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K Mochizuki

Publications and source records attributed to K Mochizuki.

At least 19 recordsLinked to original sources
PubMed1992

[Magnetic resonance (MR) imaging of chordoma and chondroma in the skull base--differential diagnosis by IR sequence].

Differential diagnosis of chordoma and chondroma in the skull base is sometimes difficult. We retrospectively reviewed the MR images of 14 patients with skull base tumors (nine chordomas, four chondromas and one chondrosarcoma). MR imaging was performed with a 0.5 Tesla system (Picker International). Inversion recovery (IR) (2500-2100/600-500/40), T1-weighted spin echo (SE) (800-600/40), and T2-weighted SE (2500-1800/120) images were obtained. On IR images, seven of eight chordomas showed heterogeneous low signal intensity, and one chordoma and all chondromas showed markedly low signal intensity similar to that of CSF. Calcified or ossified portions of the chondromas were demonstrated as areas of moderately low intensity on IR images. Chondrosarcoma showed moderately low intensity similar to that of chordoma. T1-weighted SE images of chordoma and chondroma showed no difference in signal intensity. On T2-weighed SE images, six of nine chordomas and all chondromas showed markedly high signal intensity. Three chordomas and one chondrosarcoma showed moderately high signal intensity. In the diagnosis of skull base tumors, the IR sequence seems to be useful for differentiating chondroma from chordoma.

Adolescent↗
PubMed1992

Different preparations of zymosan induce glycogenolysis independently in the perfused rat liver. Involvement of mannose receptors, peptide-leukotrienes and prostaglandins.

Zymosan (non-boiled) induced glycogenolysis biphasically, with no lag time, in the perfused rat liver. After the zymosan was boiled, it could be separated into two fractions, both of which stimulated glycogenolysis independently. The soluble fraction of boiled zymosan (zymosan sup) showed homologous desensitization, indicating that zymosan sup-induced glycogenolysis is a receptor-mediated event. Mannan (polymannose), which is known to be a biologically active component of zymosan, induced a glycogenolytic response similar to that produced by zymosan sup, and desensitized the response to the latter. Preinfusion of platelet-activating factor (PAF, 20 nM) or isoprenaline (10 microM) did not extinguish the glycogenolytic response to zymosan sup, while the response to a secondary infusion of PAF was blocked. The glycogenolytic response to zymosan sup was completely inhibited by nordihydroguaiaretic acid (NDGA, 10 microM), a lipoxygenase inhibitor, and by ONO-1078 (100 ng/ml), a leukotriene (LT) D4 receptor antagonist. On the other hand, the glycogenolytic effect of zymosan pellet (the particulate fraction of boiled zymosan) was not affected by preinfusion of zymosan sup, and was inhibited by ibuprofen (20 microM), a cyclo-oxygenase inhibitor. Prostaglandins (PGs) detected in the perfusate were augmented with infusion of zymosan pellet. Opsonization of the zymosan pellet by serum (complement) enhanced the glycogenolytic response without a lag period, and with a concomitant enhancement of PG output. Correlations between glucose production and PGs were r = 0.832 (PGD2), r = 0.872 (PGF2 alpha), r = 0.752 (PGE2) and r = 0.349 (6-oxo-PGF1 alpha). The glycogenolytic response to non-boiled zymosan was delayed and the biphasic glycogenolytic response was not observed when mannan was infused first. NDGA mimicked the effects of the preinfusion of mannan, while ibuprofen had no effect on the non-boiled-zymosan-induced glycogenolysis. These results suggest: (1) that non-boiled zymosan stimulates glycogenolysis through a mannose receptor-dependent, but unidentified, pathway, (2) that zymosan sup induces glycogenolysis via mannose receptor activation through the production of peptide-LTs but not PAF, and (3) that zymosan pellet causes glycogenolysis through the production of prostanoids, which is enhanced in the presence of complement.

Animals↗
PubMed1992

Single site hydrolysis of 2',3'-O-(2,4,6-trinitrophenyl)-ATP by the F1-ATPase from thermophilic bacterium PS3 is accelerated by the chase-addition of excess ATP.

