Biomedical subjects

T Kato

Publications and source records attributed to T Kato.

At least 325 records · Page 18Linked to original sources

PubMed2001

Intestinal transplantation for the treatment of desmoid tumors associated with familial adenomatous polyposis.

BACKGROUND: Desmoid tumors associated with familial adenomatous polyposis (FAP) are locally invasive. Often occurring in the mesentery of the intestine, they sometimes recur after resection. Complications can include intestinal failure and dependence on parenteral nutrition. We describe 9 patients who underwent intestinal transplantation for the treatment of desmoid tumors associated with FAP. METHODS: Records of patients undergoing intestinal transplantation for desmoid tumors at 2 transplant centers were reviewed for patient age, sex, type of graft, procedure date, tumor site, desmoid complications, medications, extracolonic manifestations, status at follow-up, and length of survival. RESULTS: Nine patients with FAP and intestinal failure caused by desmoid tumors were treated with isolated intestinal (n = 6), multivisceral (n = 2), or combined liver-intestinal transplantation (n = 1). Desmoid tumors recurred in the abdominal walls of 2 patients. Two patients died: one as a result of sepsis, the other because of a rupture of a mycotic aneurysm of the aortic anastomosis. One graft lost to severe rejection was replaced with a second intestinal graft. Eleven to 53 months after transplantation, 7 patients were alive, well, independent of parenteral treatment, and leading apparently normal lifestyles. CONCLUSIONS: Transplantation of the intestine alone or as part of a multivisceral transplantation may help rescue otherwise untreatable patients with complicated desmoid tumors.

Adenomatous Polyposis Coli↗

PubMed2001

Effects of a hydroxyl radical scavenger, EPC-K1, and neutrophil depletion on reperfusion injury in rat skeletal muscle.

Oxygen free radicals (OFR) and neutrophils are potent sources of reperfusion injury. We compared the effect of EPC-K1, a new OFR scavenger, and neutrophil depletion on the reperfusion injury in skeletal muscle, using an ischemic revascularized hindlimb model in rats. Warm ischemia, produced by vascular pedicle clamping, was sustained for 4 h. After 24 h of reperfusion, muscle function and damage were evaluated in 4 groups: a sham operation group, a control study group, a group treated by EPC-K1 (EPC group), and a group that received nitrogen mustard to induce neutropenia (NM group). Both the EPC and NM groups had limited muscle damage compared to the control group. The EPC group preserved muscle function significantly better than the control group and the mean isometric tetanic tension in the EPC group appeared to be higher than that in the NM group. Furthermore, levels of lipid peroxides in muscle and serum, and muscle edema in the EPC group, were significantly lower than in the NM group. Histological examinations supported these results. These findings suggest that limiting OFR generation by EPC-K1 in the early phase of reoxygenation is more potent than depletion of neutrophils in reducing reperfusion injury.

Animals↗

PubMed2001

Effects of dietary spirulina on meat colour in muscle of broiler chickens.

1. The present study was undertaken to determine the effects of dietary spirulina on growth performance and pigmentation in the muscle of growing broiler chickens and to examine the possibility that zeaxanthin in spirulina may affect yellow colour development in the meat. 2. Twenty-four, 21-d-old, male broiler chicks were fed an experimental diet containing spirulina at 0, 40, or 80 g/ kg for 16 d. No significant differences among treatments were observed in body weights, nor weights or yields (as a percentage of body weight) for any of the selected traits, including liver, abdominal fat, kidney and Pectoralis profundus. 3. Spectrocolourimetric analyses revealed that the redness of Pectoralis superficialis, profundus and Sartorius muscles reached a maximum in chicks fed the 40 g/kg spirulina diet, while the yellowness of all fillets, including the Semitendinosus muscle, increased in a sub-linear fashion with increased spirulina in the diet. The overall correlation between the yellowness and zeaxanthin content in the Pectoralis muscle was significant. 4. This study provides the first conclusive evidence that dietary spirulina influences both the yellowness and redness of broiler flesh and that the increments in yellowness with dietary spirulina content may possibly be reflected in the common yellow pigment related to the accumulation of zeaxanthin within the flesh.

