The Effect of Aging on Nitric Oxide Production during Cerebral Ischemia and Reperfusion in Wistar Rats and Spontaneous Hypertensive Rats: An In Vivo Microdialysis Study.

Nitric oxide (NO) is involved in the pathogenesis of cerebral ischemic injury. Here, we investigated the effects of aging on NO production during cerebral ischemia-reperfusion (IR). Male Wister rats (WRs) were assigned to 12-month-old (older; n = 5) and 3-month-old (younger; n = 7) groups. Similarly, male spontaneous hypertensive rats (SHRs) were allocated to 12-month-old (older; n = 6) and 3-month-old (younger; n = 8) groups. After anesthesia, their NO production was monitored using in vivo microdialysis probes inserted into the left striatum and hippocampus. Forebrain cerebral IR injuries were produced via ligation of the bilateral common carotid arteries, followed by reperfusion. The change in the NO3- of the older rats in the SHR groups in the striatum was less compared to that of the younger rats before ischemia, during ischemia, and after reperfusion (p < 0.05). In the hippocampus, the change in the NO3- of the older rats in the SHR groups was lower compared to that of the younger rats after reperfusion (p < 0.05). There were no significant differences between the two WR groups. Our findings suggested that aging in SHRs affected NO production, especially in the striatum, before and during cerebral ischemia, and after reperfusion. Hypertension and aging may be important factors impacting NO production in brain IR injury.

Developing an artificial intelligence-based headache diagnostic model and its utility for non-specialists' diagnostic accuracy.

BACKGROUND: Misdiagnoses of headache disorders are a serious issue. Therefore, we developed an artificial intelligence-based headache diagnosis model using a large questionnaire database in a specialized headache hospital. METHODS: Phase 1: We developed an artificial intelligence model based on a retrospective investigation of 4000 patients (2800 training and 1200 test dataset) diagnosed by headache specialists. Phase 2: The model's efficacy and accuracy were validated. Five non-headache specialists first diagnosed headaches in 50 patients, who were then re-diagnosed using AI. The ground truth was the diagnosis by headache specialists. The diagnostic performance and concordance rates between headache specialists and non-specialists with or without artificial intelligence were evaluated. RESULTS: Phase 1: The model's macro-average accuracy, sensitivity (recall), specificity, precision, and F values were 76.25%, 56.26%, 92.16%, 61.24%, and 56.88%, respectively, for the test dataset. Phase 2: Five non-specialists diagnosed headaches without artificial intelligence with 46% overall accuracy and 0.212 kappa for the ground truth. The statistically improved values with artificial intelligence were 83.20% and 0.678, respectively. Other diagnostic indexes were also improved. CONCLUSIONS: Artificial intelligence improved the non-specialist diagnostic performance. Given the model's limitations based on the data from a single center and the low diagnostic accuracy for secondary headaches, further data collection and validation are needed.

Investigating the effects of weather on headache occurrence using a smartphone application and artificial intelligence: A retrospective observational cross-sectional study.

OBJECTIVE: To investigate the relationship between weather and headache occurrence using big data from an electronic headache diary smartphone application with recent statistical and deep learning (DL)-based methods. BACKGROUND: The relationship between weather and headache occurrence remains unknown. METHODS: From a database of 1 million users, data from 4375 users with 336,951 hourly headache events and weather data from December 2020 to November 2021 were analyzed. We developed statistical and DL-based models to predict the number of hourly headache occurrences mainly from weather factors. Temporal validation was performed using data from December 2019 to November 2020. Apart from the user dataset used in this model development, the physician-diagnosed headache prevalence was gathered. RESULTS: Of the 40,617 respondents, 15,127/40,617 (37.2%) users experienced physician-diagnosed migraine, and 2458/40,617 (6.1%) users had physician-diagnosed non-migraine headaches. The mean (standard deviation) age of the 4375 filtered users was 34 (11.2) years, and 89.2% were female (3902/4375). Lower barometric pressure (p < 0.001, gain = 3.9), higher humidity (p < 0.001, gain = 7.1), more rainfall (p < 0.001, gain = 3.1), a significant decrease in barometric pressure 6 h before (p < 0.001, gain = 11.7), higher barometric pressure at 6:00 a.m. on the day (p < 0.001, gain = 4.6), lower barometric pressure on the next day (p < 0.001, gain = 6.7), and raw time-series barometric type I (remaining low around headache attack, p < 0.001, gain = 10.1) and type II (decreasing around headache attack, p < 0.001, gain = 10.1) changes over 6 days, were significantly associated with headache occurrences in both the statistical and DL-based models. For temporal validation, the root mean squared error (RMSE) was 13.4, and the determination coefficient (R2 ) was 52.9% for the statistical model. The RMSE was 10.2, and the R2 was 53.7% for the DL-based model. CONCLUSIONS: Using big data, we found that low barometric pressure, barometric pressure changes, higher humidity, and rainfall were associated with an increased number of headache occurrences.