The interaction of 2',3'-O-(2,4,6-trinitrophenyl)-adenosine 5'-triphosphate (TNP-ATP) and TNP-ADP to F1-ATPase from a thermophilic bacterium PS3 (TF1) was investigated. When TNP-ADP or TNP-ATP was added to the isolated alpha or beta subunit of TF1, characteristic difference spectra were generated for each subunit. Difference spectra generated on addition of these analogs to TF1 resembled those observed for the beta subunit, indicating TNP analogs bind to the beta subunits in the molecule of TF1. Results of equilibrium dialysis showed that TNP-ADP binds to a single high affinity site on TF1 in the presence of Mg2+ with a dissociation constant of 2.2 nM. When TNP-ATP was added to TF1 in a substoichiometric molar ratio, it rapidly bound to TF1 and was slowly hydrolyzed. The hydrolysis proceeded nearly to completion without showing stable equilibrium between bound species of TNP-ATP and TNP-ADP. Similar to beef heart mitochondrial F1, this hydrolysis was greatly accelerated by the chase-addition of 100 microM ATP. However, the hydrolyzed product, TNP-ADP, remained bound on the beta subunit even after the chase.

Adenosine Diphosphate↗
PubMed1992

Atrial natriuretic peptide (ANP): a study of ANP and its mRNA in cardiocytes, and of plasma ANP levels in non-obese diabetic mice.

Atrial natriuretic peptide (ANP) levels in cardiocytes and plasma were examined by using immunohistochemistry, electron microscopy, and radioimmunoassay in non-obese diabetic mice (NOD). Cardiocyte ANP mRNA expression was measured by the polymerase chain reaction method. ANP immunoreactivity in the auricular cardiocytes was more prominent in hyperglycemic mice (NOD-h) than in normoglycemic mice (NOD-n). Ultrastructural examination showed that auricular cardiocytes of the NOD-h group contained more cytoplasmic granules than cells of the NOD-n group. Ultrastructural morphometry indicated that the number of granules per auricular cardiocyte was significantly larger in the NOD-h group than in the NOD-n group (P less than 0.01), whereas the granule diameter was significantly smaller in the NOD-h group (P less than 0.01). Radioimmunoassay showed that ANP levels in the NOD-h auricular cardiocytes were significantly higher than those in the NOD-n cardiocytes (P less than 0.01); the opposite was true in plasma. Cardiocyte ANP mRNA expression was lower in the NOD-h group than in the NOD-n group.

Animals↗
PubMed1992

Serodiagnosis of cancers by ELISA of anti-histone H2B antibody.

An enzyme-linked immunosorbent assay method for serodiagnosis of cancers was developed by employing histone H2B. This method measures anti-histone H2B antibody levels in sera and includes a device for coating the plastic immunoplate with a mixture of histone H2B and diluted fetal calf serum. The coating of immunoplates with this mixture decreased apparent sensitivity of the assay compared with that in the absence of fetal calf serum, but effective reduction of nonspecific background enabled a specific assay of anti-histone H2B antibody with excellent reproducibility. By this method cancer patients were discriminated from normal healthy subjects at detection rates of 37% for lung cancer, 33% for liver cancer, 50% for pancreatic cancer, 42% for colon cancer, and 78% for cervical cancer. However, stomach and esophagus cancers showed detection rates of less than 17%, which are comparable to the values for benign diseases. It is likely that this assay method detects squamous cell carcinomas at relatively high rates.

Antibodies, Neoplasm↗
PubMed1992

Impairment of macrophage function in Mongolian gerbils.

Chemiluminescence studies on superoxide generation by phagosomes using opsonized zymosan showed the highest fluorescence in murine splenic macrophages among four different kinds of splenic or peritoneal macrophages from mice or gerbils. Murine splenic macrophages phagocytized two to three times more latex particles than gerbil splenic macrophages, but peritoneal macrophages did not show a significant difference in phagocytic activity between mice and gerbils. Phagocytosis by macrophages was determined by a technique based on measurement of the release of hydrogen peroxide and myeloperoxidase from phagosomes using microspheres conjugated with 3-(p-hydroxyphenyl) propionic acid (HPPA-MS). HPPA is a substrate of lysosomal myeloperoxidase. The fluorescence of HPPA-HPPA-MS produced by phagocytized HPPA-MS was measured with an immunoreaction analysis system (IMRAS), and the enzyme activities of the four different kinds of peritoneal or splenic macrophages from mice and gerbils were compared. All four kinds of macrophages produced HPPA-HPPA-MS in their phagosomes during phagocytosis and murine splenic macrophages showed the highest level of enzyme activity.

Animals↗
PubMed1992

Intramedullary spinal cord tumors: significance of associated hemorrhage at MR imaging.

