Biomedical subjects

K Mochizuki

Publications and source records attributed to K Mochizuki.

At least 109 records · Page 6Linked to original sources

PubMed1993

Enhanced production of human monoclonal antibodies by the use of fructose in serum-free hybridoma culture media.

It was found that the production of human monoclonal antibodies (MoAbs) by human-human hybridomas can be significantly enhanced by replacing glucose with fructose in the dish culture medium. Optimization of initial concentrations of fructose and glutamine, another influencing factor for MoAb production, enabled an enhanced production of human MoAb 2.1 times higher than that obtained using the conventional culture media employing glucose. It was shown by kinetic analysis that enhanced MoAb production at the optimum fructose concentration can be attributed to the retention of high specific antibody production rates and diminished time lag during the course of culture. These dish culture results with fructose-containing medium were successfully applied to the continuous perfusion culture with a slight modification, where 2.9- and 1.9-fold enhancements in specific antibody production rate and MoAb concentration, respectively, were attained as compared with the conventional glucose-containing medium. An inverse relationship was observed between the secreted concentrations of lactic acid and MoAb when the hybridoma was cultured in the media containing varying concentrations of fructose, i.e., the lower the lactic acid concentration, the higher the MoAb production and vice versa, suggesting that fructose at appropriate concentrations in the medium can serve as an alternative sugar for the efficient production of human MoAbs, with reduced pH shifts, for the serum-free culture of human-human hybridomas.

Antibodies, Monoclonal↗

PubMed1993

Effects of probucol and pravastatin on plasma lipids, activities of postheparin lipoprotein lipase, and lecithin cholesterol acyltransferase and apo A-I containing lipoproteins with and without apo A-II in patients with moderate hypercholesterolemia.

In this study, plasma HDL fractions were separated by ultracentrifugation and apo A-I containing lipoproteins (A-I Lp) were then isolated using anti-apo A-I immunoaffinity chromatography. The A-I Lp were further separated into two fractions with the use of anti-apo A-II immunoaffinity chromatography. One fraction, Lp A-I, contained apo A-I without apo A-II, while the other, Lp A-I/A-II, contained both apo A-I and apo A-II. These techniques were applied to investigate the changes in HDL apoprotein composition in hypercholesterolemic subjects treated with either probucol or pravastatin. Treatment with probucol (500 mg/day) or pravastatin (10 mg/day) reduced mean plasma total cholesterol concentrations by 24% (p < 0.01) and 16% (p < 0.05), respectively. Both drugs caused some reduction in lipoprotein lipase activity, but neither had any influence on the activity of hepatic triglyceride lipase or lecithin cholesterol acyltransferase. Their effects on HDL-cholesterol levels and apoprotein composition differed markedly. Probucol significantly decreased the HDL-cholesterol concentration, the plasma apo A-I/apo A-II ratio, and the number of large particles of diameter greater than 10.4 nm. When the ratios of Lp A-I and Lp A-I/A-II for the probucol-treated subjects were compared with those in the normolipidemic controls, and with the ratios before and after administration of probucol, a remarkable decrease in the level of Lp A-I was apparent. It is presumed that the decrease in HLD-cholesterol by prolonged probucol administration reflects the decrease of Lp A-I more than the decrease of Lp A-I/A-II.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein A-I↗

PubMed1993

Magnesium regulates both the nucleotide binding and the enzyme activity of isolated chloroplast coupling factor 1.