Development of an artificial intelligence-based diagnostic model for Alzheimer's disease.

Introduction: The diagnosis of Alzheimer's disease (AD) is sometimes difficult for nonspecialists, resulting in misdiagnosis. A missed diagnosis can lead to improper management and poor outcomes. Moreover, nonspecialists lack a simple diagnostic model with high accuracy for AD diagnosis. Methods: Randomly assigned data, including training data, of 6000 patients and test data of 1932 from 7932 patients who visited our memory clinic between 2009 and 2021 were introduced into the artificial intelligence (AI)-based AD diagnostic model, which we had developed. Results: The AI-based AD diagnostic model used age, sex, Hasegawa's Dementia Scale-Revised, the Mini-Mental State Examination, the educational level, and the voxel-based specific regional analysis system for Alzheimer's disease (VSRAD) score. It had a sensitivity, specificity, and c-static value of 0.954, 0.453, and 0.819, respectively. The other AI-based model that did not use the VSRAD had a sensitivity, specificity, and c-static value of 0.940, 0.504, and 0.817, respectively. Discussion: We created an AD diagnostic model with high sensitivity for AD diagnosis using only data acquired in daily clinical practice. By using these AI-based models, nonspecialists could reduce missed diagnoses and contribute to the appropriate use of medical resources.

Impact of COVID-19 pandemic on migraine management in the United States: insights from migraine tracking app users.

BACKGROUND: The nature of COVID-19 pandemic measures has altered the clinical management of migraine, and has also created barriers to evaluate the impact of such measures of migraine patients. Using the Migraine Buddy smartphone application, we assessed the impact of the COVID-19 pandemic on migraine in users residing in the United States. METHODS: Migraine Buddy is a smartphone application by individuals to record their migraine headache episodes, characteristics, and coping mechanisms. For this study, anonymized self-reported data from 163,176 adult Migraine Buddy users in the United States between January 2020 and May 2020, were analyzed for migraines associated with stress. A stress-related migraine is defined as one in which stress or anxiety was reported as a trigger or symptom. A questionnaire on the impact of COVID-19 on migraine and its management was also completed by 923 users from the United States in the app between April 2020 and May 2020. RESULTS: 88% of the Migraine Buddy database extract and 84% of the respondents are female, with a mean age of 36.2 years. The proportion of stress-related migraine attacks peaked at 53% on March 21 to 23, although the number of migraine attacks decreased. This followed the declaration of the COVID-19 national emergency on March 13 and a spike in the number of COVID-19 cases in the United States. Questionnaire respondents felt that the following added more stress: social isolation (22.6%), information overdose (21.2%), access to essentials (food, medication, etc.) (18.7%), and financial concerns (17.8%). To help manage migraine during COVID-19, respondents suggested stress and diet coaching programs and resources (medical articles, etc.) (34.0%), having the option for home delivery of medication (30.6%) and tele-consulting (25.5%). CONCLUSION: Here, we report the change in the proportion of self-reported stress-related migraine in relation to evolution of the COVID-19 pandemic, as well as its impact of migraine management. Our data will help increase the understanding of patients' needs and help with planning and execution of mitigating strategies.

Naratriptan in the Prophylactic Treatment of Cluster Headache.

