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Biomedical subjects

M A Fujino

Publications and source records attributed to M A Fujino.

At least 37 records · Page 2Linked to original sources
PubMed2000

Topographical difference of cytoskeletal organization in smooth muscle cells of rat duodenum revealed by quick-freezing and deep-etching method.

The sarcolemmal domain of rat duodenal smooth muscle cells includes caveolae and associated cytoskeletal or filamentous elements. We have used the quick-freezing, deep-etching method to examine the three dimensional relationships between these components. Replica membranes for separated strips of rat duodenal muscle layers were routinely prepared after extraction soluble proteins from cytoplasm and extracellular matrix. As results, 1) cytoskeletal elements in smooth muscle cells consisted mainly of striated thin filaments; 2) thin filaments were connected with some plasma membranes through filaments associated with the sarcolemma, which formed fine network structures beneath the sarcolemma; 3) many bridging structures between the filaments associated with the sarcolemma and the extracellular matrix were frequently detected in the plasma membrane; and 4) compact filaments associated with the sarcolemma almost disappeared near the caveolae, and only thin filaments were anchored to their neck parts. The special arrangement of the cytoskeletal components, which is probably necessary for the intestinal motility, characterizes the topographical difference of the smooth muscle sarcolemma.

Animals↗
PubMed2000

[Aging-related physical and life style changes in the patients with reflux esophagitis].

Incidence of reflux esophagitis(RE) has increased over the past 10 years in Japan, where aging of the population is rapidly progressing. The majority(73.6%) of the patients with RE consisted of non-elderly males having life style problems and of elderly females suffering from posture alterations. This suggested the importance of the disease onset among elderly female population in addition to that of the non-elderly male population. The risk factors specific to the elderly patients include not only persistent acid secretion and presbyesophagus, but also complication with orthopedic regression diseases with posture changes and osteoporosis. The association with the latter orthopedic regression diseases has been significantly increasing and is suggested to promote development of RE. Further increase in the prevalence of RE is foreseen in this aging-accelerating country.

Adult↗
PubMed1999

Induction and suppression of endothelial cell apoptosis by sphingolipids: a possible in vitro model for cell-cell interactions between platelets and endothelial cells.

Because sphingosine (Sph) is actively incorporated into platelets and rapidly converted to sphingosine 1-phosphate (Sph-1-P), which is then released extracellularly, it is important to study the effects of Sph and Sph-1-P on endothelial cells from the viewpoint of platelet-endothelial cell interaction. In this study, we found that Sph, as well as ceramide, induces apoptosis in human umbilical vein endothelial cells (HUVECs). In contrast, Sph-1-P acts as a HUVEC survival factor; this bioactive lipid was shown to protect HUVECs from apoptosis induced by the withdrawal of growth factors and to stimulate HUVEC DNA synthesis. In metabolic studies, [3H]Sph, incorporated into HUVECs, was converted to [3H]Cer and further to [3H]sphingomyelin in a time-dependent manner, whereas [3H]Sph-1-P formation from [3H]Sph was weak and transient. These findings in HUVECs are very different from those of platelets, which possess a highly active Sph kinase but lack Sph-1-P lyase. As a result, platelets abundantly store Sph-1-P, whereas HUVECs contain much less Sph-1-P. Finally, HUVECs, in contrast to platelets, failed to release Sph-1-P extracellularly, indicating that HUVECs themselves are not able to supply the survival factor Sph-1-P, but receive it from activated platelets. Our results suggest that platelets may maintain the integrity of endothelial cells by incorporating Sph and releasing Sph-1-P.

Acetic Anhydrides↗
PubMed1999

Characterization of a 1200-kb genomic segment of chromosome 3p22-p21.3.

We previously determined the nucleotide sequence and characterized the 685-kb proximal half of CEPH YAC936c1, which corresponds to a portion of human chromosome 3p21.3. In the study reported here, we characterized the remaining 515-kb of this YAC clone corresponding to the telomeric half of its human insert. The newly sequenced region contained a total of ten genes including six reported previously: phospholipase C delta 1 (PLCD1), human activin receptor type IIB (hActR-IIB), organic cation transporter-like 1 (OCTL1), organic cation transporter-like 2 (OCTL2), oxidative stress response 1 (OSR1), and human xylulokinase-like protein (XYLB). The remaining four genes present in the telomeric region included two known genes, MyD88 and ACAA, and two novel genes. One (designated ENGL) of the novel sequences was found to encode an amino-acid sequence homologous to the family of DNA/RNA endonucleases, especially endonuclease G. The other gene F56 revealed no significant homology to any known genes. These results disclosed complete physical and transcriptional maps of the 1200-kb region of 3p present in YAC 936c1.

