Oxytocin's neurochemical effects in the medial prefrontal cortex underlie recovery of task-specific brain activity in autism: a randomized controlled trial.

The neuropeptide oxytocin may be an effective therapeutic strategy for the currently untreatable social and communication deficits associated with autism. Our recent paper reported that oxytocin mitigated autistic behavioral deficits through the restoration of activity in the ventromedial prefrontal cortex (vmPFC), as demonstrated with functional magnetic resonance imaging (fMRI) during a socio-communication task. However, it is unknown whether oxytocin exhibited effects at the neuronal level, which was outside of the specific task examined. In the same randomized, double-blind, placebo-controlled, within-subject cross-over clinical trial in which a single dose of intranasal oxytocin (24 IU) was administered to 40 men with high-functioning autism spectrum disorder (UMIN000002241/000004393), we measured N-acetylaspartate (NAA) levels, a marker for neuronal energy demand, in the vmPFC using (1)H-magnetic resonance spectroscopy ((1)H-MRS). The differences in the NAA levels between the oxytocin and placebo sessions were associated with oxytocin-induced fMRI signal changes in the vmPFC. The oxytocin-induced increases in the fMRI signal could be predicted by the NAA differences between the oxytocin and placebo sessions (P=0.002), an effect that remained after controlling for variability in the time between the fMRI and (1)H-MRS scans (P=0.006) and the order of administration of oxytocin and placebo (P=0.001). Furthermore, path analysis showed that the NAA differences in the vmPFC triggered increases in the task-dependent fMRI signals in the vmPFC, which consequently led to improvements in the socio-communication difficulties associated with autism. The present study suggests that the beneficial effects of oxytocin are not limited to the autistic behavior elicited by our psychological task, but may generalize to other autistic behavioral problems associated with the vmPFC.

Intestinal amoebiasis in a patient with acute graft-versus-host disease after allogeneic bone marrow transplantation successfully treated by metronidazole.

Amoebiasis has rarely been reported in patients undergoing hematopoietic stem cell transplantation, although it is a world-wide infection and extremely common. We present a case of intestinal amoebiasis unexpectedly revealed by colonoscopy after allogeneic bone marrow transplantation from a human leukocyte antigen-mismatched unrelated donor for acute myeloid leukemia arising from chronic myelomonocytic leukemia and successfully treated by metronidazole.

Quantitative autistic traits ascertained in a national survey of 22 529 Japanese schoolchildren.

OBJECTIVE: Recent epidemiologic studies worldwide have documented a rise in prevalence rates for autism spectrum disorders (ASD). Broadening of diagnostic criteria for ASD may be a major contributor to the rise in prevalence, particularly if superimposed on an underlying continuous distribution of autistic traits. This study sought to determine the nature of the population distribution of autistic traits using a quantitative trait measure in a large national population sample of children. METHOD: The Japanese version of the Social Responsiveness Scale (SRS) was completed by parents on a nationally representative sample of 22 529 children, age 6-15. RESULTS: Social Responsiveness Scale scores exhibited a skewed normal distribution in the Japanese population with a single-factor structure and no significant relation to IQ within the normal intellectual range. There was no evidence of a natural 'cutoff' that would differentiate populations of categorically affected children from unaffected children. CONCLUSION: This study provides evidence of the continuous nature of autistic symptoms measured by the SRS, a validated quantitative trait measure. The findings reveal how paradigms for diagnosis that rest on arbitrarily imposed categorical cutoffs can result in substantial variation in prevalence estimation, especially when measurements used for case assignment are not standardized for a given population.

Amiodarone-induced liver cirrhosis and parkinsonism: a case report.