The inactivation and the activation of the ATPase of isolated CF1 as assayed by the hydrolysis of ATP in 10 s depended on prior binding of ADP-Mg and ATP-Mg. The effects of Mg2+ on the nucleotide binding kinetics were studied by monitoring the time courses of UV spectral changes induced by the interaction between CF1 and ADP or ATP using a rapid-scan spectrophotometer equipped with a stopped-flow cell. The apparent rate constant of ADP binding to the two high-affinity sites on CF1 (designated sites B and C in the previous report [Hisabori, T. & Sakurai, H. (1984) Plant Cell Physiol. 25, 483-493]) was drastically increased by prior binding of Mg2+ to CF1, but not ATP. The inhibitory effect of Mg2+ was attributed to a marked increase in kon for the inhibitory ADP binding at the high-affinity sites induced by the previous binding of Mg2+ to the enzyme. The location of site B is suggested to be on the beta subunit based on the difference spectral change induced by binding of the ADP analog 2',3'-O-(2,4,6-trinitrophenyl)ADP to CF1.

Adenosine Diphosphate↗

PubMed1993

Intravitreal flomoxef sodium in rabbits.

We studied the intraocular concentration of flomoxef sodium in nonvitrectomized and vitrectomized eyes of albino rabbits after intravenous administration of 100 mg/kg flomoxef sodium. The concentration of flomoxef sodium in the vitreous body was undetectable (< 0.1 micrograms/ml) in nonvitrectomized eyes. Retinal toxicity of flomoxef sodium was investigated with ophthalmoscopy, electroretinography (ERG) and light microscopy after intravitreal injection of 200, 500, 1,000 and 2,000 micrograms flomoxef sodium in albino and pigmented rabbits. No ERG changes were induced with 200 micrograms. Other higher doses caused transient ERG changes. After the 200-micrograms injection, the intravitreal concentration decreased exponentially, the half-life being 4.4 h. The antibacterial activity, broad coverage and low intravitreal toxicity of flomoxef sodium suggest that this compound may be used to treat bacterial endophthalmitis.

Animals↗

PubMed1993

Sudden blindness in the fourth month of pregnancy led to diagnosis of moyamoya disease.

We report a 31-year-old woman in her 4th month of pregnancy who presented with a sudden decrease in her right visual acuity. The right ocular fundus showed marked retinal edema and a cherry-red spot. A cranial computerized tomographic scan showed cerebral infarction. Cerebral angiography disclosed moyamoya disease. Ischemia of the ophthalmic artery due to constriction of the origin of the internal carotid artery and hypercoagulability due to pregnancy have presumably caused visual impairment in this patient.

Adult↗

PubMed1993

Classification and relationships of rice strains with AA genome by identification of transposable elements at nine loci.

We analyzed the presence of p-SINE1 members at five loci in the rice strains belonging to seven species with AA genome in the Oryza genus by the methods including polymerase chain reaction (PCR). Four p-SINE1 members (p-SINE1-r3, r4, r5 and r7) were present at the corresponding loci in all the strains examined. One member (p-SINE1-r6) was, however, not present at the corresponding locus in most of the African strains of O. glaberrima and O. barthii, but was in the other strains. The PCR-amplified fragments containing p-SINE1-r4 in many strains were found to be larger due to insertion of either one of two transposable elements, named Tnr2 and Ret1, within or near p-SINE1-r4, respectively: Tnr2 is 157 bp in length with terminal inverted repeat sequences of about 56 bp; Ret1 is only 13 bp in length with a T stretch at its end. Tnr2 was not present in the corresponding locus in all the strains belonging to O. sativa Japonica and in some strains of O. rufipogon and O. longistaminata, while Ret1 was present only in the two strains of O. longistaminata. These results and previous ones obtained from the analysis of the other two p-SINE1 members (p-SINE1-r1 and r2) in the Wx gene indicate that the elements, such as p-SINE1-r6, Tnr2, Ret1 and p-SINE1-r2, have been inserted into the respective loci during divergence of the rice species with AA genome. The patterns for the presence and absence of the transposable elements at the respective loci enabled us to classify the rice strains with AA genome into ten groups and to infer their relationships.

Base Sequence↗

PubMed1993

Characterization of cultured cells derived from Mongolian gerbil's (Meriones unguiculatus) ascitic malignant melanoma.

