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Biomedical subjects

T Yajima

Publications and source records attributed to T Yajima.

At least 37 records · Page 2Linked to original sources
PubMed2001

Retinal ischemia and angle neovascularization in proliferative diabetic retinopathy.

PURPOSE: To analyze the relationship between the extent of retinal ischemia in proliferative diabetic retinopathy and angle neovascularization. METHODS: Panoramic fundus fluorescein angiography and 360-degree fluorescein gonioangiography to detect the angle neovascularization were performed on 70 eyes of 46 patients with proliferative diabetic retinopathy. Statistical significance was evaluated by chi-squared test. Statistical significance was evaluated if the value (T) was greater than the level of significance, chi(0.05)(2)(2) = 5.99. RESULTS: Retinal ischemia in fluorescein angiography was evaluated in four areas: capillary occlusion in (1) temporal raphe; (2) radial peripapillary capillaries; (3) the midperiphery (grade I, less than 25% of the area; grade II, 25% to 50%; grade III, 50% to 75%; grade IV, more than 75%); and (4) optic disk with neovascularization. The angle neovascularization was divided into two types: type I (14 eyes) and type II (12 eyes). Capillary occlusion in the temporal raphe and radial peripapillary capillaries, and papillary leakage significantly increased the risk of angle neovascularization (T = 8.28, 10.04, 6.44 respectively). Grade III and IV capillary occlusion in the midperiphery had a significant risk of angle neovascularization when compared with grade I (between grade III: T = 9.03, grade IV: T = 19.36) and II (between grade III: T = 6.31, grade IV: T = 16.09). CONCLUSION: Risk factors for angle neovascularization were retinal nonperfusion in the midperiphery wider than grade III, capillary occlusion in the radial peripapillary capillaries and temporal raphe, and optic disk. Fluorescein gonio angiography was found to be a powerful tool for the early detection of angle neovascularization, especially in dark irides.

Adult↗
PubMed2001

Perinuclear-antineutrophil cytoplasmic antibodies are associated with vasculitis.

We describe a 62-year-old man with perinuclear-antineutrophil cytoplasmic antibodies-associated vasculitis, which involved the heart, lung, and kidneys. The patient's care was complicated by total occlusions of the brachiocephalic and right renal arteries and a stenosis of the left renal artery. Involvement of large-sized vessels has not been reported in patients with perinuclear-antineutrophil cytoplasmic antibodies-associated vasculitis.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2001

Molded bone augmentation by a combination of barrier membrane and recombinant human bone morphogenetic protein-2.

OBJECTIVES: To provide the histological background to a new method of local bone augmentation, we examined the events occurring beneath a barrier membrane applied with recombinant human bone morphogenetic protein-2 (rhBMP-2). MATERIALS AND METHODS: The effects on bone augmentation of rhBMP-2, applied with a membrane mold (BMP-Memb), over surgically-induced bone defects in rat calvaria were examined histologically, and the results compared with those from application of rhBMP-2 (BMP) alone, or of a molded membrane (Memb) alone. RESULTS: At postoperative week 2, the BMP group showed the most marked bone formation. However, the bone diminished in size by week 8. The Memb group showed slow but continuous bone formation by week 8. In the BMP-Memb group, bone filled the space in the mold at week 2, and this was maintained until week 8. Moreover, the soft tissue that had intervened between newly formed bone and the membrane in the Memb group was not evident in the BMP-Memb group, in which bone had formed directly on the membrane. CONCLUSIONS: The results suggest that the combination of rhBMP-2 and barrier membrane has advantages in producing and maintaining bone in the intended shape by inducing osteoblasts directly on the inner surface of the membrane.

Animals↗
PubMed2001

Biphasic alterations in gastrointestinal transit following endotoxaemia in mice.

