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Biomedical subjects

K Ibuki

Publications and source records attributed to K Ibuki.

At least 37 records · Page 2Linked to original sources
PubMed1996

Genomic and biological alteration of a human immunodeficiency virus type 1 (HIV-1)-simian immunodeficiency virus strain mac chimera, with HIV-1 Env, recovered from a long-term carrier monkey.

A macaque monkey infected with NM-3, a human immunodeficiency virus type 1 (HIV-1)-simian immunodeficiency virus strain mac (SIVmac) chimeric virus with env, rev, tat and vpu derived from HIV-1 and LTR, gag, pol, vif and vpx derived from SIVmac, became a long-term carrier (more than 2.8 years). This monkey produced neutralizing antibodies to the original NM-3 as well as to the parental HIV-1. The virus recovered at 116 weeks replicated more rapidly and productively in macaque peripheral blood mononuclear cells than the original virus. The recovered virus was not neutralized either by antibodies raised early in the monkey or by a neutralizing monoclonal antibody that recognizes the V3 loop of HIV-1 Env, whereas both the early antibodies and the monoclonal antibody neutralized the original NM-3. Analysis of the virus genomic population revealed a few common mutations in the V3 region that caused amino acid changes. These data are consistent with the hypothesis that the virus escaped from the early antibodies and that the observed mutations contributed to this, as with HIV-1-infected humans. The observed mutations could equally well be the result of adaptation to simian cells. These results suggest that the HIV-1-SIVmac chimeric virus will be useful for investigating genetic variation of HIV-1 env and alteration of biological properties in vivo in relation to the host immune response.

Amino Acid Sequence↗
PubMed1995

HTLV-I from Iranian Mashhadi Jews in Israel is phylogenetically related to that of Japan, India, and South America rather than to that of Africa and Melanesia.

A new endemic focus of human T-lymphotropic virus type I (HTLV-I) was recently reported among Mashhadi Jews, a group of immigrants from northeastern Iran to Israel. We extracted DNAs from fresh peripheral blood mononuclear cells (PBMCs) and/or gargle mouthwash from 10 HTLV-I carriers, who consisted of members of one family, and HTLV-I-associated myelopathy (HAM) and adult T-cell leukemia (ATL) patients. Long terminal repeat (LTR) regions of proviral DNAs were sequenced and analyzed phylogenetically. In a phylogenetic tree, all the Mashhadi HTLV-I isolates belonged to subtype A, one of the three subtypes of the cosmopolitan type of HTLV-I, and made a tight cluster distinct from the other isolates of subtype A from Japan, India, the Caribbean Basin, and South America. Although a few nucleotide substitutions were observed among the clones sequenced, no characteristic sequence variation was found in different disease manifestations, even in one family or different sources of DNA preparation.

Adult↗
PubMed1992

Infection of macaque monkeys with a chimeric human and simian immunodeficiency virus.

Two macaque monkeys were inoculated with a chimeric human and simian immunodeficiency virus carrying the tat, rev, vpu and env genes of human immunodeficiency virus type 1. Infectious virus was recovered from one of the monkeys at 2 and 6 weeks post-infection. The hybrid nature of the isolated viruses was verified by Southern and Western blotting analyses. Both of the monkeys infected with the chimera elicited a humoral antibody response against the virus.

Animals↗
PubMed1983

Visual training for velopharyngeal closure in cleft palate patients; a fibrescopic procedure (preliminary report).

Velopharyngeal closure in various tasks was examined in 59 cleft palate patients with persistent velopharyngeal incompetence using nasopharyngeal fibrescopic (NPF) examination. The degree of velopharyngeal closure was analyzed according to the categories reported previously by Yamaoka (1973) and Matsuya et al. (1979). The NPF self-training system was developed and applied to those patients so as to investigate a longitudinal effect of the NPF in velopharyngeal closure mechanism. The training was performed every two weeks for nearly one year. The results indicated that the patient who showed complete velopharyngeal closure during blowing and/or several productions of speech samples could attain a much better improvement in all speech samples after one year of self-training. On the other hand, the patients who did not show complete velopharyngeal closure during all tasks, failed to improve the velopharyngeal closing mechanism. The ability to close the velopharynx during swallowing was seen in all patients examined. However, it appeared to have nothing to do with the prognosis of velopharyngeal closure. The data suggested that the NPF self-training system provided a strong neuro-muscular signal for velopharyngeal movement. Besides, it was considered that the NPF was a useful tool for activation of velopharyngeal activity by way of visual feed-back control.

Adolescent↗
PubMed1983

Reliability of the nasopharyngeal fiberscope (NPF) for assessing velopharyngeal function.

