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Biomedical subjects

M Fujiki

Publications and source records attributed to M Fujiki.

At least 55 records · Page 3Linked to original sources
PubMed1997

The ability of children with specific language impairment to access and participate in an ongoing interaction.

This study investigated the ability of 6 children with specific language impairment (SLI), ages 8;10 to 12;5 (years; months), to enter and participate in an ongoing dyadic interaction. Performance was compared to that of 6 chronological age-matched (CA) peers and 6 language-similar (LS) peers. All children in the LS and CA groups successfully accessed the interaction, and most did so quickly. Two children from the SLI group did not access, and the 4 remaining subjects required varying amounts of time to access. Following successful access, the triadic interactions of subjects were examined. The accessing children with SLI talked significantly less, were addressed significantly less, and collaborated less than either of the partners within their triads. Few significant differences were observed between LS or CA children and their partners.

Child↗
PubMed1997

The effects of medetomidine on maternal and fetal cardiovascular and pulmonary function, intrauterine pressure and uterine blood flow in pregnant goats.

To investigate the effects of medetomidine on late pregnant goats, medetomidine induced changes in maternal or fetal circulation and acid-base balance, as well as changes in intrauterine pressure (IUP) and uterine blood flow (UBF), were studied. Intramuscular administration of medetomidine (40 micrograms/kg b.w.) decreased the heart rate (HR) and arterial blood pressure (ABP) of the mother, and the change in HR was significant statistically (p < 0.05). In the fetus, HR and ABP showed a transient decrease and increase (p < 0.05), respectively. A decrease in maternal arterial blood pH and oxygen partial pressure (PO2) and an increase in carbon dioxide partial pressure (PCO2) were recorded after the injection, but none was significant. In the fetus, arterial blood PO2 decreased significantly (p < 0.05) after 5 min of administration, and a significant metabolic acidemia supported by a decrease in base excess was observed. Within 1 to 4 min after the administration of medetomidine, IUP began to rise and remained high for 10 to 14 min. Thereafter, the rise in IUP was frequent and periodical. After the injection, UBF significantly (p < 0.05) decreased, and the fall in UBF was associated with a rise in IUP. The maternal and fetal serum medetomidine concentration increased remarkably after the injection of medetomidine into the mother. These observations in late pregnant goats suggested that medetomidine induced a decrease in maternal cardiac output, a decrease in UBF arising from the induction of uterine contractions, and transplacental medetomidine can have a suppressive effect on the fetus.

Adrenergic alpha-Agonists↗
PubMed1997

Treatment of brain abscess associated with ventricular rupture--three case reports.

Three patients presented with brain abscess associated with ventricular rupture. The origins of infection were sepsis, congenital heart disease, and unknown, and the organisms were Gram-negative cocci in one and Streptococcus species in two. Ventricular rupture occurred before administration of antibiotics and caused consciousness disturbance in all three patients. Continuous ventricle drainage was begun and antibiotics were directly administered into the ventricles. Aspiration and drainage from the abscess was also performed in two patients. Ventricular irrigation resulted in an excellent effect in one patient. The outcomes were excellent in two patients and fair in one. Aggressive ventricular drainage in the very early stage and direct intraventricular administration of antibiotics are very important to obtain a favorable outcome in patients with brain abscess and ventricular rupture.

Adult↗
PubMed1996

A cell wall-associated, receptor-like protein kinase.

Physical connections between higher plant cell walls and the plasma membrane have been identified visually, but the molecules involved in the contact are unknown. We describe here an Arabidopsis thaliana protein kinase, designated Wak1 for wall-associated kinase, whose predicted extracytoplasmic domain contains several epidermal growth factor repeats and identity with a viral movement protein. Wak1 fractionates with insoluble material when plant tissue is ground in a variety of buffers and detergents, suggesting a tight association with the plant extracellular matrix. Immunocytochemistry confirms that Wak1 is associated with the cell wall. Enzymatic digestion of the cell wall allows the release of Wak1 from the insoluble cell wall fraction, and protease experiments indicate that Wak1 likely has a cytoplasmic kinase domain, and the EGF containing domain is extracellular. Wak1 is found in all vegetative tissues of Arabidopsis, and has relatives in other angiosperms, but not Chlamydomonas. We suggest that Wak1 is a good candidate for a physical continuum between the cell wall and the cytoplasm, and since the kinase is cytoplasmic, it also has the potential to mediate signals to the cytoplasm from the cell wall.

