Biomedical subjects

M Kaga

Publications and source records attributed to M Kaga.

At least 37 records · Page 2Linked to original sources

PubMed2001

Mechanical ventilation care in severe childhood neurological disorders.

Forty-five patients underwent long-term life-sustaining mechanical ventilation care in the Child Neurology Ward, National Center Hospital for Mental, Nervous and Muscular Disorders from 1990 to 2000. Twenty patients had chronic respiratory insufficiency due to neuromuscular disorders, nine of whom underwent home mechanical ventilation care. Nineteen of the 45 patients had chronic respiratory insufficiency due to progressive central nervous system disorders, three of whom underwent home mechanical ventilation care. Six patients with chronic respiratory insufficiency due to the sequelae of transient events were on ventilation, two of whom underwent home mechanical ventilation care. In some patients, especially ones with neuromuscular disorders, mechanical ventilation care is very useful for improving their daily activity and quality of life. In other patients, however, mechanical ventilation care is merely a means of prolonging life without visible improvement of their quality of life. As medical resources are limited, home mechanical ventilation care is a recommended method for patients who need life-sustaining mechanical ventilation care. Considering an individual or social consensus, the indication of long-term life-sustaining mechanical ventilation care for chronic respiratory insufficiency due to severe childhood neurological disorders should be further discussed.

Adolescent↗

PubMed2001

An isolated and sporadic auditory neuropathy (auditory nerve disease): report of five patients.

Five patients of various ages with difficulty in speech discrimination were evaluated. All showed evidence of abnormal auditory brainstem responses (ABRs) beginning with the VIIIth cranial nerve. Broad summating potentials were evoked on their electrocochleograms (EcochGs) and they all exhibited almost normal cochlear outer hair cell function by otoacoustic emissions (OAEs) recordings. Behavioural audiometric testing revealed a mild to moderate elevation of pure-tone threshold in all patients. The shape of their pure-tone losses varied, being predominantly low-frequency in four patients (rising slope pattern) and flat across all frequencies in one patient. Speech intelligibility scores of all patients were poor and out of proportion to what would have been expected if threshold elevation of pure-tone was of cochlear origin (i.e. markedly poor scores on the speech audiogram with good scores on the auditory comprehension test). Patients were neurologically normal when the hearing impairment was first manifested. We suggest that this type of hearing impairment is due to an isolated and sporadic disorder of auditory nerve function. It occurs in isolation and does not seem to be part of a generalized neuropathological process.

Adolescent↗

PubMed2001

[Life-sustaining mechanical ventilation care for children with progressive or degenerative brain disorders].

In the past 10 years, we have treated 25 patients with chronic respiratory insufficiency due to a progressive or degenerative brain disorder. Ten patients died and the other 15 survived. Five of the former and 12 of the latter received life-sustaining mechanical ventilation care. Even in the terminal stage of progressive or degenerative brain disorders, patients can survive for a longer period than previously, if life-sustaining mechanical ventilation care is given. In Japan we do not have a guideline for medical indication or decision-making for children with progressive or degenerative brain disorders. Whenever we see such patients, we have great difficulty in making a decision. It may therefore be necessary to discuss whether we should have such a guideline.

Adolescent↗

PubMed2001

[A girl with chief compliance of "easy to forget"--cognitive neuropsychological evaluations and cerebral blood flow].

Cognitive-neuropsychological evaluations were performed on a 12-year-old girl with memory disorder to study the higher brain function of this patient. The cerebral blood flow (r-CBF) was also studied. The results showed that the auditory-verbal memory of this patient were impaired. The regional cerebral blood flow was reduced in the left hippocampus which reportedly cause memory disorder. The disturbance of visual cognition and disability of construction in this patient seem to be related to reduced cerebral blood flow in the left parietal region.

Cerebrovascular Circulation↗

PubMed2001

[Three cases of Costello syndrome presenting with intractable epilepsy and profound psychomotor retardation/regression].

