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Biomedical subjects

Y Hata

Publications and source records attributed to Y Hata.

At least 271 records · Page 15Linked to original sources
PubMed1993

Roles of Ca2+ and protein kinase C in regulation of prostaglandin E2 release by cultured rabbit gastric epithelial cells.

Prostaglandin (PG) has been reported to be one of the important protective factors in the gastric mucosa. However the mechanism of the regulation of endogenous PG production has not been well studied. We investigated the possible roles of Ca2+, cAMP, and protein kinase C (PKC) in the regulation of PGE2 release from cultured rabbit gastric mucosal cells. PGE2 was measured by radioimmunoassay. A23187 (Ca2+ ionophore) at 2 x 10(-6) M significantly increased PGE2 release. Deprivation of Ca2+ from the medium blocked the A23187-induced increase of PGE2. TMB-8 (a putative inhibitor of Ca2+ release from intracellular stores) did not have any significant effects on the increase of PGE2-induced by A23187. Thus, A23187 increased PGE2 through the influx of extracellular Ca2+. W7 or compound 48/80 (calmodulin inhibitors) did not alter the response of PGE2 caused by A23187. Exogenous administration of cAMP, forskolin (an activator of adenylate cyclase), or 2-chloroadenosine (a possible activator of adenylate cyclase through adenosine A2 receptor) had neither significant effects on PGE2 release nor an effect on A23187-induced increase of PGE2 release. 12-O-tetradecanoylphorbol 13-acetate (TPA, an activator of PKC) significantly stimulated PGE2 release in a dose-dependent fashion, whereas another phorbol ester with no biological activity did not. A23187 at 0.8 x 10(-6) M, but not cAMP, potentiated the TPA-induced increase of PGE2. Mepacrine (a phospholipase A2 inhibitor) reduced the A23187- and TPA-induced increase of PGE2. These results suggest that Ca2+ and protein kinase C may play important roles in the regulation of PGE2 release by cultured rabbit gastric cells.

2-Chloroadenosine↗
PubMed1993

Anomalous excretion of bile and pancreatic juice in a patient with choledochal cyst.

The authors report the findings of endoscopic retrograde cholangiopancreatography in a 1-year-old girl with choledochal cyst; contrast dye injected through the common channel was excreted solely through the duct of Santorini. The obstruction to the bile and pancreatic juice caused by marked bending of the common channel was responsible for the abnormal drainage of bile and pancreatic juice.

Bile↗
PubMed1993

Regulation of deoxycytidine kinase activity and inhibition by DFDC.

(1) Deoxycytidine kinase activity increased in a transformation- and progression-linked fashion in rat hepatomas of different proliferation rates. The activity also increased and was growth rate-linked in a series of tissue culture cell lines of human and animal tumors. (2) Deoxycytidine kinase activity was stringently linked with expression of the neoplastic proliferative program as it sharply increased in log phase in tissue culture cells of hepatoma 3924A and several human carcinoma strains. (3) Deoxycytidine kinase is subject to nutritional and hormonal regulation. On starvation the activity in liver decreased and on refeeding it returned to normal. Steroid hormone increased liver enzymic activity. Deoxycytidine kinase is substrate-inducible, since deoxycytidine injections in rat led to a 2- to 3-fold increase in hepatic enzyme activity. (4) Actinomycin or cycloheximide treatment blocked the increase in liver deoxycytidine kinase activity induced by steroid or deoxycytidine treatment. Therefore, it is assumed that the rise in deoxycytidine kinase activity requires new RNA and protein synthesis. (5) Cycloheximide treatment of rats carrying hepatomas yielded a t1/2 = 3.4 hr in the tumor for deoxycytidine kinase activity which was the shortest among the examined enzymes of purine and pyrimidine biosynthesis. (6) Actinomycin treatment of rats carrying hepatomas yielded a t1/2 of 5.8 hr for deoxycytidine kinase activity in the tumor which was one of the shortest in the examined enzymes of purine and pyrimidine biosynthesis. (7) Difluorodeoxycytidine (DFDC) is a competitive inhibitor (Ki = 7-28 microM) of deoxycytidine kinase from rat hepatoma and from human pancreatic carcinoma and ovarian carcinoma cells in culture.

Animals↗
PubMed1993

Primary colonic epithelial cell culture of the rabbit producing prostaglandins.