Objective Naratriptan has been reported to reduce the frequency of cluster headache. The purpose of this study was to determine whether naratriptan is effective as a prophylactic treatment for cluster headache in Japan. Methods We retrospectively reviewed all 43 patients with cluster headache who received preventive treatment with naratriptan from April 2009 to April 2015. The International Classification of Headache Disorders, 3rd Edition (beta version) (ICHD-3 beta) was used to diagnose cluster headache. This study was conducted at 3 centers (Department of Neurology, Saitama Medical University; Saitama Neuropsychiatric Institute; Saitama Medical University International Medical Center). Patients were recruited from these specialized headache outpatient centers. Naratriptan was taken before the patient went to bed. Results The study population included 30 men (69.8%) and 13 women (30.2%). Twenty-two cases received other preventive treatments (51.2%), while 21 cases only received naratriptan (48.8%). Among the 43 cases, 37 patients (86.0%) achieved an improvement of cluster headache on naratriptan. Conclusion Naratriptan has been suggested as a preventive medicine for cluster headache because of the longer the biological half-life in comparison to other triptans. The internal use of naratriptan 2 hours before attacks appears to achieve a good response in patients with cluster headache.

Evaluation of the Differences in the Effects of Antihypertensive Drugs on Blood Pressure Variability by 24-Hour Ambulatory Blood Pressure Monitoring in Chronic Cerebrovascular Disease.

BACKGROUND: It has been suggested that antihypertensive drug therapy is attributable to the lower blood pressure variability, we investigated the effects of 4 classes of antihypertensives on the blood pressure variability; in addition, we also compared the effects among 4 calcium channel blockers. METHODS: We measured the 24-hour blood pressure variability in 309 patients with a history of cerebrovascular disease treated with angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, ß blocker, or calcium channel blocker. RESULTS: The daytime blood pressure variability treated with ß blockers (14.3 ± 3.1) was higher than that treated with an angiotensin receptor blockers (11.5 ± 3.1) or calcium channel blockers (12.6 ± 3.4) in patients with cerebrovascular disease (P < .05). In the analysis of the patient distribution of blood pressure variability, patients receiving ß blockers occurred more frequently in the higher blood pressure variability (P = .0023). Treatment with angiotensin receptor blockers and cilnidipine, which blocks N-type calcium channels, was shown to be more frequently associated with the lower blood pressure variability (P = .0202 and .0467). The mean blood pressure of patients grouped by distribution of blood pressure variability was found to be independent to blood pressure variability, for any of the antihypertensive drugs or calcium channel blockers examined. CONCLUSIONS: From the results, it is suggested that angiotensin receptor blocker and calcium channel blockers rather than ß blockers may be more favorable for blood pressure management in patients with cerebrovascular disease. Among the calcium channel blockers, cilnidipine may be more favorable than other calcium channel blockers.

[Recent pathophysiology of cluster headache (trigeminal autonomic cephalalgias; TACs)].

BACKGROUND: Cluster headache (CH), known as one of the trigeminal autonomic cephalalgias, is a stereotyped primary pain syndrome characterized by unilateral severe pain, the pathophysiology of which are not well understood. PATHOPHYSIOLOGY: The underlying pathophysiology of CH is incompletely understood. The periodicity of the attacks suggests the involvement of a biologic clock within the hypothalamus which controls circadian rhythms, with central disinhibition of the nociceptive and autonomic pathways, the trigeminal nociceptive pathways. Positron emission tomography and voxel-based morphometry have identified the posterior hypothalamic gray matter as the key area for the basic defect in CH. Functional hypothalamic dysfunction has been confirmed by abnormal metabolism based on the N-acetylaspartate neuronal marker in magnetic resonance spectroscopy. A recent case study demonstrated the release of both trigeminal and parasympathetic neuropeptides during a bout of pain in the same pattern previously described in CH. It is hypothesis that trigeminal activation leads to reflex autonomic activation. At a clinical level, there should be a pain threshold above which autonomic symptoms occur, modified by the highly somato- topic and functionally organized central connections of the trigeminovascular system.

Cerebral antioxidant enzyme increase associated with learning deficit in type 2 diabetes rats.

