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T Nara

Publications and source records attributed to T Nara.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Topography, size and number of cortical tubers in tuberous sclerosis with West syndrome].

To predict the prognosis of tuberous sclerosis with West syndrome, we studied the relation between the cortical tubers and the neurological evolution. We reviewed the clinical data on the seizure evolution and developmental status of 7 patients (3 males and 4 females) and estimated the number, size and location of cortical tubers on 5 mm-thick T2-weighted MR images. The cortical tubers were grouped into categories: small (10 mm or less in maximum diameter), medium (10 to 25 mm) and large (25 mm or more). The first MRI study was performed at ages form 3 months to 18 years, and the follow-up study was performed on 6 out of the 7 patients. We also estimated the interval change of cortical tubers. The average number of cortical tubers was 12.1 per patient, being larger than the values previously reported for the patients of tuberous sclerosis without West syndrome. However, the numbers varied widely from 1 to 29. Two patients with good outcome had more than 10 tubers, whereas two patients with poor outcome had less than 5 tubers. All the patients with good outcome were female. Follow-up MRI in one patient revealed a marked increase in the number of cortical tubers, from 15 (at the age of 5 months) to 23 (at 4 years 2 months), which probably resulted from physiological hypomyelination during infancy. Some tubers corresponded to a electroencephalographic focus, whereas others did not. There was no difference in the topography of cortical tubers between the patients with good prognosis and those with poor prognosis. Thus, it was hard to make the prognosticate a case of tuberous sclerosis based solely on the number and topography of cortical tubers on MRI.

Cerebral Cortex↗
PubMed1997

Ultrasonographic analysis of sucking behavior of newborn infants: the driving force of sucking pressure.

The sucking behaviors of 15 low-risk full-term newborns were observed with ultrasonography and a special device directly measuring sucking pressure. In this study, the sequential changes in the movement of a tongue and other intra-oral structures and the sequential changes of the sucking pressure were successfully examined simultaneously. It was indicated that sucking pressure could be generated by sequential changes of an intra-oral volume caused by a peristalsis of the tongue in the sucking behavior.

Female↗
PubMed1997

Development of the human principal sensory trigeminal nucleus: a morphometric analysis.

The anatomical development of the principal sensory trigeminal nucleus was assessed with morphometric features using serial celloidin sections of 15 human brains, including 12 brains obtained from fetuses and neonates. A microscope and an optical electronic planimeter combined with a computer were employed for morphometric measurements of columnar areas, neuronal numbers, neuronal areas and neuronal perimeters to statistically analyze and evaluate the development of neuronal densities, neuropil indexes and circularity ratios. We could not detect the principal sensory trigeminal nucleus in the specimen of 12 gestational weeks (GW). Microscopic observation disclosed that the fetal principal sensory trigeminal neurons approached those of the adult around 33 GW in terms of cell arrangements, amounts of Nissl bodies and morphology of neurons. Our morphometric analysis showed that the columnar volume, the neuronal area and the neuropil index increased with gestational age. The neuronal density decreased with gestational age, especially from 16 to 32 GW. Comparing the neuronal area with the columnar volume, it developed before the columnar volume during the fetal period. The neurons of the principal sensory trigeminal nucleus matured around 33 GW under microscopic observation and in terms of the distribution of neuronal areas. The development of the neuropil may accelerate after individual neurons of principal sensory trigeminal nucleus mature.

Adolescent↗
PubMed1997

Light and electron microscopic investigation of the process of healing of the naevus of Ota by Q-switched alexandrite laser irradiation.

Melanocytes in the naevus of Ota were destroyed by irradiation using the Q-switched alexandrite laser. This laser is highly selective and highly absorbed by melanosomes. Other cells and tissue components of the dermis remained almost intact. Melanosomes were vaporized or fragmented to subelectron microscopical size, or degenerated. If the irradiated energy was sufficient, melanocytes vanished and large vacuoles several times the size of dermal melanocytes formed at the sites. If it was too weak, dermal melanocytes were also vaporized, but vacuoles formed within them. Nuclei were no longer discernible. Following irradiation macrophages infiltrated the irradiated areas and scavenged degenerated melanosomes and cellular debris. Thus, discoloration of the skin was markedly reduced. Although a few melanocytes and melanophages remained, pigmentation cleared to a satisfactory level. Melanocytes and keratinocytes were also injured in the epidermis; however, the epidermis recovered completely. No scarring was observed.

