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Biomedical subjects

M Matsuzawa

Publications and source records attributed to M Matsuzawa.

At least 19 recordsLinked to original sources
PubMed2001

Activation during endogenous orienting of visual attention using symbolic pointers in the human parietal and frontal cortices: a functional magnetic resonance imaging study.

Brain activation induced by endogenous orienting with a motor response was investigated by functional magnetic resonance imaging. We conducted four cued-attention experiments in which peripheral attention was caused by one of three symbolic pointers (eyes, squares as artificial eyes, or an arrow) that was predictive or not predictive of the target location. Attentional shift caused by the predictive and non-predictive cues induced right and left parietal activation across cue modalities, respectively. Regardless of the predictability of the target location, the eyes and arrow induced left parietal and frontal activation, and the arrow induced left parietal activation more than the squares. These results suggested that the left parieto-frontal network was involved in motor attention caused by natural or familiar pointers, whereas the right parietal cortex was involved in endogenous orienting.

Adult↗
PubMed2001

Visual language and handwriting movement: functional magnetic resonance imaging at 3 tesla during generation of ideographic characters.

A functional magnetic resonance imaging experiment at 3 tesla was performed to investigate the collaborative mechanism between visuospatial processing and motor execution in performing visual language generation tasks. Japanese Kanji, ideographic characters, were utilized to design tasks. The bilateral border portions between the inferior parietal lobule and the occipital lobe were involved during a Kanji puzzle task, which required subjects to combine several parts into a Kanji. The higher motor areas, such as the premotor areas and the pre-supplementary motor areas, were also activated bilaterally during the puzzle task. The parieto-occipital activation may be related to analysis of configuration or segmentation/integration of Kanji figures. Activation in the higher motor areas may be induced by cognitive components related to motor function to perform the visuospatial language task, such as intense reference for displayed characters and finding a proper character for puzzle solution. A collaborative mechanism in these areas may explain the effectiveness of tactile reading in letter recognition by patients with pure alexia or kinesthetic facilitation by Kanji users when recalling difficult Kanji.

Adult↗
PubMed2001

Development of saccade target selection in infants.

To investigate the development of the target selection process for saccade generation, saccade latencies toward one of two targets were compared with those toward a target presented alone, under conditions where the timing of fixation stimulus offset was varied. 12 2-mo.-olds (7 boys and 5 girls), 12 3-mo.-olds (6 boys and 6 girls), and 12 5-mo.-olds (8 boys and 4 girls) participated. The latencies were longer when two saccade targets were presented on the left and right sides of the display (Double-target condition) than when one target was presented either on the left or right side of the display (Single-target condition). The difference between the Single and Double-target conditions tended to be larger in 2-mo. old infants than in 5-mo.-old infants when a central fixation target remained on after the onset of peripheral stimuli (Overlap condition). However, there was no difference between the 2-mo.-olds and the 5-mo.-olds when the fixation target was turned off before the peripheral stimuli were presented (Gap condition). The results provided evidence of the maturational development of a target selection process for saccade generation during 2 to 5 mo. of age.

Female↗
PubMed2000

Simultaneous determination of 6beta- and 6alpha-hydroxycortisols and 6beta-hydroxycortisone in human urine by stable isotope dilution mass spectrometry.

A capillary gas chromatographic-mass spectrometric method for the simultaneous determination of 6beta-hydroxycortisol (6beta-OHF, 6beta,11beta,17alpha,21-tetrahydroxypregn-4-ene- 3,20-dione), 6alpha-hydroxycortisol (6alpha-OHF, 6alpha,11beta,17alpha,21-tetrahydroxypregn-4-ene -3,20-dione) and 6beta-hydroxycortisone (6beta-OHE, 6beta,17alpha,21-trihydroxypregn-4-ene-3,11,20-trione) in human urine is described. Deuterium-labelled compounds, 6beta-[1,1,19,19,19-2H5]OHF (6beta-OHF-d5), 6alpha-[1,1,19,19,19-2H5]OHF (6alpha-OHF-d5) and 6beta-[1,1,19,19,19-2H5]OHE (6beta-OHE-d5) were used as internal standards. Quantitation was carried out by selected-ion monitoring of the characteristic fragment ions ([M-31]+) of the methoxime-trimethylsilyl (MO-TMS) derivatives of 6beta-OHF, 6alpha-OHF and 6beta-OHE. The sensitivity, specificity, precision and accuracy of the method were demonstrated to be satisfactory for measuring 6beta-OHF, 6alpha-OHF and 6beta-OHE in human urine.