Lipopolysaccharide (LPS)-induced alterations of gastrointestinal transit were studied in mice using activated charcoal. LPS (10 mg kg-1) induced biphasic alterations of intestinal transit. Increase (acceleration phase) and delay (lag phase) in gastrointestinal transit were observed at 90 and 480 min after LPS injection, respectively. LPS administration induced significant increases in tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and nitrate levels in blood serum with maximal levels observed at 1.5, 4, and 8 h after LPS administration, respectively. The effects of recombinant human lzactoferrin (rhLF) on LPS- induced alteration of gastrointestinal transit, and production of TNF-alpha, IL-1beta and nitrate were also studied. Animals were pretreated with rhLF 24 hours before intraperitoneal administration of LPS. RhLF significantly increased gastrointestinal transit during the lag phase. In addition, rhLF decreased the level of TNF-alpha in endotoxaemic animals. The levels of IL-1beta and nitrate were not significantly changed by rhLF. In conclusion, the effect of LPS on gastrointestinal transit is biphasic and the mechanism controlling the second phase most likely depends on TNF-alpha production, while the first phase most likely does not depend on TNF-alpha. On the other hand, it may be regulated by IL-1beta and nitric oxide production.

Animals↗
PubMed2001

Immunohistochemical localization of membrane type 1-matrix metalloproteinase (MT1-MMP) in osteoclasts in vivo.

Membrane type 1-matrix metalloproteinase (MT1-MMP) is capable of mediating proteolysis of extracellular matrix. The enzyme has been demonstrated in osteoclasts, in vitro. However, the precise localization in vivo, and therefore the function of the enzyme in osteoclasts, is still unclear. In this study, we immunohistochemically examined the localization of MT1-MMP in rat osteoclasts to clarify the role of MT1-MMP in osteoclastic bone resorption and bone turnover. The localization of MT1-MMP was visualized by the pre-embedding method using anti-MT1-MMP antibody and horseradish peroxidase (HRP) or gold-conjugated antibody. Immunoreactivity of anti-MT1-MMP was found in osteoclasts at the osteoclast-bone interface, but it was not uniform. Ultrastructurally, the immunoreactivity visualized by HRP was found in sealing zone. The plasma membrane at this site showed an irregular border and some invaginations. Immunoreactivity was also found on the surface of certain small vesicles in the cytoplasm. Enhanced silver granules were mainly associated with the sealing membrane. In this study, we demonstrated, for the first time, the localization of MT1-MMP in the sealing zone of osteoclast in vivo. Its distribution suggests that the enzyme modifies the bone surface to facilitate the migration and attachment of osteoclasts as well as scavenging the resorption lacunae.

Animals↗
PubMed2001

Bacterial translocation in neonatal rats: the relation between intestinal flora, translocated bacteria, and influence of milk.

BACKGROUND: A high incidence of bacterial translocation in neonates results not only from immaturity of host-defense functions, but also from the dominant colonization of aerobic bacteria in the intestine. Bacterial colonization develops differently among breast-fed, formula-fed, premature, and full-term infants. The purpose of this study was to examine the incidence of bacterial translocation and to identify the translocated bacterial species, relating these findings to the intestinal microflora and to the type of feeding in neonatal rats. METHODS: Animals were divided into three groups: breast-fed normal pups (MR group), formula-fed pups fed via an intragastric cannula implanted esophageally (AR group), and breast-fed pups after the removal of the cannula (Sham group). Artificial rearing was achieved using a machine feeding system. Culture and identification of the bacteria in the intestine, mesenteric lymph nodes, liver, portal blood, and lungs were made using a simplified version of Mitsuoka's method. RESULTS: At 14 days of age, the dominant bacteria in the feces of the MR and Sham Groups were Enterobacteriaceae, Lactobacillus, and Enterococcus, but Enterobacteriaceae and Clostridium were significantly more common in the AR group than in the MR group. The dominant bacteria in the mesenteric lymph nodes were Enterobacteriaceae, Lactobacillus, and Staphylococcus. The extent of systemic bacterial translocation decreased earlier in the Sham group than in the AR group. CONCLUSIONS: The frequency with which species of bacteria were cultured from mesenteric lymph nodes and other peripheral sites did not mirror the composition of the intestinal flora. Among the translocated bacteria, Staphylococcus may be especially hard to recognize and difficult for the host-defense systems to destroy. Breast-feeding inhibited systemic bacterial translocation in the suckling period of the rat.

