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Biomedical subjects

Y Aihara

Publications and source records attributed to Y Aihara.

At least 55 records · Page 3Linked to original sources
PubMed2000

[The efficacy and safety of the nicardipine prolonged-release implant in a canine double hemorrhage model].

A drug delivery system using copoly (lactic/glycol acid) was tested to determine its efficacy and safety in preventing cerebral vasospasm following subarachnoid hemorrhage in dogs. Rod shaped implants (1 mm diameter, 10 mm length, and approximately 10% of nicardipine) was prepared by a heat compression method. Ten dogs were assigned to two groups: double hemorrhage group and double hemorrhage group treated with implants. Vertebral angiography and arterial blood injection into the cisterna magna were performed, followed by midline suboccipital craniectomy and laminectomy of the atlas and placement of nicardipine implants in the cisterna magna. On day 2, arterial blood injection into the cisterna magna was repeated (double hemorrhage model). On day 7, vertebral angiography was repeated. The animals were then sacrificed and the brain and blood clot were taken out. All the animals involved in both groups had been clinically well. Though 5 animals of the control group showed severe vasospasm, no vasospasm was observed in 3 animals and only very mild vasospasm in 2 of the nicardipine-treated group. There was a statistically significant difference in diameter between the two groups (0.5 mm vs 1.1 mm, p = 0.009). Histological examination showed no specific changes related to implants. Furthermore, left frontotemporal craniotomy and placement of nicardipine implants in the carotid-optico cistern were preformed in 3 dogs. Neither clinical symptoms related to implants nor specific histological changes were observed (e.g. hypotension, seizure). These results suggested that nicardipine-prolonged release preparation is safe as well as effective for cerebral vasospasm.

Animals↗
PubMed1999

Effects of morphine on the distribution of Fos protein in the trigeminal subnucleus caudalis neurons during experimental tooth movement of the rat molar.

The present study was undertaken to disclose temporal changes in the distribution of Fos-like immunoreactive (-IR) neurons in the trigeminal subnucleus caudalis (SpVc), one of the important relay nuclei for processing the nociceptive information from the oro-facial regions, following induction of experimental tooth movement in rat upper molars. Furthermore, the effect of morphine and naloxone on the levels of Fos-IR neurons in the SpVc was examined. The experimental tooth movement was induced by insertion of an elastic rubber between the first and second upper molars. In normal animals, Fos-IR neurons were rarely observed in the SpVc. Immediately after insertion of the elastic band, the distribution of Fos-IR neurons was comparable to that observed in normal animals. The number of Fos-IR neurons increased significantly from 1 to 4 h following the induction of experimental tooth movement, reaching a maximum at 2 h, and then decreasing gradually. Most of the neurons were localized in the dorsomedial portion of the superficial layers of the ipsilateral SpVc near the obex, but a few were observed at the ventral portion of the SpVc. The neurons at the superficial layers and ventral portion of the contralateral SpVc also showed Fos-like immunoreactivity, but their numbers were significantly smaller than those on the ipsilateral side. Pretreatment with morphine (3 and 10 mg/kg, i.p.) significantly reduced the induction of Fos-IR neurons at the superficial layers of the ipsilateral SpVc in a dose-dependent manner, and its effect was antagonized by the subsequent treatment of naloxone (2 mg/kg, i.p.). Naloxone pretreatment enhanced the expression of Fos-IR neurons on the ipsilateral SpVc. The present results of a reduction of Fos-IR neurons by morphine pretreatment suggest that the induction of Fos-IR neurons may be due to the noxious stimulation caused by induction of experimental tooth movement.

Analgesics, Opioid↗
PubMed1999

The effect of stimulus discriminability on stimulus-preceding negativities prior to instructive and feedback stimuli.

Stimulus-preceding negativity (SPN) was recorded in time estimation tasks that allowed the pre-instruction SPN and the pre-feedback SPN to be compared. In the task in which an acoustic tone was presented 3 s after a voluntary movement, (a) the level of stimulus discriminability (easy and difficult), and (b) the information content of the acoustic tone (feedback and instruction) were manipulated. The pre-instruction SPN over the right hemisphere tended to be larger under the difficult than under the easy level of discriminability, but the difference was only marginally significant. In contrast, the pre-feedback SPN over the right hemisphere was significantly larger under the easy than under the difficult level of discriminability. These findings suggest that the level of stimulus discriminability influences the pre-instruction and the pre-feedback SPN differently, and that it is probable that the pre-feedback and the pre-instruction SPN do not have the same functional significance.

