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Biomedical subjects

H Kitano

Publications and source records attributed to H Kitano.

At least 145 records · Page 8Linked to original sources
PubMed1990

Effect of anoxia on spontaneous discharges of the cochlear single unit in guinea pigs.

The present experiment examined the effect of anoxia on the spontaneous discharges of cochlear single units in guinea pigs; several additional animals were tested for the combined effect of anoxia and sodium salicylate. Following the induction of anoxia, initial increases in the number of spontaneous discharges were seen in 19 of the 34 cochlear single units tested. Neurons showing high frequencies during normal respiration tended toward increased rates of discharge during anoxia. In the 5 animals pretreated with sodium salicylate, remarkable increases in the spike rates were noted following the induction of anoxia.

Animals↗
PubMed1989

Direct examination of chemical kinetic laws by visual imagery. IV. Association processes between antigen- and fragmented antibody carrying fluorescent latex particles.

The binary association process was further examined by direct visual observation using a fluorescence microscope connected to an image-processing system and by a spectrophotometric method. In the present paper, we used human serum albumin (HSA)- and fragmented anti-HSA antibody-carrying fluorescent latex particles in order to attain higher sensitivities and exclude complexities that might be caused by dissociation of the association product. The rate constant of the binary association process was estimated to be 6.0 x 10(8) M-1 s-1 at 30 degrees C and pH 7.6. The activation parameters of the association process were evaluated. The effects of pH and viscosity of the suspension on the association process were also examined.

Antigen-Antibody Complex↗
PubMed1989

Kinetic study of the effects of solvation on the dimerization process of alpha-chymotrypsin.

The dimeric association process of alpha-chymotrypsin has been studied with the aid of a stopped-flow spectrophotometer at various temperatures and pH values. From the temperature dependences of the forward reaction rate constant (kf) and the equilibrium dimerization constant (KD), the reaction system observed here is concluded to be entropy-driven. The increase in entropy can be attributed to the release of water molecules from both the active site and the surface part of the protein molecule during the course of dimerization. From the pH dependences of the reaction rate constants and the equilibrium constant, the reaction is concluded to depend strongly on the dissociations of the site between the carboxyl group of the aspartic acid and imidazolyl group of the histidine residues (in the higher pH region), and the site between the imidazolyl group of the histidine and the carboxyl group of the tyrosine residue (in the lower pH region), respectively.

Chymotrypsin↗
PubMed1989

Intratemporal facial nerve neurinoma--case report.

A 59-year-old female had episodes of vertigo for 13 years, right tinnitus for 6 years, and right hearing difficulty for 2 years. She had no facial nerve dysfunction or other neurological deficits. Postcontrast computed tomography (CT) did not show abnormalities, but a wide, high-window CT scan revealed erosion of the petrous pyramid on the right side. Magnetic resonance imaging clearly delineated the entirety of a small tumor transecting the petrous bone. At operation a neurinoma was found to originate from the facial nerve proximal to the geniculate ganglion; it was totally removed. This case is unique in that she had a long history of signs and symptoms of acoustic nerve disturbance, but no facial nerve dysfunction whatsoever.

Cranial Nerve Neoplasms↗
PubMed1988

Mutual recognition between polymerized liposomes: enzyme and enzyme inhibitor system.

In order to examine the usefulness of polymerized liposomes as a model for cell membranes, a mutual recognition phenomenon between different liposomes on which complementary ligands were attached was examined. We used trypsin- and soybean trypsin inhibitor (STI)-carrying polymerized liposomes to attain high sensitivities. The STI which was immobilized on the polymerized mono-dienoylphosphatidylcholine liposome showed a definite inhibitory effect on the catalytic activity of the trypsin which was immobilized on another polymerized liposome, whereas the inhibitory effect of the STI which was immobilized on the di-dienoylphosphatidylcholine liposome was much smaller than that of the mono-dienoylphosphatidylcholine system because of the larger rigity of the di-dienoylphosphatidylcholine liposome. These results suggest that the mutual recognition between complementary ligands can be realized by using polymerized liposomes with a physical stability and moderate deformability as their carriers.