Calibration↗
PubMed2000

Formation of hippocampal synapses on patterned substrates of a laminin-derived synthetic peptide.

We created a new culture system which provides simple, stereotyped neuronal circuitries suitable for investigating synaptic events between mammalian central neurons. We used surface chemistry and laser-lithography to produce geometrical patterns of neuron-compatible substrate spaced by less neuron-compatible surfaces. The patterned substrates were composed of a laminin-derived synthetic peptide, PA22-2, and the spacing surfaces of either decyldimethylsilane (DDMS) or trimethylsilane (TMS). Dissociated rat hippocampal neurons survived on the patterned substrates for several days without the aid of glia and extended their neurites along the substrates. The TMS spacing surfaces appeared more favourable for the excitability development and axonal differentiation of the hippocampal neurons, but less favourable for the development of the resting conductance than the DDMS spacing surfaces. Furthermore, neurons grown on the patterned substrates frequently made synaptophysin-positive contacts with one another. Spontaneous post-synaptic currents recorded from such neurons suggest that these contacts were indeed functional synapses. When hippocampal neurons were plated at a very low density, they often formed circuitries consisting of only two neurons on the patterned substrate. Such a simple circuitry allowed us to analyse synaptic transmission in a single neuronal pair without the influence of the third neurons. With the clarity of analysis and the readiness of manipulation, our culture system would offer a powerful tool for studying development and functions of mammalian central synapses.

Animals↗
PubMed1999

The role of the posterior parietal cortex in human object recognition: a functional magnetic resonance imaging study.

The mechanisms involved in visual object recognition from non-canonical viewpoints were investigated using functional magnetic resonance imaging (fMRI). We used a passive observation task and found three areas activated more strongly in the non-canonical viewing condition compared with the canonical viewing condition. First, it was found that the fusiform gyrus and posterior part of the inferior temporal cortex were involved in the processing of shape information. Next, it was found that the posterior parietal cortex, mainly the superior parietal lobule and the ventral part of premotor area were involved in visuospatial processing and accessing sensorimotor knowledge. These results may indicate that recognition from non-canonical viewpoints is supported by using functional properties of the object, which require more real-time processing for object manipulation.

Adult↗
PubMed1999

A functional magnetic resonance imaging study of listening comprehension of languages in human at 3 tesla-comprehension level and activation of the language areas.

Passive listening comprehension of native and non-native language was investigated using high resolution functional magnetic resonance imaging (fMRI) at a static magnetic field strength of 3 tesla. Wernicke's area was activated by comprehensive and non-comprehensive languages indicating that this area is associated with common phonological processing of language. The task with comprehensive but non-native language activated Broca's area and angular gyrus most frequently. The activations in these areas may be related to demand in semantic and syntactic processing in listening comprehension. Supplementary motor area and pre-motor area were activated by comprehensive languages but not by non-comprehensive language. These motor controlling areas may be involved in semantic processing. Listening to comprehensive but non-native language seems to demand more networked co-processing.

Adult↗
PubMed1999

Transient mutism resolving into cerebellar speech after brain stem infarction following a traumatic injury of the vertebral artery in a child.

A 3.7-year-old girl presented with an anterior neck injury followed by progressive subcutaneous emphysema and loss of consciousness. After resuscitation, a laceration on the first tracheal cartilage was closed surgically. As she was extubated one week later, she was found to have right hemiplegia and muteness. MRI showed a T2-bright lesion on the tegmentum of the left midbrain down to the upper pons. Right vertebral angiography disclosed an intimal flap with stenosis at the C3 vertebral level presumably caused by a fracture of the right C3 transverse process later confirmed in a cervical 3D-CT scan. Her muteness lasted for 10 days, after which she began to utter some comprehensible words in a dysarthric fashion. Her neurological deficits showed improvement within 3 months of her admission. Transient mutism after brain stem infarction has not been reported previously. We discuss the anatomical bases for this unusual reversible disorder in the light of previous observations and conclude that bilateral damage to the dentatothalamocortical fibers at the decussation of the superior cerebellar peduncle may have been responsible for her transient mutism.

Brain Mapping↗
PubMed1999

Novel neuronal effects of midkine on embryonic cerebellar neurons examined using a defined culture system.