BACKGROUND: Amiodarone-induced hepatotoxicity consists of mild liver test abnormalities and rare cases of acute hepatitis and chronic hepatic lesions, and histologically resembles the whole spectrum of alcoholic liver disease, i.e., non-alcoholic steatohepatitis. Amiodarone-induced neurotoxicity, including tremor, ataxia and peripheral neuropathy, is known, and some cases of parkinsonism following amiodarone use have also been reported. OBJECTIVE: To study the pathology of amiodarone-associated parkinsonism. DESIGN: Light and electromicroscopic examinations of a patient with liver cirrhosis and amiodarone-induced parkinsonism. RESULTS: On postmortem examination, the liver showed micronodular cirrhosis. Striking steatosis and frequent Mallory bodies were present on light microscopy. There were lysosomal inclusion bodies on electron microscopy. From these findings, amiodarone-induced liver cirrhosis was diagnosed. Brain atrophy and infarcts were not observed, and pigmentation in the substantia nigra was preserved. Histologically, there was a slightly lesser degree of neuronal loss with astrocytosis in the substantia nigra, locus ceruleus, and dorsal vagal nucleus. Lewy bodies were not found. In the cerebral white matter and basal ganglia, Alzheimer Type II astrocytes, which are abundant in hepatic encephalopathy, had deposition of electron-dense materials within the lysosomes and mitochondrial matrices. The materials were compatible with the accelerated amiodarone. CONCLUSIONS: This is the first case in which the accumulation of amiodarone in the brain was morphologically observed. Amiodarone accumulation in the brain may play a role in neurotoxicity inducing parkinsonism.

Inhaled corticosteroid use and asthma hospitalization rates in Japan.

This epidemiological study assessed whether the use of anti-inflammatory drugs, in particular inhaled corticosteroids, affected hospitalization rates for asthma in Japan between 1990 and 2002. Asthma hospitalization rates were calculated from the number of asthma in-patients recorded in governmental surveys. Information concerning use of anti-inflammatory drugs was extracted from the IMS prescription database. Patients were stratified into four age groups: < or = 4 years, 5 - 19 years, 20 - 39 years and 40 - 64 years. Over the study period, the number of prescriptions for inhaled corticosteroids per year increased dramatically and hospitalizations for asthma decreased in all groups except those < or = 4 years of age. Increased use of leukotriene receptor antagonists was also noted in all age groups. The use of anti-inflammatory drugs may have contributed to the observed decrease in asthma hospitalizations. Increased use of inhaled corticosteroids in infants and very young children may help prevent hospitalization in this age group.

Trends in psychological distress and alcoholism after The Great East Japan Earthquake of 2011.

AIMS: Many studies have shown that natural disasters affect mental health; however, longitudinal data on post-disaster mental health problems are scarce. The aims of our study were to investigate the trend in psychological distress and alcoholism after The Great East Japan Earthquake and tsunami in north eastern Japan, in March 2011. METHODS: A longitudinal study was conducted using annual health check data for the general population, in the city of Higashi-Matsushima, which was affected by the high impact of tsunami. In 2012 and 2013, the Kessler Psychological Distress Scale and the CAGE questionnaire (for screening for alcoholism) were used to assess psychological distress and prevalence of alcoholism. RESULTS: Of 11,855 total eligible residents, 2192 received the annual check in 2012 and 2013. The prevalence of mental illness and the mean score of alcoholism tendency increased during the follow-up period. The majority of respondents (43.8%) with baseline serious mental illness (SMI) continued to have SMI at follow-up; only 16.7% reported recovering. Older age, female sex, and severity of home damage predicted higher psychological distress, while male sex was a risk factor for alcoholism at follow-up. CONCLUSIONS: Psychological distress deteriorated 2 years after the huge natural disaster, compared with 1 year after the disaster. Long-term mental health care is needed for those affected by natural disasters, particularly those who have suffered loss.

Acute leukemia during pregnancy: an investigative survey of the past 11 years.