Arabidopsis↗
PubMed1996

Genetic influences on cellular reactions to spinal cord injury: activation of macrophages/microglia and astrocytes is delayed in mice carrying a mutation (WldS) that causes delayed Wallerian degeneration.

Reactive changes in macrophages/microglia and astrocytes were evaluated following spinal cord injury in normal mice of the C57BL/6J strain and in mice carrying a mutation (WldS) which delays the onset of Wallerian degeneration in damaged axons. Crush injuries were produced at the T8 level by using an extradural approach; animals were allowed to survive for 2 days to 12 weeks, and spinal cords were prepared for immunocytochemistry using antibodies against Mac1 and glial fibrillary acidid protein (GFAP). In normal mice, Mac1-positive macrophages accumulated at the injury site by 4 days and immunostaining of these cells peaked at 6-8 days. Cells in the gray matter near the crush site and in the ascending dorsal column also exhibited increased Mac1 staining that was prominent at 1 week and remained high at 2-4 weeks. In mice carrying the WldS mutation, the accumulation of macrophages at the injury site and the increase in immunostaining of these cells were delayed, as were the increases in immunostaining in the gray matter and dorsal columns. Both normal and mutant mice exhibited pronounced increases in glial fibrillary acidic protein immunostaining at the edge of the crush site and for some distance both rostral and caudal to the injury; increased immunostaining was also prominent along the ascending dorsal columns. The center of the crush site, which contained connective tissue, remained completely unstained for GFAP. In normal mice, immunostaining for GFAP reached a peak at 1 week postinjury and then declined. In mice carrying the WldS mutation, increases in GFAP immunostaining did not reach a peak until 2-3 weeks postinjury. These results indicate that activation of macrophages, microglia, and astrocytes is delayed and prolonged in mice carrying the WldS mutation.

Animals↗
PubMed1996

Genetic influences on cellular reactions to spinal cord injury: a wound-healing response present in normal mice is impaired in mice carrying a mutation (WldS) that causes delayed Wallerian degeneration.

Progressive tissue necrosis is a process unique to the injured mammalian spinal cord which often leads to gradually increasing cavitation and enlargement of the lesion. To evaluate the role of neuronal degeneration in initiating this response, histopathological changes were compared in C57BL and WldS (delayed Wallerian degeneration mutation) mice. The spinal cord was crushed at T8, producing a primary lesion at the site of the trauma and a secondary lesion extending rostrocaudally in the dorsal columns (where long ascending and descending fiber tracts undergo Wallerian degeneration). Cavitation was relatively mild at both sites and developed mainly at the margins of the lesions. In striking contrast to spinal cord injury in rats, progressive necrosis did not occur in mice; instead, the primary and secondary lesion sites became filled in by macrophages and fibroblasts embedded in a well-vascularized collagenous stroma. Quantitative image analysis revealed that the primary lesion decreased dramatically in size and cavitation between 2 and 3 weeks in C57BL, whereas in WldS the reduction in size and cavitation began later (at 4 weeks) and was less complete. The initial development of the secondary lesion began later and its healing was less complete in WldS than C57BL. These results are consistent with the hypothesis that neuronal damage, including Wallerian degeneration, triggers inflammatory responses leading to tissue repair. For this reason, any delay in neuronal degeneration, as in the WldS mutation, results in deficient tissue repair as reflected in the larger size of both primary and dorsal column lesions.

Animals↗
PubMed1996

Corticospinal direct response to transcranial magnetic stimulation in humans.