Magnetic resonance (MR) images obtained in 35 patients with intramedullary spinal tumors were reviewed. Hypointense areas on both T1- and T2-weighted images were seen within or around eight tumors, all of which were in the cervical cord. Hypointensity at the tumor margin was seen in seven cases. Hypointensity within the tumor was seen in two cases. (One case had both types of hypointensity). In seven surgically confirmed cases, hypointensity at the tumor margin was found to be a relatively firm pseudocapsule, and hypointensity within the tumor corresponded to intratumoral hematoma. All of the tumors with hypointensity were ependymomas at histologic examination. When MR imaging shows an intramedullary tumor with hypointensity at the tumor margin, it is suggestive, but not pathognomonic, of an ependymoma.

Adult↗
PubMed1992

Intraocular kinetics of ceftazidime (Modacin).

The concentration of ceftazidime was determined in the aqueous humor and the vitreous body of normal, vitrectomized and aphakic/vitrectomized eyes and in the serum of albino rabbits 1 h after intravenous injection of 100 mg/kg ceftazidime. The intravitreal ceftazidime concentration was low (0.1-0.2 microgram/ml) in normal eyes 1 h after intravenous injection, and high (8.7 +/- 8.5 micrograms/ml) in vitrectomized and aphakic/vitrectomized eyes when injected immediately after surgery. The ceftazidime concentration was also determined in the aqueous humor and the vitreous body of normal eyes and in the serum of albino rabbits 3, 6, 12, 24 and 48 h after intravitreal injection of 200 micrograms. The intravitreal ceftazidime concentration after intravitreal injection decreased exponentially for 12 h (half-life about 7.4 h). It decreased more slowly thereafter and remained at 13.0 micrograms/ml (mean) even 48 h after injection. This concentration exceeded the minimum inhibitory concentrations against common gram-positive and gram-negative organisms causing endophthalmitis.

Animals↗
PubMed1992

Characterization of a plant SINE, p-SINE1, in rice genomes.

We have previously found that a short interspersed element (SINE), named p-SINE1, is present in the Waxy gene of Oryza sativa in two copies. Here, we cloned five members of p-SINE1 located at other loci in O. sativa and determined their nucleotide sequences. These sequences had a T-rich pyrimidine tract at their defined 3' end and were flanked by direct repeats of a sequence of mostly 14-15 bp long like p-SINE1s in the Waxy gene. The consensus sequence derived from total seven members of p-SINE1 was 123 bp in length and had an internal promoter region for RNA polymerase III. The 5'-half region of the sequence was partially homologous to the tRNA-related block of rabbit C family, one of SINEs in the animal system. Two of the seven p-SINE1 members were not present in the corresponding loci in African rice, Oryza glaberrima, and may thus be available for classification of some rice strains. Comparison of the nucleotide sequences of the Waxy gene between O. sativa and O. glaberrima showed that base substitutions have frequently occurred in a p-SINE1 member (p-SINE1-r1) and a transposable element Tnr1 also present in the Waxy gene, suggesting that these elements, which appear as repetitive sequences in the rice chromosome, tend to acquire base substitutions at a higher frequency than do unique sequences.

Base Sequence↗
PubMed1992

Fine structure of atrial natriuretic peptide (ANP)-granules in the atrial cardiocytes in the hamster, guinea pig, rabbit, cat and dog.

In the hamster, guinea pig, rabbit, dog and cat, the right and left atria and ventricles were examined by immunohistochemistry, and the right auricular cardiocytes were studied by transmission electron microscopy. Moreover, ANP-granules in the cardiocytes were analyzed by ultrastructural morphometry. Immunohistochemically, the most intensely ANP-reactive cardiocytes were localized in the right auricle, particularly more prominent in the hamster and guinea pig than in the rabbit, dog and cat. The immunoreaction in the dog and cat was weaker than that in the rabbit. ANP-immunoreactivity was not detected in the ventricular myocardium of any of all species examined, but was occasionally observed in the subendocardium of the ventricular septum. Ultrastructurally, ANP-granules were localized principally in the perinuclear region associated with the Golgi apparatus and scattered throughout the sarcoplasmic layers. The Golgi apparatus of the cardiocytes was better developed in the hamster and guinea pig than in the rabbit, dog and cat. It was poorly-developed in the dog and cat. By ultrastructural morphometry, the number of granules was greatest in the hamster followed by the guinea pig, rabbit and dog or cat, in this order. On the other hand, the diameter of granules was largest in the guinea pig and reduced via the hamster to the rabbit. The diameter was significantly smaller in the dog than in the rabbit. The diameter of granules of the cat was lay between the rabbit and dog.