Cell Communication↗
PubMed1988

Prostaglandins in type II collagen-induced ear diseases.

This study examines the role of prostaglandins in type II collagen-induced inner ear disease. Hartley guinea pigs were immunized with type II collagen in complete Freund's adjuvant. Auditory brain stem response was measured initially and at 2, 3, 4, and 6 months after immunization. The presence of PGE2 and 6-keto-PGF1 alpha in the perilymph was determined by radioimmunoassay. Perilymph from immunized animals contained about five times more PGE2 and about three times more 6-keto-PGF1 alpha than the perilymph from control animals. However, the two groups showed no difference in the level of either PGE2 or 6-keto-PGF1 alpha in cerebrospinal fluid and serum. Immunized guinea pigs also showed evidence of hearing loss. The temporal bones showed the following changes: spiral ganglion degeneration; mild to moderate degeneration in the organ of Corti; and infrequent and very mild endolymphatic hydrops. Thus, prostaglandins might play an important role in the pathogenesis of type II collagen-induced inner ear disease.

Animals↗
PubMed1988

Functional properties of proteins immobilized on albumin microspheres.

Bovine serum albumin (BSA) microspheres with an average diameter of 12.5 micron were prepared by crosslinking of BSA molecules with glutaraldehyde in the presence of polymethylmethacrylate dissolved in chloroform-toluene. Trypsin and anti-human IgG antibody were immobilized onto their surfaces by the glutaraldehyde-activation method. The catalytic activity and storage stability of the immobilized trypsin were satisfactorily high. The enzyme immunoassay (EIA) method using BSA-microspheres as a solid phase has a high sensitivity (the minimum concentration of detectable antigen in the sample: 0.2 ng/ml) and a wide concentration range (final concentration 0.027-3000 ng/ml) for the detection of human IgG.

Enzyme-Linked Immunosorbent Assay↗
PubMed1987

Pulse injection analysis of the binding of serum proteins to porous polymer gels modified with formyl groups.

Highly porous spherical polymer gels were modified with formyl groups by a modified Friedel-Crafts reaction and the interaction of serum proteins with the modified gels were examined by pulse injection analysis. The introduction of formyl groups into the polymer greatly increases its protein-binding capacity, and the protein bound to the gel is not eluted by washing with acid, alkali or urea solution. The effects of temperature and the percentage of formyl group substitution on the binding capacity indicate that the binding process can be interpreted as initial approach of the protein to the polymer surface, caused by the hydrophobic interaction, followed by formation of a stable Schiff base between the polymer gel and the protein. Theoretical treatment of the elution behaviour of the protein from the polymer-packed column is also examined, with the assumption that there are three kinds of binding site in the polymer gel: surface, macropore and micropore regions. These polymers are shown to be useful for the removal of proteins from biological samples in clinical assays using immobilized enzymes.

Animals↗
PubMed1987

Serum osmolality in Menière's disease.

Serum osmolality in patients with Meniere's disease was measured by a Wescore 5100B osmometer to reveal the relationship between a vertiginous attack, the effect of isosorbide, the effect of glycerol, and the osmolality. The following results were obtained: First, the osmotic pressure of the control group ranged from 275 mOsm/kg to 285 mOsm/kg, and that of the Meniere's group ranged from 270 mOsm/kg to 290 mOsm/kg. Both groups showed normal distribution, and mean values of both were 284 mOsm/kg. There was no statistically significant difference between them with regard to serum osmolality. Second, patients with values of 283 mOsm/kg or less were more often in a vertiginous attack period, and patients with values of 284 mOsm/kg or more were more often in an attack-free period. Third, patients with values of 283 mOsm/kg or less were more often in the positive glycerol test group; those with values of 284 mOsm/kg or more were more often in the negative glycerol test group. Finally, there was no significant difference in serum osmolality between patients receiving isosorbide therapy and patients given no treatment.

