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Biomedical subjects

A Mochizuki

Publications and source records attributed to A Mochizuki.

At least 19 recordsLinked to original sources
PubMed2003

Progressive supranuclear palsy presenting with primary progressive aphasia--clinicopathological report of an autopsy case.

We report a Japanese autopsy case of progressive supranuclear palsy (PSP). The male patient was 74 years old at the time of death. At age 64, he developed non-fluent aphasia that progressed slowly over 8 years, eventually associated with behavioral abnormality, postural instability, and dysphagia at 2 years prior to his death. Magnetic resonance imaging of the brain at age 73 demonstrated marked atrophy of the frontal lobes, particularly on the left side. Neuropathological examination revealed the typical pathology of PSP: loss of neurons, gliosis, occurrence of neurofibrillary tangles, oligodendroglial coiled bodies, and tuft-shaped astrocytes in the frontal cortex, associated with argyrophilic threads in the underlying white matter, in the basal ganglia, including the thalamus, globus pallidus, and subthalamic nucleus, and in the brainstem nuclei, including the substantia nigra, pontine nucleus, and inferior olivary nucleus. No astrocytic plaques or ballooned neurons were observed. Protein analysis revealed accumulation of hyperphosphorylated tau of 68 and 64 kDa consisting of the four repeat tau isoforms. We conclude that the present case represented PSP with an 8-year history of primary progressive aphasia (PPA). Although focal cortical symptoms in PSP are rare or absent, we should keep in mind the possibility of atypical PSP in which cortical pathology is predominant, particularly in the frontal lobe, and could result in PPA.

Aged↗
PubMed2001

Suppressive effects of F-1322 on the antigen-induced late asthmatic response and pulmonary eosinophilia in guinea pigs.

We investigated the effects of F-1322 (N-[2-[4-(benzhydryloxy)piperidino]ethyl]-3-hydroxy-5-(3-pyridylmethoxy)-2-naphthamide), a new compound that inhibits both thromboxane A2 synthetase and 5-lipoxygenase and that functions as a histamine antagonist, on the Ascaris antigen-induced late asthmatic response and pulmonary eosinophilia in guinea pigs. Oral administration of F-1322 (10-100 mg/kg) inhibited the antigen-induced late asthmatic response in a dose-dependent manner. Histological analysis revealed that F-1322 prevented the accumulation of eosinophils in the airways and this was paralleled by a decrease in the number of eosinophils and lymphocytes recovered in bronchoalveolar lavage fluid. F-1322 (0.1-10 microM) inhibited eotaxin-induced chemotaxis and actin polymerization of eosinophils in vitro in a concentration-dependent manner, while oral administration of F-1322 dose-dependently suppressed the migration of eosinophils into the airways in vivo in response to infusion of interleukin 5 and eotaxin in combination. F-1322 may, thus, improve the late asthmatic response in this model, in part, by preventing the accumulation of eosinophils in the airways. The pharmacological profile of F-1322 indicates that this drug is likely to be useful in the treatment of allergic diseases such as asthma.

Airway Resistance↗
PubMed2001

Single fiber EMG and repetitive nerve stimulation of the same extensor digitorum communis muscle in myasthenia gravis.

OBJECTIVE: To compare voluntary single fiber electromyography (v-SFEMG) and repetitive nerve stimulation (RNS) at the same extensor digitorum communis (EDC) muscle in myasthenia gravis (MG). METHODS: We examined v-SFEMG and RNS successively on the same day in the same EDC muscle. We studied 45 examinations of both v-SFEMG and RNS in 29 patients suffering from MG, together with examinations of RNS in 30 control subjects. RESULTS: Forty-one of 45 (91%) v-SFEMGs showed abnormal results, whereas only 18/45 (40%) RNSs showed an abnormal decrement. The percentage of decrement showed similar correlations with 3 v-SFEMG parameters: percentage of abnormal pairs, percentage of blocking pairs, and the mean MCD value. Examinations showing a significant decrement in RNS had at least 60%, and usually no less than 90%, abnormal pairs, and 10-80% blocking pairs. Some muscles without a decrement had up to 50% blocking pairs. CONCLUSIONS: These results suggest that the blocking phenomenon observed in v-SFEMG is not a direct counterpart of the decrement in RNS. This must be partly because fibers contributing to the decrement are continuously blocked during voluntary contraction, and partly, because smaller motor units explored by v-SFEMG are probably more abnormal in MG than larger motor units mainly contributing to a decrement. Both factors make v-SFEMG much more sensitive than RNS.