Adult↗
PubMed1999

[Computed tomography with normal chest radiography in childhood tuberculosis].

During the recent 2 years we experienced 5 children (2 months-5 years old) with lung tuberculosis, all of whom had positive tuberculin skin-tests, and were in close contact with their family members who had active tuberculosis. However, no abnormal findings on chest X-ray films were pointed out by 2 independent roentogenologists, and no increased levels of inflammatory markers including WBC numbers, CRP, and ESR were detected in all but one child. Moreover, mycobacterial examination of sputa and/or gastric aspirates by microscope, culture technique, and PCR amplification revealed no causative bacilli in 4 children. To clarify whether these children were affected by Mycobacterium tuberculosis, chest CT scan was applied. Surprisingly, all 5 children were revealed to have abnormal changes including primary complexes in the lung field. Taken together, it is important to pursuit the apparent lung tuberculosis in children with a positive family history and positive tuberculin skin-test.

Child↗
PubMed1999

[Analysis of tuberculin reaction of tuberculous children below 4 years of age].

To clarify whether the size of tuberculin reaction could be used as an useful index of the severity of tuberculosis, we analyzed the sizes of tuberculin reaction (TR) of 60 children below 4 years of age with active tuberculosis at the time of diagnosis. Of 60 patients, 53 (88.9%) had positive reactions to tuberculin. The mean size of TR of 60 patients was 24.0 +/- 13.9 mm and maximum size was 60 mm. Seven patients who had no reaction to the tuberculin skin test consisted of three primary complex and four serious tuberculosis (two miliary tuberculosis and two tuberculous meningitis). The patients without BCG vaccination showed significantly smaller TR than the patients with BCG vaccination (p < 0.05). The patients less than 1 year of age showed significantly smaller TR than the patients of 4 years of age (p < 0.05). The patients with serious tuberculosis showed significantly smaller TR than the patients with primary complex (p < 0.05). Of patients with primary complex, there were no difference of the size of TR between the patients with pulmonary tuberculosis (III) and hilar lymphadenopathy (H). Together with, it did not necessarily mean that negative TR showed no infection with tuberculosis and the sizes of TR depended on the severity of tuberculosis in infantis and young children.

Child, Preschool↗
PubMed1999

[Influence of proprioceptive input from leg, thigh, trunk and neck muscles on the equilibrium of standing].

To investigate and compare the roles of proprioceptive input from the leg, thigh, trunk and neck muscles on equilibrium, we performed static posturography in 50 normal subjects in the standing position on a force platform by applying vibratory stimulations to the muscles. The length of the displacement of the center of gravity, maximum sway length and sway area were measured. The amplitude of the body sway was maximum when the stimulation was applied to the dorsal neck. The forward shift of the center of gravity was also marked by stimulation applied to the dorsal neck. The amplitude of the body sway on stimulation of the leg muscles was also marked, although less than that of dorsal neck stimulation. The backward shift during stimulation of the gastrocnemius and the forward shift during stimulation of the anterior tibialis were remarkable. The results indicate that the leg muscles, which directly regulate the movement of the ankle joint, and the dorsal neck muscles, which change the static equilibrium through the central nervous system, are important for maintaining the standing posture.

Adult↗
PubMed1999

Cardiac sympathetic activity estimated by 123I-MIBG myocardial imaging in patients with dilated cardiomyopathy after beta-blocker or angiotensin-converting enzyme inhibitor therapy.