Adolescent↗
PubMed1997

The B cell epitope of paramyosin recognized by a protective monoclonal IgE antibody to Schistosoma japonicum.

Passive immunization of mice with a monoclonal IgE antibody to Schistosoma japonicum (SJ18 epsilon. 1) induces significant protection to a challenge infection and the target molecule of SJ18 epsilon. 1 is paramyosin. In the present study, we demonstrate the B cell epitope of paramyosin recognized by SJ18 epsilon. 1 by using a series of deletion mutants expressed in Escherichia coli. SJ18 epsilon 1 reacted with the recombinant paramyosin containing 113 amino acids (Glu301. Ala413) but not with a shorter peptide (Glu301-Asp343). Further epitope mapping carried out by a multi-pin system using heptameric peptides synthesized sequentially from 71 amino acids of paramyosin (Asp343-Ala413) demonstrated significant binding of SJ18 epsilon. 1 to the sequence, 359Ile-Arg-Arg-Ala362. Replacement set analysis of the pentameric peptide, 358Leu-Ile-Arg-Arg-Ala362, revealed that replacement of each residue with a hydrophobic or hydrophilic amino acid did not inhibit binding of SJ18 epsilon. 1, whereas replacement of positively charged Arg. or hydrophobic Ala with a negatively charged amino acid, Glu, showed reduction in binding of the antibody. Moreover, replacement of each amino acid including Arg with a positively charged amino acid, Lys, resulted in a drastic loss of the binding, indicating that binding of the antibody was markedly affected by the change of charges of the peptide as well as by the conformational alteration. The target epitope of SJ18 epsilon. 1 was common among paramyosins of S. mansoni, Taenia solium and Echinococcus granulosus but not among nematode paramyosins, suggesting that the epitope is specific for platyhelminthes.

Amino Acid Sequence↗
PubMed1997

Drug extrusion in Corynebacterium glutamicum.

We selected a mutant of Corynebacterium glutamicum, EBR, which can grow in a medium containing cytotoxic ethidium bromide (EtBr) at a high concentration of 100 microM. The resistance to EtBr in the mutant was reversed by 2 microM reserpine, a potent inhibitor of mammalian p-glycoprotein and bacterial multidrug resistance (MDR) transporter, whereas reserpine alone had a minimal effect on cell growth. The mutant showed a much higher efflux rate of EtBr than wild-type cells, and the efflux was completely inhibited by 2 microM reserpine. In addition to reserpine, structurally unrelated chemicals such as quinidine, trifluorperazine, tetraphenylarsonium chloride, chlorpromazine and quinine inhibit the EtBr efflux, revealing that the putative efflux system(s) can recognize a variety of chemicals. The efflux activity was correlated with the membrane potential but not the intracellular ATP contents. We, therefore, concluded that the EtBr resistance may be involved by proton-motive-force driven multidrug efflux system(s).

Adenosine Triphosphate↗
PubMed1997

Thermosensing properties of mutant aspartate chemoreceptors with methyl-accepting sites replaced singly or multiply by alanine.

The aspartate chemoreceptor Tar has a thermosensing function that is modulated by covalent modification of its four methylation sites (Gln295, Glu302, Gln309, and Glu491). Without posttranslational deamidation, Tar has no thermosensing ability. When Gln295 and Gln309 are deamidated to Glu, the unmethylated and heavily methylated forms function as warm and cold sensors, respectively. In this study, we carried out alanine-scanning mutagenesis of the methylation sites. Although alanine substitutions influenced the signaling bias and the methylation level, all of the mutants retained aspartate-sensing function. Those with single substitutions had almost normal thermosensing properties, indicating that substitutions at any particular methylation site do not seriously impair thermosensing function. In the posttranslational modification-defective background, some of the alanine substitutions restored thermosensing ability. Warm sensors were found among mutants retaining two glutamate residues, and cold sensors were found among those with one or no glutamate residue. This result suggests that the negative charge at the methylation sites is one factor that determines thermosensor phenotypes, although the size and shape of the side chain may also be important. The warm, cold, and null thermosensor phenotypes were clearly differentiated, and no intermediate phenotypes were found. Thus, the different thermosensing phenotypes that result from covalent modification of the methylation sites may reflect distinct structural states. Broader implications for the thermosensing mechanism are also discussed.

Alanine↗
PubMed1997

Comparative studies on schistosomulicidal activity of mouse and rat eosinophils.

