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Biomedical subjects

M Kaga

Publications and source records attributed to M Kaga.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Deficit of language comprehension in a child with semantic-pragmatic disorder--dissociation between the phonemic and semantic processing abilities].

We studied the language comprehension deficit of a 11-year-old child with a semantic-pragmatic disorder. We used an original test battery using abstract nouns common to the tasks of repetition, reading aloud, auditory comprehension and comprehension of written words. Although he could repeat and read aloud words as good as normal controls, he could not choose correct pictures from semantically or phonemically resembling pictures by listening to or reading target words. This test demonstrated the dissociation between his phonemic and semantic processing abilities. An examination of the cerebral blood flow with SPECT suggested that the dysfunction of the left temporal lobe caused the deficit in language comprehension.

Brain↗
PubMed1998

Early forms of microtubule-associated protein are strongly expressed in cortical dysplasia.

We report the enhanced expression of early forms of microtubule-associated proteins (MAPs) in cortical dysplasia in surgical resections from 17 children with intractable epilepsy. Large neurons, which represent one of the characteristic cellular features of cortical dysplasia, showed strong immunoreactivity for MAP1B, as well as the low-molecular-weight isoform of MAP2 (MAP2c). In situ hybridization with MAP1B antisense riboprobe showed markedly increased hybridization signal intensities in the large neurons, whereas neurons in the normal-appearing cortex and most of the normal-sized neurons in the dysplastic cortex had faint signals. Because MAP2c and MAP1B are early forms of MAPs, which are abundantly expressed in the developing brain and down-regulated in the adult, and are thought to be involved in neuronal outgrowth and plasticity, our results suggest that the structural remodeling of neuronal processes is activated in cortical dysplasia.

Adolescent↗
PubMed1998

Somatosensory evoked potentials with a unilateral migration disorder of the cerebrum.

The somatosensory evoked potentials in two children with a unilateral migration disorder (pachygyria) of the cerebrum, which was detected by MRI, were examined in order to evaluate the function of the malformed sensory cortex. A 5-year-old girl had slight left hemiparesis, seizures, and mental retardation, and a 4-month-old boy had left hemiparesis. Neither patient showed distinct sensory disturbance. Short latency somatosensory evoked potentials and somatosensory evoked potentials recordings demonstrated that the early cortical component, N20, was absent and a positive wave appeared on paretic left-hand stimulation. On nonparetic right-hand stimulation, the primary evoked response (N20-P30) of the left hemisphere, which originates in Broadmann area 3b, was almost normal. Multichannel recordings on the scalp of one patient revealed that a positive wave without polarity inversion appeared posterior to the right central sulcus on median nerve stimulation on the paretic side. The radial dipole in the sensory cortex (area 1 or area 3a) or motor cortex (area 4) could have formed the positive/negative biphasic wave in the relatively wide centroparietal area in the present patients. In the case of unilateral cortical dysplasia, the malformed cortex with subnormal function of sensation might induce the change in the early component of somatosensory evoked potentials.

Cerebral Cortex↗
PubMed1997

Development of a polymerase chain reaction assay for Mycoplasma salivarium by using the nucleotide sequence within aminopeptidase My gene.

A polymerase chain reaction assay for a 278-nucleotide DNA fragment within aminopeptidase My gene of Mycoplasma salivarium was developed. The assay amplified M. salivarium DNA, but did not amplify DNAs of other mollicutes, bacteria and mammalian cells. The detection limit of the assay was 10 fg of DNA, approximately equivalent to 10 organisms.

Adult↗
PubMed1997

Hypoxia-induced ABR change and heat shock protein expression in the pontine auditory pathway of young rabbits.

The auditory brainstem response (ABR) was compared with the immunohistochemical expression of heat shock protein (HSP-72) and microtubule-associated protein 2 (MAP-2) of the brainstem auditory pathway in young rabbits subjected to hypoxic stress. Severe hypoxia for 2 h produced significant prolongation and decreased amplitude of the later component of ABR. HSP-72 expression was distinctly increased in the cochlear nucleus, but there was less induction in the inferior colliculus under severe hypoxia. MAP-2 immunostaining of neuropiles in the inferior collicular nucleus was decreased slightly after severe-long hypoxia, but cytoplasmic staining did not change. The present ABR change, which was produced by brainstem hypoxia-ischemia and acidosis, may be due to the neural cytoarchitectural derangement and less induction of stress proteins in the upper brainstem.

Animals↗
PubMed1997

Recipient age determines the success of intraperitoneal transplantation of peritoneal cavity B cells.

