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Biomedical subjects

A Yasuhara

Publications and source records attributed to A Yasuhara.

At least 19 recordsLinked to original sources
PubMed1992

A case of deletion of the short arm of chromosome 10 with severe hearing loss and brainstem dysfunction.

A male newborn infant with a deletion of the short arm of chromosome 10p 14 was described. In addition to the typical clinical features, electrophysiologic studies showed brainstem dysfunction and severe hearing loss when examined with auditory brainstem response and photopalpebral reflex. These electrophysiologic studies may be of benefit for early evaluation of brainstem functions and hearing ability of the patients of such chromosomal aberration and may also be useful predictors of psychomotor development.

Abnormalities, Multiple↗
PubMed1992

Cerebral blood flow velocity and failure of autoregulation in neonates: their relation to outcome of birth asphyxia.

Using the continuous wave Doppler technique, we examined the pulsatility index (PI) of the anterior cerebral artery in 14 asphyxiated infants. We also measured the blood pressure (BP) and fontanel pressure (FP) and calculated the cerebral perfusion pressure (CPP). According to the neurological prognosis, we divided the 14 infants into two groups and studied correlation of each factor. In the good-prognosis group (n = 11), PIs are within normal limits. There is a negative correlation between BP, CPP and PI, suggesting that the autoregulation of cerebral blood flow has been lost. On the other hand, there is no significant correlation between BP, CPP and PI in the poor-prognosis group (n = 3). These infants are thought to have lost the autoregulation, but their cerebral blood flow is not pressure-passive. Not only BP but also brain edema, vasodilation, and possibly other factors may contribute to determine the cerebral blood flow. Concerning FP, no remarkable correlations are found between two groups. It is therefore very important to monitor the PI, BP, FP in asphyxiated infants even if the degree of asphyxia is mild.

Asphyxia Neonatorum↗
PubMed1992

[Statistical survey of multiple primary cancers of the head and neck].

The incidence and factors associated with multiple primary cancer were surveyed and analyzed from April 1978 through December 1990 in our clinic. Fifty-nine cases with multiple primary cancers were selected for study from among 579 cases with malignant head and neck region tumors. The cancers involved the larynx in 17 cases (8.4%), oral cavity in 14 (19.4%), oropharynx in 13 (41.9%), hypopharynx in 7 (8.0%) and nasal cavity or paranasal sinus in 7 (8.0%). Twenty-one cases (35.6%) arose synchronously within one year. From our observations, heavy drinking and smoking were most strongly suspected to be risk factors for induction of malignancy. Most multiple primary cancers in the head and neck region were observed to coexistent in a "so called multicentric zone" consisting of the oral area, pharyngeal area, larynx, esophagus, stomach, and tracheobronchial tree. To avoid overlooking concealed cancer in the multicentric zone, upper gastro-intestinal endoscopy, bronchial endoscopy, chest X-ray and sputum examination should be performed for screening of patients with head and neck malignancies.

Adult↗
PubMed1992

[A case of transfusion-associated GVHD after total laryngectomy].

We report a case of fatal transfusion-associated graft versus host disease (GVHD) that developed in a patient with laryngeal cancer. After a 39.6Gy irradiation dose, total laryngectomy with right radical neck dissection was performed. The postoperative course was uneventful. However, seven days after blood transfusion, high fever (38.5 degrees C) suddenly appeared. On the ninth day, watery diarrhea and facial erythema were observed. On the 12th day, liver disturbance and pancytopenia developed. The patient died on the 16th day because of overwhelming sepsis. Transfusion-associated GVHD has a mortality rate of more than 90%. Therefore, the most important procedure for preventing GVHD is the use of irradiated blood products. Furthermore unnecessary blood transfusion should be avoided.

Graft vs Host Disease↗
PubMed1992

Serial electrophysiological study on two infants with acute facial palsy.