We have established primary colonic epithelial cell culture from adult rabbits and examined effects of anti-inflammatory drugs on prostaglandin (PG) E2 production. Colonic epithelium of adult rabbits was scraped and minced into small pieces. They were incubated for isolation in Hanks' balanced salt solution with 0.35% collagenase and Earle's solution with 1 mM EDTA. Isolated cells were cultured in Coon's modified Ham's F-12 medium with 10% fetal bovine serum and antibiotics on collagen coated cell wells. The medium was refed twice a week. The production of PGs was assessed by high pressure liquid chromatography (HPLC). PGE2 and PGF2 alpha were measured by radioimmunoassay. Within 24 hours after inoculation, the cell clumps attached to the surface of the wells and cells began to spread out and grow. Monolayer cultures became confluent in 4 days. Phase contrast microscopy showed that these cells consisted of a homogeneous population of epithelial cells with large oval nuclei, polyhedral shape, and organized sheet-like growth pattern. HPLC profile showed synthesis of 6-keto-PGF1 alpha, thromboxane B2, PGF2 alpha, PGE2, and PGD2 by cultured cells. Quantitatively, 117 +/- 7 ng/mg-protein/hour PGE2 and 7.4 +/- 0.7 ng/mg-protein/hour PGF2 alpha were produced. While hydrocortisone (10(-4) - 10(-2) M) did not show a significant effect on PGE2 production, indomethacin (10(-8) - 10(-6) M), and 5-aminosalicylic acid (2X10(-4)-5X10(-3) M) inhibited PGE2 production. We have established relatively convenient procedure for primary culture of colonic epithelial cells from adult rabbits. Different actions of anti-inflammatory drugs on PGE2 synthesis suggest that these cultured cells might be a good tool for the various cellular functional studies of normal colonic epithelial cells.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Experimental study on alkaline skin injuries--periodic changes in subcutaneous tissue pH and the effects exerted by washing.

A skin alkaline injury model was constructed using rats and 2N-NaOH. The changes over time, paying special attention to subcutaneous tissue pH, were recorded and included a comparative study of the effect on subcutaneous tissue pH of washing with water at 1, 10 and 30 min after injury. After inflicting alkaline injury, the subcutaneous tissue pH reached its peak value at the 32nd minute and had not recovered to the pre-experimental level by the 90th minute. The peak pH values of the 1-, 10- and 30-min delays before washing groups were 7.97, 10.57 and 12.17, respectively. When washing was started within 1 min of injury the tissue pH values did not exceed 8.00. Washing had virtually no effect on lowering the raised pH levels when the delay between injury and the start of washing was 10 and 30 min.

Animals↗
PubMed1993

Interaction of synaptotagmin with the cytoplasmic domains of neurexins.

Synaptotagmin, a major intrinsic membrane protein of synaptic vesicles that binds Ca2+, was purified from bovine brain and immobilized onto Sepharose 4B. Affinity chromatography of brain membrane proteins on immobilized synaptotagmin revealed binding of alpha- and beta-neurexins to synaptotagmin in a Ca(2+)-independent manner. Using a series of recombinant proteins in which glutathione S-transferase was fused to the cytoplasmic domains of three different neurexins or of control proteins, it was found that synaptotagmin specifically interacts with the cytoplasmic domains of neurexins but not of control proteins. This interaction is dependent on a highly conserved, 40 amino acid sequence that makes up most of the cytoplasmic tails of the neurexins. Our data suggest a direct interaction between the cytoplasmic domains of a plasma membrane protein (the neurexins) and a protein specific for a subcellular organelle (synaptotagmin). Such an interaction could have an important role in the docking and targeting of synaptic vesicles in the nerve terminal.

Amino Acid Sequence↗
PubMed1993

The effect of tube feeding on postprandial gastroesophageal reflux.

Distal esophageal pH in supine position was monitored for 6 hours in 13 asymptomatic infants. During this period the patients received 15 to 20 mL/kg of 5% glucose solution twice every 3 hours. Each meal was fed orally or through a pH sensor tube. When the patient was fed through a tube, the meal was introduced into the stomach or into the distal esophagus. The extent of reflux during 2 hours after feeding was compared between oral and tube feeding. Comparing oral and intragastric tube feeding, intragastric tube feeding showed significantly fewer reflux events, a smaller percentage of time in the esophageal pH below 4, and a shorter duration of the longest single reflux event. Comparing oral and intraesophageal tube feeding, intraesophageal tube feeding showed the same pattern. The data indicated that tube feeding significantly diminishes the postprandial reflux.

Enteral Nutrition↗
PubMed1993

Experimental study of subcutaneously transferred intestine: effect of the presence of serous membrane on acceptance rate.

The serous membrane is considered suspect as one of the obstacles responsible for delaying the acceptance of free jejunal grafts. A model was created of subcutaneous transfer of jejunum from which the serous membrane had been experimentally removed and the authors compared acceptance rates for intestine with and without a serous membrane. Results showed acceptance rates of 0 percent, 37.5 percent, 87.5 percent, and 100 percent respectively, for intestine devoid of serous membrane in which the vascular pedicle had been ligated 4, 5, 7 and 14 days after transfer. When these findings were compared with the results of an experiment on intestine with an intact serous membrane, statistically significant differences were detected between the acceptance rates of the groups ligated 5 and 7 days after transfer. The acceptance time required for intestine devoid of serous membrane was shown to be shorter.