UNLABELLED: Impaired cardiac sympathetic activity can be evaluated by 123I-metaiodobenzylguanidine (MIBG) imaging. METHODS: We studied the significance of MIBG imaging for 24 patients (age 58+/-12 y) with dilated cardiomyopathy (DCM). We compared 12 patients (group A) treated with metoprolol (dose from 30-60 mg/d) with 12 patients treated with angiotensin-converting enzyme (ACE) inhibitors. Patients were studied before treatment, after 5 mo of treatment (only in group A) and after 1 y of treatment. Cardiac MIBG uptake was assessed as the heart-to-mediastinum activity ratio (H/M) and total defect score (TDS) from anterior planar and SPECT MIBG images, which were acquired in 4 h after tracer injection. New York Heart Association (NYHA) class and left ventricular ejection fraction (LVEF) calculated by echocardiography were also assessed. RESULTS: TDS decreased in both groups (in group A, from 30+/-7 through 23+/-9 to 18+/-10; P < 0.01, in group B, from 30+/-6 to 24+/-8; P < 0.01) and H/M was increased in both groups (in group A, from 1.87+/-0.31 through 2.03+/-0.28 to 2.14+/-0.29; P < 0.01, in group B, from 1.82+/-0.28 to 1.94+/-0.26; P < 0.05). But TDS and H/M were more improved in group A than in group B (P < 0.05). LVEF was significantly increased in only group A (from 38+/-6 through 43+/-8 to 49%+/-9%; P < 0.01). NYHA improved in both groups (in group A, from mean 2.5 through 2.1 to 1.8; P < 0.01, in group B, from mean 2.6 to 2.1; P < 0.05) but was more improved in group A than in group B (P < 0.05). CONCLUSION: Cardiac function, symptom and cardiac sympathetic activity evaluated by MIBG images improved after the beta-blocker therapy more than with the treatment that used ACE inhibitors.

3-Iodobenzylguanidine↗
PubMed1999

[Effective combination therapy of plasma exchange and subsequent cyclophosphamide pulses for catastrophic antiphospholipid antibody syndrome: a case report].

A 7-year-old girl with catastrophic antiphospholipid antibody syndrome was described. She firstly admitted to the local hospital with the complaints of persistent fever and abdominal pain, and was diagnosed as systemic lupus erythematosus with the laboratory findings as follows; positive for antinuclear antibody, anti-DNA antibody, and platelet-associated IgG, thrombocytopenia, and hypocomplementemia. 10 days after the initiation of oral prednisolone, she suddenly manifested tonic convulsion and unconsciousness accompanied by high fever. Because of the unresponsiveness to the methylprednisolone pulse therapy for supposed CNS lupus, she was transferred to our hospital. Her unconsciousness persisted, and pulsation on dorsalis pedis was not palpable on admission. Laboratory investigation revealed the falsely positive VDRL, a prolonged aPTT, positive for lupus-anticoagulant and antiphospholipid antibody. The magnetic resonance image demonstrated multiple spotty hyperintensity (T2) in the brain consistent with multiple hemorrhagic infarcts. Arteriogram demonstrated the infarct of dorsalis pedis, and coronary aneurysms. These findings were compatible with the criteria of catastrophic antiphospholipid antibody syndrome, she was diagnosed as catastrophic antiphospholipid antibody syndrome. The plasma exchange and subsequent cyclophosphamide-pulse therapy, which was given once a month for first 6 months, and later, at 3 months intervals, was effectively administered. This combination and oral anti-thrombotic therapy revealed effective for this kind of fatal disorder.

Anticoagulants↗
PubMed1999

[A child of microscopic polyarteritis nodosa effectively treated with intravenous methylprednisolone pulses and serial cyclophosphamide pulse therapy].

Microscopic polyarteritis nodosa (mPAN) is a rare disorder in pediatric field of systemic small vessel vasculitis, and affects skin and musculoskeletal system accompanied by progressive necrotizing glomerulonephritis. We described here a 15-year-old boy with positive anti-neutrophil cytoplasmic antibody (MPO-ANCA) and severe mPAN, who was effectively treated with intravenous methylprednisolone pulse therapy followed by monthly cyclophosphamide pulses for 1 year. The histologic examination of renal biopsy specimen showed a severely desolated disease characterized by fibrinoid necrosis, crescent formation of most glomeruli and interstitial infiltration of inflammatory cells. The elevated titers of MPO-ANCA were useful markers for diagnosis, and the serial determinations of the antibody titers were indicative of disease activity. Moreover, dramatic clinical improvement after the induction of the combinatorial therapy and the disappearance of MPO-ANCA was correlated in the disease course. In this report, the serial determination of MPO-ANCA constituted a useful diagnostic tool and a sensitive marker of disease activity.