Two infants with acute unilateral facial palsy were examined serially as to the electrically and mechanically elicited blink reflex, photo-evoked eyelid microvibration and auditory brainstem response (ABR). The results indicated that in hemifacial palsy beside the affection of the facial nerve also central pathways in the brainstem were involved in the pathogenetic processes. In particular, a neurapraxic change of the facial nerve itself in one case played an important role in pathogenesis, while a wide spread involvement was observed in another case. The clinical recovery of a patient with a wide spread involvement was more prolonged. We suggest that serial determinations of blink reflexes and ABR are helpful in clarifying the underlying pathogenetic processes concerning the brainstem affection during facial nerve palsy.

Blinking↗
PubMed1991

Recovery functions of fast frequency potentials in the initial negative wave of median SEP.

Following far-field potential of P14 after median nerve stimulation, we identified several small wavelets, designated here as fast frequency potentials or FFP, over the ascending and descending phases of the major negative wave of 'N20.' In 10 normal subjects who had well defined FFP, namely N16, N17, N18 and N19, we studied recovery functions of FFP by applying paired (condition and test) stimuli of various interstimulus intervals (ISIs) ranging from 3 to 150 msec. Recovery of FFP was determined by the difference wave forms, i.e., subtracting the response of conditioning stimuli from the response to paired stimuli. Measuring latencies and amplitude of FFP and also of the far-field potential of P14, we found recoveries of P14 and each FFP to be different; P14 recovered with the shortest ISI while progressively longer ISIs were required for full recovery of the later FFP. This finding suggests the existence of progressively increased number of interspersed synapses from the early to late FFP. It is unlikely that FFP represents passage of the afferent volley from one anatomical site to the next, but rather that they are cortically generated via a closely situated polysynaptic network. The polysynaptic nature of FFP is consistent with the observation that they disappear in sleep and also during anesthesia. The study indicates that FFPs represent different physioanatomical systems from the primary negative wave of 'N20' that results from specific sensory input to the primary sensory cortex.

Adolescent↗
PubMed1991

Mutagenicity of 3-nitrodibenzofuran and 3-aminodibenzofuran.

Mutagenicities of 3-nitrodibenzofuran and 3-aminodibenzofuran were examined using Salmonella typhimurium TA98 and TA100. Strong mutagenicity was found in both compounds. The mutagenic potency of 3-nitrodibenzofuran was approximately 3.5-fold stronger in TA98 and twice stronger in TA100 than that of benzo[a]pyrene. Mutagenicity of 3-aminodibenzofuran was observed under metabolic activation and was 10 times stronger in TA98 and about 5 times stronger in TA100 than that of benzo[a]pyrene.

Benzofurans↗
PubMed1991

Prediction of the prognosis in neonatal asphyxia by photo-evoked eyelid microvibration.

Neonatal asphyxia causes hypoxic-ischemic encephalopathy and may damage the central nervous system. We studied neonatal asphyxia with photo-evoked eyelid microvibration (PEMV) which is a blink reflex elicited by photic stimuli. The latency of PEMV changed according to the severity of encephalopathy and the degree of unconsciousness. All of the neonate who had showed disappearance of PEMV died. When the prolonged latency persisted, the infant had a strong probability of sustaining neurological sequelae. PEMV provides useful information for predicting the outcome of neonatal asphyxia.

Asphyxia Neonatorum↗
PubMed1990

Electrically and mechanically elicited blink reflexes in infants and children--maturation and recovery curves of blink reflex.

We studied the electrically and mechanically elicited blink reflexes in 2 groups of subjects, i.e., 237 newborn infants, 25-41 weeks of conceptional age, and 74 children, 1 month-12 years of age. In infants after 25 weeks of conceptional age we could usually induce the early response (R1) and ipsilateral late response (R2), while the contralateral late response (R2') of the electrical blink reflex became apparent after 33 weeks of conceptional age and the frequency of the appearance of R2' reached more than 60% after 38 weeks of conceptional age. After 7 months of age, R2' was usually observed. The R1 latency in full-term newborns was close to adult values, while the R2 and R2' latencies reached adult values at 7-12 years. After 1 year of age the latency of the R2 mechanical blink reflex had a tendency to be shorter than that of the electrical blink reflex. Under 35 weeks of conceptional age, the recovery curves of the blink reflex were considerably different from those of full-term infants, and premature infants showed little or no evidence of inhibition. These results indicate the absence of inhibitory interneurones in premature infants.