The corticospinal motor evoked potential (MEP) response to transcranial magnetic stimulation of the motor cortex was investigated in comparison with the direct (D) response to electrical stimulation of the exposed motor cortex from the spinal epidural space in 7 neurologically normal patients during brain tumor surgery. The D response during operation was obtained by transcranial magnetic stimulation of the scalp over the areas of the cerebral motor cortex, the hand or arm areas. The magnetic induced D response showed a conduction velocity of 50.5-72.7 m/sec and was resistant to anesthesia and unaffected by muscle relaxants and tolerant to high frequency (500 Hz) paired magnetic stimulus, and the latencies of magnetic MEPs corresponded to those with direct electrical stimulation. Thus, recordings of the D response by transcranial magnetic stimulation are useful for not only identifying the location of the motor cortex during intracranial surgery but also for non-invasive recording of pyramidal tract activity during extracranial surgery under general anesthesia.

Aged↗
PubMed1996

Distribution of dystrophin and dystrophin-associated protein 43DAG (beta-dystroglycan) in the central nervous system of normal controls and patients with Duchenne muscular dystrophy.

In skeletal muscles of patients with Duchenne muscular dystrophy (DMD), the absence of dystrophin was thought to lead to the large reduction in all of the dystrophin-associated proteins (DAPs). Of the seven types of DAPs identified in skeletal muscle, only the 43-kDa glycoprotein (beta-dystroglycan) has recently been found in the monkey brain. To clarify the distribution and characterization of dystrophin and beta-dystroglycan in the brain of humans, we carried out immunostaining and immunoblotting studies on tissues from three DMD patients with intellectual disturbances (ages 17,22, and 26 years) and in five controls (age range, 42-74 years). An antidystrophin antibody revealed dystrophin to be localized in neuronal cells and in the vascular wall in control brains, but it was absent from these tissues in DMD patients. In contrast, beta-dystroglycan was distributed throughout neuronal cells and in the vascular wall of control brains, and was well preserved in the brain of patients with DMD.

Adolescent↗
PubMed1995

Effect of spinal cord stimulation on cerebral blood flow in cats.

Effects of electric spinal cord stimulation (SCS) on cerebral blood flow (CBF) were investigated in anesthetized adult cats. SCS was performed under various stimulus conditions for 1 h via a wire electrode inserted into the dorsal epidural space at various levels in the spinal cord. CBF was measured in the subcortex of the parietal lobe by hydrogen clearance method before, during, and after SCS. After the start of SCS in the high cervical cord with a frequency of 20 Hz, CBF gradually increased up to 140% of the pre-SCS value, and remained high for 15 min after the end of SCS. SCS of the low cervical or midthoracic cord under the same condition caused no significant increase in CBF. Nor did SCS of the high cervical cord with frequencies of 200 and 2,000 Hz increase CBF. No CBF increase was observed after SCS of the high cervical cord with 20 Hz when the dorsal column was sectioned at the medullo-cervical junction. These results suggest that the ability of SCS to increase CBF is peculiar to high cervical cord stimulation with moderately low frequencies.

Analysis of Variance↗
PubMed1994

Ability of institutionalized and community-based adults with retardation to respond to questions in an interview context.

This study examined the ability of adults with mild and moderate levels of retardation to respond to simple and complex questions. The sample consisted of 20 subjects living in an institutional setting and 20 subjects living in the community. A 30-minute language sample, structured as a job interview, was elicited from each subject by an investigator. During the interview, the investigator asked a number of questions interspersed within the conversation. Two levels of questions were presented: simple and complex. Ten questions were presented at each level. Responses were scored in terms of how informative and truthful the subject was (specific scoring conventions were based upon the work of Grice, 1975). The community group produced a significantly greater number of appropriate answers to both simple and complex questions than did the institutional group. Group differences were observed along both parameters of informativeness and truthfulness.

Adult↗
PubMed1993

Coupling of cytosolic protein synthesis and mitochondrial protein import in yeast. Evidence for cotranslational import in vivo.