Adult↗
PubMed2001

Lower cervical origin of the P13-like potential in median SSEPS.

The authors studied the origin of the scalp P13-like potential in median somatosensory evoked potentials, which have been reported to be preserved in patients with cervicomedullary lesions or in brain death. There were five patients with high to middle cervical lesions (C2/3 or C3/4 level). Small P13-like potentials after P11 were identified for all patients with a noncephalic reference but not with an ear reference. Their onset latencies were slightly earlier than the expected latency of the true P13/14 onset. In two patients, delayed true P13/14s followed by N18s were identified with both noncephalic and ear references. The authors argue that the P13-like potential observed in these patients is a different entity from scalp P13 in normal subjects. Because the C3/4 vertebral level corresponds to the C5 cord level, the origin of the P13-like potential must be below C5, contradicting the previous opinion that it is generated at the cervicomedullary junction or at the high cervical dorsal column. The authors named this potential lower cervical P13 (or lcP13), and present an opinion that it is generated by the beginning of the second spinal ascending volley, which has been described by direct-recording studies in humans.

Adult↗
PubMed2001

[A case of eosinophilic myositis proven by immunohistochemistry using antibodies against eosinophilic granule protein].

A 50-year-old man had been well until three months earlier, when he felt general fatigue, and cutaneous rash with itching. Thereafter a general muscular weakness developed and the patient could not walk for a month. Four weeks before referral to our hospital, he had high fever and could not role over in the bed. On admission, the patient was able to walk. He had no skin rash. Neurologically, he showed mild weakness in proximal muscles. Hematologic examination showed mild eosinophilia and serum creatine kinase was mildly elevated. Needle electromyogram revealed a diffuse myogenic pattern in extremities. Eosinophilic myositis was diagnosed by a biopsy of the left calf muscle showing mild infiltration of eosinophilis which was identified using antibodies against eosinophilic granule protein.

Autoantibodies↗
PubMed2000

Expression of genes responsible for ethylene production and wilting are differently regulated in carnation (Dianthus caryophyllus L.) petals.

Carnation petals exhibit autocatalytic ethylene production and wilting during senescence. The autocatalytic ethylene production is caused by the expression of 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase genes, whereas the wilting of petals is related to the expression of the cysteine proteinase (CPase) gene. So far, it has been believed that the ethylene production and wilting are regulated in concert in senescing carnation petals, since the two events occurred closely in parallel with time. In the present study, we investigated the expression of these genes in petals of a transgenic carnation harboring a sense ACC oxidase transgene and in petals of carnation flowers treated with 1,1-dimethyl-4-(phenylsulfonyl)semicarbazide (DPSS). In petals of the transgenic carnation flowers, treatment with exogenous ethylene caused accumulation of the transcript for CPase and in-rolling (wilting), whereas it caused no or little accumulation of the transcripts for ACC oxidase and ACC synthase and negligible ethylene production. In petals of the flowers treated with DPSS, the transcripts for ACC synthase and ACC oxidase were accumulated, but no significant change in the level of the transcript for CPase was observed. These results suggest that the expression of ACC synthase and ACC oxidase genes, which leads to ethylene production, is differentially regulated from the expression of CPase, which leads to wilting, in carnation petals.

