Echocardiographic estimation of pulmonary hypertension in COVID-19 patients.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is the cause of a devastating global pandemic and is not likely to be fully resolved in the near future. In most cases COVID-19 presents with mild symptoms, but in a minority of patients respiratory and multi-organ failure may ensue. Previous research has focused on the correlation between COVID-19 and a variety of cardiovascular complications. However, the effect of COVID-19 on pulmonary hypertension (PH) and correlated cardiovascular parameters has not been evaluated extensively. METHODS: This study was designed as a single-centre, semi-quantitative analysis. PH was considered to be present if echocardiographic measurements estimated right ventricular systolic pressure at rest to be 36 mm Hg or higher in combination with indirect indicators of right ventricular overload. RESULTS: In total, 101 patients (67.3% male) were included in this study, with a mean age of 66 years (range 23-98 years). PH was diagnosed by echocardiographic estimation in 30 patients (29.7%). Echocardiographically estimated PH (eePH) was not correlated with a diagnosis of heart failure or pulmonary embolism. Mortality was significantly higher among COVID-19 patients with eePH (p = 0.015). In all 10 of 20 surviving eePH patients in whom echocardiographic follow-up was obtained, echocardiographic estimations of pulmonary pressures showed a significant decrease after a median of 144 ± 72 days. CONCLUSION: eePH is frequently observed in COVID-19 patients and is correlated with increased mortality. COVID-19-related eePH appears to be reversible after recovery. Vigilant attention and a low threshold for performance of echocardiography in COVID-19 patients seems warranted, as eePH may be applicable as a prognostic risk factor.

Allelic variation for alpha-Glucan Water Dikinase is associated with starch phosphate content in tetraploid potato.

KEY MESSAGE: Association analysis resulted in the identification of specific StGWD alleles causing either an increase or decrease in starch phosphate content which was verified in diploid and tetraploid potato mapping populations. Potatoes are grown for various purposes like French fries, table potatoes, crisps and for their starch. One of the most important aspects of potato starch is that it contains a high amount of phosphate ester groups which are considered to be important for providing improved functionalization after derivatization processes. Little is known about the variation in phosphate content as such in different potato varieties and thus we studied the genetic diversity for this trait. From other studies it was clear that the phosphate content is controlled by a quantitative trait locus (QTL) underlying the candidate gene α-Glucan Water Dikinase (StGWD) on chromosome 5. We performed direct amplicon sequencing of this gene by Sanger sequencing. Sequences of two StGWD amplicons from a global collection of 398 commercial cultivars and progenitor lines were used to identify 16 different haplotypes. By assigning tag SNPs to these haplotypes, each of the four alleles present in a cultivar could be deduced and linked to a phosphate content. A high value for intra-individual heterozygosity was observed (Ho = 0.765). The average number of different haplotypes per individual (Ai) was 3.1. Pedigree analysis confirmed that the haplotypes are identical-by-descent (IBD) and offered insight in the breeding history of elite potato germplasm. Haplotypes originating from introgression of wild potato accessions carrying resistance genes could be traced. Furthermore, association analysis resulted in the identification of specific StGWD alleles causing either an increase or decrease in starch phosphate content varying from 12 nmol PO4/mg starch to 38 nmol PO4/mg starch. These allele effects were verified in diploid and tetraploid mapping populations and offer possibilities to breed and select for this trait.

The TRACK-PD study: protocol of a longitudinal ultra-high field imaging study in Parkinson's disease.