Eosinophils from interleukin (IL)-5 transgenic mice were shown to have antibody-dependent killing activity against the larvae of Schistosoma japonicum. However, in comparison with rat eosinophils, the schistosomulicidal activity of mouse eosinophils was lower. Flow cytometric analysis of the cells binding to mouse immunoglobulins demonstrated that rat cells were superior to mouse cells in the binding of mouse IgG. However, the adherence and schistosomulicidal activity of mouse cells were inhibited by rat anti-mouse Fcgamma receptor monoclonal antibody. These results suggest that the mechanism of killing by mouse eosinophils is mediated by IgG antibodies.

Animals↗
PubMed1997

Rapid enlargement of cardiac rhabdomyoma during corticotropin therapy for infantile spasms.

OBJECTIVE: To investigate the influence of corticotropin therapy on cardiac rhabdomyoma. DESIGN: Analysis of data from echocardiography performed on in-patients. PATIENTS: Six patients with rhabdomyoma who were admitted to the authors' medical centre with either convulsion (five cases) or prematurity (one case) between 1985 and 1995. Five had tuberous sclerosis. INTERVENTION: Size of cardiac tumours of each patient was measured by echocardiography, and volume index was calculated as the ratio of the tumour volume to its initial volume. MAIN RESULT: Increase in size of some of the tumours was found during corticotropin therapy on follow-up echocardiography. Maximum volume indexes of tumours in the case of patients (n = 4) who did not receive corticotropin therapy was 1.2 to 3.7, whereas those of patients (n = 2) who received therapy was 9.1 to 12; one of the latter patients died. CONCLUSION: Corticotropin may contribute to the enlargement of cardiac rhabdomyoma. The size of cardiac rhabdomyomas must be carefully followed when patients are treated with corticotropin.

Adrenocorticotropic Hormone↗
PubMed1997

[A case of PEHO (progressive encephalopathy with edema, hypsarrhythmia and optic atrophy) syndrome: changes in clinical and neuroradiological findings].

We reported serial clinical, radiological, and neurophysiological findings of a patient with PEHO (progressive encephalopathy with edema, hypsarrhythmia and optic atrophy) syndrome. The case was a 4-year-and-8-month-old boy. He had no apparent problems during pregnancy, but after his birth severe hypotonia and developmental delay were evident. Infantile spasms appeared at 3 months of age, and progressive opisthotonic posture and loss of his visual acuity at 8 months. Eye fixation was lost, and optic atrophy was observed. Seizures and progressive atrophy of the cerebellum and brainstem developed during the same period. These findings of our case support the hypothesis that brainstem lesions are related to infantile spasms.

Brain Diseases↗
PubMed1997

[Fulminant subacute sclerosing panencephalitis: clinical and neuropathological observations].

We describe a 3-year-old boy with subacute sclerosing panencephalitis (SSPE) who died 4 months after its onset. His initial symptoms were drowsiness and left hemiplegia. He became comatose in 10 days, and developed a decortical posture after 45 days. He suffered from multiple cerebral hemorrhage and infarction 3 months later. Oligodendrocytes were positively stained by immunocytochemical stain with a complement-fixing measles antibody. Light microscopy revealed glial nodules, perivascular cuffing and reactive gliosis. Small arteries showed intimal thickening with resultant occlusion and occasional recanalization. These findings suggested vascular involvement in SSPE. This case illustrates the difference between the fulminant and chronic forms of SSPE.

Brain↗
PubMed1996

Interstitial duplication 8q22-q24: report of a case proven by FISH with mapped cosmid probes.

We report on a 6-month-old malformed female infant with a de novo interstitial duplication of an 8q22-q24 segment. She had an excess dark-band on the 8q distal region by GTG-banded chromosome analysis, which was likely to be 8q23. We performed FISH analysis using cosmid probes mapped to 8q23 and proved that the patient had an 8q duplication including the 8q23 region.

Chromosome Banding↗
PubMed1996

Modulation of the thermosensing profile of the Escherichia coli aspartate receptor tar by covalent modification of its methyl-accepting sites.