In this study, we examined alterations in the enzymatic antioxidant defenses associated with learning deficits induced by type 2 diabetes, and studied the effects of the peroxisome proliferator-activated receptor γ agonist pioglitazone on these learning deficits. Learning ability was assessed by visual discrimination tasks in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, as a model of spontaneous type 2 diabetes. Levels of the antioxidant enzymes glutathione peroxidase (GPx), Cu(2+)-Zn(2+) superoxide dismutase (CuZn-SOD) and manganese SOD were measured in the cortex, hippocampus and striatum. Half the rats received oral pioglitazone (20mg/kg/day) from the early stage of diabetes (22 weeks old) to 27 weeks old. OLETF rats showed learning deficits compared with control, Long-Evans Tokushima Otsuka (LETO) rats. GPx levels in the cortex and hippocampus were increased in OLETF rats compared with LETO rats, with an inverse correlation between GPx in the hippocampus and learning score. CuZn-SOD levels were also increased in the hippocampus in OLETF rats. Pioglitazone reduced blood glucose and increased serum adiponectin levels, but had no effect on learning tasks or antioxidant enzymes, except for CuZn-SOD. These results suggest that an oxidative imbalance reflected by increased brain antioxidant enzymes plays an important role in the development of learning deficits in type 2 diabetes. Early pioglitazone administration partly ameliorated diabetic symptoms, but was unable to completely recover cerebral oxidative imbalance and functions. These results suggest that diabetes-induced brain impairment, which results in learning deficits, may have occurred before the appearance of the symptoms of overt diabetes.

Renoprotective effect of pioglitazone by the prevention of glomerular hyperfiltration through the possible restoration of altered macula densa signaling in rats with type 2 diabetic nephropathy.

BACKGROUND/AIMS: Pioglitazone (PGZ), one of the thiazolidinediones, has been known to show renoprotective effects. In this study, we focused on the effect of PGZ on glomerular hyperfiltration (GHF), resultant glomerular injury and altered macula densa signaling as a cause of sustained GHF through modified tubuloglomerular feedback in rats with diabetic nephropathy. METHODS: Kidneys from 24-week-old male OLETF rats and LET rats, nondiabetic controls, were used for the experiment. PGZ was administered (10 mg/kg/day, p.o.) for 2 weeks from 22 to 24 weeks of age in some of the OLETF rats (OLETF+PGZ). RESULTS: Parameters relating GHF, kidney weight, creatinine clearance, urine albumin/creatinine ratio and glomerular surface were all increased in OLETF rats and partially restored in OLETF+PGZ rats. Expressions of desmin and TGF-ß were also increased in OLETF rats and restored in OLETF+PGZ rats. The changes in TGF-ß expression were confirmed to be independent of podocyte number. Finally, the immunoreactivity of neuronal nitric oxide synthase (nNOS) and cyclooxygenase 2 (COX-2) in the macula densa was assessed for the evaluation of macula densa signaling. Altered intensities of nNOS and COX-2 in OLETF rats were restored in OLETF+PGZ rats, which agreed with the gene expression analysis (nNOS: 100.2 ± 2.9% in LET, 64.2 ± 2.7% in OLETF, 87.4 ± 12.1% in OLETF+PGZ; COX-2: 100.8 ± 7.4% in LET, 249.2 ± 19.4% in OLETF, 179.9 ± 13.5% in OLETF+PGZ; n = 5) and the semiquantitative analysis of nNOS/COX-2-positive cells. CONCLUSION: PGZ effectively attenuated the GHF and hyperfiltration-associated glomerular injury in diabetic nephropathy. The restoration of altered macula densa signaling might be involved in the renoprotective effect of PGZ.

Pilot data on telmisartan short-term effects on glucose metabolism in the olfactory tract in Alzheimer's disease.

The possible effect of antihypertensive therapy on Alzheimer's disease (AD) has been studied, and angiotensin II receptor blockers (ARBs) have been suggested to exert an effect on cognitive decline. The purpose of this study is to clarify the functional effects of telmisartan, a long-acting ARB, on AD brain using prospective longitudinal (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) studies. For this purpose, brain glucose metabolism of four hypertensive patients with AD was examined with FDG-PET before and after administration of telmisartan. Studied subjects underwent three FDG-PET studies at intervals of 12 weeks. Antihypertensive treatment except for telmisartan was started after the first FDG-PET and continued for 24 weeks. Then 40-80 mg of telmisartan was added after the second FDG-PET and continued for 12 weeks.Glucose metabolism was significantly decreased during the first 12 weeks without telmisartan use at an area (-10, 21, -22, x, y, z; Z = 3.56) caudal to the left rectal gyrus and the olfactory sulcus corresponding to the left olfactory tract. In contrast, the introduction of telmisartan during the following 12 weeks preserved glucose metabolism at areas (5, 19, -20, x, y, z; Z = 3.09; 6, 19, -22, x, y, z; Z = 2.88) caudal to the bilateral rectal gyri and olfactory sulci corresponding to the bilateral olfactory tracts. No areas showed decreased glucose metabolism after the introduction of telmisartan. In AD, amyloid-ß deposition is observed in the anterior olfactory nucleus (AON) of the olfactory tract. Glucose metabolism in AON may be progressively decreased and preserved by telmisartan.