Journal Article↗
PubMed2000

Identification of functional elements in the bidirectional promoter of the mouse Nthl1 and Tsc2 genes.

The gene of mammalian endonuclease III homologs (NTHL1/Nthl1), a DNA glycosylase/AP lyase involved in base excision repair, lies immediately adjacent to one of the tuberous sclerosis disease-determining genes, TSC2/Tsc2, in a head-to-head orientation. To clarify the regulation of these divergent genes, we studied the promoter activities of these transcription units by luciferase assay using HeLa cells. We found that the short spacer sequence of 63 base pairs (bp) between the mouse Nthl1 and Tsc2 genes shows bidirectional promoter activity essential for the transcription of both genes. The 63-bp sequence is well conserved among several mammalian species and contains two Ets-transcription factor binding sites (EBSs) in opposite directions. An Ets-family protein in the HeLa nuclear extract specifically bound to either EBSs. Mutation of the core motif of the EBS demonstrated that EBS positively regulates transcription of both mNthl1 and mTsc2 genes. These EBSs had an additive effect on transcription, and each EBS functioned equally in both directions.

Animals↗
PubMed2000

Intermittent light irradiation with second- or hour-scale periods controls anthocyanin production by strawberry cells*

Anthocyanin production by strawberry cells depends not only on light intensity but also on the light/dark cycle operation with hour- or second-scale periods. These findings are useful for designing and operating photobioreactors for enhanced anthocyanin production. Intermittent illumination with a second-scale period produces the same amount of anthocyanin as continuous light, suggesting that the light intensity distribution within a photobioreactor does not cause suppressed production. In the hour-scale cycle, continuous light operation enhanced anthocyanin production more than the light/dark cycle process.

Journal Article↗
PubMed2000

Blood compatible aspects of poly(2-methoxyethylacrylate) (PMEA)--relationship between protein adsorption and platelet adhesion on PMEA surface.

Platelet adhesion and spreading is suppressed when a poly(2-methoxyethylacrylate) (PMEA) surface is used, compared with other polymer surfaces. To clarify the reason for this suppression, the relationship among the amount of the plasma protein adsorbed onto PMEA, its secondary structure and platelet adhesion was investigated. Poly(2-hydroxyethylmethacrylate) (PHEMA) and polyacrylate analogous were used as references. The amount of protein adsorbed onto PMEA was very low and similar to that absorbed onto PHEMA. Circular dichroism (CD) spectroscopy was applied to examine changes in the secondary structure of the proteins after adsorption onto the polymer surface. The conformation of the proteins adsorbed onto PHEMA changed considerably, but that of proteins adsorbed onto PMEA differed only a little from the native one. These results suggest that low platelet adhesion and spreading are closely related to the low degree of the denaturation of the protein adsorbed onto PMEA. PMEA could be developed as a promising material to produce a useful blood-contacting surface for medical devices.

Acrylates↗
PubMed1999

Formation of cone mosaic of zebrafish retina.

In the zebrafish retina, four types of cone photoreceptor cells (or cones) with different sensitive frequencies are arranged in a regular pattern, named "cone mosaic". A pair of small cones, one sensitive to red and the other sensitive to green, is in close contact and forms a "double cone". In addition, there are two kinds of single cones, sensitive to blue and to UV, respectively. We study characteristics of cell-differentiation rules that realize stable formation of cone mosaic. Assumptions are: undifferentiated cells are arranged in a regular square lattice, and they are one of the three types (B, U, and D cells). A D cell has two parts (G and R-parts) and takes one of the four directions. The cells change their cell type and orientation following a continuous-time Markovian chain. The state transtion occurs faster if it increases the stabilities of the focal cell, in which the stability is the sum of affinities with neighboring cells. After the transient period, the system may reach a stable pattern (pre-pattern). The pattern becomes fixed later when the cells are fully differentiated in which B cells, U cells, and D cells become blue-sensitive, UV-sensitive, and double cones, respectively. We search for the combinations of affinities between cell states that can generate the same cone mosaic patterns as in zerbrafish retina. Successful transition rules give (1) zero or small affinity with the pairs of cell states that are absent in the zebrafish cone mosaic (lambda(UR), lambda(BG)and the contact of two cells of the same type); (2) a large affinity between a part of D cells and a non-D cell (lambda(UG)and lambda(BR)); and (3) a positive affinity of an intermediate magnitude between two non-D cells (lambda(BU)) and between two parts of D cells (lambda(GR)). The latter should be of a magnitude of about 60-90% of the former. The time needed to form a regular pattern increases with the lattice size if all the cells start pre-pattern formation simultaneously. However, the convergence time is shortened considerably if the pre-pattern formation occurs only in a narrow band of morphogenetic cell layer that sweeps from one end of the lattice to the other.