The Escherichia coli aspartate receptor Tar is involved in the thermotactic response. We have studied how its thermosensing function is affected by the modification of the four methyl-accepting residues (Gln295, Glu302, Gln309, and Glu491), which play essential roles in adaptation. We found that the primary translational product of tar mediates a chemoresponse, but not a thermoresponse, and that Tar comes to function as a thermoreceptor, once Gln295 or Gln309 is deamidated. This is the first identification of a thermosensing-specific mutant form, suggesting that the methylation sites of Tar constitute at least a part of the region required for thermoreception, signaling, or both. We have also investigated the inverted thermoresponse mediated by Tar in the presence of aspartate. We found that, whereas the deamidated-and-unmethylated form functions as a warm receptor, eliciting a smooth-swimming signal upon increase of temperature, the heavily methylated form functions as a cold receptor, eliciting a smooth-swimming signal upon decrease of temperature. Thus, it is suggested that Tar exists in at least three distinct states, each of which allows it to function as a warm, cold, or null thermoreceptor, depending on the modification patterns of its methylation sites.

Bacterial Proteins↗
PubMed1996

Rhodamine 123 efflux transporter in Haloferax volcanii is induced when cultured under 'metabolic stress' by amino acids: the efflux system resembles that in a doxorubicin-resistant mutant.

In this paper, we report that an archaebacterium, Haloferax volcanii, cultured in medium containing a large excess of amino acids showed very low levels of rhodamine 123 (RH123), which is a potent substrate for P-glycoprotein and the bacterial multidrug efflux transporter. This low level involved the active efflux of RH123 from the cells. The level of intracellular RH123 was increased and the efflux inhibited by the Ca2+-channel antagonist verapamil and also by various anti-cancer drugs. The efflux transporter was suggested to be ATP-driven. We have previously selected a mutant of H. volcanii with resistance to doxorubicin, by repeatedly culturing cells in 1.5 microM doxorubicin [Miyauchi, Komatsubara and Kamo (1992) Biochim. Biophys. Acta 1110, 144-150]. The acquisition of resistance to doxorubicin involves the active expulsion of lipophilic drugs such as RH123 and doxorubicin. It is notable that the drug spectrum and ATP-dependency of the amino acid-induced efflux transporter resemble those of the efflux transporter induced by doxorubicin.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

[MRI findings of anterior spinal artery syndrome in childhood].

We reported two cases of anterior spinal artery syndrome in childhood evaluated by MRI of the spinal cord. The T2-weighted MRI revealed high signal intensity in the anterior region of spinal cord in both cases. These findings might be related with edema of the ischemic region. Several years later, the regions of the spinal cord showed atrophic changes. The high signal intensity on the T2-weighted MRI was characteristic of the anterior spinal artery syndrome.

Arteries↗
PubMed1995

Muscle and intramuscular nerve pathology in congenital hypomyelination neuropathy.

Two patients had delayed development and generalized muscle hypotonia and weakness since early infancy. Their muscle biopsies showed slight variation in fiber size without group atrophy, and no clear evidence of an active demyelinating process in the intramuscular nerves. The most striking finding by light microscopy was the absence of myelinated fibers in the intramuscular nerve bundles. Ultrastructurally, the axons were devoid of myelin sheath or had very thin myelin sheaths, and the axons were surrounded by multilayered basal lamina forming an atypical onion bulb with no suggestions of myelin destruction. A sural nerve biopsy from one of the patients showed similar findings. Unlike the Déjèrine-Sottas type of hereditary motor and sensory neuropathy, there was no evidence of demyelination and remyelination in the muscle pathology, suggesting that the poor myelination in congenital hypomyelination neuropathy is due to a true "hypo"-myelination and not the result of demyelination.

Biopsy↗
PubMed1995

Paroxysmal kinesigenic choreoathetosis associated with prenatal brain damage.

We describe a 15 year old patient with paroxysmal kinesigenic choreoathetosis. Neurological examinations revealed a paresis of the right arm and hand that was similar to ulnar nerve palsy, a right homonymous hemianopsia and an ocular movement disturbance of smooth pursuit to left. Attacks of dystonic spasms began abruptly, usually following running, and lasted less than 5 min. Magnetic resonance imaging displayed a linear area of increased signal in the T2-weighted images along the lateral margin to the left putamen, atrophies of the frontal and temporal opercula and a large porencephalic cyst in the left parieto-temporo-occipital region. A cerebral blood flow study with single photon emission computed tomography showed hypoperfusion of the lenticular nucleus and the regions corresponding to the atrophies and the porencephalic cyst. Electroencephalograms during the attacks could not demonstrate epileptic abnormality. Only the neuronal plasticity of an immature brain could explain the discrepancy between the observed huge lesions of the brain and the minor neurological symptoms present. Attacks of paroxysmal kinesigenic choreoathetosis might occur when the basal ganglia maturate to some extent, even if the lesions in the brain were caused before birth.

Adolescent↗