BACKGROUND: The diagnosis of Parkinson's Disease (PD) remains a challenge and is currently based on the assessment of clinical symptoms. PD is also a heterogeneous disease with great variability in symptoms, disease course, and response to therapy. There is a general need for a better understanding of this heterogeneity and the interlinked long-term changes in brain function and structure in PD. Over the past years there is increasing interest in the value of new paradigms in Magnetic Resonance Imaging (MRI) and the potential of ultra-high field strength imaging in the diagnostic work-up of PD. With this multimodal 7 T MRI study, our objectives are: 1) To identify distinctive MRI characteristics in PD patients and to create a diagnostic tool based on these differences. 2) To correlate MRI characteristics to clinical phenotype, genetics and progression of symptoms. 3) To detect future imaging biomarkers for disease progression that could be valuable for the evaluation of new therapies. METHODS: The TRACK-PD study is a longitudinal observational study in a cohort of 130 recently diagnosed (≤ 3 years after diagnosis) PD patients and 60 age-matched healthy controls (HC). A 7 T MRI of the brain will be performed at baseline and repeated after 2 and 4 years. Complete assessment of motor, cognitive, neuropsychiatric and autonomic symptoms will be performed at baseline and follow-up visits with wearable sensors, validated questionnaires and rating scales. At baseline a blood DNA sample will also be collected. DISCUSSION: This is the first longitudinal, observational, 7 T MRI study in PD patients. With this study, an important contribution can be made to the improvement of the current diagnostic process in PD. Moreover, this study will be able to provide valuable information related to the different clinical phenotypes of PD and their correlating MRI characteristics. The long-term aim of this study is to better understand PD and develop new biomarkers for disease progression which may help new therapy development. Eventually, this may lead to predictive models for individual PD patients and towards personalized medicine in the future. TRIAL REGISTRATION: Dutch Trial Register, NL7558 . Registered March 11, 2019.

Interhemispheric inhibition in different phenotypes of progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is the most common atypical parkinsonian syndrome and an important differential diagnosis of parkinson's disease (PD). The clinical diagnosis of PSP relies on characteristic symptoms. There is evidence of clinical subgroups within the entity of PSP interfering with making the firm diagnosis. It was the aim of the study to clarify the differences between phenotypical subtypes of PSP and PD focusing on transcallosal inhibition (TI). A systematic chart review of 67 patients supposed to have probable PSP was done in a standardized diagnostic work-up. As only complete data sets were included into further analysis, 26 PSP patients (mean age 68.6 ± 7.1 years) could be evaluated and subdivided into Richardson's syndrome (RS) (n = 15) or PSP of parkinsonian type (PSP-P) (n = 11). Fifteen PD patients served as controls. TI was evaluated by investigation of the ipsilateral silent period (iSP) with transcranial magnetic stimulation (TMS). Cognition was assessed by the Addenbrooke's cognitive examination (ACE-R). TMS revealed a significantly more severe affection of TI in RS patients as compared to PSP-P and PD patients who showed similar neurophysiological findings. 47 % of RS patient displayed an iSP loss, whereas PSP-P and PD did not. There was a significant correlation between iSP latency and ACE-R (Spearman's coefficient -0.369, P = 0.010). In conclusion, RS patients-contrary to PSP-P and PD patients-had pathological TI at least in one hemisphere indicating more severe involvement of transcallosally projecting output neurons in RS.

Post-hoc revision of the pediatric anesthesia emergence delirium rating scale: clinical improvement of a bedside-tool?

BACKGROUND: Pediatric delirium (PD) is a severe neuropsychiatric disorder often seen at the pediatric intensive care unit (PICU). The Pediatric Anesthesia Emergence Delirium (PAED) scale assesses five behavioral items on a five-level severity scale, and is easily applicable in children. However, the five-level severity scales are rather arbitrarily anchored and subjective. This study aimed to pilot a practical and clinical improvement of the PAED by condensing the five-level scales of the five behavioral items to a more objectively anchored two- and three-point scale. METHODS: Post-hoc analysis of routine data in an eight-bed PICU in a tertiary university hospital. 144 critically ill, non-electively admitted patients, aged 1-18 years, were included between November 2006 and February 2010. Scales of the five PAED-items were condensed post-hoc from five to two- and three levels of severity. Five scale properties were analyzed: 1) internal consistency; 2) item-total score correlations; 3) inter-rater agreement; 4) sensitivity and specificity; and 5) discriminative diagnostic ability. RESULTS: Three-level PAED-items post-hoc displayed Cronbach's alpha of 0.86, and mean item-total score correlation was 0.71 (range 0.60 to 0.79). Inter-rater agreement was high (0.90). The most optimal cut-off was 8 (sensitivity=100%, specificity=96.7%) with an area under the curve (AUC) of 0.98. Likelihood ratio for a positive test result (LR+) was 30.3. CONCLUSION: A three-level severity scale for the five PAED-items may be optimal to diagnose PD. Further prospective research is required to determine whether a revised PAED has adequate psychometric properties and is applicable across different clinical settings.

Field testing and exploitation of genetically modified cassava with low-amylose or amylose-free starch in Indonesia.