Animal Feed↗

PubMed2001

Nontumorous perfusion abnormalities of liver parenchyma adjacent to the falciform ligament as revealed by angiographic helical CT and angiography.

PURPOSE: To investigate nontumorous abnormalities in the liver around the falciform ligament as revealed by arteriography and helical CT arterial portography (CTAP) and helical CT during hepatic arteriography (CTHA). MATERIAL AND METHODS: One hundred and seventeen patients simultaneously underwent hepatic arteriography and CTAP and CTHA of the common hepatic artery. The number, size, and shape of nontumorous defects of portal perfusion in the liver adjacent to the falciform ligament on CTAP as well as the nontumorous contrast enhancement in the same area on CTHA were determined. In 1 case, in which nontumorous enhancement was observed on CTHA, selective arteriography from the gastric arteries was performed. RESULTS: On CTAP a nontumorous area of decreased portal perfusion of the liver around the falciform ligament was detected in 18 (15.4%) of the 117 patients, while nontumorous enhancement on CTHA was seen in 7 (6.0%). In 4 patients, both of these nontumorous abnormalities were observed. In the patient undergoing selective gastric arteriography, nonportal venous inflow to the liver in the direction to the liver adjacent to the falciform ligament was seen. CONCLUSION: One cause of nontumorous vascular abnormalities adjacent to the falciform ligament as shown on angiographic helical CT is aberrant gastric venous inflow to this region.

Aged↗

PubMed2001

Matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in sputum from patients with bronchial asthma.

To examine a possibility that matrix metalloproteinases (MMPs) participate in the pathogenesis of asthma and/or the development of asthma attack, we measured the concentrations of MMP-2, MMP-9, and their respective tissue inhibitors of metalloproteinases (TIMP)-2 and TIMP-1, in induced sputa collected from 28 patients with moderate to severe bronchial asthma. Specimens were collected during both the attack and the remission from 15 age- and sex-matched healthy control subjects. The concentration of MMP-9 was significantly (p < 0.05) higher in the patients, even during the remission, as compared to that in healthy controls. The concentrations of MMP-9 (p < 0.05) and its specific inhibitor TIMP-1 (p < 0.01), and MMP-2 (p < 0.01) in these patients during the attack were significantly higher than those in healthy controls. In these patients, the MMP-9 concentration was significantly higher (p < 0.05) during the attack than during the remission. These results suggest that MMPs and TIMPs may be involved in the pathogenesis of bronchial asthma, and that the increased MMP-9 might be involved in the development of attack in patients with chronic asthma.

Adolescent↗

PubMed2001

Cyclic and linear peptides derived from alpha-amylase inhibitory protein tendamistat.

Tendamistat is a strong inhibitory protein of porcine pancreatic alpha-amylase (PPA) with a K(i) value of 0.2 nM. To develop potent alpha-amylase inhibitors, we synthesized six odd-length cyclic peptides (5-15 residues) and four even-length cyclic peptides (10 and 12 residues) having the inhibitory sequence of tendamistat. Their PPA inhibitory activities were evaluated, and, among them, the 11-residue cyclic peptide Ten(15-23) (K(i) = 0.27 microM) exhibited the strongest inhibitory activity (K(i) = 0.27-1.41 microM). To examine the effect of cyclic structure on PPA inhibition, ten linear peptides corresponding to the cyclic peptides were also synthesized, and their PPA inhibitory activities were evaluated (K(i) = 0.28-1.00 microM). Interestingly, the 11-residue linear peptide Ten(15-23) exhibited almost the same inhibitory activity (K(i) = 0.28 microM) as that of cyclic Ten(15-23). The results of a circular dichroism study indicated that stabilization of the beta-hairpin structure occurred only for cyclic Ten(15-23). Also, the results of proteolytic digestion experiments of the cyclic and linear Ten(15-23) peptides by trypsin and chymotrypsin suggested no differences in protease resistance between the cyclic and linear structures. Therefore, we demonstrated that both cyclic and linear peptides containing the inhibitory sequence of tendamistat exhibit potent PPA inhibitory activity.