Nitric oxide production during cerebral ischemia and reperfusion in eNOS- and nNOS-knockout mice.

The purpose of this study was to clarify the kinetics of nitric oxide (NO) induced by either endothelial NO synthase (eNOS) or neuronal NO synthase (nNOS) after transient global forebrain ischemia. We investigated NO production and ischemic changes to hippocampal CA1 neurons in eNOS knockout (-/-) mice and nNOS (-/-) mice during cerebral ischemia and reperfusion. NO production was continuously monitored by in vivo microdialysis. Global forebrain ischemia was produced by occlusion of both common carotid arteries for 10 minutes. Levels of nitrite (NO(2)(-)) and nitrate (NO(3)(-)), as NO metabolites, in dialysate were determined using the Griess reaction. Two hours after the start of reperfusion, animals were perfused with 4% paraformaldehyde. Hippocampal CA1 neurons were divided into three phases (severely ischemic, moderately ischemic, surviving), and the ratio of surviving neurons to degenerated neurons was calculated as the survival rate. The relative cerebral blood flow (rCBF) was significantly higher in nNOS (-/-) mice than in control mice after reperfusion. Levels of NO(3)(-) were significantly lower in eNOS (-/-) mice and nNOS (-/-) mice than in control mice during ischemia and reperfusion. NO(3)(-) levels were significantly lower in nNOS (-/-) mice than in eNOS (-/-) mice after the start of reperfusion. Survival rate tended to be higher in nNOS (-/-) mice than in control mice, but not significantly. These in vivo data suggest that NO production in the striatum after reperfusion is closely related to activities of both nNOS and eNOS, and is mainly related to nNOS following reperfusion.

Acute functional recovery of cerebral blood flow after forebrain ischemia in rat.

After complete cerebral ischemia, the postischemic blood flow response to functional activation is severely attenuated for several hours. However, little is known about the spatial and temporal extent of the blood flow response in the acute postischemic period after incomplete cerebral ischemia. To investigate the relative cerebral blood flow (rCBF) response in the somatosensory cortex of rat to controlled vibrissae stimulation after transient incomplete ischemia (15-min bilateral common carotid artery occlusion+hypotension), we employed laser speckle imaging combined with statistical parametric mapping. We found that the ischemic insult had a significant impact on the baseline blood flow (P<0.005) and the activation area in response to functional stimulation was significantly reduced after ischemia (P<0.005). The maximum rCBF response in the activation area determined from the statistical analysis did not change significantly up to 3 h after ischemia (P>0.1). However, the time when rCBF response reached its maximum was significantly delayed (P<0.0001) from 2.4+/-0.2 secs before ischemia to 3.6+/-0.1 secs at 20 mins into reperfusion (P<0.001); the delay was reduced gradually to 2.9+/-0.2 secs after 3 h, which was still significantly greater than that observed before the insult (P=0.04).

[Pure amnesia due to the right capsular genu infarction].

A 77-year-old right-handed woman was admitted to our hospital with memory disturbance. Neurological examination was normal except for amnesia. Neuropsychological tests showed severe impairments in verbal and visual memories. Brain MRI revealed a fresh lacunar infarction in the genu of the right internal capsule. Decreased perfusion in the right thalamus and frontal lobe on (99m)Tc-ECD SPECT was attributable to disconnection of the thalamo-cortical tract by infarction. We consider that the patient's amnesia in this case was induced by infarction of the capsular genu, which includes some fibers from the anterior and inferior thalamic peduncles. Our findings demonstrated that lacunar infarction in the genu of the right internal capsule caused severe and persistent amnesia.

Electrical forepaw stimulation during reversible forebrain ischemia decreases infarct volume.