The development and testing in the field of genetically modified -so called- orphan crops like cassava in tropical countries is still in its infancy, despite the fact that cassava is not only used for food and feed but is also an important industrial crop. As traditional breeding of cassava is difficult (allodiploid, vegetatively propagated, outbreeding species) it is an ideal crop for improvement through genetic modification. We here report on the results of production and field testing of genetically modified low-amylose transformants of commercial cassava variety Adira4 in Indonesia. Twenty four transformants were produced and selected in the Netherlands based on phenotypic and molecular analyses. Nodal cuttings of these plants were sent to Indonesia where they were grown under biosafety conditions. After two screenhouse tests 15 transformants remained for a field trial. The tuberous root yield of 10 transformants was not significantly different from the control. Starch from transformants in which amylose was very low or absent showed all physical and rheological properties as expected from amylose-free cassava starch. The improved functionality of the starch was shown for an adipate acetate starch which was made into a tomato sauce. This is the first account of a field trial with transgenic cassava which shows that by using genetic modification it is possible to obtain low-amylose cassava plants with commercial potential with good root yield and starch quality.

[Long-term efficacy of deep brain stimulation in patients with dystonia]. / Langzeiteffekte der tiefen Hirnstimulation bei Dystonie-Patienten.

In patients with primary generalized or segmental dystonia controlled studies have shown that bilateral pallidal deep brain stimulation (DBS) can reduce disability scores by 40 to 60 %. Up to now, the data base on the therapeutic effects of DBS in selected patients with focal dystonia is less extensive. Long-term efficacy of DBS in dystonia has been demonstrated, but reports have focused mainly on patients with primary generalized dystonia so far, with a mean observation period of approximately 5 years. Predictors of a favourable long-term efficacy of DBS in primary generalized dystonia patients are young age at surgery, a shorter duration of the disease, a lower severity of disability, and a posteroventrolateral localization of the DBS electrode within the globus pallidus internus (GPi). Controlled studies are needed to identify also the factors determining the best long-term outcome of non-generalized dystonia patients treated with DBS.

Deep brain stimulation of globus pallidus internus in a 16-year-old boy with severe tourette syndrome and mental retardation.

A 16- year-old boy with long-standing severe Tourette syndrome (TS) and mental retardation, non-responsive to complex pharmocological and behavioural treatment was selected for bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi). Pre-operative and post-operative Yale Tourette syndrome scale (YTSS) scores and several other scores were used to quantify the effect of DBS up to one year follow-up. Although subscores of the YTSS improved, the overall outcome of chronic GPi-DBS showed no substantial therapeutic effect. This finding is in contrast to markedly improved TS of the only two adolescent TS patients in whom DBS has been performed so far. In this article we discuss possible reasons for the poor therapeutic effect of GPi-DBS in our patient contributing to the on-going debate on DBS inclusion criteria for adolescent TS patients.

Transcallosal inhibition in amyotrophic lateral sclerosis.

OBJECTIVE: Assessment of upper motor neuron (UMN) involvement is essential for the diagnosis of amyotrophic lateral sclerosis (ALS). In a number of ALS cases, mirror movements (MM) suggest an involvement of transcallosal fibre tracts in conjunction with UMN involvement. The present study analysed whether deficient transcallosal inhibition (TI) tested by TMS enables detection of cortical affection in ALS, even at early stages of the disease. METHODS: In three patients with definite ALS and 12 patients with early ALS (aged 64.1+/-7.8 years) TMS investigation included analysis of contralateral (cMEP) and ipsilateral (iMEP) motor evoked potentials as well as measurement of TI (latency, duration) with recording from both first dorsal interosseus muscles. RESULTS: Clinical UMN signs were present in four patients. 83.3% of patients showed a pathological TI (prolongation or loss of TI). Five out of eight ALS patients showing a pathological TI had no clinical UMN signs. Two of these patients showed MM. One patient displayed also pathological findings in TI investigation. CONCLUSIONS: Our findings suggest a functional deficit of transcallosal fibre tracts even at early stages of the disease still lacking clinical UMN signs. SIGNIFICANCE: Measurement of TI tested by TMS can detect an involvement of the cortical output system in ALS and may be helpful in an early assessment of the diagnosis.

Overactive bladder in Parkinson's disease: alteration of brainstem raphe detected by transcranial sonography.