Animals↗
PubMed1992

Effect of intravitreal injection of norfloxacin on the retina in pigmented rabbits.

The effect of an intravitreal injection of norfloxacin on the retina was evaluated by in-vivo electroretinogram (ERG) and histological examination in pigmented rabbits. The intraocular pharmacokinetics after an intravitreal injection of norfloxacin were also investigated. An intravitreal injection of 50 micrograms norfloxacin produced no significant change in the ERG. An injection of 500 micrograms norfloxacin decreased the amplitude of the oscillatory potentials, and delayed their peak latencies 3 hours after the injection, but these changes recovered within 7 days. A marked suppression of the c-wave was noted in one pigmented rabbit. Neither 50 micrograms nor 500 micrograms norfloxacin caused any apparent changes in the visual evoked potential and in the retinal histology 7 days after the injection. The intraocular pharmacokinetic study showed that the concentration of norfloxacin in the choroid-retina was almost the same level as that in the vitreous body 3 hours after the injection. However, the former was higher than the latter 7 days after the injection, suggesting the persistency of norfloxacin in the choroid-retina. An intravitreal injection of 50 micrograms norfloxacin could be used without retinal toxicity. A high dose-intravitreal use of norfloxacin needs careful attention with respects to its persistency in the pigmented ocular tissues.

Animals↗
PubMed1992

Intraocular penetration and effect on the retina of fluconazole.

The intraocular concentration of fluconazole was measured in nonvitrectomized and vitrectomized eyes after an intravenous administration of 5 or 25 mg/kg fluconazole in albino rabbits. Respective fluconazole concentrations in the aqueous, vitreous and serum 1 hour after administration were 2.87, 1.72 and 4.60 micrograms/ml at 5 mg/kg administration, and 14.93, 7.05 and 20.63 micrograms/ml at 25 mg/kg administration, indicating high and dose-dependent intraocular penetration of fluconazole. Intraocular penetration of intravenously administered fluconazole was moderately, not very much, enhanced by vitrectomy. The in-vitro electroretinogram (ERG) remained unchanged after perfusion with 20 micrograms/ml of fluconazole. The in-vivo ERG and the visual evoked potential was unchanged after the daily administration of 25 mg/kg fluconazole for 8 days. The toxicity of fluconazole on the retina would be low and within safety limits so far as it is used at clinical dosage. Fluconazole may have a place in the treatment of fungal ocular infections.

Animals↗
PubMed1991

Fine structure of atrial natriuretic peptide(ANP)-granules in the atrial cardiocytes in the pig, cattle and horse.

In the pig, cattle and horse, the right and left atria and ventricles were examined by immunohistochemistry, and the right atrial and auricular cardiocytes were studied by transmission electron microscopy. Moreover, ANP-granules in the cardiocytes were analyzed by ultrastructural morphometry. Immunohistochemically, the most intensely ANP-reacted cardiocytes were localized in the right auricle, particularly more prominent in the pig and cattle than in the horse. Ultrastructurally, ANP-granules were located principally in the perinuclear region associated with the Golgi apparatus and throughout the sarcoplasmic layers. They were classified into 2 types, A and B. A-granule had a conspicuous electron-dense core enveloped by a membrane. B-granule had a fibrillogranular core enveloped by an indistinct membrane. By TEM equipped with a goniometer stage, a part of the limiting membrane of B-granules became visible as the stage tilt progressed. By ultrastructural morphometry, the number of each type of granules was significantly greater in the pig and cattle than in the horse. In the pig and cattle, the total number of both types of granules in the auricular cardiocytes was significantly greater than that in the atrial ones. The diameter of each type of granules was significantly larger in the pig and cattle than in the horse. The diameter of A-granules was significantly larger than that of B-granules.

Animals↗
PubMed1991

Fine structure of atrial natriuretic peptide (ANP)-granules in the atrial cardiocytes of the mouse, rat and Mongolian gerbil.