We report three cases of Costello syndrome (CS) presenting with intractable epilepsy and profound psychomotor retardation/regression. Previous reports on CS described mild to moderate psychomotor retardation, and epilepsy in only 8% of the cases. The details of these neurological complications have not been reported so far. All the present cases had intractable epilepsies and profound psychomotor retardation/regression. Two of them had symptomatic localization-related epilepsies and the other had Lennox-Gastaut syndrome following West syndrome. Unusual complication of profound psychomotor retardation/regression in our cases seems to be caused by intractable epilepsy. It should be noted that CS patients with epilepsy may have more severe central nervous symptoms than those previously reported.

Abnormalities, Multiple↗

PubMed2001

Resin-tooth adhesive interfaces after long-term function.

PURPOSE: To characterize with scanning electron microscopy (SEM), the morphology of adhesive interfaces that had been functioning in an oral cavity for several years. MATERIALS AND METHODS: Cavities were prepared in vivo in caries-affected primary molars under local anesthesia. After removal of the entire carious lesion, the cavity was restored with a dentin adhesive system (Scotchbond Multi-Purpose). After several yrs, as the successor permanent teeth erupted, the resin-filled teeth were extracted. Then, the extracted resin-restored primary molars were cross-sectioned perpendicular to the adhesive interface using a low speed diamond saw and then polished for SEM examination. RESULTS: Morphological changes, such as digestion of the collagen fibrils and deterioration of the bonding resin and hybrid layer, were observed at the interface of the oral environment specimens. The results of this study demonstrated that degradation of resin-dentin bond structures appeared to occur in the human oral environment over time.

Child↗

PubMed2001

Fractographical analysis of resin-dentin bonds.

PURPOSE: To characterize resin-dentin bond structures of three adhesive resin systems using fractographic analysis to measure the area of failure at the fractured surface. MATERIALS AND METHODS: Flat dentin surfaces were ground perpendicular to the long axis of the tooth. The prepared dentin surfaces were treated by one of three adhesive resin systems (Mac Bond II, One-Step, and Single Bond). The samples were sectioned perpendicular to the adhesive interface to produce a square bar-shaped specimen (adhesive area: 0.9 mm2) using a diamond saw. A micro-tensile test was then conducted at a crosshead speed of 1.0 mm/min. The mean tensile bond strengths were statistically compared using one-way ANOVA and Fisher's PLSD test (P< 0.05). The fractured surfaces of all specimens were examined using SEM and the area of failure was measured using an image analyzer on SEM microphotographs. RESULTS: No significant differences in tensile bond strength were observed between Single Bond (62.1+/-18.2 MPa) and One-Step (53.8+/-13.1 MPa) (P > 0.05). However, the bond strength of Mac Bond II (36.5+/-13.7 MPa) was significantly lower than that of One-Step or Single Bond (P< 0.05). At the fractured surface, except for the cohesive failure of the bonding resin and resin-based composite, different failure patterns were observed for each resin system as follows: the failure of the hybrid layer and demineralized dentin was observed in the two wet bonding systems (One-Step and Single Bond) and of the hybrid layer but not the demineralized dentin in the self-etching primer system (Mac Bond II). The results demonstrated that the integrity of the hybrid layer depends on the adhesive system.

Analysis of Variance↗

PubMed2000

The effect of hybrid layer thickness on bond strength: demineralized dentin zone of the hybrid layer.