Urinary dysfunction is very common in idiopathic Parkinson's disease (PD) and manifests primarily with symptoms of overactive bladder (OAB). Affection of central serotonergic systems has been suggested to play a role in OAB. The objective of this study was to evaluate whether in PD patients with OAB symptoms a specific alteration of the brainstem raphe (BR), which contains serotonergic neurons, can be detected with transcranial sonography (TCS). Of 116 PD patients enrolled, 19 had PD-related OAB symptoms (OAB+) unlike remaining 97 patients (OAB-). Patients were examined by a sonographer blinded to the clinical data. Reduced echogenicity of BR was found in 12 (63%) OAB+ patients but only in 18 (19%) of 93 assessable OAB- patients (Mann-Whitney U-test, P < 0.001). In OAB+ patients, lower raphe echogenicity score was associated with longer duration of OAB symptoms (anova, P = 0.033). Other TCS findings such as echogenicity of substantia nigra, thalami, lenticular and caudate nuclei, and widths of third and lateral ventricles did not differ between OAB+ and OAB- patients. TCS findings suggest a pathogenetic role of BR in OAB related to PD. Alterations may reflect disturbance of its central serotonergic system.

Modulation of transcallosally mediated motor inhibition in children with attention deficit hyperactivity disorder (ADHD) by medication with methylphenidate (MPH).

Motor hyperactivity is one of the most outstanding symptoms of attention deficit hyperactivity disorder (ADHD) which might be caused by a disturbed inhibitory motor control. Using focal transcranial magnetic stimulation (TMS) we tested the cortico-callosal inhibition (duration and latency of the ipsilateral Silent Period, iSP) in 23 children with ADHD (mean age 11+/-2.6 years) before and on treatment with methylphenidate (MPH). iSP latency was age correlated, whereas iSP duration as well as Conners scores were age independent. Analyses of mean differences revealed a significant prolongation of iSP duration (p=0.001), shortening of iSP latency (p=0.027) and reduction of Conners score (p=0.001) under medication. Increase of iSP duration and reduction of Conners score under medication were significantly correlated (t=-9.87, p=0.016). Reduced iSP duration and prolonged iSP latency in ADHD children could be the result of a disturbed transcallosally mediated inhibition, most probable due to a combination of maturation deficits of callosal fiber tracts as well as neuronal synaptical transmission within the neuronal network between ipsilaterally stimulated cortex layer III--the origin of transcallosal motor-cortical fibers--and contralateral layer V, the origin of the pyramidal tract. MPH may indirectly improve the dysbalance between excitatory and inhibitory interneuronal activities of this neuronal network via dopaminergic modulatory effects of the striato-thalamo-cortical loop.

Morphological basis for the spectrum of clinical deficits in spinocerebellar ataxia 17 (SCA17).

Spinocerebellar ataxia 17 (SCA17) is a rare genetic disorder characterized by cerebellar, extrapyramidal, pyramidal as well as psychiatric signs. The pathoanatomical basis of this disorder is still not well known. A total of 12 patients and 12 age- and sex-matched controls were examined by in vivo MRI voxel-based morphometry (VBM). Besides general patterns of disease-related brain atrophy, characteristic syndrome-related morphological changes in SCA17 patients were studied. In comparison with normal controls, SCA17 patients showed a pattern of degeneration of the grey matter centred around mesial cerebellar structures, occipito-parietal structures, the anterior putamen bilaterally, the thalamus and other parts of the motor network, reflecting the cerebellar, pyramidal and extrapyramidal signs. A correlation analysis revealed a clear association between the clinical cerebellar, extrapyramidal and psychiatric scores and degeneration in specific areas. Two degeneration patterns were found as follows: regarding motor dysfunction, atrophy of the grey matter involved mainly the cerebellum and other motor networks, in particular the basal ganglia. In contrast, correlations with psychiatric scores revealed grey matter degeneration patterns in the frontal and temporal lobe, the cuneus and cingulum. Most interestingly, there was a highly significant correlation between the clinical Mini-Mental State Examination scores and atrophy of the nucleus accumbens, probably accounting for the leading psychiatric signs.

Post-transcriptional gene silencing of GBSSI in potato: effects of size and sequence of the inverted repeats.

