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Biomedical subjects

E Matsuda

Publications and source records attributed to E Matsuda.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Visual acuity measured by pattern visual evoked potential].

We investigated the appropriateness of a method for the assessment of visual acuity using pattern visual evoked potentials (PVEP) in which retinal X-ganglion cells are predominantly stimulated. Eighteen normal eyes (average 22.2 years old) with normal acuity of 1.0 were examined. The stimulus consisted of white and black checkerboards (39', 26', 15' and 9') with a visual angle of eight degrees and a contrast level of 15%. The pattern reversal frequency was 0.7 Hz. This resulted in 100 averaged PVEP per session. We judged visual acuity from responses of the P100 component. Visual acuity was judged to be 0.1, so that there was response to the 39' checkerboard stimulus pattern, but not to the 26' pattern. Consequently, the accuracy for visual acuity was 76.9% for 0.1, 71.4% for 0.2, 70.0% for 0.5 and 58.3% for 1.0. This method, which uses a stimulus pattern with a small visual angle, low contrast, and low pattern reversal frequency, is useful for subjective measurement of the visual acuity of infants or handicapped children whom it is difficult to measure by the conventional objective method of measuring visual acuity with Landolt's rings.

Adult↗
PubMed1996

Detection of all single-base mismatches in solution by chemiluminescence.

A rapid in-solution method for the detection of all 12 single-base mismatches is described. The technique is based on the hybridization protection assay (HPA) format that utilizes oligonucleotide probes labeled with a highly chemiluminescent acridinium ester (AE). Hydrolysis by weak base renders AE permanently non-chemiluminescent. When an AE-labeled probe hybridizes to an exactly complementary target, AE is protected from hydrolysis relative to the unhybridized conformation. Single-base mutations in the duplex adjacent to the site of AE attachment disrupt this protection resulting in rapid AE hydrolysis and loss of chemiluminescence. The discrimination effect was seen in both DNA and RNA. Studies of Tm values revealed that this effect is not due to a decrease in the overall stability of the duplex, suggesting the AE is responding to local structural changes in the double helix induced by mismatches. Using this principle all 12 single mismatches were clearly discriminated from the corresponding matched sequences. The assay is homogeneous, simple, sensitive, applicable to both amplified and non-amplified targets, and is completed in 30-60 min. An example showing discrimination between wild-type and mutant sequences corresponding to the reverse transcriptase coding region of HIV-1 is given.

Acridines↗
PubMed1996

Simultaneous detection of multiple nucleic acid targets in a homogeneous format.

The acridinium ester 4-(2-succinimidyloxycarbonylethyl)phenyl-10-methylacridinium 9-carboxylate trifluoromethane sulfonate (AE), which reacts rapidly with alkaline hydrogen peroxide to produce light, has been used as a detection label in a number of assay procedures, including nucleic acid probe-based systems [Nelson et al. (1995) in Nonisotopic Probing, Blotting and Sequencing (Kricka, L. J., Ed.) pp 391-428, Academic Press, Inc., San Diego, CA]. We have synthesized a number of derivatives of this AE and characterized their chemiluminescent properties. These derivatives display significant differences in the kinetics of the chemiluminescence reaction as well as optimal pH for light production. These differences allow two or more derivatives to be simultaneously detected and quantitated in a single reaction vessel. Several of these derivatives have been covalently linked to nucleic acid probe molecules and have been further characterized in regard to chemiluminescence properties as well as hydrolysis of the ester bond in both single- and double-stranded conformations. On the basis of these properties, homogeneous assay formats utilizing DNA probes labeled with various AE derivatives were developed. Simultaneous detection and quantitation of Chlamydia trachomatis and Neisseria gonorrhoeae, the gag and pol regions of HIV, and wild-type and mutant HIV sequences was achieved with high sensitivity and discrimination.

Acridines↗
PubMed1996

Sleep apnea syndrome: comparison of MR imaging of the oropharynx with physiologic indexes.

