performed in 30 male Lewis rats (3 months, 250 g). Using lavage or magnetic capture, CTXII was assessed in the OA-affected and contralateral knee at 1 week (n = 6 per group) or 4 weeks (n = 8 per group) after surgery. RESULTS: While lavage detected elevated CTXII concentrations in the OA-affected knee at 1 week (P = 0.002), magnetic capture detected elevated CTXII levels in the OA-affected knee at 4 weeks (P = 0.016). While magnetic capture did not detect significant elevation of CTXII at week 1, five of six rats evaluated with magnetic capture had higher CTXII levels in the OA-affected joint relative to the contralateral limb. Moreover, with magnetic capture, CTXII levels increased from 1 week to 4 weeks, corresponding to histological damage. CTXII concentrations evaluated via lavage were relatively constant across time. CONCLUSIONS: Magnetic capture and lavage evaluate CTXII in different ways: Magnetic capture measures total CTXII in the joint, while lavage measures concentration. Our data indicate magnetic capture may be advantageous at later time points, where CTXII can be diluted by effusions.

Segmental resection is a safe oncological alternative to total proctocolectomy in elderly patients with ulcerative colitis and malignancy.

AIM: The standard approach for the surgical management of colorectal cancer (CRC) in the setting of ulcerative colitis (UC) involves total proctocolectomy (TPC). However, some patients also undergo a partial resection (PR). This may be an attractive option in older patients with a high risk for surgery. The aim of this study was to compare the risk of metachronous cancer after PR or TPC for CRC in the setting of UC. METHOD: This was a retrospective cohort study conducted through the Nationwide Veterans Affairs Healthcare System (VA). Patients who had UC and underwent a PR or TPC for CRC were followed from the time of their surgery to their most recent clinical follow-up. The primary outcome was development of metachronous cancer in the PR group. Secondary outcomes included surgical and medical outcomes. RESULTS: Fifty-nine patients were included: 24 (40.7%) underwent PR and 35 (59.3%) underwent TPC. The median age at cancer diagnosis was 73.0 and 61.7 years in PR and TPC groups, respectively (P < 0.0005). Amongst patients undergoing PR, 15 (60%) had no active UC at the time of surgery, whereas in patients undergoing TPC, at the time of surgery eight (23.5%) had no active UC (P = 0.005). No patient who underwent a partial colectomy developed a metachronous cancer in the retained colonic segment during the follow-up period (median 7 years). CONCLUSION: Our study suggests that PR for CRC in the setting of UC may be a viable option in a selected cohort of patients, especially among the elderly.

Efficient coupling of double-metal terahertz quantum cascade lasers to flexible dielectric-lined hollow metallic waveguides.

The growth in terahertz frequency applications utilising the quantum cascade laser is hampered by a lack of targeted power delivery solutions over large distances (>100 mm). Here we demonstrate the efficient coupling of double-metal quantum cascade lasers into flexible polystyrene lined hollow metallic waveguides via the use of a hollow copper waveguide integrated into the laser mounting block. Our approach exhibits low divergence, Gaussian-like emission, which is robust to misalignment error, at distances > 550 mm, with a coupling efficiency from the hollow copper waveguide into the flexible waveguide > 90%. We also demonstrate the ability to nitrogen purge the flexible waveguide, increasing the power transmission by up to 20% at 2.85 THz, which paves the way for future fibre based terahertz sensing and spectroscopy applications.

Hollow metallic waveguides integrated with terahertz quantum cascade lasers.

We present the realization of a compact, monolithically integrated arrangement of terahertz quantum cascade lasers with hollow metallic cylindrical waveguides. By directly mounting a copper pipe to the end facet of a double metal waveguide, it was possible to significantly improve the far field emission from such a sub-wavelength plasmonic mode, while preserving the characteristic performance of the laser. Careful alignment of the quantum cascade laser and the hollow waveguide is required in order to prevent the excitation of higher order/mixed modes as predicted with a high degree of accuracy by a theoretical model. Finally, this approach proved to be a superior method of beam shaping when compared to other in situ arrangements, such as a silicon hyper-hemispherical lens glued to the facet, which are presented.

A case of an extremely rare unilateral subscapular trunk and axillary artery variation in a male Caucasian: comparison to the prevalence within other populations.