In the past, silencing of granule-bound starch synthase (GBSSI) in potato was achieved by antisense technology, where it was observed that inclusion of the 3' end of the GBSSI coding region increased silencing efficiency. Since higher silencing efficiencies were desired, GBSSI inverted repeat constructs were designed and tested in potato. First, large inverted repeats comprising the 5' and the 3' half of the GBSSI cDNA were tested. The 5' IR construct gave a significantly higher silencing efficiency than the 3' IR construct. Since it was not known whether the observed difference was due to the sequence or the orientation of the inverted repeat, the GBSSI cDNA was divided into three regions, after which each region was tested in small inverted repeats in two orientations. To this end large numbers of independent transformants were produced for each construct. The results suggested that there was no effect of inverted repeat orientation on silencing efficiency. The percentage of transformants showing strong inhibition varied from 48% for a 3'-derived construct to 87% for a 5' as well as a middle region-derived construct. Similar to the large inverted repeats, the 3' sequences induced the least efficient silencing implying that the observed differences in silencing efficiency are caused by sequence differences. The small inverted repeat constructs with a repeat size of 500-600 bp and a spacer of about 150 bp were more efficient silencing inducers than the large inverted repeat constructs where the size of the repeat was 1.1 or 1.3 kb whilst the size of spacer was 1.3 or 1.1 kb. The results presented here show that size and sequence of the inverted repeat influenced silencing efficiency.

Sonographic discrimination of corticobasal degeneration vs progressive supranuclear palsy.

OBJECTIVE: To study the use of brain parenchyma sonography (BPS) in discriminating between patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). METHODS: Thirteen patients with PSP and eight with CBD were studied with BPS according to a standardized protocol. RESULTS: Seven (88%) of the eight CBD patients showed marked hyperechogenicity of the substantia nigra (SN) but none of eleven PSP patients (Mann-Whitney U test, p < 0.001). This finding indicated CBD with a positive predictive value of 100%. Marked dilatation of the third ventricle (width > 10 mm) was found in 10 (83%) of 12 PSP patients, but in none of the CBD patients (p < 0.005). BPS measurements of ventricle widths closely matched MRI measurements (Pearson correlation, r = 0.90, p < 0.001). The presence of at least one of the BPS findings 1) marked SN hyperechogenicity and 2) third-ventricle width < 10 mm indicated CBD with a sensitivity of 100%, a specificity of 83%, and a positive predictive value of 80%. Other BPS findings such as echogenicity of lentiform and caudate nuclei and widths of the frontal horns did not discriminate between CBD and PSP. One PSP patient could not be assessed because of insufficient acoustic temporal bone windows. CONCLUSIONS: Substantia nigra hyperechogenicity, reported earlier as characteristic brain parenchyma sonography finding in idiopathic Parkinson disease, is also typical for corticobasal degeneration.

Disturbed transcallosally mediated motor inhibition in children with attention deficit hyperactivity disorder (ADHD).

OBJECTIVE: The aim of this study was to investigate mechanisms of motor-cortical excitability and inhibition which may contribute to motor hyperactivity in children with attention deficit hyperactivity disorder (ADHD). METHODS: Using transcranial magnetic stimulation (TMS), involvement of the motor cortex and the corpus callosum was analysed in 13 children with ADHD and 13 sex- and age-matched controls. Contralateral silent period (cSP) and transcallosally mediated ipsilateral silent period (iSP) were investigated. RESULTS: Resting motor threshold (RMT), amplitudes of motor evoked potentials (MEP) and cSP were similar in both groups whereas iSP-latencies were significantly longer (p<0.05) and their duration shorter (p<0.01) in the ADHD group. For the ADHD group iSP duration tended to increase and iSP latency to decrease with age (n.s.). Conners-Scores did neither correlate with iSP-latencies and -duration nor with children's age. CONCLUSIONS: The shortened duration of iSP in ADHD children could be explained by an imbalance of inhibitory and excitatory drive on the neuronal network between cortex layer III-the projection site of transcallosal motor-cortical fibers-and layer V, the origin of the pyramidal tract. The longer iSP-latencies might be the result of defective myelination of fast conducting transcallosal fibers in ADHD. iSP may be a useful supplementary diagnostic tool to discriminate between ADHD and normal children.

Analysis of the dynamics of fungal communities in soil via fungal-specific PCR of soil DNA followed by denaturing gradient gel electrophoresis.