PURPOSE: To compare magnetic resonance (MR) imaging of the oropharynx in patients with sleep apnea syndrome with fiberoptic nasopharyngoscopy, and oropharyngeal pressure and apnea index values. MATERIALS AND METHODS: After sleep induction, 24 patients with sleep apnea syndrome and nine patients with non-sleep-apnea snoring underwent MR imaging and fiberoptic nasopharyngoscopy combined with subsequent measurement of oropharyngeal pressure. Patients were previously classified with apnea index values obtained at polysomnography. MR imaging and fiberoptic nasopharyngoscopic findings of severity and location of oropharyngeal abnormalities were compared. Oropharyngeal pressure and apnea index values were also compared with MR findings. RESULTS: A statistically significant correlation was observed between MR and fiberoptic nasopharyngoscopic findings (r = .931; P < .0001). The degree of decompression in oropharyngeal pressure and apnea index values in the multiple-site abnormality group were statistically significantly higher than those in the single-site abnormality group. CONCLUSION: MR imaging is useful for localization of sites of oropharyngeal abnormalities and for evaluation of the severity of apnea.

Adult↗
PubMed1996

MRI of the pharynx in young patients with sleep disordered breathing.

15 patients, aged 1-14 years, with sleep disordered breathing underwent turbo fast low angle shot MRI during drug-induced sleep. The site of obstruction within the pharynx was identified. Data from MRI were compared with fibroscopic findings. The degree of hypertrophy of the palatine tonsils as determined by MRI was also compared with that determined by visual inspection while awake. MRI was completed in all cases, whereas fibroscopy was completed in only six of the 10 cases examined. MRI findings agreed with those of fibroscopy in all the patients who underwent both investigations. On MRI, the pharynx was obstructed in 12 of the 15 cases examined (80%); the palatine tonsils were involved in all of these while both the palatine tonsils and nasopharynx were obstructed in three of the 12 cases. One of the 12 patients was graded as Grade I of Mackenzie's scale. One of the cases graded as Grade II showed no obstruction. In conclusion, fast MRI proved useful in identifying the site of pharyngeal obstruction in young patients with sleep disordered breathing.

Adolescent↗
PubMed1995

Effectiveness of an inactivated goose parvovirus vaccine in Muscovy ducks.

With goose parvovirus (GPV) strain IH, an inactivated vaccine was prepared from allantoic fluid of embryonating Muscovy duck eggs inoculated with GPV. The response to vaccination was measured by virus neutralizing antibody titer against GPV. Offsprings from the vaccinated flock were introduced in a farm in which GPV infection had been experienced and examined for resistance to exposure to GPV. The results showed that the intramuscular vaccination to Muscovy ducks at any age stimulated significant virus neutralizing antibody levels, and that more than 90% Muscovy ducklings from the vaccinated parent flock survived after the exposure to GPV. Muscovy ducklings that passively possessed high level virus neutralizing antibodies also could respond to the vaccination and the induced antibodies remained for more than 2 months.

Aging↗
PubMed1995

The antibody to plasminogen activator inhibitor-1 suppresses pulmonary metastases of human fibrosarcoma in athymic mice.

We studied the effects of the plasminogen activator inhibitor-1 (PAI-1), the urokinase-type plasminogen activator (uPA) and their antibodies on hematogeneous pulmonary metastases formation of human fibrosarcoma in athymic mice. We used a human fibrosarcoma cell line (HT-1 080) with low metastatic potential, and a subpopulation of HT-1 080 (HT-1 080-P4) with high metastatic potential which was selected by repeating injections into the tail veins of athymic mice. We examined the effects of these drugs on pulmonary metastases formation according to Wexler's method and the number of tumor cell emboli in the lung subsequent to an injection of radio-labeled tumor cells. Pulmonary metastases formation from HT-1 080 was not affected by any of the tested drugs. Pulmonary metastases from HT-1 080-P4 increased with uPA and anti-uPA antibody injections. PAI-1 slightly increased pulmonary metastases from HT-1 080-P4, and the anti-PAI-1 antibody decreased it (60.9 + 27.7% of control, p < 0.05). While none of the drugs altered the number of HT-1 080 cells in the lung at 24, 48 and 72 hours after the injection, PAI-1 increased the number of HT-1 080-P4 cells in the lung, whereas uPA and PAI-1 decreased it. The result that these drugs did not affect the metastatic potential of HT-1 080 but only that of HT-1 080-P4, indicates that fibrinolysis plays an important role in hematogenous pulmonary metastases formation of tumor cells with high metastatic potential. The effects of uPA suggest that uPA facilitates pulmonary metastasis formation probably due to an increase in the invasive ability of tumor cells. The effects of PAI-1 and its antibody of HT-1 080-P4 cells suggest that PAI-1 may facilitate tumor cell lodgement in vessels and the anti-PAI-1 antibody could be able to suppress pulmonary metastases of tumor cells with high metastatic potential by inhibition of tumor cell lodgement in vessels.