INTRODUCTION: The management of pregnant women with acute leukemia is usually challenging. We collected data concerning pregnant women with acute leukemia in the Kanagawa area in Japan. METHODS: A questionnaire was sent to 24 institutions in the Kanagawa area. RESULTS: Data were obtained for 11 patients, median age of 31 years (range, 20-36). Eight patients had acute myeloid leukemia and three had acute lymphoblastic leukemia. Six patients were diagnosed in the first trimester of pregnancy, one in the second trimester, and four in the third trimester. Five of six patients diagnosed in the first trimester had abortions before chemotherapy, and one had an elective abortion after receiving chemotherapy. All patients diagnosed in the second or third trimester delivered live infants. Of the six patients diagnosed in the first trimester, two died of recurrent leukemia, and four remained in remission. Of the five patients diagnosed in the second or third trimester, four achieved complete remission and remained in remission. One patient died of sepsis 4 days after cesarean section. CONCLUSIONS: Careful surveillance and monitoring of the fetus and close co-operation among hematologists, gynecologists, and pediatricians are essential to successfully treat pregnant women with acute leukemia.

Michaelis-Menten constraints improved cerebral glucose metabolism and regional lumped constant measurements with [18F]fluorodeoxyglucose.

In the three-compartment model of transfer of native glucose and [18F]fluorodeoxyglucose (FDG) into brain, both transport across the blood-brain barrier and phosphorylation by hexokinase can be described by the Michaelis-Menten equation. This permits the use of fixed transport (tau = K*1/K1) and phosphorylation (psi = k*3/k3) ratios and a common partition volume (Ve = K1/k2) for tracer and glucose. By substituting transfer constants of FDG for those of glucose, using tau and psi, the lumped constant was determined directly by positron tomography. The same constraints also eliminated k*2 and k*3 from the model, thus limiting the parameters to K* [equivalent to K*1k*3/(k*2 + k*3)], K*1, and the cerebral vascular volume (Vo). In six healthy elderly men (aged 61 +/- 5 years), time-activity records of cerebral cortical regions were analyzed with tau = 1.1 and psi = 0.3. The results were compared with those of the conventional FDG method. At 20 min, the goodness of fit by the new equation was as good as that of the conventional method at 45 min. The estimates obtained by the constrained method had stable coefficients of variation. After 20 min, regional differences between the estimates were independent of time, although we observed steady decreases of K* and (k*3). The decrease strongly suggested dephosphorylation of FDG-6-phosphate, particularly after 20 min. All estimates of variables with the constrained method were more accurate than those of the conventional method, including the cerebral glucose metabolic rate itself, as well as physiologically more meaningful, particularly with respect to k*2 and k*3.

Reduction of functional capillary density in human brain after stroke.

The blood flow of brain tissue often returns to normal after an ischemic episode. As "luxury" rather than "reactive" reperfusion, this hyperemia is associated with low metabolism. It is not known to what extent the high blood flow accompanies a high, normal, or low density of capillaries. The resolution of this question may indicate whether the functional capillary density is variable and, if so, whether it is coupled to blood flow or metabolism. To answer these questions, we defined functional capillaries as capillaries that transport glucose. We then calculated the density of functional capillaries (Dcap) and the mean time of transit of blood through the capillaries (tcap) from hemodynamic variables obtained in vivo by positron tomography of five patients afflicted by cerebral ischemic stroke. Each patient was studied twice, within 36 h of the insult and 1 week later. We identified nominally "ischemic" regions in the first study as cortical gray matter regions, contiguous with the ischemic focus, in which the magnitude of blood flow did not exceed 20 ml 100 g-1 min-1. In these regions, values of metabolism and functional capillary density were proportionately low compared with normal values obtained in the contralateral hemisphere. The studies revealed a reduction of the functional density of exchange vessels in postischemic brain tissue as soon as 36 h after the insult. In "ischemic" regions, within 36 h of the insult, the net extraction of oxygen was inversely related to the capillary transit time and appeared to be limited mainly by the low functional density of the capillaries. Contrary to expectations, the reduced density persisted, even when more than adequate perfusion of the tissue returned. For these reasons, we concluded that changes of the capillary density were associated with changes of the metabolism of the tissue rather than with blood flow.

[3H]DOPA formed from [3H]tyrosine in living rat brain is not committed to dopamine synthesis.