BACKGROUND AND PURPOSE: Functional stimulation is accompanied by increases in regional cerebral blood flow which exceed metabolic demands under normal circumstances, but it is unknown whether functional stimulation is beneficial or detrimental in the setting of acute ischemia. The aim of this study was to determine the effect of forepaw stimulation during temporary focal ischemia on neurological and tissue outcome in a rat model of reversible focal forebrain ischemia. METHODS: Sprague-Dawley rats were prepared for temporary occlusion of the right middle cerebral artery (MCA) using the filament model. Cerebral blood flow in the MCA territory was continuously monitored with a laser-Doppler flowmeter. Subdermal electrodes were inserted into the dorsal forepaw to stimulate either the forepaw ipsilateral or contralateral to the occlusion starting 1 minute into ischemia and continuing throughout the ischemic period. A neurological evaluation was undertaken after 24 hours of reperfusion, and animals were then euthanized and brain slices stained with 2,3,5-triphenyltetrazolium chloride. Cortical and striatal damage was measured separately. RESULTS: The cortical and striatal infarct volumes were both significantly reduced in the contralateral stimulated group compared with the ipsilateral stimulated group (48% total reduction). There were no statistically significant differences in the neurobehavioral scores between the 2 groups, or in the laser-Doppler flow measurements from the MCA core. CONCLUSIONS: Functional stimulation of ischemic tissue may decrease tissue damage and improve outcome from stroke. Although the precise mechanism of this effect remains to be determined, functional stimulation could readily be translated to clinical practice.

[Aging of the autonomic nervous system].

Aging is associated with structural and functional changes in the autonomic nervous system (ANS), which innervates the whole body, and its altered function may influence almost all body systems. Changes related to aging are found in autonomic nerves and ganglia, and ANS controlled functions including cardiovascular functions. Much of the current knowledge about age-related changes in sympathetic nervous function is derived from studies of circulating catecholamine levels, norepinephrine kinetics and microneurographic recordings from sympathetic nerves of skeletal muscle. Significant evidence suggests that basal plasma noradrenaline levels increase with age. These data indicates that healthy aging is associated with elevated basal sympathetic nervous activity. In contrast, the reactivity of the sympathetic and the parasympathetic nervous activity are reduced with aging.

A peroxisome proliferator-activated receptor-gamma agonist reduces infarct size in transient but not in permanent ischemia.

BACKGROUND AND PURPOSE: Activators of peroxisome proliferator-activated receptor-gamma (PPARgamma), a member of the PPAR family, increase levels of CuZn-superoxide dismutase (SOD) in cultured endothelium, suggesting a mechanism by which it may exert its protective effect within the brain. These properties raise the question of whether a PPARgamma agonist may be neuroprotective in models of ischemia without reperfusion, in which oxidative injury is less prevalent. METHODS: In 2 groups of rats, 90 minutes of middle cerebral artery (MCA) occlusion was followed by 1 day of reperfusion, with 1 group receiving pioglitazone (a PPARgamma agonist) starting 72 hours before MCA occlusion (MCAO) and continuing through the day of occlusion, whereas the other group received vehicle only. In 2 comparable groups, the MCA was occluded permanently. One day after occlusion, the animals were tested neurologically and infarct volumes were calculated. In a separate group, rats were treated with pioglitazone or vehicle for 4 days. Tissue was obtained from the cortex and the striatum 2 hours into reperfusion after 90 minutes of MCAO, and the tissue was examined for CuZn-SOD by Western blot. RESULTS: Results show a significant reduction in infarct size in the treated rats, with transient MCAO but not permanent MCAO. There was also an improvement in neurological score in the treated animals after transient MCAO. The level of CuZn-SOD was increased in the cortex in treated animals. CONCLUSIONS: These data, which show that a PPARgamma agonist reduces infarct size in transient but not permanent MCAO, suggest that the role of PPARgamma is specific to events occurring during reperfusion. Our data point to CuZn-SOD as the mediator of this neuroprotection.

Synthesis and evaluation of N,N-dimethyl-2-(2-amino-5-[18F]fluorophenylthio)benzylamine (5-[18F]-ADAM) as a serotonin transporter imaging agent.