Blinking↗
PubMed1990

Auditory brain stem response in newborn infants--masking effect on ipsi- and contralateral recording.

Ipsilateral and contralateral auditory brain stem responses (ABR) were recorded in 10 full-term neonates. We investigated the effect of the masking level on the peak latency and amplitude on ipsi- and contralateral recordings. Clicks were presented at 85 dB HL to the ipsilateral ear and the masking white noise was presented at 75, 65, 55, 45 and 0 dB HL on the contralateral one, respectively. Masking had no significant effect on the ipsi- and contralateral recording in regard to latency and amplitude except for wave CVI (contralateral wave VI). In addition, ABR was recorded in an infant with total unilateral hearing loss. Crossover responses on both sides were observed with-out contralateral masking, but these responses were completely eliminated when 45 dB HL contralateral masking masked the 85 dB HL clicks to the dead ear. Therefore, it is suggested that such crossover responses will contribute to the ipsi- and contralaterally recorded ABR waveform when an ABR recording is carried out without contralateral masking. Our results indicate that contralateral masking is necessary and should be used in cases of unilateral hearing loss.

Audiometry, Evoked Response↗
PubMed1990

Lesch-Nyhan syndrome with delayed onset of self-mutilation: hyperactivity of interneurons at the brainstem and blink reflex.

We studied a case of Lesch-Nyhan syndrome with delayed onset of self-mutilation. Athetotic cerebral palsy and mental retardation were diagnosed at 1 year old, but the disease was not suspected until age 8 years when he began biting his lips and fingers. There was no obvious alteration of catecholamine in urine and CSF. We attempted to induce a series of blink reflexes by electric, mechanical and photic procedures. The R1 amplitude increased and the latency of the R2 shortened compared with controls. This shows that not only orbicularis motoneuron itself, but also uncrossed interneurons, are in a state of hyperexcitability. The contralateral R2 was poor which was in favour of hypoexcitability of the crossed interneurons at the brainstem. The significant large response was obtained by photic procedure which was in favour of hyperexcitability of the motoneurons. Therefore, it is demonstrated that a thorough examination of blink reflexes provides a useful method for examination of a state of the underlying neural activity.

Blinking↗
PubMed1990

Tap-induced blink reflex and central nervous system dysfunction in diabetics with hyperosmolality.

We studied the effect of hyperosmolality on the tap-induced blink reflex (TBR) in patients with diabetes. The TBR, consisting of R1 and R2 components, was either absent or delayed in patients compared to controls. The abnormalities correlated better with the degree of hyperosmolality than with the level of blood glucose. TBR was usually absent in unconscious patients with greatly elevated serum osmolality. In some patients with similar elevations in serum osmolality the R2' component was absent at a time when consciousness was preserved. Hence, TBR may be useful in monitoring CNS dysfunction in diabetics with hyperosmolality.

Adult↗
PubMed1990

Photo-evoked eyelid microvibration in neonates with hyperosmolality.

We studied neonates with hyperosmolar syndrome using photo-evoked eyelid microvibration, a blink reflex elicited by photic stimuli. Patients with hyperosmolality showed disturbance of consciousness, convulsive seizures, hyperexcitability, and tachypnea. The latency of photo-evoked eyelid microvibration tended to be prolonged with an elevation of the plasma osmolality. Photo-evoked eyelid microvibration is believed to be a suitable method for monitoring brain disturbance due to hyperosmolality.

Asphyxia Neonatorum↗
PubMed1989

Neonatal intracerebral teratoma.

A neonate, who presented with a large head but no neurological abnormalities, was diagnosed by ultrasound and CT scan as having a brain tumor. The pathological diagnosis was teratoma with matured tissues. The literature is briefly reviewed and the clinical manifestations and histological classification are documented.

Brain Neoplasms↗
PubMed1988

Auditory brainstem response in neonates--an attempt to reduce the number of stimuli.

We tried to shorten the ABR testing time by reducing the number of stimuli. There was no difference in both the wave form and latency of each wave between 256 times-averaged ABR and 1,024 times-averaged ABR. The total testing time, using 256 stimuli, was about 20 minutes shorter than the testing time using 1,024 stimuli.

Audiometry, Evoked Response↗