Tyrosine hydroxylase of catecholamine neurons catalyzes the synthesis of 3,4-dihydroxphenylalanine (DOPA), which is subsequently metabolized to dopamine by DOPA decarboxylase (DDC). However, DOPA is not committed to decarboxylation in vivo because export of DOPA from brain and metabolism of DOPA other than decarboxylation are possible. To estimate the relative magnitudes of the several fates of DOPA, the kinetics of the uptake and metabolism of L-[3H]tyrosine ([3H]Tyr, intravenous infusion) was measured in brain of rats pretreated with NSD 1015, an inhibitor of DDC. Some rats were pretreated with haloperidol before the blockade of DDC. The [3H]Tyr was incorporated into brain protein at a rate constant of 0.03 min(-1). The relative tyrosine hydroxylase activity in striatum was 0.005 min(-1) at 30 minutes after NSD 1015, 0.011 min(-1) 3 hours later, and 0.020 min(-1) after haloperidol treatment. The rate constant for the clearance of DOPA from brain (0.06 min(-1)) and earlier estimates of the rate constant of DDC activity in striatum (0.26 min(-1)) together predict that 80% of DOPA formed in normal rat striatum normally is available for dopamine synthesis. It follows that modulation of DDC activity can influence the rate of DA synthesis by affecting the relative magnitude of the several fates of DOPA in living brain.

Pharmacokinetics of plasma 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]Fdopa) in humans.

Like native DOPA, [18F]-6-fluoro-L-3,4-dihydroxyphenylalanine ([18F]FDOPA) is subject to methylation and decarboxylation. To determine the rates of formation and elimination of [18F]FDOPA metabolites, plasma from human subjects undergoing positron emission tomographic (PET) studies was analyzed by high-performance liquid chromatography (HPLC). In addition to the principal metabolite O-methyl-[18F]FDOPA (OMe[18F]FDOPA), two decarboxylated metabolites were detected in plasma from carbidopa pretreated subjects. The concentrations of each metabolite during 90 min following tracer injection could be described as a function of the concentration of [18F]FDOPA, and two rate constants; k0, the rate of formation, and k-1, the rate of clearance. Plasma metabolite time series generated from total plasma activity curves and measured rate constants were in close agreement with the actual concentrations determined by HPLC fractionation. Population means for k0 (0.011 +/- 0.002 min-1) and k-1 (0.010 +/- 0.003 min-1) were used to generate "simulated" plasma curves. The measured and generated plasma curves were used as inputs for estimation of partition and decarboxylation coefficients of [18F]FDOPA in brain. The use of generated input functions from normal population means of transfer coefficients did not introduce a systematic error into the estimate of the enzyme activity. However, the high variability of these estimates in patients precludes the use of this technique as an alterative to individual HPLC measurements.

In vivo regulation of DOPA decarboxylase by dopamine receptors in rat brain.

To test the hypothesis that dopamine (DA) receptors influence cerebral DOPA-decarboxylase (DDC) activity in vivo, we used HPLC to measure the kinetics of the cerebral uptake and metabolism of [3H]DOPA in carbidopa-treated rats, and in rats also treated acutely with a DA receptor antagonist (flupenthixol, 2 mg/kg, intraperitoneally) or a DA receptor agonist (apomorphine, 200 microg/g, subcutaneously). The unidirectional blood-brain clearance of [3H]DOPA (K1DOPA, 0.030 mL g(-1) min(-1)) increased by 50% after flupenthixol. The magnitudes of the relative DDC activity (k3DOPA) in striatum (0.20 min(-1)), olfactory tubercle (0.11 min(-1)), and hypothalamus (0.15 min(-1)) of carbidopa-treated rats were doubled with flupenthixol, but cortical DDC activity was unaffected (0.02 min(-1)). Apomorphine reduced the magnitude of k3DOPA in striatum by 20%. The rate constant for catabolism of [3H]DA formed in brain (k7', monoamine oxidase [MAO] activity), which ranged from 0.025 min(-1) in striatum to 0.08 min(-1) in hypothalamus of carbidopa-treated rats, globally increased 2- to 4-fold after flupenthixol, and decreased to 0.003 min(-1) in striatum after apomorphine. These in vivo results confirm the claim that acute blockade of DA receptors with flupenthixol stimulates the synthesis of [3H]DA from [3H]DOPA, and that this [3H]DA is subject to accelerated catabolism. Conversely, activation of the DA receptors with apomorphine inhibits DDC activity and DA catabolism.