A molecular method for profiling of fungal communities in soil was applied in experiments in soil microcosms, with two objectives, (1) to assess the persistence of two selected fungal species in soil, and (2) to analyze the response of the natural fungal community to a spill of sulphurous petrol in the same soil. To achieve the aims, two soil DNA extraction methods, one originally designed for the direct extraction of bacterial community DNA and the other one aimed to obtain fungal DNA, were tested for their efficiency in recovering DNA of fungal origin from soil. Both methods allowed for the efficient extraction of DNA from introduced Trichoderma harzianum spores as well as Arthrobotrys oligospora mycelial fragments, at comparable rates. Several PCR amplification systems based on primers specific for fungal 18S ribosomal RNA genes were tested to design strategies for the assessment of fungal communities in soil. The PCR systems produced amplicons of expected size with DNA of most fungi studied, which included members of the Ascomycetes, Basidiomycetes, Zygomycetes and Chytridiomycetes. On the other hand, the 18S rRNA genes of Oomycetes (including key plant pathogens) were poorly amplified. Plant (Solanum tuberosum), nematode (Meloidogyne sp.) and bacterial DNA was not amplified. For studies of soil fungal communities, a nested PCR approach was selected, in which the first PCR provided the required specificity for fungi, whereas the second (nested) PCR served to produce amplicons separable on denaturing gradient gels. Denaturing gradient gel electrophoresis (DGGE) allowed the resolution of mixtures of PCR products of several different fungi, as well as products resulting from mixed-template amplifications, into distinct banding patterns. The persistence of fungal species in soil was assessed using T. harzianum spores and A. oligospora hyphal fragments added to silt loam soil microcosms. Using PCR-DGGE, these fungi were detectable for about 14 days and 2 months, respectively. Both singly-inoculated soils and soils that had received mixed inoculants revealed, next to bands resulting from indigenous fungi, the expected bands in the DGGE profiles. The A. oligospora specific amplicon, by virtue of its unique migration in the denaturing gradient, was well detectable, whereas the T. harzianum specific product comigrated with products from indigenous fungi. PCR-DGGE analysis of DNA obtained from the silt loam soil treated with dibenzothiophene-containing petrol showed the progressive selection of specific fungal bands over time, whereas this selection was not observed in untreated soil microcosms. Cloning of individual molecules from the selected bands and analysis of their sequences revealed a complex of targets which clustered with the 18S rDNA sequences of the closely-related species Nectria haematococca, N. ochroleuca and Fusarium solani. Fungal isolates obtained from the treated soil on PDA plates were identified as Trichoderma sp., whereas those on Comada agar fell into the Cylindrocarpon group (anamorph of Nectria spp).

Gene silencing in potato: allelic differences and effect of ploidy.

Silencing of genes is mostly studied in diploid, homozygous, self-fertile and sexually propagated species. However, conclusions drawn for these species are not always applicable to crops like potato, which is an autotetraploid, highly heterozygous, vegetatively propagated species. Factors influencing the level of silencing in potato are discussed, with emphasis on inhibition of the granule-bound starch synthase I (GBSSI) gene. Type of construct, number of integrated T-DNA copies, structural arrangement of the T-DNA locus, integration site, target tissue and genetic background are important factors for all plant species. Ploidy level and multiple allelism are factors deserving special attention when the efficiency of silencing of endogenous genes is studied in polyploid, heterozygous species such as potato.

Multiple solenoidal microcoil probes for high-sensitivity, high-throughput nuclear magnetic resonance spectroscopy.

Two designs for incorporating multiple solenoidal microcoils into a single probe head are presented to increase the throughput of high-resolution NMR. Through a combination of radio frequency switches and low-noise amplifiers, multiple NMR spectra can be acquired in the same time as a single spectrum from a conventional probe consisting of one coil. Since this method does not compromise sensitivity with regard to the individual microcoils, throughput increases linearly with the number of coils. Only one receiver is needed, and data acquisition parameters can be optimized for each sample. Specifically, a four-coil system has been implemented for proton NMR at 250 MHz using a wide-bore magnet, with an observe volume of 28 nL for each microcoil. Signal cross-contamination was approximately 0.2% between individual coils, and simultaneous one- and two-dimensional spectra have been obtained from samples of fructose, galactose, adenosine triphosphate, and chloroquine (7 nmol of each compound). A more compact two-coil configuration has also been designed for operation at 500 MHz, with observe volumes of 5 and 31 nL for the two coils. One- and two-dimensional spectra were acquired from samples of 1-butanol (55 nmol) and ethylbenzene (250 nmol).