OBJECTIVES: The purpose of this study was to evaluate the correlation between hybrid layer thickness and bond strength using specimens acid-conditioned for varying lengths of time. METHODS: The dentin surfaces of human premolars, sectioned to remove the enamel from the labial surface, were conditioned with 35.0% phosphoric acid of an adhesive resin system (Scotchbond Multi-Purpose; 3M) for 15 (as directed by the manufacturer), 60, 120, or 180 s (experimental acid-conditioning times). The bonded specimens were then sectioned perpendicular to the adhesive interface to measure the hybrid layer thickness by SEM. The specimens for the micro-tensile test were sectioned perpendicular to the adhesive interface and trimmed to an hourglass-shape. Then, the micro-tensile test was performed at a crosshead speed of 1.0 mm/min. The bond strengths and hybrid layer thickness were statistically compared with Student's t-test (p < 0.05). All fractured surfaces were also observed by SEM. RESULTS: Significant differences between the groups exposed to acid for 15 and 60 s, and those exposed for 120 and 180 s were observed in hybrid layer thickness and bond strength (p < 0.05). SEM observation of the fractured surfaces revealed that a demineralized dentin zone without resin impregnation remained within the hybrid layer. SIGNIFICANCE: A demineralized dentin zone was formed in the bond structures after prolonged acid-conditioning, resulting in low bond strength. The shrinkage of the hybrid layer due to desiccation during the SEM examination process provided evidence of the presence of the demineralized dentin zone within the hybrid layer.

Acid Etching, Dental↗

PubMed2000

Otoacoustic emission in patients with neurological disorders who have auditory brainstem response abnormality.

Otoacoustic emissions (OAEs) were evaluated in 51 ears of 30 patients with a severe auditory brainstem response (ABR) waveform abnormality. Thirteen ears showed no ABR to click sound of higher intensity than 100 dBSPL (group 1). Fourteen ears exhibited only wave V or a decreased amplitude pattern of ABR (group 2). Twenty-four ears showed a predominant wave I or no wave III pattern (group 3). Almost all the ears with absent ABR showed no OAE, which strongly suggested hearing loss of cochlear origin, although one patient with alternating hemiplegia of childhood exhibited definite OAEs and auditory reactions without ABR. One patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) and her mother in group 2 had OAE abnormalities, which also suggested mild to severe hearing impairment. When OAEs are present, an accompanying ABR abnormality may be produced by brainstem dysfunction of the underlying disorder such as Pelizaeus-Merzbacher disease. There was a significant relationship (chi-square test P<0.001) between the positivity of the distortion product OAE response and the clinical auditory reactions in 24 patients, although their ABR abnormalities did not reflect hearing impairment directly. Careful examination of both audiometry and OAEs might be necessary for further assessment of the hearing function in pediatric patients with neurological disorders and specific auditory nerve disease.

Acoustic Stimulation↗

PubMed2000

Developmental changes of distortion product and transient evoked otoacoustic emissions in different age groups.

The developmental changes of distortion product otoacoustic emissions (DPOAEs) and transient evoked otoacoustic emissions (TEOAEs) were evaluated in 275 normal subjects aged from 1 month to 39 years. The DP-grams showed an M-shaped pattern with peaks at 1587 Hz and 5042 Hz for all age groups. In subjects younger than 3 years, low frequency DPOAEs did not rise above the noise floor. The DP levels at high frequency (5042 Hz) did not change much from infancy to young adulthood (12.9-16.5 dB SPL), however, those at low and middle frequency significantly decreased with age. Total echo power (TEP) of TEOAE was greatest in early infancy, decreased rapidly before 6-7 years old, and then decreased gradually (TEP = 16.6 - 1.9 X ln (age)). Wave reproducibility was constant across age. The frequency area peak power (FAPP) to middle and high frequency sounds changed little with age, however, FAPP at low frequency sounds dramatically increased with age. FAPP at 5000 Hz was relatively depressed levels at each age. The TEOAE value was more prominent at middle and low frequencies while DPOAE was predominant at high frequencies. These two measurements may reflect different functions of outer hair cells in the developing cochlea.

Adolescent↗

PubMed2000

Cerebral cortical dysplasia: assessment by MRI and SPECT.