Animal Feed↗
PubMed2001

Lactoferrin protects against development of hepatitis caused by sensitization of Kupffer cells by lipopolysaccharide.

BALB/c mice were intravenously injected with lipopolysaccharide (LPS) (0.05 microg/g of body weight) 7 days after being primed with zymosan. Recombinant human lactoferrin (250 microg/g of body weight), intravenously administered 1 day before the injection of LPS, significantly lessened the severity of hepatitis, as assessed by levels of serum alanine transaminase compared to those seen when casein was administered. The transient rise of serum tumor necrosis factor alpha (TNF-alpha) after LPS treatment was also significantly lowered by the intravenous administration of lactoferrin, suggesting that the effect of lactoferrin was due to the suppression of TNF-alpha production. The following results indicate that the sites of action of lactoferrin for the suppression of the development of this type of hepatitis are Kupffer cells. Gadolinium chloride, a substance known to eliminate Kupffer cells, administered 1 day before LPS, inhibited the transient rise of TNF-alpha and protected against the development of hepatitis. Kupffer cells isolated from mice intraperitoneally injected with recombinant human lactoferrin became refractory to LPS. The specific interaction of recombinant human lactoferrin with the Kupffer cells was shown by a binding assay, which revealed two types of binding sites on mouse Kupffer cells. Of the two dissociation constants determined in this way, the lower dissociation constant, 0.47 x 10(-6) M, was within the range of the 50% effective doses for the suppression of TNF-alpha production. These results suggest that recombinant human lactoferrin administered to mice suppresses the production of TNF-alpha by Kupffer cells by directly associating with the binding sites on these cells.

Alanine Transaminase↗
PubMed2001

Potential fascial dome made by the upper leaf of the phreno-esophageal membrane.

We describe the configuration and size of the artificial fascial dome created in 57 cadavers. This dome protrudes into the thoracic cavity from the esophageal hiatus. This dome was a potential space realized by finger dissection (i.e., a specific but common surgical procedure during surgery of the upper part of the stomach). The vagus nerves penetrated the top of the dome and ran down along the esophagus. The height of the ventral wall of the dome ranged from 10-60 mm, while the dorsal wall was 10-40 mm longer than the ventral one since the dorsal wall attached to the lower, dorsal limb of the esophageal hiatus. Accordingly, the dorsal wall separated the "thoracic" aorta from the "abdominal" esophagus. We considered that the upper leaf of the phreno-esophageal membrane forms the fascial dome, although the lower leaf of the membrane was not identified in this study. According to the results, we proposed a schematic representation of the phreno-esophageal membrane.

Aged↗
PubMed2000

An immuno-polymerase chain reaction assay for human interleukin-18.

Conventional enzyme-linked immunosorbent assays (ELISA) are sufficient to measure normal and elevated serum interleukin (IL)-18 concentrations, but have limited sensitivity when measuring low concentrations of IL-18 such as in patients with the acquired immunodeficiency syndrome. We have developed a highly sensitive method for detecting human (h) IL-18 using an immuno-polymerase chain reaction (PCR). A mouse monoclonal anti-hIL-18 antibody and rabbit polyclonal anti-hIL-18 antibody was used for an indirect sandwich ELISA with a detection limit of 40 ng/l and a very low background. For immuno-PCR, biotinylated DNA was produced from the plasmid Bluescript by PCR amplification with biotinylated M13-20 primer and nonbiotinylated M13 reverse primer. Immuno-PCR for hIL-18 was performed for 40 cycles using 1 ng/l of biotinylated DNA. This immuno-PCR has a detection limit of 2.5 pg/l, 1.6x10(4) times lower than that of the ELISA. In addition, our system avoids sampling error caused by heat transfer from the ELISA plate to the PCR tube because all procedures from immobilization of the antibody to PCR amplification can be performed in the same tube. This immuno-PCR for hIL-18 is the most sensitive method for detecting hIL-18 reported to date.