A male Caucasian cadaver was found to have a large common trunk that branched off of the first part of the axillary artery of the left arm. This trunk gave rise to all but two arterial branches of the axillary region. The large common trunk first gave off a thoracoacromial artery followed by the main branch, the subscapular artery. The subscapular was the origin of the posterior circumflex humeral and lateral thoracic arteries immediately proximal to bifurcating into its two terminal branches, the circumflex scapular and thoracodorsal arteries. Only the superior thoracic and anterior circumflex humeral arteries arose directly from the axillary artery. Also found was a high origin of the radial artery, noteworthy by its serpentine route. In comparison, in the right arm, no variants appeared in the axillary, subscapular, or brachial arteries. A comparison with branching patterns of axillary arteries from demographically similar and dissimilar populations revealed the extreme rarity of this set of anomalies.

Prognostic value of rapid test for diagnosis of dengue in Nepalese patients during 2010 epidemic.

BACKGROUND: Dengue is an emerging vector borne disease in Nepal and rapid diagnostic test is important for early diagnosis of the disease. OBJECTIVES: The aim of the study was to evaluate the diagnostic accuracy of commonly used rapid immunochromatographic test kit in Nepal during 2010 dengue epidemic and to assess disease burden of dengue. METHODS: A total of 131 acute and nonacute serum samples were collected during recent epidemic of dengue in 2010 from clinically suspected Nepalese patients of different hospitals. Rapid immunochromatographic test kit was used for early diagnosis and enzyme immunosorbent was chosen as a reference assay. RESULTS: The sensitivity and specificity of rapid test was 70% and 76.54% respectively whereas the prevalence of the disease was 38.17%. The odds ratio for males was 1.8 however; the association with the disease was statistically not significant. CONCLUSION: The diagnostic accuracy of rapid immunochromatographic test for dengue diagnosis was low (k=0.46). So, it should be substituted by highly sensitive test device for prompt diagnosis and health personnel should consider appropriate timing of sample collection for better performance of rapid test.

ABO-Incompatible Kidney Transplantation: Low Rates of Infectious Complications and Excellent Patient Survival.

BACKGROUND: A significant gap exists between demand and supply of organs for patients with end-stage renal disease. To increase the donor pool, kidney transplantation is performed across ABO- and HLA-incompatible barriers. ABO-incompatible kidney transplant (ABOi-KT) recipients are at increased risk of antibody-mediated rejection, infection, and mortality. Hypogammaglobulinemia secondary to immunosuppression is highly prevalent after solid organ transplantation, and intravenous immunoglobulin (IVIG) has been reported to reduce the risks of infections in various settings. We use high-dose IVIG in ABOi-KT recipients perioperatively. We aimed to determine the rate of infectious complications along with graft and patient survival in our ABOi-KT recipients. METHODS: We included all adult patients who underwent ABOi-KT from the year 2007 to 2016. Patients received rituximab, plasma exchange, and IVIG (2 g/kg body weight). Thymoglobulin and intravenous methylprednisolone were used as induction treatment. Oral prednisone, mycophenolate mofetil, and tacrolimus were used as maintenance therapy. RESULTS: A total of 77 ABOi-KTs were performed, and the recipients were followed up for a median of 1557 days. Two patients were diagnosed as having BK nephropathy. No patients were diagnosed as having pneumocystis infection, cytomegalovirus disease, herpes simplex, varicella zoster, or fungal infection. One-year graft and patient survival was 94.8% and 100%, respectively. CONCLUSIONS: In our series of ABOi-KTs, we observed a low risk of infectious complications and excellent patient survival. High-dose IVIG might have reduced infections.

Safety of herpes zoster vaccination among inflammatory bowel disease patients being treated with anti-TNF medications.