Animals↗
PubMed1994

Effect of type-1 plasminogen activator inhibitor on human leukocyte elastase.

When human leukocyte elastase (HLE) activity (1.0 microgram/ml) was analysed in the presence of PAI-1 (0.15.0 micrograms/ml), HLE activity, measured with the low molecular weight paranitroanilide substrate L-pyroglutamyl-prolyl-L-valine-p-nitroanilide was increased time and dose dependently (a plateau of stimulation was reached after 30 minutes) with a simultaneous decrease in PAI-1 inhibitory activity. This effect was neither influenced by the presence of vitronectin nor heparin. When PAI-1 was converted into its latent form by incubation for 48 hours at 37 degrees C or incubated with an excess of recombinant t-PA to convert free PAI-1 into t-PA-PAI-1 complexes, the stimulatory effect of both the latent and the complexed form of PAI-1 was significantly greater than that of the active form. Analysing HLE PAI-1 interaction on a molecular level using SDS-PAGE, no SDS stable complex formation between HLE and PAI-1 could be observed but lower molecular weight cleavage products of PAI-1 were generated. The stimulatory effect of PAI-1 on HLE activity was not restricted to the low molecular weight pNA-substrate but was also revealed using a natural substrate assay (bovine neck ligament elastin solubilization). Therefore interaction of HLE and PAI-1 seems not to be restricted just to decrease PAI-1 activity but would simultaneously also increase HLE activity, thereby supporting enzymatic activity necessary for migration of leukocytes, dissolution of blood clots and tissue remodelling.

Glycoproteins↗
PubMed1992

A rapid and sensitive method for HLA-DRB1 typing by acridinium-ester-labeled DNA probes.

A rapid and accurate detection of HLA class II antigen is essential for transplantation and for the understanding of disease susceptibility. Recent molecular genetic studies have revealed that the number of class II loci and the number of alleles at these loci are greater than had been previously detected. It is, therefore, of great importance to detect these extensive polymorphisms. A great deal of effort has been made on identification of individual HLA class II specificities at the DNA level, called "DNA typing." What seems to be lacking, however, is handling simplicity. Here we accomplished a simple method for HLA-DRB1 typing based on hybridization of acridinium-ester (AE)-labeled DNA probes to amplified DNA. This method is called hybridization protection assay (HPA). By using 13 AE-labeled probes, 20 homozygous B-cell lines and leukocytes from 80 healthy individuals were typed by HPA. The results were completely consistent with those obtained by polymerase chain reaction--restriction fragment length polymorphism. This method is suitable for mass screening because of its procedural simplicity and swiftness.

Acridines↗
PubMed1992

A chimeric analog of human and salmon calcitonin eliminates antigenicity and reduces gastrointestinal disturbances.

The minimum region in salmon calcitonin (sCT) which induces antigenicity and gastrointestinal disturbances has been identified by examining the cross-reactivity of several sCT fragments and CT analogs with antisera from sCT-treated patients, and by examining inhibition of gastrointestinal motility of these sCT fragments and CT analogs in conscious dogs. Sixteen residues at the N-terminus of sCT comprised the minimum fragment capable of inducing both activities. Human CT (hCT) showed no antigenicity and a four-order weaker inhibition of gastrointestinal motility than sCT. Based on these data, we synthesized the human and salmon chimeric CT, ACT-15, in which the 16 N-terminal residues were those of hCT and the 16 C-terminal residues were those of sCT. ACT-15 had no cross-reactivity with the antisera and had almost the same weak gastrointestinal inhibition effect as hCT in dog and rat models. Nevertheless, it retained a hypocalcemic activity and an analgesic activity comparable to sCT. These results suggest that the amino acid residues in the N-terminal half of CT are responsible for the formation of antibodies and the induction of gastrointestinal disturbances, but may not influence calcium metabolism or analgesia. Clinical studies of ACT-15 will be needed to confirm this hypothesis.