In vivo studies of lymphocyte biology have used intravenous (i.v.) injection as the primary mode of cell transfer, a protocol consistent with the anatomic distribution of most lymphocytes. However, for study of peritoneal cavity B cells, i.v. injection does not correlate with anatomical localization. This report describes the restoration of B-cell function in B lymphocyte-defective X-chromosome-linked immune-defective (XID) mice after intraperitoneal transfer of immunoglobulin heavy chain (Igh)-disparate peritoneal cavity (PerC) cells. In contrast to i.v. transfer, intraperitoneal (i.p.) transfer restored B-cell function in young, but not adult (> 8 weeks), XID mice. When host and donor Igh allotype matched, PerC B-cell engraftment was noted in older recipients; this reconstitution however, was also age-dependent. Migration from the peritoneum to systemic circulation was necessary for serum IgM production as shown by the presence of donor antibody-secreting cells in the host spleen. Host lymphocytes also influenced the success of i.p. transplantation as severe combined immune-deficient mice, regardless of age, exhibited donor serum IgM production. Recipient age, Igh allotype, and immune-deficiency were found to have an impact on the ability of i.p.-transferred PerC B cells to restore B-cell function in XID mice.

Aging↗
PubMed1997

[Developmental dyslexia and dysgraphia--a case report].

We reported a 7-year-old, right-handed boy whose reading and writing of kana and kanji were impaired. He also showed a severe deficit in visuo-spatial perception skills. Nevertheless, his ability to read and write kana characters was facilitated by means of the Japanese Syllabaries. It is generally considered that the Syllabary involve two kinds of language modalities: auditory-verbal and visuo-verbal language systems. In spite of his intact auditory-verbal language system, his visuo-verbal language skills involved in writing kanji were severely impaired. It was suggested that a severe deficit of visuo-spatial perception skills influenced performance of visuo-verbal language systems. Accordingly, we inferred that the patient recalled a kana character by use of the Japanese Syllabaries based on his good auditory-verbal language system, and supposed that his reading and writing disorders were similar to alexia with agraphia in adult patients with angular lesions.

Agraphia↗
PubMed1997

[A semantic-pragmatic learning disabled child who showed a discrepancy between the abilities of verbal and non-verbal comprehension].

A learning disabled (LD) child with disorder of verbal semantic comprehension was reported. This case showed normal ability of non-verbal semantic comprehension. He was not able to understand the meaning of what he read aloud and/or repeated, which he did well. The focus of his brain dysfunction in the left temporal lobe was revealed by SPECT in spite of MRI findings of no particular lesions. Neuropsychological and cognitive-psychological findings were similar to those reported of adult sensory aphasias with localized lesions.

Child↗
PubMed1997

[A child showing memory disorders].

We report a girl with memory disorders. Her memory remained disturbed regardless of input or output modalities. She could recognize items and recall them randomly, but she could not recall them in the correct order. She showed memory impairment with regard to temporal context. We could clearly demonstrate this by cognitive psychological and neuropsychological tests and by analyzing the results of ordinary intelligence tests by input and output modalities. These results suggest that subjects who show memory disorders should undergo further resting to clarify the qualitative aspects of these disorders and the possibility that learning disabilities caused by memory disorders should be considered a specific type of learning disability.

Child↗
PubMed1997

[Mismatch negativity of patients with hydranencephaly].

We examined auditory evoked potentials and passive event-related potentials in two patients with hydranencephaly. In the middle latency response, a Na component was observed in both cases. Mismatch negativity was elicited in response to tone bursts and three patterns of vowel sounds in Patient 1, and three patterns of vowel stimuli in Patient 2. These results implicate the subcortical components of the auditory system in the generation of mismatch negativity.

Adolescent↗
PubMed1996

Degradation of T-kininogen by cathepsin D and matrix metalloproteinases.

Cathepsin D, matrix metalloproteinase (MMP)-2, MMP-3 (stromelysin), and MMP-9 were isolated from rat granulomatous tissues. HT1080 human fibrosarcoma cells and rheumatoid synovial cell CM. At acidic conditions, cathepsin D cleaved T-kininogen into small peptides and released Met-T-kinin-Leu (kinin precursor), but failed to release kinin. MMP-3 cleaved T-kininogen into a 57 kDa fragment as measured by SDS-PAGE and Western blot analysis using anti-T-kininogen antiserum. On the other hand, no degradation of T-kininogen occurred during incubation with MMP-2 or MMP-9100/1) at pH 7.5 for 7 h.

Cathepsin D↗
PubMed1996

Blink reflex in cerebral palsy: evaluation of late components in patients with normal auditory brainstem responses.