Oxygen consumption of cerebral cortex fails to increase during continued vibrotactile stimulation.

The coupling of oxidative metabolism to the blood flow of the sensory motor hand area is uncertain. The authors tested the hypothesis that continued vibrotactile stimulation ultimately must lead to increased oxygen consumption consumption. Twenty-two healthy right-handed young volunteers underwent positron emission tomography (PET) with the [(15)O]water bolus injection method to measure water clearance (K1H2O an index of blood flow (CBF), and with the [(15)O]oxygen bolus inhalation method to measure CMR(O2). The CMR(O2) was measured 30 seconds and 20 minutes after onset of intermittent (1 second on, 1 second off) vibrotactile stimulation (110 Hz) and compared with baseline measurements without stimulation. The K1H2O and CMR(O2) changes (delta K1H2O and delta CMR(O2)) were determined using intersubject averaging, together with magnetic resonance imaging based stereotaxic registration technique. The K1H2O increase was 21 +/- 4% and 12 +/- 4% at 30 seconds and 20 minutes after onset of stimulation, respectively. No significant increase of CMR(O2) was found until 30 minutes after the onset of stimulation. The authors conclude that blood flow and oxidative metabolism undergo uncoupling during sustained phasic stimulation of the sensory hand area. Therefore, neuronal activity stimulated in this manner does not rely on significantly increased oxidative phosphorylation.

Blood-brain transfer and metabolism of 6-[18F]fluoro-L-dopa in rat.

In a study designed to reveal the rates of blood-brain transfer and decarboxylation of fluoro-L-3,4-dihydroxyphenylalanine (FDOPA), we discovered a major discrepancy between the DOPA decarboxylase activity reported in the literature and the rate of FDOPA decarboxylation measured in the study. "Donor" rats received intravenous injections of 6 mCi fluorine-18-labeled FDOPA. The donor rats synthesized methyl-FDOPA. Arterial plasma, containing both FDOPA and methyl-FDOPA, was sampled from the donor rats at different times and reinjected into "recipient" rats in which it circulated for 20 s. The blood-brain clearance of the mixture of labeled tracers in the plasma was determined by an integral method. The individual permeabilities were determined by linear regression analysis, according to which the average methyl-FDOPA permeability in the blood-brain barrier was twice that of FDOPA, which averaged 0.037 ml g-1 min-1. The permeability ratio was used to determine the fractional clearance from the brain of FDOPA (and hence of methyl-FDOPA), which averaged 0.081 min-1. In the striatum, the measured average FDOPA decarboxylation rate constant (kD3) was 0.010 min-1, or no more than 1% of the rate of striatal decarboxylation of DOPA measured in vitro and in vivo. We interpreted this finding as further evidence in favor of the hypothesis that striatum has two dopamine (DA) pools, of which only DA in the large pool is protected from metabolism. Hence, no more than 1% of the quantity of fluoro-DA theoretically synthesized was actually retained in striatum.

Cerebral [15O] water clearance in humans determined by positron emission tomography: II. Vascular responses to vibrotactile stimulation.