The synthesis and evaluation of a new serotonin transporter (SERT) imaging agent, N,N-dimethyl-2-(2-amino-5-[18F]fluorophenylthio)benzylamine (5-[18F]-ADAM) is reported. Nucleophilic substitution of N,N-dimethyl-2-(2-nitro-5-bromophenylthio)benzylamine with K[18F]/Kryptofix 2.2.2 in DMSO at 125 degrees C followed by reduction with NaBH4-Cu(OAc)2 in EtOH at 78 degrees C and purification with HPLC produces the desired compound with an unoptimized yield of approximately 5-10% in a synthesis time of 150 min from EOB. The biodistribution of 5-[18F]-ADAM in rats showed a high initial uptake and relatively rapid clearance in the brain (3.221+/-0.762, 0.440+/-0.059, 0.160+/-0.035 and 0.028+/-0.003% injected dose/organ at 2, 30, 60 and 120 min after I.V. injection, respectively) with the specific binding peaking at 1 h postinjection (hypothalamus/cerebellum and hippocampus/cerebellum were 2.97 and 3.59, respectively). The initial uptake in blood, lung, kidney and heart were also high, but it cleared rapidly. The radioactivity in the femur increased with time for 5-[18F]-ADAM indicating that in vivo defluorination may occur. Metabolism studies in rats showed that 5-[18F]-ADAM was not metabolized in rat brain, but was metabolized rapidly in the blood. Blocking experiments showed that there were significant decreases in the uptake of 5-[18F]-ADAM in the brain regions (hypothalamus, hippocampus and striatum) where SERT concentrations are high when rats were pretreated with (+)McN 5652 (2 mg/kg, 5 min prior to IV injection of 5-[18F]-ADAM). These results suggest that 5-[18F]-ADAM may be a potential new serotonin transporter PET imaging agent. However, due to its rapid wash-out from the brain, defluorination in vivo and lower uptake in the brain than 4-[18F]-ADAM, 5-[18F]-ADAM may not be as useful as 4-[18F]-ADAM as a SERT imaging agent.

[Diplopia in Wallenberg's syndrome].

The incidence and mechanism of diplopia were investigated in 31 patients with Wallenberg's syndrome resulting from acute dorsolateral medullary infarction. Diplopia was found in 10 of 31 patients (32%), with 5 patients reporting vertical diplopia alone and 5 reporting vertical and horizontal diplopia. Diplopia in Wallenberg's syndrome is considered to be caused by a lesion involving the otolith-ocular system. Vertical diplopia is simply explained by ocular skew deviation due to a lesion involving the vestibular nucleus; in which the affected eye becomes deviated inferiorly. In this situation, rotation of the eye due to ocular tilt reaction also occurs. Concomitant horizontal diplopia may require involvement of the medial longitudinal fasciculus (MLF), which produces skew deviation in mirror image; the unaffected eye becomes deviated inferiorly. When downward deviation of the eye affected by dysfunction of the vestibular nucleus and that due to MLF dysfunction affecting the other eye are comparable, only horizontal diplopia becomes apparent. MLF syndrome may be accompanied by paralytic pontine exotropia (PPE) or non-paralytic pontine exotropia (NPPE), both of which may also participate in the appearance of horizontal diplopia.

Hyperphosphorylated tau deposition parallels prion protein burden in a case of Gerstmann-Sträussler-Scheinker syndrome P102L mutation complicated with dementia.

Hyperphosphorylated tau (p-tau) deposition has been documented in a limited population of patients with Gerstmann-Sträussler-Scheinker syndrome (GSS) with particular point mutations of the prion protein (PrP) gene. Although its pathogenesis is only poorly understood, p-tau in GSS is known to be identical to that in Alzheimer's disease (AD). We conducted immunohistochemical and quantitative image studies on the brain from a 44-year-old man with a 7-year history of dementia, diagnosed as having GSS with a point mutation of the PrP gene at codon 102 (GSS102), the commonest mutation in GSS. Severe spongiform degeneration and numerous PrP plaques were disclosed in the cerebral cortices and hippocampus, consistent with the diagnosis. However, rarely described in GSS102, prominent p-tau deposits as pretangles, neurofibrillary tangles and degenerating neurites were demonstrated adjacent to or around PrP plaques. beta-Amyloid protein (Abeta) plaques were generally sparse and appeared invariably to be of a diffuse type. Double-labeling immunohistochemistry yielded co-localization of p-tau with PrP but not with Abeta. Most PrP plaques did not contain Abeta. These results excluded a diagnosis of concomitant AD. Quantitative analysis on a fractional area density of immunoreactive pixels demonstrated that burdens of PrP and p-tau but not Abeta were significantly correlated. These results suggest that p-tau deposition in this GSS102 is secondarily induced by PrP but not by Abeta (secondary tauopathy). Our study also suggests that p-tau deposition might be a more common phenomenon in long-standing GSS.