Amino Acid Sequence↗
PubMed1999

Ultrastructure of rat duodenal myenteric plexus revealed by quick-freezing and deep-etching method.

A quick-freezing and deep-etching (QF-DE) method was employed with whole-mount strips of rat duodenal muscle walls to exhibit the cytoskeletons of the myenteric plexus. Nerve fibers in the myenteric plexus, which contained fewer neurofilaments than other types of neurons examined, had many varicosed contours, and were bundled by enteroglial cells. Cytoskeleton arrays were rarely observed in the varicosed regions, where synaptic vesicles were often seen, although other nerve regions contained many neurofilaments running almost in parallel with the nerve fiber bundle. Enteroglial cells had short cytoskeletons predominantly across the cytoplasm, becoming thinner the around varicosed regions of the nerve bundles. Such enteroglial extruded areas were often in close association with neighboring nerve fibers, indicating intercommunications between the nerve fibers. In distal parts of enteric nerve processes, there were numerous synaptic vesicles, but few neurofilaments. Smooth muscle cells were closely associated with the enteric nerve processes. Fine network structures, responsible for the extracellular matrix, were present between the smooth muscle cells and the enteric nerve processes. These specific structures of the myenteric plexus could be important for signalling or for the transportation of neurotransmitters involved in gut motility.

Animals↗
PubMed1999

Urocortin reduces food intake and gastric emptying in lean and ob/ob obese mice.

BACKGROUND & AIMS: Gastric emptying plays an important role in regulating food intake. This study was designed to investigate whether intraperitoneally injected urocortin reduces gastric emptying, feeding, and body weight in lean and ob/ob obese mice. METHODS: Food intake and body weight were measured after intraperitoneal injections of one of the following: urocortin, deamidated form of urocortin (urocortin OH), corticotropin-releasing factor (CRF), CRF6-33, cholecystokinin octapeptide (CCK-8), and leptin in 16-hour food-deprived animals. Gastric emptying was assessed 2, 4, or 8 hours after intraperitoneal injection. Repeated injections of urocortin were continued for 5 days in ob/ob mice. RESULTS: Urocortin (0.003-3 nmol) dose-dependently and potently decreased food intake and body weight gain in lean mice. The ranking order of potency was urocortin > urocortin OH >/= CRF > CCK-8 > CRF6-33 > leptin. Gastric emptying was also potently reduced by urocortin with a similar ranking order of potency of urocortin > CRF > urocortin OH > CCK-8. Simultaneous administration of urocortin and CRF receptor antagonist, alpha-helical CRF9-41, blocked the effects of urocortin. Urocortin reduced food intake and body weight gain, as well as the rate of gastric emptying, in ob/ob mice, which was significantly faster than that of lean mice. Five daily injections of urocortin significantly lowered body weight and improved glycemic control in ob/ob mice. CONCLUSIONS: The urocortin-induced decrease in food intake and body weight in lean and ob/ob mice is closely related to gastric emptying and opens new possibilities for the treatment of obesity.

Animals↗
PubMed1999

Endoscopic urease sensor system for detecting Helicobacter pylori on gastric mucosa.

BACKGROUND: It is now accepted that the curing of Helicobacter pylori infection will result in healing of chronic active gastritis and will change the natural history of gastroduodenal ulcer disease. Both endoscopic observation and evaluation of H. pylori status of the stomach are necessary for diagnosis and treatment of such patients. We carried out a clinical evaluation of an endoscopic tube type urease sensor system for the detection of H. pylori on the gastric mucosa. The differential output of two pH-sensitive field effect transistors at the tip of the endoscopic tube reflects the pH change in a urea solution depending on the existence of urease. METHODS: In vitro experiments and clinical evaluation of the system were performed. Fifty-one patients who were suspected to have a gastroduodenal disorder were examined for H. pylori infection with this system, using the combination of histologic and bacteriologic examinations and rapid urease test as the references. RESULTS: Clinical sensitivity and specificity of this system were 26 of 28 (92.9%) and 22 of 23 (95.7%), respectively. A measurement at 1 site is completed in about 1 minute. Repetition of the procedure provides multi-site measurements. CONCLUSIONS: The present system makes possible quick on-site detection of H. pylori under endoscopic observation, with satisfactory sensitivity and specificity.