Animals↗
PubMed2000

Prediction of suitable amount of water addition for wet granulation.

The purpose of this study was to predict the amounts of water addition suitable for pharmaceutical formulations in wet granulation, using a high-speed mixer or a fluidized bed granulator, before granulation trials. In order to determine the suitable amount of water addition, each excipient was first subjected to kneading with water in a mortar and a refractive near-infrared moisture sensor (IR sensor) measured the amount of water at the powder surface. Further by analysis the plot (output value of the IR sensor vs. amount of added water) for each excipient, the amount of water addition for granulation was determined for it. As a second step, two model formulations were designed and suitable amounts of water for granulation were predicted by summation of the obtained excipient values. The predicted value was compared with the experimental value for high-speed mixer granulation. The predicted and experimental amounts of water addition corresponded for the two model formulations, suggesting that the above method is useful for estimating suitable amounts of addition of water for formulations before granulation trials.

Chemistry, Pharmaceutical↗
PubMed2000

Establishment of quantitative reverse transcription--polymerase chain reaction assays for human telomerase-associated genes.

Telomerase is an enzyme that synthesizes and adds repetitive telomeric sequences of (TTAGGG)n to the ends of chromosomes. Recently, several telomerase-associated genes have been cloned, making it possible to study the expression of these genes. Quantitative comparisons of the expression of these genes and of telomerase activity might help clarify the regulation of telomerase activity. Therefore, we established the validity of a quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay for the human telomerase catalytic subunit (hTERT) mRNA and telomerase associated protein (TEP1) mRNA using the TaqMan fluorogenic detection system. Using this assay, we quantitated hTERT mRNA and TEP1 mRNA expression in two human pancreatic cancer cell lines, AsPC-1 and PANC-1. Our results indicated that the levels of hTERT mRNA and TEP1 mRNA expression in AsPC-1 were 1.50 and 2.31 times higher than in PANC-1 cells. This TaqMan RT-PCR assay appears to be useful in determining the quantities of hTERT and TEP1 mRNAs in clinical specimens. Taken together, our results indicate that it is possible to measure the expression of the major telomerase genes subunits. Furthermore it is possible to apply this technique to determine the amount of other types of mRNA.

Carrier Proteins↗
PubMed2000

Differential roles of interleukin 15 mRNA isoforms generated by alternative splicing in immune responses in vivo.

At least two types of interleukin (IL)-15 mRNA isoforms are generated by alternative splicing at the 5' upstream of exon 5 in mice. To elucidate the potential roles of IL-15 isoforms in immune responses in vivo, we constructed two groups of transgenic mice using originally described IL-15 cDNA with a normal exon 5 (normal IL-15 transgenic [Tg] mice) and IL-15 cDNA with an alternative exon 5 (alternative IL-15 Tg mice) under the control of an MHC class I promoter. Normal IL-15 Tg mice constitutionally produced a significant level of IL-15 protein and had markedly increased numbers of memory type (CD44(high) Ly6C(+)) of CD8(+) T cells in the LN. These mice showed resistance to Salmonella infection accompanied by the enhanced interferon (IFN)-gamma production, but depletion of CD8(+) T cells exaggerated the bacterial growth, suggesting that the IL-15-dependent CD8(+) T cells with a memory phenotype may serve to protect against Salmonella infection in normal IL-15 Tg mice. On the other hand, a large amount of intracellular IL-15 protein was detected but hardly secreted extracellularly in alternative IL-15 Tg mice. Although most of the T cells developed normally in the alternative IL-15 Tg mice, they showed impaired IFN-gamma production upon TCR engagement. The alternative IL-15 transgenic mice were susceptible to Salmonella accompanied by impaired production of endogenous IL-15 and IFN-gamma. Thus, two groups of IL-15 Tg mice may provide information concerning the different roles of IL-15 isoforms in the immune system in vivo.

Alternative Splicing↗
PubMed2000

Circulating autoantibodies against purified colonic mucin in ulcerative colitis.