Adolescent↗
PubMed1999

[Improvement of the maintenance therapy after methylprednisolone pulse therapy--effect of prednisolone combined with immunosuppressants].

OBJECTIVES: We investigated the effect of the combination therapy of prednisolone (PSL) and immunosuppressants after methylprednisolone pulse therapy. METHODS: A protocol of PSL (15-20 mg/day) and mizoribine (150-200 mg/day) after methylprednisolone (mPSL) pulses was used for 2 years to treat 7 patients (PSL + MZB group). Cyclophosphamide (CYC) pulse therapy was added to the combined therapy in 4 patients with severe lupus nephritis. The total dose of predinisolone, and side effects were compared with those in 6 patients who were treated with PSL (30 mg/kg) alone after mPSL pulse therapy (PSL group). RESULTS: No relapses occurred in the PSL + MZB group, although all of 6 patients relapsed in the PSL Group. The total doses of PSL in the PSL + MZB group was about 70% of the PSL Group. There were two patients with Herpes-Zoster infection and one patient with liver dysfunction as side effects, with no differences in the frequency of side effects between the was groups. CONCLUSIONS: Combination maintenance therapy with prednisolone and immunosuppressants after methylprednisolone pulse therapy was effective in preventing relapse.

Adolescent↗
PubMed1998

Molecular cloning of rat klotho cDNA: markedly decreased expression of klotho by acute inflammatory stress.

We have recently identified a novel gene, termed klotho, that is involved in the suppression of several aging phenotypes. The gene encodes a membrane protein that shares sequence similarity with the beta-glucosidases of bacteria and plants. In this study, we isolated rat klotho cDNA and examined its tissue distribution in rats. The deduced amino acid sequence of rat Klotho protein was 1014 amino acids in length and 94 and 85% homologous to those of mouse and human Klotho proteins, respectively. Northern blot analysis using the rat klotho cDNA probe identified a single transcript of 5.2 kb in size expressed predominantly in the kidney, while RT-PCR detected low levels of expression also in the brain, lung, intestine, and ovaries. During development, klotho expression in the kidney was markedly augmented after birth. Chromosomal localization of rat klotho was mapped to 12q12. Northern blot analysis showed that expression of klotho was markedly decreased by lipopolysaccharide (LPS) in vivo, suggesting that expression of klotho is affected by acute inflammatory stress. The present study leads to a better understanding of the physiologic and pathophysiologic roles of Klotho.

Amino Acid Sequence↗
PubMed1998

Dynamics of human cardiorespiratory responses to standing on one leg with eyes closed.

The postural control system has been extensively studied in terms of somatic motor function but little is known about its connection with human autonomic function. The purpose of this study was to determine the cardiorespiratory changes in response to the 1-min balance test that was performed by standing on one leg with eyes closed (SOLEC) or eyes open (SOLEO) in 12 healthy young women [mean age 20.7 (SD 3.3) years]. Heart rate (HR), respiratory rate (RR), duration of inspiration and expiration, tidal volume (VT), and oxygen uptake (VO2) were measured during the test. The SOLEC test produced rapid increases in HR at the onset. There were significant increases in HR later during the test (P < 0.05). Metabolic rate (VO2) showed a gradual increase during the SOLEC test, indicating that the late responses could have been partly due to metabolic changes. The RR increased significantly at the onset of the test (P < 0.05), and remained elevated until the end of the test. The early responses were considered to be mediated neurally through the postural control system which receives the afferent inputs arising from the vestibular system and from muscle proprioceptors of the leg. In contrast, SOLEO caused small insignificant changes in HR, RR, VT and VO2, suggesting that a visual input is essential for balancing a postural change. The SOLEC test may have potential as a test of autonomic function.

Adolescent↗
PubMed1998

The effect of exposure to negative air ions on the recovery of physiological responses after moderate endurance exercise.