Simultaneous side-view nasopharyngeal fiberscopic (NPF) and lateral cinefluoroscopic (cine) recordings were taken for two normal subjects to determine the stability of NPF placement for the study of velopharyngeal function, and the reliability and validity of NPF findings. The results indicate that the NPF was highly stable during the several velopharyngeal activities examined, the NPF tip maintaining a relatively constant relationship within the vertebral complex. Therefore, it seems likely that similar NPF views are obtained on different occasions with a subject. The findings also indicate that measurements can be made from NPF still photos for several aspects of the velopharyngeal mechanism. However, measurements of the left lateral wall movement were not reliable. Measurement of velar movement from NPF correlated well with cine measures of velar movement, indicating validity of that NPF measure.

Adult↗
PubMed1983

Reliability of the nasopharyngeal fiberscope (NPF) for assessing velopharyngeal function: analysis by judgment.

The reliability and validity of data about velopharyngeal function obtained with the nasopharyngeal fiberscope was assessed in normal subjects. The experimental design included data reduction procedures that are likely to have clinical utility (clinical ratings). The results indicated that relative velar movement and size of the velopharyngeal port may be reliably and validly estimated using the procedures. However NPF estimates of lateral pharyngeal wall movement were not reliable. Finally, the data indicated that velar movement and size of V-P port were consistent within subjects and tasks across data collection sessions. Data about consistency of lateral wall movement across sessions was inconclusive, however. Additional research involving similar procedures with subjects who have morphologic deficits is indicated.

Cineradiography↗
PubMed1981

Velopharyngeal closure in patients with facial paralysis: the fiberscopic examination of the velopharyngeal movements.

The present study was intended to clarify the role of the facial nerve in velopharyngeal movement and to determine the pathway of the facial nerve innervating the muscles related to velopharyngeal closure in man. Velopharyngeal function in 100 patients with idiopathic peripheral facial paralysis was analyzed using the nasopharyngeal fiberscope (NPF) and neuro-otological examinations. Lack of velopharyngeal closure was observed during Japanese isolated vowels and vowels in consonant-vowel (CV) syllables in patients with facial paralysis. Velopharyngeal opening was found in 85.7% of the subjects with suprastapedial paralysis and in 22.2% of those with infrastapedial paralysis. The facial nerve seemed to affect velopharyngeal movement, at least during vowel productions, through the greater petrosal nerve. Velopharyngeal closure in swallowing and blowing was always demonstrated. Hypernasality during connected speech was not heard in these patients.

Adolescent↗
PubMed1978

The course of facial nerve innervation for the levator veli palatini muscle.

The present study was designed to determine the motor nerve pathway of the facial nerve to the levator veli palatini muscle. The experiments were carried out on 10 anesthetized rhesus monkeys. Recorded and analyzed were evoked EMG responses of the levator veli palatini and the orbicularis oris muscles by electrical stimulation to both the facial nerve and its branch within the cranium. Muscle action potentials (M-waves) from the two muscles could be recognized on stimulating the facial nerve at the petrosal area of the temporal bone. On stimulating the greater petrosal nerve, M-waves from the levator muscle could be elicited. By cutting off the greater petrosal nerve at the middle cranial fossa, M-waves from the levator muscle completely disappeared on stimulating the facial nerve at the petrosal area. Results indicated that the course of the facial nerve for the levator veli palatini muscle is through the greater petrosal nerve.

Action Potentials↗
PubMed1976

Roles of the facial, glossopharyngeal and vagus nerves in velopharyngeal movement.

The present study was designed to clarify the role of the motor nerves in velopharyngeal movements. Experiments were carried out on 15 anesthetized rhesus monkeys on the assumption that their velopharyngeal structures are similar to those of human beings. The pattern and degree of velopharyngeal movements with stimulation to the facial, glossopharyngeal, and vagus nerves in the petrosal area were analyzed by means of fiberscopic observations. The results obtained were as follows: 1. Velopharyngeal movements were most active with stimulation to the vagus, then the glossopharyngeal, and, finally, the facial nerve. 2. Complete closure by unilateral stimulation was elicited only by the vagus nerve and not the facial or glossopharyngeal nerves. 3. The pattern of velopharyngeal movements observed when stimulating the facial nerve was quite different from those seen when the glossopharyngeal or the vagus nerve was stimulated. That is, movements in a plane at the upper part of the nasopharynx were observed on stimulating the facial nerve while upward movements from all of the velopharyngeal structures were seen when the glossopharyngeal or vagus nerve was stimulated. 4. Combined stimulation to the nerves sometimes resulted in additive effects on velopharyngeal movements, but these could be recognized in only a few cases. This study reveals that the motor nerves innervating the velopharyngeal muscles play different roles in velopharyngeal movements.

Animals↗