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Biomedical subjects

Naoki Tomita

Publications and source records attributed to Naoki Tomita.

13 recordsLinked to original sources
PubMed2006

Uncaria rhynchophylla, a Chinese medicinal herb, has potent antiaggregation effects on Alzheimer's beta-amyloid proteins.

Because the deposition of beta-amyloid protein (Abeta) is a consistent pathological hallmark of Alzheimer's disease (AD) brains, inhibition of Abeta generation, prevention of Abeta fibril formation, or destabilization of preformed Abeta fibrils would be attractive therapeutic strategies for the treatment of AD. We examined the effects of several medicinal herbs used in traditional Chinese medical formulae on the formation and destabilization of Abeta fibrils by using the thioflavin T binding assay, atomic force microscopic imaging, and electrophoresis. Our study demonstrates that several of these herbs have potent inhibitory effects on fibril formation of both Abeta(1-40) and Abeta(1-42) in concentration-dependent manners; in particular, Uncaria rhynchophylla inhibited Abeta aggregation most intensively. Significant destabilization of preformed Abeta(1-40) and Abeta(1-42) fibrils was also induced by Uncaria rhynchophylla as well as some other herb extracts. Three-dimensional HPLC analysis indicated that the water extract of this herb contains several different chemical compounds, including oxindole and indol alkaloids, which have been regarded as neuroprotective. Our results suggest that Uncaria rhynchophylla has remarkably inhibitory effects on the regulation of Abeta fibrils, and we conclude that this medicinal herb could have the potency to be a novel therapeutic agent to prevent and/or cure AD.

Alzheimer Disease↗
PubMed2006

Randomized phase II trial comparing nitroglycerin plus vinorelbine and cisplatin with vinorelbine and cisplatin alone in previously untreated stage IIIB/IV non-small-cell lung cancer.

PURPOSE: To investigate the efficacy and safety of nitroglycerin plus vinorelbine and cisplatin in patients with previously untreated stage IIIB/IV non-small-cell lung cancer (NSCLC) as the experimental arm for the next phase III trial. PATIENTS AND METHODS: One hundred twenty patients with stage IIIB/IV NSCLC were randomly assigned to vinorelbine 25 mg/m2 on days 1 and 8 and cisplatin 80 mg/m2 on day 1, with transdermally applied nitroglycerin (25 mg/patient daily for 5 days; arm A) or with placebo patch (arm B) every 3 weeks for a maximum of four cycles in a double-blind and controlled trial. Primary efficacy end points were the best confirmed response rate and time to disease progression (TTP). RESULTS: The response rate in arm A (72%; 43 of 60 patients) was significantly higher than that for patients in arm B (42%; 25 of 60 patients; P < .001). Median TTP in arm A was longer than that in arm B (327 v 185 days). No severe adverse effect was recognized for either arm. The rate of grade 1 to 2 headache in arm A (30%; 18 of 60 patients) was significantly higher than that in arm B (2%; one of 60 patients; P < .001, chi(2) test). CONCLUSION: Use of nitroglycerin combined with vinorelbine and cisplatin may improve overall response and TTP in patients with stage IIIB/IV NSCLC. The arm A regimen is being evaluated in a large phase III trial.

Adult↗
PubMed2005

Cerebrospinal fluid neprilysin is reduced in prodromal Alzheimer's disease.

Amyloid beta peptide (A beta) has been implicated in Alzheimer's disease (AD) as an initiator of the pathological cascades. Several lines of compelling evidence have supported major roles of A beta-degrading enzyme neprilysin in the pathogenesis of sporadic AD. Here, we have shown a substantial reduction of cerebrospinal fluid (CSF) neprilysin activity (CSF-NEP) in patients with AD-converted mild cognitive impairment and early AD as compared with age-matched control subjects. The altered CSF-NEP likely reflects changes in neuronal neprilysin, since transfer of neprilysin from brain tissue into CSF was demonstrated by injecting neprilysin-carrying viral vector into the brains of neprilysin-deficient mice. Interestingly, CSF-NEP showed an elevation with the progression of AD. Along with a close association of CSF-NEP with CSF tau proteins, this finding suggests that presynaptically located neprilysin can be released into CSF as a consequence of synaptic disruption. The impact of neuronal damages on CSF-NEP was further demonstrated by a prominent increase of CSF-NEP in rats exhibiting kainate-induced neurodegeneration. Our results unequivocally indicate significance of CSF-NEP as a biochemical indicator to pursue a pathological process that involves decreased neprilysin activity and A beta-induced synaptic toxicity, and the support the potential benefits of neprilysin up-regulation in ameliorating neuropathology in prodromal and early AD.