The electrically elicited blink reflex was examined and evaluated quantitatively in 60 controls and seven patients with cerebral palsy due to perinatal asphyxia who exhibited normal auditory brainstem responses. In the controls, the early component (R1) latency changed slightly from infancy to adulthood, and the late component (R2 and R2') latencies decreased to adult values by 4 to 6 years of age. The electromyographic activity of R2 and R2' increased later and became mature in the young adolescent period. Prolonged R2 latency and decreased R2 amplitude were observed more frequently than R1 abnormalities in the patients. The electromyographic activity of R2 in the patients was lower than that in control subjects more than 13 years old. Almost all patients showed bilateral cerebral atrophy and dilated lateral ventricles, but only one patient exhibited distinct pontine atrophy on cranial computed tomographic scan. These electrophysiologic abnormalities suggest that decreased excitability of interneurons of the reflex arc was present in the patients, particularly in older ones. The blink reflex test seems to be more sensitive than the auditory brainstem response for detecting brainstem dysfunction in patients with cerebral palsy due to neonatal asphyxia.

Adolescent↗
PubMed1996

Gallium alloy restorations in primary teeth: a 12-month study.

The authors placed 60 Class I and Class V restorations in the primary molars of children aged 4 to 10 years using a gallium alloy. Within one year after placement, the surfaces of all the restorations had deteriorated significantly due to corrosion, and the authors found remarkable amounts of corrosion products on restorations retrieved after tooth extraction or loss. The marginal integrity of many of the Class I restorations deteriorated slightly during the study; the Class V restorations showed no marginal breakdown. No other problems were detected after one year. These data indicate that the gallium alloy tested had insufficient resistance to corrosion to serve as a permanent restorative material. However, the authors suggest consideration of this alloy for use in primary teeth to reduce the exposure of children and dental professionals to mercury-containing amalgam.

Alloys↗
PubMed1996

[A specific disorder in Kanji writing in a learning disabled child with a visual cognition disorder--a cognitive-neuropsychological and electrophysiological analysis].

We reported a learning disabled child with a specific disorder involving Kanji writing. The patient was a 13-year-old boy. Although he manifested generally normal intellectual ability and his performance on WISC-R indicated that VIQ was 101 and PIQ 84, he could only write approximately 20% of Kanji, which he learned at age 6 to 7. On cognitive-psychological tests, he showed a visual cognition disorder that was different from that in a previously reported case during information processing. Electrophysiologically, he showed a disorder in visual task-relevant potentials. The mechanism underlying this patient appears to be a retrieval disorder for complex graphic forms in addition to a visual cognition disorder because of two reasons. One is that he could distinguish Kanji from similar graphic forms. The other is that he could read Kanji aloud.

Adolescent↗
PubMed1996

[Neonatal brain injury and evoked potentials].

Marked abnormalities in ABR at discharge from NICU can predict overall prognosis in patients with neonatal asphyxia. However, in patients with neonatal asphyxia as a single risk factor, the incidence of ABR abnormalities was low and ABR was not indicative of their long-term prognosis. Over the past 10 years, we encountered 13 patients with deterioration of ABR and progressive hearing impairment after discharge from NICU. All patients showed severe cardiorespiratory symptoms in the neonatal period. Nine of thirteen patients were diagnosed as persistent neonatal pulmonary hypertension. Multimodal evoked potential studies could predict life expectancy and functional state in patients with severe motor and intellectual impairment. These kind of neurophysiological test can show the patients' functional state at the time of the examination. Discrepancies in evoked potentials and clinical symptoms provide important information regarding the pathophysiology of the patients.

Asphyxia Neonatorum↗
PubMed1996

[Auditory perception in patients with multiple and severe handicaps: study of mismatch negativity to speech sounds].

We have found that the mismatch negativity (MMN) of event-related potentials (ERPs) to the tone burst sound is generated passively in some multiple and severe handicapped patients. This study investigated whether 10 patients with severe handicaps, whose auditory perception is hard to be evaluated clinically, exhibited MMN to the speech sound (SS). The stimuli included tone bursts of 700 and 1000 Hz in frequency, and 4 patterns of SS (1 phoneme: [a, ae], [a, o]; and 2 phonemes: [amo, ano], [ao, aka]) presented at an 85: 15 occurrence with 75 dBSPL. In the tone burst paradigm, 7 patients had a definite MMN wave followed by an N1 wave. However, a few patients showed MMN to some patterns of SS. The latency of MMN to SS was almost within normal limits. These results suggest that these patients could discriminate subtle differences of frequency in some speech sounds, although their auditory response to actual speech sounds were poor.

Adolescent↗