The objective of this study was to establish correlations between image findings and pathologic deficits in patients with cerebral cortical malformations. The results of magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) in addition to clinical data for 15 patients with cerebral cortical malformations were reviewed retrospectively. MRI led to the diagnoses of bilateral perisylvian syndrome, hemimegalencephaly, focal polymicrogyria, band-heterotopia, and focal cortical dysplasia (FCD). Interictal SPECT did not reveal hypoperfusion in any case of polymicrogyria. Ictal SPECT images revealed hyperperfusion of the lesion in three patients with polymicrogyria, with accompanying hyperperfusion of the basal ganglia in two of the three patients. On the other hand, interictal SPECT images demonstrated hypoperfusion of the lesion in four patients with FCD. Ictal SPECT images revealed hypoperfusion of the lesion in two patients, hyperperfusion of the lesion in one patient, and hypoperfusion of the basal ganglia in two patients with FCD. This difference in perfusion between polymicrogyria and FCD observed in this study may reflect histologically different characteristics. This relative hyperperfusion of the cortex and the basal ganglia observed on ictal SPECT, which was found in two polymicrogyria patients with complex partial seizures and partial seizures evolving to secondary generalized seizures, respectively, suggests that the cortical-subcortical interaction is related to the mechanism of loss of consciousness or seizure generation.

Adolescent↗

PubMed2000

In vivo degradation of resin-dentin bonds in humans over 1 to 3 years.

The longevity of resin restorations is currently an area of great interest in adhesive dentistry. However, no work has been conducted to investigate the durability of resin-dentin bond structures using human substrate in vivo. The purpose of this study was to investigate the degradation of the resin-dentin bond structures aged in an oral environment for 1, 2, or 3 years. Cavities were prepared in primary molars, and an adhesive resin system (Scotchbond Multi-Purpose) was applied to the cavity. After 1 to 3 years, following the eruption of the succedaneous permanent teeth, the resin-restored teeth were extracted. Immediately after extraction, those teeth were sectioned perpendicular to the adhesive interface and trimmed to produce an hourglass-shaped specimen. Then, a micro-tensile test was performed at a crosshead speed of 1.0 mm/min. The mean bond strengths were statistically compared with one-way ANOVA and Fisher's PLSD test (p < 0.05). Further, all fractured surfaces were observed by SEM, and the area fraction of failure mode was calculated by means of a digital analyzer on SEM photomicrographs. There were significant differences in tensile-bond strength among all 3 groups (p < 0.05), with mean values ranging from 28.3 +/- 11.3 MPa (control), to 15.2 +/- 4.4 MPa (1 to 2 years), to 9.1 +/- 5.1 MPa (2 to 3 years). Moreover, under fractographic analysis, the proportion of demineralized dentin at the fractured surface in specimens aged in an oral environment was greater than that in control specimens. Furthermore, degradation of resin composite and the depletion of collagen fibrils was observed among the specimens aged in an oral environment. Analysis of the results of this study indicated that the degradation of resin-dentin bond structures occurs after aging in the oral cavity.

Adhesives↗

PubMed2000

Long-term follow-up of auditory agnosia as a sequel of herpes encephalitis in a child.

We report a pediatric patient with auditory agnosia as a sequel of herpes encephalitis. His early development was completely normal. He uttered three words at 12 months old. Disease onset was 1 year and 2 months of age. He was discharged from the hospital seemingly with no sequel; however, he could not recover his intelligible words even at age 2 years. He was diagnosed as having auditory agnosia caused by bilateral temporal lobe injury. We began to train him at once, individually and intensively. Adult patients with pure auditory agnosia followed by two episodes of temporal lobe infarction have impairment in central hearing but not inner language. Therefore, they can communicate by reading and writing. Moreover, impairment in hearing is not always severe and is often transient. However, despite long-term (more than 15 years) energetic education and almost normal intellectual ability (Performance IQ of Wechsler Intelligence Scale for Children-Revised was 91), our patient's language ability was extremely poor. Cerebral plasticity could not work fully on our patient, whose bilateral temporal lobe was severely injured in early childhood. The establishment of a systematic training method in such patients is an urgent objective in this field.

Adolescent↗

PubMed2000

Semantic category discrimination and N400.