Animals↗
PubMed1999

Exacerbation of myasthenia gravis in a patient after interferon-beta treatment for chronic active hepatitis C.

We report the case of a 53-year-old female patient, who developed bilateral blepharoptosis, limb weakness, dysphagia, and dyspnea several days after human natural interferon-beta (IFN-beta) treatment for chronic active hepatitis C. A positive edrophonium test, an elevated anti-acetylcholine receptor antibody titer, and decrements in the amplitude of muscle action potentials evoked by repetitive stimulation confirmed the diagnosis of myasthenia gravis (MG). Since she had been suffering from drooping of her right eyelid, fluctuating diplopia and easy fatiguability of limbs before receiving IFN-beta, her symptoms of MG were considered to be exacerbated by IFN-beta. It is recommended that IFN-beta should be used with particular care in patients with known MG or its compatible symptoms.

Antiviral Agents↗
PubMed1999

Estimating cell lineage from distributions of randomly introduced markers.

Cell lineage of a multicellular organism has been analysed by introducing a genetic or chemical marker that is inherited from a cell to its daughter cells and is detectable even after several cell divisions. To construct a complete cell lineage, all the cells at different developmental stages need to be identified, and then the intracellular marker must be introduced to each cell. In this paper, I study a new method of estimating cell lineage based on distributions of intercellular markers observed at a single stage, which are introduced randomly at earlier stages. Assumptions are: (1) cell lineage is invariant between embryos; (2) a small number of cells are marked in each experiment; and (3) the total number of replicate experiments is sufficiently large. Then we identify the most likely cell lineage pattern (or tree topology) as the one that requires the least marker insertions to be compatible with the observed distributions of cell markers. This method is essentially the same as the principle of persimony widely used for ancestral phylogeny reconstruction in evolutionary biology. When the total number of cells is small, we can generate all the possible cell lineages and calculate the minimum number of marker insertions for each candidate, and then choose the cell lineage that requires the least marker insertions. If the number of cells is large, we can use clustering method in which a pair of cells with the highest correlation in marker labelling are merged sequentially. The efficiency of the clustering method in estimating the correct cell lineage is confirmed by computer simulations. Finally, the clustering method is applied to reconstruct the cell lineage of ascidian from experimental data.

Animals↗
PubMed1999

Emergence of symbolic behavior from brain like memory with dynamic attention.

An important feature of human intelligence is the use of symbols. This is seen in our daily use of language and logical thinking. However, the use of symbols is not limited to humans. We observe planned action sequences in primate behavior and prediction-based action in higher mammals. For the representation and operation of symbols by the brain neural circuit, no specific construction principle or computational theory is known so far. In this paper, we regard the brain as a complex of associative memory and dynamic attentional system, and starting from two hypotheses on information representation and operation in the brain, we propose a model of primitive symbolic behavior emergence that is consistent with the conventional symbolic processing model. We also describe a computational theory of the symbolic processing model in associative memory. Through computer simulation studies on a language-like memory search and map learning by a moving robot, we discuss the validity of the model.

Journal Article↗