Amino Acid Sequence↗

PubMed2001

Role of the putative membrane-bound endo-1,4-beta-glucanase KORRIGAN in cell elongation and cellulose synthesis in Arabidopsis thaliana.

A temperature-sensitive, elongation-deficient mutant of Arabidopsis thaliana was isolated. At the non-permissive temperature of 31 degrees C, the mutation impaired tissue elongation; otherwise, tissue development was normal. Hypocotyl cells that had established cell walls at 21 degrees C under light-dark cycles ceased elongation and swelled when the mutant was shifted to 31 degrees C and darkness, indicating that the affected gene is essential for cell elongation. Analysis of the cell walls of mutant plants grown at 31 degrees C revealed that the cellulose content was reduced to 40% and the pectin content was increased to 162% of the corresponding values for the wild type grown at the same temperature. The increased amounts of pectin in the mutant were bound tightly to cellulose microfibrils. No change in the content of hemicellulose was apparent in the 31 degrees C-adapted mutant. Field emission-scanning electron microscopy suggested that the structure of cellulose bundles was affected by the mutation; X-ray diffraction, however, revealed no change in the crystallite size of cellulose microfibrils. The regeneration of cellulose microfibrils from naked mutant protoplasts was substantially delayed at 31 degrees C. The recessive mutation was mapped to chromosome V, and map-based cloning identified it as a single G-->A transition (resulting in a Gly(429)-->Arg substitution) in KORRIGAN, which encodes a putative membrane-bound endo-1,4-beta-glucanase. These results demonstrate that the product of this gene is required for cellulose synthesis.

Arabidopsis↗

PubMed2001

The AHK4 gene involved in the cytokinin-signaling pathway as a direct receptor molecule in Arabidopsis thaliana.

We previously identified a set of structurally related genes, AHK2, 3 and 4, each encoding a sensor histidine kinase in Arabidopsis thaliana. To determine the relevant biological functions, we identified a loss-of-function mutation of the AHK4 gene. The mutant exhibited the cytokinin-resistant phenotype not only in inhibition of root growth by cytokinin but also in greening and shoot induction of calli. Moreover, AHK4 expressed in budding yeast showed histidine kinase activity in a manner dependent on the presence of cytokinin. These results strongly suggested that AHK4 is involved in the cytokinin-signaling pathway, as a direct receptor molecule, in Arabidopsis.

Arabidopsis↗

PubMed2001

Morphological and biochemical changes of isolated chicken egg-envelope during sperm penetration: degradation of the 97-kilodalton glycoprotein is involved in sperm-driven hole formation on the egg-envelope.

The chicken egg-envelope is made of two major glycoprotein components, which are designated as gp97 and gp42 (after their molecular masses). To elucidate how these two components are involved in macromolecular organization of the chicken egg-envelope, the isolated egg-envelope was characterized by immunochemical and biochemical methods. The gp97 was suggested to be a homologue of mouse ZPB based on the similarities of N-terminal and internal sequences. Immunoblotting using anti-gp97 monoclonal antibodies and two-dimensional gel electrophoresis with or without mercaptoethanol treatment revealed that gp97 formed a homodimer through disulfide bonds, whereas gp42 did not. Under indirect immunofluorescence microscopy, the anti-gp97 antibody visualized indistinct, small spots on the egg-envelope, whereas the anti-gp42 antibody showed a meshwork of blurry, fibrous structures. The hole formation on the egg-envelope by in vitro sperm penetration was completely inhibited by two anti-gp97 monoclonal antibodies. Interestingly, the anti-gp97 monoclonal antibodies blocked the proteolysis not only of gp97 but also of gp42 during incubation of the egg-envelope with either sperm or the crude chicken acrosin. Taken together, these results indicate that gp97 may play pivotal roles not only in constitution of the macromolecular organization of the egg-envelope but also in triggering hydrolysis of the egg-envelope during sperm penetration.

Amino Acid Sequence↗

PubMed2001

Extremely short small bowel induces focal tubulointerstitial fibrosis.