Glycerol↗
PubMed1985

Binding of serum proteins to polymer gels. II. Binding mechanism to polyoxyphenol-formaldehyde gels.

The binding mechanism of proteins to an amorphous polymer gel [formaldehyde-hydroquinone (FA-HQ)], which is a product of addition condensation of hydroquinone with formaldehyde, is examined. Proteins such as serum albumin and gamma-globulin bound to the FA-HQ gel rapidly and irreversibly (without elution by acid, alkali, urea, or detergent solution). The binding of a modified bovine albumin to the FA-HQ gel showed that the blocking of the amino groups in the albumin molecule decreased the amount of protein bound to the gel. Amino acids bound to the FA-HQ gel to a larger extent at alkaline than at neutral pH. These results supported the essential role of the amino groups in binding to the FA-HQ gel. Using the FA-HQ gel-packed glass column or polymer tube, rapid and complete removal of proteins from serum could be carried out, which suggests the usefulness of the gel for the easy pretreatment of biological samples for clinical assays using immobilized enzyme columns.

Amino Acids↗
PubMed1985

Inhibitory effect of ouabain on the palytoxin-induced contraction of human umbilical artery.

Palytoxin (PTX), C129H223O3N54, isolated from marine coelenterates of Palythoa tuberculosa, caused contraction of the human umbilical artery in a dose-dependent manner (10(-11)-10(-8) M). Pretreatment with ouabain (10(-5) M) abolished the PTX (10(-8) M)-induced contraction but had no effect on the serotonin- (10(-6) M) and potassium- (40 mM) induced contractions. When the muscle was exposed to a potassium-free medium, application of PTX was able to cause a contraction similar to the contraction in normal medium. In the presence of verapamil (3 X 10(-6) M) or in the calcium-free medium. PTX-induced contraction was inhibited. In the depolarized muscle with 126 mM potassium, PTX did not induce a contraction whereas serotonin did. Our results suggest that PTX causes calcium influx through the plasma membrane of the umbilical artery, causing contraction. The site of action of PTX is presumably related to the Na,K-ATPase on the plasma membrane, although the precise relation between the site of action and increase in calcium influx is not known now.

Acrylamides↗
PubMed1985

Pressure effects on catalysis by alkaline phosphatase reconstituted in lipid bilayers.

Bovine intestinal alkaline phosphatase (EC 3.1.3.1) was reconstituted into lipid bilayers by a dilution method using n-octylglucopyranoside. From the kinetic measurements at various pressures, the volume of activation (delta V not equal to) and volume change in substrate binding (delta V) were estimated for free and reconstituted ALP. The delta V not equal to and delta V values for free ALP and reconstituted ALP in the gel state liposome showed opposite tendencies (-23 ml . mol-1 [delta V not equal to], 35 ml . mol-1 [delta V] for free ALP and 27 ml . mol-1 [delta V not equal to], -36 ml . mol-1 [delta V] for reconstituted ALP, respectively), which suggest both strong desolvation effect of enzyme molecule by the surrounding lipids and drastic conformational change of the enzyme molecule by the reconstitution into liposomes.

Alkaline Phosphatase↗
PubMed1984

Transuncodiscal approach to dumbbell tumors of the cervical spinal canal.

A combined anterior and lateral approach to the anterior cervical spinal canal with fusion was performed on five patients with cervical dumbbell-shaped tumors. The procedure consists of anterior discectomy and ipsilateral uncectomy, and removal of the posterolateral corners and posterior transverse ridges of the upper and lower vertebral bodies at the level of the tumor. In the case of a large tumor in the spinal canal, additional removal of a limited segment from the lateral part of the vertebral body was performed. The bone defect was filled with a T-shaped iliac bone graft. Two vertebral bodies were fused in each case. The highest level of the operation was C-2 and the lowest was T-1. The authors believe that any cervical dumbbell-shaped tumor below the C-2 level can be removed via an anterolateral approach as long as no more than three levels of the spine are involved.

Adult↗