Adult↗
PubMed1999

Mouse pancreatic polypeptide modulates food intake, while not influencing anxiety in mice.

This study was designed to investigate the effects of synthetic mouse pancreatic polypeptide (mPP) on feeding and anxiety in mice. The intracerebroventricular (i.c.v.) injection of mPP (0.003-3 nmol) dose-dependently increased food intake. A significant increase was observed 20 min after i.c.v. injection and continued for 4 h. The intraperitoneal (i.p.) injection of mPP (0.03-30 nmol) dose-dependently decreased food intake. A significant decrease was observed 20 min after i.p. injection and continued for 4 h. In the elevated plus maze test, the i.c.v. injection of mPP (0.003-3 nmol) did not affect anxiety behavior. These results suggest that mPP modulates food intake and the Y4 receptor in the brain may contribute to the regulation of feeding, whereas appearing not to influence anxiety in mice.

Animals↗
PubMed1999

Ultrasonographic evidence of association of polyps and stones with gallbladder cancer.

OBJECTIVE: The purpose of this study was to evaluate the level of gallbladder cancer risk associated with polyps and stones of the gallbladder by ultrasound examinations. METHODS: We investigated abdominal ultrasonographic findings for gallstones and polyps of the gallbladder and the relationship of these findings to malignancy in 194,767 asymptomatic participants in health screening examinations. RESULTS: Gallstones were detected in 7,985 participants (4.1%), at a prevalence of 5.3% in male and 4.5% in female participants. The prevalence was highest in the participants' seventh decade, followed by the sixth and the fifth decades, in both male and female participants. Polyps were found in 10,926 (5.6%), at a prevalence of 6.9% in the male and 4.5% in the female participants. In the male participants, prevalence was highest in the fourth decade, followed by the third and the fifth decades, whereas in the female participants it was highest in the fifth decade, followed by the fourth and third. High prevalence of polyps > or = 10 mm in diameter was found in the fifth to seventh decades in both sexes. Nineteen participants (0.01%) were diagnosed as having gallbladder cancer, and many of them were in the sixth or seventh decade in both sexes. Patients with stones showed a higher prevalence of gallbladder cancer. This difference was shown to be statistically significant by age-adjusted analysis (p < 0.01). The age distribution of the participants with polyps > or = 10 mm in diameter was correlated with that of patients diagnosed with gallbladder cancer. Furthermore, polyp incidence was significantly related to cancer by statistical analysis (p < 0.01). CONCLUSION: These results suggest an association between gallstone or polyp of the gallbladder and increased risk of malignancy, implying that an etiological association may also exist.

Adult↗
PubMed1999

Accuracy of screening for gastric cancer using serum pepsinogen concentrations.

BACKGROUND/AIMS: The characteristics of pepsinogen screening for gastric cancer were investigated to establish a suitable cut off point for identifying gastric cancer, using endoscopic diagnosis as the yardstick. SUBJECTS/METHODS: Serum pepsinogen concentrations were measured in 5113 subjects who were also screened for gastric cancer by endoscopy. The cut off point for pepsinogen was determined using receiver operator characteristics curves. RESULTS: The most suitable cut off point was a pepsinogen I concentration of less than 70 ng/ml and a ratio of pepsinogen I to pepsinogen II of less than 3. 0. Using this cut off point, the sensitivity and specificity of pepsinogen screening for gastric cancer were 84.6% and 73.5% respectively. All cases of gastric cancer in patients with severe atrophic gastritis were detected. However, two of four cases of gastric cancer in patients with mild atrophic gastritis were overlooked. In subjects with mild atrophic gastritis, when gastric cancer arises within the fundic gland region, the size of the lesion determines whether it is possible to detect cancer by serum pepsinogen screening. CONCLUSION: Pepsinogen screening has many advantages, including its suitability for combination with other screening methods because it is simple and inexpensive.

Aged↗
PubMed1998

Endomorphins have orexigenic and anxiolytic activities in mice.