14 subjects performed a semantic category-discrimination task in which they were presented pairs of words and asked to judge whether these belonged to the same category. Three semantic distance conditions, established for the word pairs on the basis of a survey, were semantically close condition (mammals and birds condition) and two semantically distant conditions (mammals and tools condition and birds and tools condition). The reaction times and the percentage of errors were significantly greatest for the mammals and bird condition. There were no significant differences among the three different conditions in N400 latency for target, but the amplitude of N400 tended to be largest for the mammal and bird condition. Comparison N400 of prime and target for each of the conditions showed that the latency for prime was longer than for target in all three conditions.

Adult↗

PubMed1999

Detection of Mycoplasma fermentans in saliva sampled from infants, preschool and school children, adolescents and adults by a polymerase chain reaction-based assay.

Attempts were made to detect Mycoplasma fermentans in saliva sampled from 201 subjects (108 males and 93 females) aged from 4 months to 59 years by a polymerase chain reaction-based assay. M. fermentans was detected in saliva from 110 (54.7%) of 201 subjects, and 10 (28.6%) of 35 subjects aged from 4 months to 3 years. Of ten positive subjects, three were aged from 16 to 23 months and five were from 26 to 31 months. The incidence tended to increase with age up to the teens. The incidence was significantly greater in teenagers than in subjects aged from 7 to 12 years, but there was no significant difference in the incidence between the group of teenagers and each of the groups of subjects older than the teenagers. Thus, it was suggested that M. fermentans colonized the mouth at the age of about 16 months up to the age of 19 years.

Adolescent↗

PubMed1999

Language disorders in Landau-Kleffner syndrome.

In the present long-term study, we analyzed language disorders in four patients with Landau-Kleffner syndrome. Their common first symptoms were disability in understanding spoken words, followed by inarticulation and a decreased amount of speech. All patients showed auditory verbal agnosia to some degree at some stage of their illness. However, one patient showed typical sensory aphasia as the first symptom, and another patient showed nonverbal auditory agnosia followed by pure word deafness. Thus, patients with Landau-Kleffner syndrome show sequential and sometimes hierarchical language disorders beginning with sensory aphasia, followed by auditory agnosia, and finally word deafness during their disease process. During long-term follow-up (20 to 30 years), all patients showed marked recovery in language without any intellectual handicap, but with some disability in spoken language, auditory verbal perception, and a discrepancy between Wechsler Verbal and Performance IQ scores.

Adult↗

PubMed1999

The value of serial auditory brainstem response in patients with subacute sclerosing panencephalitis.

A total of 98 serial auditory brainstem responses from 17 patients (11 boys and 6 girls) with subacute sclerosing panencephalitis were compared with their clinical course and stages. These patients were exposed to measles early in life (at 1.8 +/- 1.4 years old) with the average onset of the disease at 8.8 +/- 0.7 years of age. The main abnormalities of their auditory brainstem responses were a prolongation of waves I, III, and V, and of the I to V interpeak interval. Wave V thresholds were also elevated. These effects on the auditory brainstem responses started 1 to 2 years after onset of neurologic signs. I to V interpeak latency became prolonged with the progress of clinical stages, especially in Jabbour's clinically advanced stage IV. In two patients with an acute progressive type of subacute sclerosing panencephalitis, very rapid deterioration with a distorted wave pattern of later components was observed. These findings suggest rostrocaudal progression in the central nervous system of both long-term and fulminant cases.

Acute Disease↗

PubMed1999

[Mental health of families caring for people with developmental disabilities: the present situation and strategies for improvement].

The authors assessed the status of mental health of families caring for relatives with developmental disabilities and neurological diseases. They were caring for their children in good morale, however, "burnouts" or neurotic conditions were more frequent in these families than in the medical staffs, the latter being studied in our previous researches. Mentally healthy persons consulted their spouse about their children as well as other things, and received his/her assistance in daily care. Families helped by unrelated persons were in better mental state. Families who had utilized inpatient care before entering a school had higher expectations from their surroundings. Therefore, medical services should provide support to such families to help improve their mental health.

Adult↗