1. Midkine (MK) is known to be a member of a family of heparin-binding neurotrophic factors. We used a chemically defined culture system to examine neuronal activities of MK on embryonic rat cerebellar cells. 2. In the culture system, a substrate surface was chemically modified either with amine or with laminin peptide to homogenize substrate conditions for culturing neurons. 3. At the optimal concentration (2.5 ng/ml), MK moderately promoted survivability (1.3-fold) and accelerated neurite outgrowth (1.4-fold) of cerebellar cells, putatively granule neurons, grown on an amine-modified surface. 4. Higher dosages (10 ng/ml or more) of MK, however, caused cellular fragmentation and detachment. Such degenerative effects were diminished by increasing the surface adhesiveness using laminin peptide, suggesting that the cellular degeneration might be caused by changes in the adhesive property of the neuron. 5. Using this culture system, we have found that MK has a novel modulatory activity of neuronal adhesiveness on the cultured cerebellar granule cells. Together with the expression pattern of MK, our study supports the idea that MK may be involved in the developmental events of the cerebellum.

Animals↗
PubMed1999

A clinicopathological study of postoperative pulmonary metastasis of uterine cervical carcinomas.

OBJECTIVE: To investigate the clinicopathological backgrounds and prognostic factors of uterine cervical carcinomas metastatic to the lung. METHODS: A total of 519 patients with invasive cervical carcinoma (Stage pTIb-IIb) treated by abdominal radical hysterectomy at the Saitama Cancer Center from January 1, 1976 to December 31, 1989 were analyzed clinicopathologically. RESULTS: The frequencies of pulmonary metastasis were 6.4% (24/377) and 11.3% (16/142) in patients with negative and positive pelvic lymph nodes, respectively. Among 24 negative lymph node patients, 15 had pulmonary metastasis only. The overall 5-year survival rate of these 15 patients was 36% after relapse. Of the 15, the prognosis of 12 patients with 1-3 pulmonary metastases only was better, that is, 46% after surgical resection (mean size of resectable tumor = 2.8 cm) and/or chemotherapy. But the other patients died within 3.3 years after relapse. CONCLUSIONS: The occurrence of pulmonary metastasis only, its number (1-3) and size (mean size = 2.8 cm), and no lymph node metastasis are important prognostic factors. For these patients, active surgical resection of the pulmonary lesion(s) and further chemotherapy are recommended in order to improve their prognosis.

Adenocarcinoma↗
PubMed1999

Cytokine secretion of periodontal ligament fibroblasts derived from human deciduous teeth: effect of mechanical stress on the secretion of transforming growth factor-beta 1 and macrophage colony stimulating factor.

The periodontal ligament may play an important role in tooth eruption, root development and resorption. The tissue physiologically receives mechanical force during mastication. We focused on the effects of intermittent mechanical strain on the cytokine synthesis of periodontal ligament (PDL) fibroblasts in vitro. The cells were derived from human periodontal ligament of deciduous teeth (HPLF-Y) and permanent teeth (HPLF). The two kinds of PDL cells and human gingival fibroblasts (HGF) were cultured in flexible bottomed culture plates. The cells were mechanically stretched at 5% elongation, 3-cycles/min for 24 h on d 7 in culture using a Flexercell strain unit. After the stretching, we measured DNA content and alkaline phosphatase activity in the cell layer, transforming growth factor beta 1 (TGF-beta 1) and macrophage colony stimulating factor (M-CSF) contents in the conditioned medium. The TGF-beta 1 level in the conditioned medium of HPLF was significantly higher than that of HPLF-Y and HGF. It was stimulated by mechanical stretching only on HPLF, whereas no significant effect was observed on HPLF-Y and HGF. M-CSF secretion was inhibited by the stretching on all of HPLF, HPLF-Y and HGF. 1 alpha, 25 dihydroxy vitamin D3 (D3) stimulated M-CSF secretion into the culture medium of both HPLF and HPLF-Y, but the stretching inhibited M-CSF secretion and completely blocked the enhancement by D3. These data suggest that periodontal ligament cells synthesize and secrete the molecules as autocrine or paracrine factors that affect bone remodelling and root resorption and the level of those factors change in response to mechanical stress.

Alkaline Phosphatase↗
PubMed1999

Contribution of a high dose of L-ascorbic acid to carnitine synthesis in guinea pigs fed high-fat diets.