Abdomen↗
PubMed1993

Polypeptide folding of Bacillus cereus ATCC7064 oligo-1,6-glucosidase revealed by 3.0 A resolution X-ray analysis.

The crystal structure of an oligo-1,6-glucosidase from Bacillus cereus ATCC7064 was determined by the X-ray diffraction method at 3.0 A resolution. The structure was solved by the multiple isomorphous replacement method and refined to a crystallographic R-factor of 0.208, using the molecular dynamics refinement program, X-PLOR. The electron density map revealed the folding of a polypeptide chain consisting of 558 amino acid residues. The molecule can be subdivided into three domains (N-terminal domain, subdomain, and C-terminal domain). The N-terminal domain has an (alpha/beta)8-barrel structure called the TIM-barrel structure. The C-terminal domain is characterized by a beta-barrel structure composed of eight antiparallel beta-strands, while the subdomain has a loop-rich structure with a small alpha-helix and a beta-sheet. The enzyme has a large cleft between the N-terminal domain and the subdomain. The cleft leads from the molecular surface to the molecular center. The bottom of the cleft is at the C-terminal end of the parallel beta-strands of the (alpha/beta)8-barrel. These structural features closely resemble those of alpha-amylases from Aspergillus oryzae and pig pancreas.

Bacillus cereus↗
PubMed1993

Epidermal cell viability in rat skin preserved at 4 degrees C.

To determine the longest storage period for the clinical application of epidermal cells and a better method of preservation at 4 degrees C, we stored skin in various fluids and assessed the changes in epidermal cell viability. The time course of changes in the viability of epidermal cells from skin in various preservation fluids was similar to the results obtained with whole skin in previous studies. The best preservation fluid was found to be RPMI 1640 medium, and the best method of preservation was immersion in RPMI 1640 at 4 degrees C with a medium change every 3 days.

Animals↗
PubMed1993

Antiulcer drugs and gastric prostaglandin E2: an in vitro study.

Prostaglandin (PG) has been reported to be an important protective and acid-suppressive factor in the gastric mucosa. Although the mechanisms of some antiulcer drugs are attributed to their stimulatory effects on endogenous prostaglandins, an understanding of these actions has not been established. In the present study we investigated the effects of antiulcer drugs on PGE2 using cultured gastric mucosal cells. Rabbit gastric mucosal cells were cultured after isolation with collagenase and ethylenediaminetetraacetic acid. PGE2 was measured by enzyme-linked immunoassay. Histamine H2-blockers (cimetidine, ranitidine, famotidine), omeprazole, and sucralfate did not modulate the media content of PGE2, whereas sofalcone dose- and time-dependently increased it. Sofalcone-induced increase of PGE2 was dose-dependently prevented by indomethacin. Sofalcone did not affect intracellular Ca2+ as assessed by the calcium-sensitive probe indo-1. Deprivation of Ca2+ in the media did not modulate the action of sofalcone. Sofalcone significantly suppressed 15-OH-PG dehydrogenase. These results suggest that among the various antiulcer drugs only sofalcone increases PGE2, which may be a factor in its therapeutic effect against peptic ulcer diseases.

Animals↗
PubMed1993

Keratoacanthoma with glandular proliferation.

A case of keratoacanthoma (KA) with glandular proliferation was reported. The tumor was a firm, dome-shaped, elevated nodule on the cheek of an 82-year-old Japanese male. Generally, the tumor showed the typical histopathological features of KA; slight nuclear atypia and mitotic figures were present in a cup-shaped proliferation of keratinocytes and, in the center of the lesion, a keratin-filled crater with nests of dyskeratotic and acantholytic cells was seen. In the bottom of the lesion, a glandular structure forming branching, thin lumina was observed. The epithelium of the lumina was made up of two or more layers of columnar or cuboidal cells without keratinization. Tall columnar cells with oval nuclei were located in the luminal row and small cuboidal cells with round nuclei and scanty cytoplasm were in the outer layer. Immunohistochemical staining revealed that only the glandular structure was carcinoembryonic antigen positive. Lectin binding patterns observed in the glandular proliferation were similar to those reported for the apocrine gland. KA sometimes exhibits an adenoid structure in its lesion because of acantholytic changes. However, KA associated with true glandular proliferation has not been reported as far as we know, and our case is the first reported one. KA is thought to be a tumor of follicular origin, and the glandular proliferation observed in the present case seemed to have certain characteristics that suggest its apocrine origin.

Aged↗
PubMed1993

Immunoadsorption plasmapheresis for severe generalised myasthenia gravis.