This study was designed to investigate the effects of endomorphin 1 and 2, recently identified mu-opioid receptor selective peptides, on food intake and anxiety in non-food-deprived mice. The intracerebroventricular (i.c.v.) injection of either endomorphin 1 or 2 (0.03-30 nmol) increased food intake in a dose-related manner. A significant increase was observed 20 min after i.c.v. injection of endomorphin 1 or 2 and continued for 4 h. In the elevated plus maze test, the i.c.v. injection of endomorphin 1 (30 nmol) significantly decreased the normal preference for the closed arms. These results suggest that endomorphin produces orexigenic and anxiolytic effects, and that the mu-opioid receptor contributes to the regulation of feeding and anxiety in mice.

Animals↗
PubMed1998

Motilin increases food intake in mice.

The effect of motilin on food intake was investigated in nonfood-deprived mice. A significant increase in food intake was observed 1 h after ICV administration of motilin (3 nmol/mouse) and continued for 2 h. This effect was attenuated markedly by the motilin receptor antagonist GM-109 (0.3-3 nmol/mouse) in a dose-related manner. GM-109 alone had no effect on food intake. These results indicate that motilin receptors are present in the brain and may have a role in the regulation of food intake.

Animals↗
PubMed1998

Quantification of sphingosine derivatives in human platelets: inducible formation of free sphingosine.

To elucidate the physiologic role of sphingolipid-derived products as signaling molecules, we analyzed the levels of endogenous sphingosine (Sph) derivatives in human platelets. When the platelets were stimulated with thrombin or 12-O-tetradecanoylphorbol 13-acetate, neither ceramide formation nor sphingomyelin hydrolysis was observed, which suggests that the sphingomyelin cycle may not be an essential part of the signaling pathway under these conditions. In contrast, Sph was found to increase in platelets upon stimulation. The level of Sph 1-phosphate, which is formed from Sph by the action of Sph kinase, was not affected under our conditions. Although it has been established that Sph inhibits protein kinase C, which regulates the functional responses of the platelets, Sph levels which exert an inhibitory effect on protein kinase C cannot be attained under physiological conditions (without exogenous Sph). Considering the stimulation of the synthesis of Sph by the physiological agonist thrombin, we speculate that Sph is a signaling molecule of physiological importance in platelets, but protein kinase C may not be its target.

Adult↗
PubMed1998

Inhibitory effects of nitric oxide donors on nitric oxide synthesis in rat gastric myenteric plexus.

We investigated whether nitric oxide (NO) exerts an inhibition on its own synthesis in the gastric myenteric plexus in rats. Nonadrenergic, noncholinergic relaxations in response to transmural electrical stimulation (TS) were markedly antagonized by NG-nitro-L-arginine methyl ester, (10(-4) M) and abolished by tetrodotoxin (10(-6) M). Pretreatment with various NO donors (3-morpholino-sydnonymide [SIN-1 (3 x 10(-7) to 3 x 10(-6) M)], S-nitroso-N-acetylpenicillamine (10(-6) to 10(-5) M), sodium nitroprusside (10(-8) to 3 x 10(-8) M) and 8-bromoquanosine 3', 5'-cyclic monophosphate [8-bromo-cGMP (10(-6) to 3 x 10(-6) M)]) significantly inhibited TS-evoked nonadrenergic, noncholinergic relaxations in a dose-dependent manner. In contrast, vasoactive intestinal polypeptide (10(-8) M)-induced relaxations were not affected by SIN-1 or 8-bromo-cGMP. TS evoked a significant increase in 3H-citrulline formation, which was completely abolished by calcium-free medium, NG-nitro-L-arginine methyl ester, (10(-4) M) and tetrodotoxin (10(-6) M). 3H-citrulline formation evoked by TS was significantly inhibited by SIN-1 (10(-7) to 10(-5) M) and 8-bromo-cGMP (10(-7) to 10(-5) M) in a dose-dependent manner. The inhibitory effect of SIN-1 was partially prevented by 1H-[1,2, 4]oxadiazolo[3,4-a]quinoxalin-1-one (10(-5) M), a guanylate cyclase inhibitor. We conclude that NO synthesis in the gastric myenteric plexus is negatively regulated by NO and cGMP. This suggests an autoregulatory feedback mechanism of NO synthesis in the gastric myenteric plexus.

Animals↗