To clarify the role of colonic mucin in the autoimmune process of ulcerative colitis, circulating antibodies against human colonic mucin were investigated. Purified colonic mucin, obtained from human colonic mucosa by gel filtration, using a Bio-Gel A-1.5-m column and CsCl equilibrium density gradient, was divided into soluble mucin (S-mucin) secreted extracellularly and membranous mucin (M-mucin) binding to cell membrane. Sodium dodecylsulfate polyacrylamide gel electrophoresis and Western blotting analysis showed that antibodies in the serum samples of some patients with ulcerative colitis recognized purified S- and M-mucin of >180-kD. By enzyme-linked immunosorbent assay (ELISA), anti-mucin antibodies were detected in 11 of 60 patients with ulcerative colitis (18%). In contrast, the antibodies were not detected in 22 patients with Crohn's disease. The titers of antimucin antibodies against S-mucin and M-mucin were not different in each patient. By ELISA using mucin in which the sugar chains were destroyed by neuraminidase or NaIO4 treatment, it was demonstrated that anti-mucin antibodies recognized the epitopes of either the sugar chain or the core protein exposed through destruction of the sugar chains. We then investigated the relationship between anti-mucin antibodies and the patients' clinical features. Anti-mucin antibodies were detected in 6 of 15 patients with chronic continuous type ulcerative colitis (40%) and in 5 of 26 patients with relapsing-remitting type (19%), but there was no antimucin antibody-positive serum in patients who had had only one attack without any relapse. These results suggest that anti-mucin antibodies could be a disease marker for ulcerative colitis and that immunological abnormalities in colonic mucin contribute to the persistence of colonic mucosal inflammation.

Autoantibodies↗
PubMed2000

Helicobacter pylori infection: augmentation of telomerase activity in cancer and noncancerous tissues.

Telomerase adds hexameric repeats of 5'-TTAGGG-3' to the ends of chromosomal DNA (telomere) and has been implicated in cell immortalization and cellular senescence. The aim of this study was to measure quantitatively the telomerase activity and human telomerase RNA component (hTR) content in gastric cancer and to examine the relation between these values and histologic factors including Helicobacter pylori as a risk factor for gastric cancer. Telomerase activity was measured by a modified telomeric repeat amplification protocol in cancerous and noncancerous tissues (intestinal metaplasia, chronic gastritis, normal mucosa) from 27 gastric cancer patients; hTR expression was examined by the quantitative reverse transcriptase-polymerase chain reaction using fluorescent probes. Telomerase activity was higher in cancers (total product generated: 33.7) than in noncancerous tissues. Telomerase activity was higher in intestinal metaplasia (16.7) and chronic gastritis (10.6) than in normal mucosa (3.5). In patients with intestinal-type gastric cancer, telomerase activity was higher in intestinal metaplasia with H. pylori infection than in that without infection. hTR expression was not correlated with telomerase activity. H. pylori infection may influence telomerase activity in cancer and noncancerous tissues.

Aged↗
PubMed2000

No clinically important effects on intraocular pressure after short-term administration of sildenafil citrate (Viagra).

PURPOSE: To assess the short-term effects of sildenafil citrate on intraocular pressure in healthy male volunteers and participants in clinical trials. METHODS: Intraocular pressure and pupil diameter were measured in two placebo-controlled studies. Oral doses of sildenafil citrate (VIAGRA; Pfizer Inc, New York, New York) ranged from 10 mg to 150 mg. RESULTS: No major changes in intraocular pressure or pupillometry were detected at any time (1.0-24 hours) after administration of sildenafil. Additionally, of 36 subjects with a medical history of increased intraocular pressure in the sildenafil safety database, none were reported to have a clinically significant increase of their intraocular pressure. During clinical trials, two glaucoma cases were listed as serious adverse events, but were not considered treatment related. CONCLUSION: No clinical abnormalities were observed in intraocular pressure or pupil diameter in subjects receiving sildenafil. Currently, no evidence suggests that long-term treatment with sildenafil has an effect on intraocular pressure or is associated with the development or worsening of glaucoma.

3',5'-Cyclic-GMP Phosphodiesterases↗