Aged↗
PubMed2005

Plasma homocysteine and risk of coexisting silent brain infarction in Alzheimer's disease.

BACKGROUND: Cerebrovascular disease is common in Alzheimer's disease (AD). Elevated plasma homocysteine (pHcy) levels are reported to be associated with an increased risk of poor cognition and dementia. OBJECTIVE: To determine whether high pHcy levels are associated with an increased risk of coexisting silent brain infarctions (SBIs) in AD. METHODS: Study population comprising 143 outpatients with clinical diagnosis of probable AD (73.3 +/- 7.0 years) were classified into 2 groups according to the presence or absence of SBIs on magnetic resonance imaging. RESULTS: SBIs were noted in 32.9% (47/143) of the AD patients. The pHcy levels in the AD with SBIs (14.0 +/- 4.5 micromol/l) were significant ly elevated compared with the AD without SBIs (11.7 +/- 4.7 micromol/l, p = 0.007). After adjusting for age and gender, high pHcy (>12.4 micromol/l), but not hypertension, was associated with an increased risk of developing SBIs in AD (OR = 4.61, 95% CI = 1.74-12.2, p = 0.002). However, age at onset, cognitive function, cerebrospinal tau or amyloid beta-peptide(1-42) levels were not significantly correlated with pHcy levels in AD. CONCLUSION: SBIs commonly coexist with AD, and may be a unique vascular condition in which homocysteine plays an important role. Homocysteine-lowering therapy rather than antihypertensive medication might be an appropriate strategy to prevent stroke associated with AD.

Aged↗
PubMed2005

A randomized, observer-blind, controlled trial of the traditional Chinese medicine Yi-Gan San for improvement of behavioral and psychological symptoms and activities of daily living in dementia patients.

OBJECTIVE: This randomized, observer-blind, controlled trial examined the efficacy and safety of the traditional Chinese herbal medicine Yi-Gan San (YGS, Yokukan-San in Japanese) in the improvement of behavioral and psychological symptoms of dementia (BPSD) and activities of daily living (ADL). METHOD: Fifty-two patients with mild-to-severe dementia (24 men and 28 women, mean +/- SD age = 80.3 +/- 9.0 years) according to DSM-IV criteria were investigated. Participants were randomly assigned to the YGS group (N = 27) or control (drug-free) group (N = 25) and treated for 4 weeks. The Neuropsychiatric Inventory (NPI) for the assessment of BPSD, the Mini-Mental State Examination (MMSE) for cognitive function, and the Barthel Index for ADL were administered at baseline and the end of the treatment. The frequency of extrapyramidal symptoms (EPS) and other adverse events was recorded. If patients showed insufficient response to treatment after 1 week, tiapride hydrochloride, a dopamine D(1) selective neuroleptic, was added to the regimen. Data were collected from January 2004 to March 2004. RESULTS: All participants in both groups completed the trial. In the control group, 11 patients required treatment with tiapride hydrochloride. Significant improvements in mean +/- SD NPI (from 37.9 +/- 16.1 to 19.5 +/- 15.6) and Barthel Index (from 56.4 +/- 34.2 to 62.9 +/- 35.2) scores were observed in the YGS group, but not in the control group. MMSE results were unchanged in both groups. EPS were not observed in either group, but dizziness and impaired postural sway were observed in 6 patients treated with tiapride hydrochloride. CONCLUSION: Yi-Gan San improves BPSD and ADL. Follow-up studies using a double-blinded, placebo-controlled design are recommended.

Activities of Daily Living↗
PubMed2004

Cerebrospinal fluid tau protein and periventricular white matter lesions in patients with mild cognitive impairment: implications for 2 major pathways.