Mouse, rat and Mongolian gerbil atrial and ventricular cardiocytes were examined by immunohistochemistry, and the right atrium including the auricle was examined by transmission electron microscopy. In addition the ANP granules of both right atrial and auricular cardiocytes were analyzed by ultrastructural morphometry. ANP immunoreactivity was detected in the atria of all three species, and the most intensely reacting cardiocytes were localized in the right auricular part of the atrium. These reactions were more prominent in the mouse and rat than in the Mongolian gerbil. ANP immunoreactivity was not detected in the ventricular myocardium of any of the three species, but was occasionally seen in the subendocardium of the ventricular septum. Ultrastructurally, the ANP granules in the auricular and atrial cardiocytes were observed to be variable in size and number, and these granules were located principally in the paranuclear region in association with the Golgi apparatus, and found throughout the sarcoplasmic layers in all three species. The ANP granules were classified into two types: A-granules containing a conspicuous electron-dense core possessing a membrane, and B-granules having profiles with a fibrillogranular, less electron-dense core than the A-granules and an indistinct membrane. The features of these granules were similar in all three species. When examined by ultrastructural morphometry, the number of each type granule and the total number of granules in the right auricular and atrial cardiocytes of the mouse and rat were significantly greater than in the Mongolian gerbil. The total number of granules in the right auricular cardiocytes was significantly greater than in the cardiocytes of the right atrium exclusive of the auricle, however, there was no significant difference between the number of A-granules and B-granules in the three species. The diameter of each type of granule in the right auricular and atrial cardiocytes of the mouse and rat was significantly greater than in the Mongolian gerbil, and the diameter of the A-granules was significantly greater than the diameter of the B-granules in all three species.

Animals↗
PubMed1991

Fine structure of the atrial cardiocytes in the house musk shrew (Suncus murinus).

The atrial and ventricular cardiocytes of the house musk shrew were examined by immunohistochemistry, and the right atrium containing the auricle was studied by transmission electron microscopy. The atrial natriuretic peptide (ANP)-granules of the cardiocytes in the auricle and the rest of the atrium were also analyzed by ultrastructural morphometry. On immunohistochemistry, ANP immunoreactivity was detected in the atria, with the most intensely reacting cardiocytes being localized in the right auricular part of the atrium. ANP immunoreactivity was not detected in the ventricular muscles. On ultrastructure, in most of the atrial cardiocytes including the auricle, ANP-granules, well-developed Golgi apparatus and rough endoplasmic reticulum were observed, and the nuclei were characteristically situated in the periphery of the cardiocytes, being different from many other mammalian hearts. The ANP-granules were classified into two types (A and B), with most of these granules being located in the paranuclear region in association with the Golgi apparatus, and a few ANP granules being observed throughout the sarcoplasmic layers intervening between the myofibrilar bundles. On ultrastructural morphometry, the total number of granules in the right auricular cardiocytes was significantly greater than those in the atrial cardiocytes, and the diameter of the A-granules was significantly greater than that of the B-granules in both the atrial and auricular cardiocytes.

Animals↗
PubMed1991

Tissue culture study on Mongolian gerbil's (Meriones unguiculatus) malignant melanoma.

We tried to culture melanoma cells from a Mongolian gerbil's (Meriones unguiculatus) malignant tumor. In primary culture, most of cells have abundant melanin granules in their cytoplasm. Melanin granules decreased through 5 to 15 serial passages and disappeared after 15 th passage. The morphology of the cells varied from spindle to large polydendritic cells. Although typical melanin granules were not seen when the cells were stained by Masson-Fontana method, the cells were positive for DOPA reaction. Electron microscopically, most of the cells have well-developed Golgi apparatus and rough-surfaced endoplasmic reticulum with dilated cistern, and premelanosome-like granules were frequently observed in their cytoplasm.

Animals↗
PubMed1991

Atrial natriuretic peptide (ANP)-granules of auricular cardiocytes in aging Mongolian gerbils.

The atrial natriuretic peptide (ANP)-granules of right auricular cardiocytes were studied in aging Mongolian gerbils by immunohistochemistry and transmission electron microscopy, and analyzed by ultrastructural morphometry. Immunohistochemically, the ANP immunoreactions were weaker in 3 and 4-year-old animals than in 90-day-old, 1- and 2-year-old animals. There was no difference in the reaction among 90-day-old, 1 and 2-year-old animals, or between 3 and 4-year-old animals. Ultrastructurally, the morphological features in 1 and 2-year-old animals were similar to those of 90-day-old animals, but distinct in 3 and 4-year old animals by the presence of a few lysosomal structures in the cell. By ultrastructural morphometry, number and diameter of ANP-granules of 3 and 4-year-old animals were significantly smaller than those in the 90-day-old, 1 and 2-year-old. There was no significant difference in number and diameter among the 90-day-old, 1 and 2-year-old, or between the 3 and 4-year-old.

Aging↗