Amino Acid Sequence↗
PubMed1992

Ultrastructural and cytochemical study of the odontoclasts in physiologic root resorption of human deciduous teeth.

Using extracted human deciduous teeth undergoing physiologic root resorption, this author studied the ultrastructural and cytochemical features of odontoclasts. The scanning electron microscopic observation of trypsin-treated dentin and cementum surfaces of resorption lacunae showed the exposure of collagen fibrils and prominent loss of the peritubular matrices around the dentinal tubules. In the resorption lacunae formed in enamel, there was dissolution of either the rod or the interrod regions. The odontoclasts developed extensive ruffled borders apposed to these resorbing matrices and had round phagosomes containing tannic acid-stainable fine amorphous inclusions, which were identical to those in the extracellular canals of the ruffled borders. The odontoclasts did not phagocytose the collagen fibrils. The odontoclasts showed the enzymatic activities of the acid trimetaphosphatase and acid p-nitrophenyl phosphatase (p-NPPase) in the Golgi-lysosome system, the ruffled border region, and along the resorbing dentin surfaces. The p-NPPase activity was inhibited by sodium tartrate. Also, the odontoclasts showed H(+)-K(+)-ATPase activity in the cytoplasm along the plasma membranes including those of ruffled border and the limiting membranes of the lysosomes. These results suggest that: 1) the odontoclasts are associated with resorption of non-collagenous organic matrices and/or extracellularly-degraded collagenous fragments rather than the incorporation of intact collagen fibrils; 2) the odontoclasts release the hydrolytic enzymes onto the lacunal surfaces and/or the lysosomes for the extra/intracellular degradation of the organic matrices; and 3) they also have H(+)-K(+)-ATPase for extracellular demineralization of the inorganic crystals.

4-Nitrophenylphosphatase↗
PubMed1987

Moving topography of human presaccadic spike potentials in visually triggered saccade and optokinetic nystagmus.

The spatio-temporal nature of presaccadic spike potentials (SP) associated with the visually evoked saccade and with the fast phase of optokinetic nystagmus was investigated by means of moving electroencephalographic topography. In both cases, SPs were recognized about 15-25 msec before the quick eye movements (peak time 3-7 msec). The amplitude of SPs was +5 to +7 microV for the visually guided saccade and +3.5 to +4.5 microV for optokinetic nystagmus. The location of the SPs was the mid-parieto-occipital region on the scalp, but their topographical character was that of a brainstem potential. In the case of the visually guided saccade, before the appearance of SP, an antecedent potential in the form of a slow positive charge appeared in the parietal region. From their spatio-temporal characteristics, the SPs investigated in this study were interpreted as mass potentials of the brainstem nuclei which generate eye movements.

Action Potentials↗
PubMed1979

Dectection of spinal cord lesion using skin electrode recordings of spinal evoked potential.

The multi-channel recording of somatosensory spinal evoked potential (SSEP) was carried out on 30 patients with various neurological disorders. In some cases, SSEP changes corresponded well with the lesioned level. In general, the lesions of thoraco-cervical level were difficult to detect, because the appearance rate of SSEP peaks are reduced over the thoraco-cervical spine even in normal controls. In cases with spinal type of MS, SSEP revealed marked changes and subclinical sensory demyelinating lesions were detectable. Chronological SSEP recording in patients with acute transverse myelitis revealed functional improvements corresponding with clinical recovery. Surface and non-invasive SSEP recording is useful for detecting lesions in the spinal cord or peripheral nerves. It also offers valuable information about chronological modification of the lesions, and may reveal subclinical changes in certain neurological disorders.

Adolescent↗