BACKGROUND: The risk of herpes zoster (HZ) is elevated in inflammatory bowel disease (IBD) patients treated with anti-TNF medications. While it is optimal to give herpes zoster vaccine prior to initiation of therapy clinical circumstances may not always allow this. AIM: To determine the safety of giving herpes zoster vaccine while patients are on anti-TNF therapy. METHODS: We conducted a retrospective cohort study involving IBD patients who were followed in the Veterans Affairs (VA) healthcare system between 2001 and 2016. Patients who received herpes zoster vaccine while on anti-TNF medication were identified through vaccination codes and confirmed through individual chart review. Our outcome of interest was development of HZ between 0 and 42 days after herpes zoster vaccine administration. RESULTS: Fifty-six thousand four hundred and seventeen patients with IBD were followed in the VA healthcare system. A total of 59 individuals were on anti-TNF medication when they were given herpes zoster vaccine, and amongst them, 12 (20%) were also taking a thiopurine. Median age at the time of herpes zoster vaccine was 64.9 years and 95% of patients had a Charlson Comorbidity Index of ≥2. Median number of encounters within 42 days after receiving herpes zoster vaccine was two. No case of HZ was found within 0-42 days of HZV administration. CONCLUSION: Our data suggest that co-administering the herpes zoster vaccine to patients who are taking anti-TNF medications is relatively safe. This study significantly expands the evidence supporting the use of herpes zoster vaccine in this population, having included an elderly group of patients with a high Charlson Comorbidity Index who are likely at a much higher risk of developing HZ.

Simultaneous appearance of keratin modifications and gamma-glutamyltransferase activity as indicators of tumor progression in mouse skin papillomas.

gamma-Glutamyltransferase (GGT), an enzyme not found in normal adult epidermis, was detected in most skin papillomas larger than 13 mm in diameter and in all squamous carcinomas induced by 7,12-dimethylbenz[a]anthracene initiation and 12-O-tetradecanoylphorbol 13-acetate promotion in noninbred Sencar mice. Furthermore, these GGT-positive lesions were also characterized by a marked decrease or absence of high-molecular-weight components of epidermal keratin. Since these characteristics are common to both carcinomas and large papillomas but are practically undetectable in normal epidermis and small papillomas, GGT activity and lack of high-molecular-weight keratin components seem to be good indicators of tumor progression, i.e., from papilloma to squamous carcinoma.

Laing distal myopathy with a novel mutation in exon 34 of the MYH7 gene.

We investigated a four-generation family of German ancestry with distal myopathy. Four individuals in two generations were affected. Foot and toe extensor paresis progressing very slowly over decades was the core neurological sign, reflected by fatty infiltration of the lower leg extensor muscles on muscle MRI. Additionally, finger extensor paresis was present in two patients and quadriceps muscle paresis in one. Distal sensory signs had initially given rise to the diagnosis of axonal Charcot-Marie-Tooth (CMT) disease. Two patients had extended verrucae of their foot sole, which may or may not be part of the disease spectrum. All four patients had a novel c.4645G > C mutation in exon 34 of the MYH7 gene that was not present in three clinically unaffected family members. Muscle biopsy of one patient revealed a myopathic pattern associated with type 1 muscle fibre atrophy and core-like lesions in many muscle fibres consistent with a myosin-related myopathy. We conclude that some of the typical clinical signs such as extensor weakness of the big toe and the little finger may only develop in the further course of the disease.

Hyperuniform disordered terahertz quantum cascade laser.

Laser cavities have been realized in various different photonic systems. One of the forefront research fields regards the investigation of the physics of amplifying random optical media. The random laser is a fascinating concept because, further to the fundamental research investigating light transport into complex media, it allows us to obtain non-conventional spectral distribution and angular beam emission patterns not achievable with conventional approaches. Even more intriguing is the possibility to engineer a priori the optical properties of a disordered distribution in an amplifying medium. We demonstrate here the realization of a terahertz quantum cascade laser in an isotropic hyperuniform disordered distribution exhibiting unique features, such as the presence of a photonic band gap, low threshold current density, unconventional angular emission and optical bistability.

Safety and diagnostic accuracy of dipyridamole-thallium imaging in the elderly.