Two patients with severe generalised myasthenia gravis of childhood were successfully treated with immunoadsorption plasmapheresis. One patient was a 5 year old girl and the other was a 12 year old girl. A dramatic improvement in bulbar symptoms and generalised muscle weakness was achieved without any side effects. Plasma exchange may also yield clinical improvement for myasthenia gravis, but the treatment is accompanied by the risk of viral infections and hypersensitivity reactions. Immunoadsorption plasmapheresis is an effective treatment for severe generalised myasthenia gravis of childhood and is superior to plasma exchange with respect to safety.

Child↗
PubMed1993

Development of local horizontal interactions in cat visual cortex studied by cross-correlation analysis.

1. To explore the functional development of local horizontal interactions in the primary visual cortex, we carried out cross-correlation analysis of spike trains recorded simultaneously from a pair of neurons separated horizontally by < 1 mm, in kittens ranging in age postnatally from the second to ninth week. 2. Significantly correlated firings were found in 87 pairs of cells among 423 pairs analyzed, and 77 pairs of them were classified into three types on the basis of their functional implications: 1) excitatory interactions, 2) inhibitory interactions, and 3) common inputs to both neurons of the pair from other sources. 3. Common inputs and excitatory linkage were observed even in animals at the second postnatal week, whereas inhibitory linkage was not seen before the fourth week of age. The probability of observing common inputs and inhibitory linkage increased during development, whereas that of excitatory linkage tended to decrease after the sixth week of age. 4. Significant correlation was rarely seen in pairs with horizontal separation > 600 microns in the seventh to ninth week. In the fourth to sixth week of age, however, approximately 30% of the pairs with horizontal separation between 600 and 800 microns were significantly correlated. 5. Cells that were not sensitive for orientation or that lacked a visual response were observed mainly before the sixth week of age. These cells tended to receive excitatory effects from and share common inputs with other orientation-sensitive cells that were located within the horizontal distance of 400 microns. 6. All three types of correlations were observed mostly in cell pairs with preferred orientations that differed < 45 degrees at all ages studied. In the fourth to sixth week, however, the similarity of orientation preference was not strict, and correlated firings were observed even in a pair with orthogonal orientation preferences; whereas in the seventh to ninth week the tuning became sharper. 7. These results suggest that functional interactions between cortical neurons exist but are much less specific with respect to horizontal separation and orientation preference before the sixth week of age, and these interactions become more specific so as to operate between neurons with similar orientation preferences in more restricted region after the seventh to ninth week of age and thus in adulthood.

Aging↗
PubMed1993

Cloning and characterization of K562 cells on hemoglobin synthetic activity.

Two clones of the K562 human leukemic cell line were isolated according to hemoglobin (Hb) expression. One clone was expressed less than 5% (K562-L) and the other more than 90% (K562-H). The two clones did not exhibit any difference in cell growth or cell cycle. However, the Hb expression of K562-H cells was reduced by succinylacetone (S.A.). The above results suggested that the difference in the Hb production of K562-L and K562-H cells depended on the heme synthetic activity. On the other hand, glycophorin A was expressed to a greater extent on K562-L cells than on K562-H cells. These findings suggested that heme synthesis and the expression of glycophorin A on K562 cells were not always related. The CD11b and the CD61 were also expressed to a greater extent on K562-L cells than on K562-H cells, but the CD34 was not expressed on these cells.

Antigens, CD↗
PubMed1993

[Nutritional assessment and nutritional support therapy in elderly patients].

In order to study nutritional assessment and nutritional support therapy for elderly patients, we conducted energy supply therapy on 15 elderly (aged over 75) patients disabled with diseases such as cerebrovascular disease, pneumonia and heart failure. After recovery from acute phase, they were divided into 3 groups, and assigned to 3 different energy supply methods for 2 weeks: Six (3 males, 3 females) could take hospital diet, but only could absorb about 50% of the energy, amounting only 1,000 to 1,400 kcal/day. Additional 246 kcal was given by peripheral parental nutrition (PPN). Five (2 males, 3 females) were unable to take nutrition orally. Therefore, they were given high caloric nutrients by total parental nutrition (TPN), giving (1,222 kcal daily for a week), then 1,666 kcal for another week. Four (1 male, 3 females) also could not take meals orally, and had to be nourished by enteral nutrition (EN) with a nutrient preparation of 1,120 kcal for one week, then with 1,600 kcal for another week. In all 3 groups, the indices of rapid turnover proteins (pre-albumin, retinol binding protein and transferrin), choline esterase and vitamin A significantly elevated after 2 weeks of therapy, though the increase of pre-albumin and RBP in TPN group was slightly below the significant level. The increase in rapid turnover proteins and choline esterase was greater in the order of EN, TPN and PPN. Vitamin C, on the other hand, decreased significantly with treatment in all the groups, while vitamin E remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