When used to measure blood flow, water leaves a residue in the vascular bed, which may contribute to the calculation of increased blood flow during functional activation of brain tissue. To assess the magnitude of this contribution with the two-compartment positron emission tomography (PET) method, we mapped the water clearance (K1) of the brain as an index of cerebral blood flow (CBF) and the apparent vascular distribution of nonextracted H2 15O (Vo). The latter map represented mainly the cerebral arterial and arteriolar volume. We also prepared subtraction maps (delta K1, delta Vo) of the response to vibrotactile stimulation of the fingertips of the right hand of six normal volunteers. Using magnetic resonance (MR) images of all subjects, the data were rendered into Talairach's stereotaxic coordinates and the averaged subtraction images (activation minus baseline) merged with the corresponding averaged MRI image. The delta K1 map revealed the expected response in the primary sensory hand area; the delta Vo response was located about 13 mm more anteriorly, close to the central fissure, most likely reflecting changes of the arteries feeding the primary sensory hand area. We conclude that cerebral perfusion and cerebrovascular responses to vibrotactile stimulation may occur in disparate locations that can be identified separately by using the two-compartment method.

Human striatal L-dopa decarboxylase activity estimated in vivo using 6-[18F]fluoro-dopa and positron emission tomography: error analysis and application to normal subjects.

DOPA decarboxylase is the enzyme directly responsible for the synthesis of the neurotransmitters dopamine and serotonin, and indirectly of noradrenaline, in brain. We used the decarboxylation coefficient (k3D) of 6-[18F]fluoro-DOPA (FDOPA) to denote the relative activity of L-DOPA decarboxylase in vivo in the human brain. To determine the relative enzyme activity with positron emission tomography (PET), we evaluated the model that separates the metabolism into compartments of nondiffusible and diffusible (i.e., transient) tracer metabolites. Error analysis indicated that the least-squares optimization alone was not sufficient to yield accurate estimates of k3D in the presence of the inherent error of PET. To improve the accuracy of the k3D estimates by optimizing the number of parameters, we introduced biological constraints which included a tracer partition volume (Ve) common to frontal cortex and striatum, and a fixed ratio (q) between the blood-brain barrier transport coefficients of O-methyl-[18F]fluoro-DOPA and FDOPA, the two sources of radioactivity in plasma. We found that a two-step analysis yielded sufficiently accurate estimates of k3D. The two steps include the initial estimation of the partition volume in frontal cortex and the subsequent use of this value to determine k3D in striatum and other structures. We studied twelve healthy controls (age 45 +/- 15 years). The average k3D value was 0.081 +/- 0.024 min-1 (coefficient of variation (COV) 30%) for caudate nucleus, 0.074 +/- 0.013 min-1 (COV 18%) for putamen, and 0.010 +/- 0.005 min-1 (COV 50%) for cerebral cortex.

6-[18F]fluoro-L-dopa metabolism in living human brain: a comparison of six analytical methods.

In 11 normal volunteers and six patients with Parkinson's disease, we compared six different analyses of dopaminergic function with L-3,4-dihydroxy-6-[18F]fluorophenylalanine (FDOPA) and positron emission tomography (PET). The caudate nucleus, putamen, and several reference regions were identified in PET images, using magnetic resonance imaging (MRI). The six analyses included two direct determinations of DOPA decarboxylase activity (k3D, k3*), the slope-intercept plot based on plasma concentration (K), two slope-intercept plots based on tissue content (k3r, k3s), and the striato-occipital ratio [R(T)]. For all analyses, the difference between two groups of subjects (normal volunteers and patients with Parkinson's disease) was larger in the putamen than in the caudate. For the caudate nucleus, the DOPA decarboxylase activity (k3D, k3*), tissue slope-intercept plots (kr3, ks3); and striato-occipital ratio [R(T)] analyses significantly discriminated between the normal volunteers and the patients with Parkinson's disease (p < 0.005) [with least significance for k3* (p < 0.05)], while the plasma slope-intercept plot (K) failed to do so. For the putamen, the values for k3D, k3*, K, k3r, k3s, and R(T) of normal volunteers were significantly higher than those of patients (p < 0.005) [with least significance for K (p < 0.025)]. Linear correlations were significant between k3D and k3s; k3D and k3r; k3D and R(T); and k3D and k3*, in this order of significance. We found no correlation between k3D and K values in the caudate nucleus.