This study examined the effects of negative air ion exposure on the human cardiovascular and endocrine systems during rest and during the recovery period following moderate endurance exercise. Ten healthy adult men were studied in the presence (8,000-10,000 cm-3) or absence (200-400 cm-3) of negative air ions (25 degrees C, 50% humidity) after 1 h of exercise. The level of exercise was adjusted to represent a 50-60% load compared with the subjects' maximal oxygen uptake, which was determined using a bicycle ergometer in an unmodified environment (22-23 degrees C, 30-35% humidity, 200-400 negative air ions.cm-3). The diastolic blood pressure (DBP) values during the recovery period were significantly lower in the presence of negative ions than in their absence. The plasma levels of serotonin (5-HT) and dopamine (DA) were significantly lower in the presence of negative ions than in their absence. These results demonstrated that exposure to negative air ions produced a slow recovery of DBP and decreases in the levels of 5-HT and DA in the recovery period after moderate endurance exercise. 5-HT is thought to have contributed to the slow recovery of DBP.

Adult↗
PubMed1998

Monoamines, amino acids and acetylcholine in the preoptic area and anterior hypothalamus of rats: measurements of tissue extracts and in vivo microdialysates.

A microbore column high-performance liquid chromatography (HPLC) system was used to measure neurotransmitters in tissue extracts and in vivo microdialysates obtained from the preoptic area (PO) and anterior hypothalamus (AH) of rats. The extracts contained norepinephrine, epinephrine, 3,4-dihydroxyphenylacetic acid (DOPAC), dopamine, 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), aspartate, glutamate, GABA, acetylcholine (ACh) and choline. The microdialysates obtained from the PO and AH of freely moving rats contained all of these substances except for norepinephrine, epinephrine, dopamine, and 5-HT. During collection of microdialysate from the PO and AH, core body temperature and locomotor activity were simultaneously measured by means of telemetry. The locomotor activity and body temperature increased during the night. This was accompanied by increased levels of 5-HIAA. The results suggest that serotonergic neuronal mechanisms in the PO and AH may be involved in hypothalamic regulation of spontaneous behaviors and body temperature.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1998

Recombinant IFN-gamma treatment of a patient with hyperimmunoglobulin E syndrome triggered autoimmune thrombocytopenia.

We report a pediatric patient with hyperimmunoglobulin E syndrome (HIES) treated with recombinant IFN-gamma (rIFN-gamma) for 2 1/4 years who developed autoimmune thrombocytopenia and was positive for serum antiplatelet antibody and antinuclear antibody (ANA). She was then treated with i.v. methylprednisolone pulse therapy followed by oral immunosuppressive drugs. With this therapy, her platelet count increased and was maintained within the normal range for more than a year. We retrospectively examined her sera stored at -40 degrees C for ANA and found that the ANA level was increased from 1:40 to 1:640 with the rIFN-y therapy. Therefore, we believe that, in this case, rIFN-y treatment may have played a crucial role in triggering autoimmune thrombocytopenia. Furthermore, this case demonstrates that caution must be observed in administering rIFN-gamma to genetically predisposed patients.

Antibodies, Antinuclear↗
PubMed1998

Epidemiological study of a food-borne outbreak of enterotoxigenic Escherichia coli O25:NM by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA analysis.

This study investigated the applicability of molecular epidemiological techniques to the identification of the causal agent of an outbreak of diarrhea caused by ingestion of food contaminated with enterotoxigenic Escherichia coli (ETEC). The outbreak occurred at four elementary schools in July 1996 and affected more than 800 people. Illness was most strongly associated with eating tuna paste (relative risk, 1.79; 95% confidence interval = 1.16 to 2.79; P = 0.0001). To evaluate the epidemiological characteristics of the pathogen, the DNAs from numerous isolated ETEC strains were subjected to randomly amplified polymorphic DNA analysis, pulsed-field gel electrophoresis of nuclease S1-treated plasmid DNA, and analysis of genomic DNA restriction fragment length polymorphisms. All ETEC isolates were of the O25:NM (nonmotile) serotype, which carries a heat-stable enterotoxin Ib gene. Genotypic analysis demonstrated that the strains isolated from the patients at all four schools were identical. The isolates of ETEC O25:NM obtained from the tuna paste that had been served for lunch at these schools were genetically indistinguishable from those isolated from the patients. Results suggest that this outbreak was food borne. The molecular biology-based epidemiological techniques used in this study were useful in characterizing the causal agent in this food-borne epidemic.

Animals↗