The noninvasive diagnosis of coronary artery disease in the elderly can occasionally be difficult. Intravenous dipyridamole-thallium imaging is a potentially useful diagnostic test to determine presence and severity of coronary disease; however, the safety of the procedure has not been determined in an older population. The side effect profile and frequency of severe ischemic responses after 0.56 mg/kg of intravenous dipyridamole were compared in 101 patients greater than or equal to 70 years old and 236 patients less than 70 years old. There were no side effects in 64% and 62% of patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). Among the 337 patients tested, there were no complications of myocardial infarction or death. The most common cardiac side effect was chest pain, which occurred in 21 (21%) of the 101 patients aged greater than or equal to 70 years and in 64 (27%) of the 236 patients less than 70 years (p = NS). Aminophylline was required to reverse cardiac or noncardiac side effects in 15 (15%) and 36 (15%) of the patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). A severe ischemic response occurred in 2% and 2.5% of patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). The sensitivity of intravenous dipyridamole-thallium imaging for obstructive coronary artery disease was 86% (25 of 29) and 83% (68 of 82) in older and younger patients, respectively (p = NS); the specificity was 75% (6 of 8) and 70% (16 of 23), respectively (p = NS). Thus, intravenous dipyridamole-thallium imaging is a safe noninvasive method for assessment of older patients with obstructive coronary disease; its side effect profile and diagnostic accuracy are similar to those seen in younger patients. The technique is associated with severe ischemic responses in only a small minority of patients.

Impaired coronary vasodilator reserve in the immediate postcoronary angioplasty period: analysis of coronary artery flow velocity indexes and regional cardiac venous efflux.

The ratio of peak hyperemic/basal mean coronary flow velocity, an index of coronary vasodilator reserve, immediately after coronary angioplasty normalizes in less than 50% of patients. To evaluate other indexes of coronary vasodilator capacity, both intracoronary arterial velocity and cardiac venous efflux were measured at rest and during vasodilator-induced coronary hyperemia (intracoronary nitroglycerin and papaverine) before and after angioplasty in 27 patients; 17 patients had measurements of intracoronary velocity alone and 10 had thermodilution measurements of great cardiac vein flow. Coronary flow velocity responses were also measured in 6 angiographically normal segments in patients undergoing angioplasty and in 10 normal left coronary artery segments in patients with normal coronary arteries or isolated right coronary artery disease. Despite significant angiographic (72 +/- 12 to 23 +/- 11% diameter narrowing) and hemodynamic (49 +/- 12 to 19 +/- 12 mm Hg aortocoronary gradient) improvement, coronary vasodilator reserve ratios for both arterial velocity and venous flow after angioplasty were only minimally affected. Angioplasty did not significantly increase rest coronary vein flow or artery flow velocities, but did result in significantly higher papaverine responses after angioplasty. Mean and phasic coronary velocity, diastolic coronary flow velocity integral and measured great cardiac vein flow ratios were significantly lower when compared with those in 16 angiographically normal coronary artery segments. These data indicate that maximal hyperemic coronary flow velocity is increased after angioplasty, but the reserve ratios, calculated by any of several flow velocity indexes, remain minimally improved. Angiographic correlations (percent coronary diameter, absolute diameter or cross-sectional area) with variables of coronary blood flow or velocity suggest that no single variable is useful in assessing angioplasty results. However, postangioplasty arterial mean velocity and diastolic flow velocity integral are nearly normalized in most patients, whereas relative changes remain attenuated. These findings are important in studies assessing coronary vasomotor responses in patients with atherosclerotic coronary disease, especially after angioplasty.

Dopamine antagonist modulation of amphetamine response as detected using pharmacological MRI.

Functional magnetic resonance imaging (fMRI), employing BOLD-contrast, was used to measure changes in regional brain activation following amphetamine administration, either alone or after pre-treatment with the dopamine D1 receptor antagonist SCH23390, or the dopamine D2 receptor antagonist, sulpiride, in anaesthetised rat. After obtaining baseline data, rats (n=8) were given amphetamine (3 g/kg i.v) and volume data sets collected for 90 mins. Acute amphetamine challenge caused widespread increases in BOLD signal intensity in many subcortical structures with rich dopaminergic innervation, with decreases in BOLD contrast observed in the superficial layers of the cortex. Pretreatment with SCH23390 (n=8, 0.5 mg/kg, i.v) substantially attenuated the increases in BOLD activity in response to amphetamine, with lesser effects on the amphetamine-evoked decreases in BOLD signal. In contrast, sulpiride (n=8, 50 mg/kg, i.v) predominantly blocked the decrease in BOLD signal, having a smaller effect on the increases in BOLD signal. In summary, these data are supportive of the notion that different dopamine receptor types are responsible for separate components of the full amphetamine response. Furthermore the utility of BOLD contrast fMRI as a means of characterising the mechanisms of drug action in the whole brain has been demonstrated. Such studies may be of particular use for investigation of localised action and interaction of different dopaminergic agents.