Ascorbate is a cofactor of two-enzyme hydroxylation in the pathway of carnitine biosynthesis. The purpose of this study was to investigate the contribution of ascorbate to endogenous carnitine in guinea pigs fed high-fat diets. The contents of carnitine in plasma, urine and tissues of guinea pigs supplemented with L-ascorbic acid were determined and compared with those supplemented with carnitine. Albino-Hartley guinea pigs were fed vitamin C-deficient diets containing lard throughout the experiment. They were administered orally with 5 mg L-ascorbic acid/d/animal for 14 d, and then divided into three groups and administered orally with the following supplements (/d/animal) for 14 d; L (5 mg L-ascorbic acid), LASA (100 mg L-ascorbic acid), and LCAR (10 mg carnitine plus 5 mg L-ascorbic acid). As a control, a normal group was fed vitamin C-deficient diets and administered orally with 5 mg L-ascorbic acid/d/animal for 28 d. The animals fed high-fat diets (L group) had higher free-carnitine contents in the muscle and urine than the normal group. The groups of LCAR and LASA had significantly higher contents of acid-soluble carnitine (p < 0.05) in plasma than the L group. Urinary excretion of carnitine in the LASA group was decreased to the same level as that in the normal group, although no significant difference between the groups of L and LCAR was observed. Moreover, the supplement of ascorbic acid, but not of carnitine, induced a significantly lower content of triacylglycerol in the plasma of the LASA group as compared to the L group (p < 0.05). These data suggest that high doses of ascorbic acid in guinea pigs fed high-fat diets contribute to the enhancement of carnitine synthesis and improvement of the triacylglycerol content in the plasma.

Animals↗
PubMed1999

[A preventive and therapeutic measures for upper gastrointestinal disorders occurred after successful eradication of Helicobacter pylori].

According to the increasing the eradication therapy of Helicobacter pylori, endoscopists should pay an attention to a newly occurrence of upper gastrointestinal disorders after therapy. Most cases with gastric and duodenal erosion were asymptomatic and temporary that therapeutic approach are unnecessary. Some cases of gastro-esophageal reflux disease (GERD) required medication for a long period. About 2/3 of the cases basically had hiatal hernia. We have to pay an attention to the occurrence of GERD, when patient have hernia. The recurrence of peptic ulcer were seen in special condition such as use of nonsteroidal anti-inflammatory drugs, mental stress, or coexistence of other disease. It is important to get fully informed consent from all patients before eradication therapy including these unsatisfactory results.

Adult↗
PubMed1998

Molecular gradient along the axon pathway is not required for directional axon growth.

We show that axon guidance of embryonic hippocampal neurons is promoted by pathways of a decapeptide (RDIAEIIKDI) derived from a neurite outgrowth domain of the gamma1 chain of laminin-1. This guidance is directly dependent on: (1) a concentration difference of the decapeptide between the peptide pathway and its surrounding areas, and (2) the optimal surface geometry of the decapeptide pathway. These results indicate that axon guidance of central neurons may proceed along a preferred substratum pathway without a concentration gradient of the guiding molecule along this pathway, or without a repulsive molecule next to the axon pathway.

Animals↗
PubMed1998

[A case of sellar T cell type malignant lymphoma].

A case of primary T cell type malignant lymphoma of the sellar region was reported. This 53-year-old male was admitted to our neurosurgical service because of slowly progressive occipitalgia and diplopia over the previous 5 months. On admission neurological examination revealed a slight limitation of the lateral movement of the left eye. Endocrinological examination showed no abnormalities. Despite a mild neurological deficit, a CT scan revealed an extensive bony destruction around the sellar region including the dorsum sellae, the bilateral petrous apices, and the upper two thirds of the clivus. Magnetic resonance imaging (MRI) disclosed that the tumor was slightly hypointense on T1-weighted image, isointense on T2-weighted image, and faintly and homogeneously enhanced after administration of Gd-DTPA. Since the tumor was enhanced faintly on MRI, it was diagnosed as an invasive pituitary adenoma, but it was thought that chordoma and germinoma should be considered. The patient underwent a transsphenoidal surgery. A firm, grayish and avascular tumor was partially removed. The histopathological examination using monoclonal surface marker of the specimen revealed the tumor was stained with UCHL-1 and CD3 antibodies directed against T cells, and diagnosed as T cell type malignant lymphoma of the sellar region (diffuse, large cell type; LSG). Postoperatively he received radiation therapy. His symptoms much improved and no regrowth of the residual tumor has been found in follow-up studies to the present. Primary malignant lymphomas very rarely occur in the skull base. As far as we are aware, this is the only second case of primary T-cell lymphoma in the sellar region reported so far in the medical literature. Although preoperative diagnosis is extremely difficult because of a paucity of data, malignant lymphomas should be kept in mind in the differential diagnosis of sellar tumors, especially if neuroimaging studies show an extensive bony destruction in the skull base.

Combined Modality Therapy↗