We have utilized a homologous cell-free mitochondrial protein import system derived from the yeast Saccharomyces cerevisiae, in addition to performing a series of in vivo experiments in yeast, to investigate the coupling between cytosolic protein synthesis and protein transport into mitochondria. We found that the import of bulk mitochondrial proteins was inhibited in both the homologous in vitro reaction and in vivo upon arrest of cytosolic protein synthesis with the addition of cycloheximide. Tight coupling of synthesis and import was also demonstrated in vivo for the beta subunit of the mitochondrial F1-ATPase. We also investigated the effect of the antifolate methotrexate on the import of a fusion protein consisting of the mitochondrial targeting signal of yeast cytochrome oxidase subunit IV fused to mouse dihydrofolate reductase (the COXIV-DHFR fusion protein). Methotrexate has previously been shown to inhibit posttranslational import of COXIV-DHFR by preventing the DHFR moiety from unfolding. However, we found that antifolate addition had no inhibitory effect on the import of COXIV-DHFR in vivo, suggesting that its import into mitochondria in yeast cells occurs cotranslationally. Further, when we treated yeast with the proton ionophore carbonyl cyanide m-chlorophenylhydrazone to collapse the mitochondrial membrane potential and induce the accumulation of extramitochondrial precursor pools, we found that the ability to be imported by a strictly posttranslational mechanism upon reestablishing the membrane potential varied from one precursor to another, suggesting that cotranslational import may be mandatory for the import of some proteins in vivo. In summary, our findings are entirely consistent with the notion that import of proteins into yeast mitochondria occurs cotranslationally under normal conditions in vivo.

Animals↗
PubMed1992

Action of endothelin-1 on rat astrocytes through the ETB receptor.

We investigated the effect of ET-1 on the state of rat cerebral astrocytes (AC) differentiation. AC ceased to proliferate and changed into its differentiated state by treatment with dibutyryl cyclic AMP (DBcAMP). The cell growth activity in DBcAMP-treated AC was stimulated by ET-1 in a dose-dependent manner. Over similar dose ranges, ET-1 suppressed the glutamine synthetase activity in DBcAMP-treated AC. The molar potency of ET-1 in this action was at least 3 orders of magnitude higher than that in mitogenic action in AC under the proliferative state previously reported. Northern blot analysis revealed that ETB receptor mRNA level in DBcAMP-treated AC was markedly higher than that in AC untreated with DBcAMP. Consistently, binding studies showed that the Bmax value for [125I]ET-1 in DBcAMP-treated AC was 16 times higher than that in AC untreated with DBcAMP. These results suggest that ET-1 potently induced a retraction of the differentiation state of AC from fully the specialized state and that the high responsiveness of differentiated AC to ET-1 was partly attributed to the high level expression of the ETB receptor.

Animals↗
PubMed1991

Coupling of protein synthesis and mitochondrial import in a homologous yeast in vitro system.

We made use of a homologous cell-free mitochondrial protein import system derived from the yeast Saccharomyces cerevisiae to investigate the coupling of protein synthesis and import. Mitochondrial precursor proteins were synthesized in a yeast lysate either in the presence or absence of isolated yeast mitochondria. We were, therefore, able to analyze protein import into mitochondria either in a strictly posttranslational reaction (when isolated mitochondria were added only after protein synthesis has been arrested by the addition of cycloheximide) or in a reaction in which synthesis and import were permitted to occur simultaneously. We found that the import of a precursor protein consisting of the amino-terminal mitochondrial targeting sequence of cytochrome oxidase subunit IV fused to mouse dihydrofolate reductase is very inefficient in a strictly posttranslational reaction, whereas efficient import is observed if precursor synthesis and import are coupled. The same result was obtained when we analyzed the import of bulk endogenous yeast mitochondrial proteins in this system. Finally, we found that the insertion of the yeast outer membrane protein porin is also several times more efficient when synthesis and insertion are coupled.

Animals↗