BACKGROUND: Mild cognitive impairment (MCI) may be a heterogeneous condition rather than a uniform disease entity. OBJECTIVE: To develop reliable tools that aid in identifying patients at risk of developing Alzheimer disease (AD) among heterogeneous populations with MCI to maximize the benefits of emerging therapies for AD. DESIGN: A 2-year prospective study. SETTING: Clinical follow-up in an outpatient memory clinic. PATIENTS: Seventy-two consecutive older patients with memory complaints. MAIN OUTCOME MEASURES: Cerebrospinal fluid tau levels, severity of periventricular and deep white matter lesions, silent brain infarction on magnetic resonance imaging, plasma homocysteine levels, apolipoprotein E genotype, and other vascular risk factors were assessed at baseline. RESULTS: Fifty-seven patients were diagnosed as having amnestic MCI. Forty-one patients with (AD-converted MCI group) or without (progressive MCI group) conversion to dementia and AD progressed over time, whereas the other 16 patients remained cognitively stable (stable MCI group). The stable MCI group was characterized by normal cerebrospinal fluid tau levels and a high grade of periventricular white matter lesions (PWMLs). The progressive MCI and AD-converted MCI groups had increased cerebrospinal fluid tau levels and low grades of PWMLs. A logistic regression model showed that age was significantly associated with developing PWMLs (P =.03; odds ratio, 1.15; 95% confidence interval, 1.0-1.3). CONCLUSIONS: Tau-related AD pathologic conditions and possibly ischemic PWMLs represent 2 major etiologies in the development of MCI, reflecting heterogeneity in the clinical progression. Because the progressive type of MCI may be a primary target of clinical trials that aim at secondary prevention of dementia, these patients should be identified by appropriate biomarkers and neuroimaging techniques.

Aged↗
PubMed2004

[Diagnosing the mild cognitive impairment stage of Alzheimer's disease].

Recently, it has become important to diagnose Alzheimer's Disease (AD) at an early stage due to the development of AD therapy. Also, there is increasing recognition of a class of elderly people with complaints of memory loss but who nevertheless do not meet the criteria for dementia. "Mild cognitive impairment" (MCI) is the term used for this disorder, and amnestic MCI is highly converted to AD. In this study we evaluated the accuracy of diagnosis of amnestic MCI by cerebrospinal fluid total-tau protein (CSF/total-tau), cerebrospinal fluid amyloid beta 1-42 protein (CSF/A beta 1-42), and cerebral blood flow in the posterior cingulate cortex using SPECT. CSF/total-tau was the most appropriate to discriminate between normal cognitive individuals and those with amnestic MCI. We also evaluated the CSF/total-tau and MRI images between patients with stable MCI and those with progressive MCI, including those who converted to AD in the following two years. The stable type was characterized by normal CSF/total-tau levels and relatively high grade periventricular white matter lesions (PWML). Conversely, the progressive type was characterized by high CSF-tau levels and relatively low grade PWML. We speculate that stable MCI is due to ischemic change with in the white matter lesion, while progressive MCI may represent a previous stage of AD.

Alzheimer Disease↗
PubMedDate not supplied

Nonviral gene delivery by tetraamino fullerene.

A fullerene derivative bearing two diamino side chains binds to a plasmid vector DNA, either 4 or 40 kbp in size, delivers it to mammalian cells on incubation, and leads to expression of the encoded gene either transiently or stably. The initial physicochemical investigations upon DNA-binding and protective properties of various fullerene compounds against nuclease led us to identify the tetraamino fullerene as an ideal candidate to probe the new concept of fullerene-mediated gene delivery to mammalian cells. Studies on transient and stable transfection of COS-1 cells using green fluorescent protein and luciferase reporter genes revealed several useful properties of the fullerene transfection as compared with the conventional lipid-based transfection method, including much higher efficiency of stable transfection and ability to transfect confluent cells. Chemical and biological studies suggested that the cell uptake of the fullerene/DNA complex takes place by an endocytosis mechanism and that the DNA internalized by endosomes is protected by the fullerene against enzymatic digestion. The stiffness of the fullerene/DNA complex may play some role in the success of the fullerene method.

Animals↗