A cell line was established from a Mongolian gerbil's (Meriones unguiculatus) homotransplantable malignant melanoma. Ascitic tumor cells detected in a gerbil when transplanted intraperitoneally were adapted to culture. In primary culture, cells were divided into 2 types, multipolar and polygonal cells. Cell masses which adhered to polygonal cells were observed after the 6th passage. The adhering cells were removed and transferred into another flasks. The cells showed multipolar and possessed projections. Then after, the cells increased in number vigorously and formed acinous structures. At early passages, abundant melanin granules in some of the cells were demonstrated by light and electron microscopical observations. Most of the cells were positive by DOPA reaction. Melanin pigments were gradually decreased through the 20th to 30th passage and most of cells became amelanotic. The doubling time of the cell line was 32 hr. Chromosome number of the cell line ranged from 68 to 82. Whitish tumors were produced in the abdominal cavity within 30 days when intraperitoneally inoculated the cells to gerbils. This cell line, designated as MGM-A, has been subcultured for more than 100 passages during 2 years.

Animals↗

PubMed1993

Developmental changes in paramesonephric and mesonephric ducts and anogenital distance in fetal Mongolian gerbils during sexual differentiation.

On day 13 of gestation in Mongolian gerbil fetuses, the mesonephric (Wolffian) duct was already visible. On day 14, the anlage of the paramesonephric (Müllerian) duct was first observed close to the mesonephric duct in both sexes at the cranial part of the mesonephros. Thereafter, the paramesonephric duct grew caudally in parallel with the mesonephric duct. On day 19, the duct reached the urogenital sinus. At this stage, the anogenital distance was significantly longer in male than in female. Also in male, the mesonephric duct was increased and the paramesonephric duct was decreased in diameter compared with those in female. These suggest that both testosterone and anti-Müllerian hormone are produced in fetal Mongolian gerbils at least before day 19 of gestation.

Anal Canal↗

PubMed1993

[Effects of lomefloxacin on the rabbit retina].

The effects of lomefloxacin on the in-vitro ERG were studied in the rabbit. The ERG was unchanged during perfusion with 100 microM lomefloxacin. The oscillatory potential was selectively diminished with 300 microM lomefloxacin. The suppressive effect of 300 microM lomefloxacin on the oscillatory potential was antagonized by 0.2 microM bicuculline or 0.2 microM picrotoxin. Bicuculline (0.2 microM) or picrotoxin (0.2 microM) antagonized the suppressive effect of GABA (50 microM) on the oscillatory potential. Bicuculline (1.0 microM) alone, picrotoxin (1.0 microM) alone or GABA (50 microM) alone did not augment the oscillatory potential. The findings of the present study suggested that lomefloxacin, a new quinolone agent, inhibits GABA receptor binding in the rabbit retina.

Animals↗

PubMed1993

Activity enhancement of a lung cancer-associated human monoclonal antibody HB4C5 by N-deglycosylation.

It has been known that the lung cancer-associated human monoclonal antibody HB4C5 comprises two lambda light chains of 30 and 32 kD and that the 30 kD species is exclusively responsible for the antibody activity. This study demonstrates that the two light chains were both N-glycosylated with glycosyl residues of different sizes, one of which was sensitive to neuraminidase and the other insensitive. Our unpublished data of DNA sequence for the light chain of this monoclonal antibody indicated that the light chain contains only one possible site for N-glycosylation, which located in the CDR-1. N-Deglycosylation of this monoclonal antibody under the denaturing condition resulted in the complete conversion of the two light chains into one identical polypeptide chain of 26 kD. Activity of this monoclonal antibody was found to be significantly enhanced by N-deglycosylation. All the facts described above consistently indicate that the activity of this monoclonal antibody is interfered with by the attachment of bulky glycosyl residues at the antigen binding site on the light chain. The N-deglycosylated antibody was stable under the storage conditions employed, suggesting that the glycosyl residues attached to the light chain do not play any important biological role except for interference with the antibody activity of binding antigen.

Adenocarcinoma↗

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↗