BACKGROUND: Arginine becomes an essential amino acid after massive resection of the small bowel as a result of decreased biosynthesis of citrulline in the remaining small bowel. It is also reported that nitric oxide (NO) is synthesized from l-arginine by NO synthase (NOS), and NO is involved in the regulation of blood flow in the kidney. The authors observed a patient with an extremely short small bowel, showing focal tubulointerstitial fibrosis. The experiment was designed to clarify whether massive small bowel resection (SBR) produces focal tubulointerstitial fibrosis in the kidney. METHODS: An experimental study was performed using 4-week-old rats with 90% proximal SBR either with or without arginine supplementation for 6 weeks after surgery. RESULTS: In rats without arginine supplementation, low plasma levels of citrulline and arginine increased urinary excretion of orotate, and focal tubulointerstitial fibrosis was observed 6 weeks after 90% SBR. The data from plasma amino acid chromatography and increased excretion of urinary orotate suggested the presence of arginine deficiency. The kidney pathology was similar to that of our patient. Rats with arginine supplementation after 90% SBR and pair-fed control rats without 90% SBR showed almost normal glomeruli and tubulointerstitium. CONCLUSIONS: Experimental study strongly suggests that arginine deficiency causes focal tubulointerstitial fibrosis in the kidney after massive SBR.

Animals↗

PubMed2001

Distinct microsatellite alterations in upper urinary tract tumors and subsequent bladder tumors.

PURPOSE: Although synchronous and/or metachronous tumor development is common in urothelial cancer, genetic and biological differences in upper urinary tract and bladder tumors are unclear. We compared the genetic alteration pattern in multifocal disease in patients with upper urinary tract and subsequent bladder tumors, and those with recurrent bladder tumor. MATERIALS AND METHODS: Using 21 microsatellite markers on the 8 chromosomal arms 2q, 4p, 4q, 8p, 9p, 9q, 11p and 17p we analyzed 34 tumors from 15 patients with upper urinary tract and subsequent bladder disease, and 70 tumors from 22 with recurrent bladder disease. RESULTS: Judging from the patterns of genetic alterations multifocal tumors were considered to have derived from an identical progenitor cell in 7 of 13 evaluable patients (54%) with upper urinary tract and subsequent bladder tumors, and 16 of 19 (84%) who were evaluable with recurrent bladder tumor. These data confirm the view that seeding or intraepithelial spread is a major mechanism for the multifocal development of urothelial cancer in general. However, a discordant microsatellite alteration pattern in multifocal tumors was observed in 6 of 7 patients (86%) with upper urinary tract and subsequent bladder lesions but in 2 of 16 (13%) with recurrent bladder cancer (p <0.005). CONCLUSIONS: Our results imply that upper urinary tract neoplasms may be genetically more unstable than bladder neoplasms. The implantation of tumor cells from upper urinary tract to bladder may involve additional and diverse genetic alterations. Furthermore, a considerable number of multifocal upper urinary tract and subsequent bladder lesions may arise independently via field cancerization mechanism. Our study indicates that the factors contributing to multifocal development are different in the 2 groups.

DNA, Satellite↗

PubMed2001

Acid stimulates E-cadherin surface expression on gastric epithelial cells to stabilize barrier functions via influx of calcium.

BACKGROUND AND AIMS: E-cadherin, which is a [Ca2+]-dependent, homotypic cell-cell adhesion molecule, is expressed in gastrointestinal epithelial cells. Much has been learned about the down-regulation of E-cadherin expression in gastrointestinal tumours, Barrett's oesophageal dysplasia, and Crohn's disease, but the functions of this molecule in normal gastrointestinal mucosa are less known. METHODS: In this study, we investigated the relationship between E-cadherin expression and permeability using rat cultured gastric and intestinal epithelial cells following a 30-min exposure to various pH solutions. We also investigated the participation of [Ca2+] in these events. RESULTS: E-cadherin expression increased under acid (pH 4) but not alkali (pH 10 or 11) exposure only for gastric epithelial cells. Gastric epithelial permeability was maintained only against acid exposure while intestinal permeability increased under both conditions. Transient influx of [Ca2+] was only observed for gastric epithelial cells just after acid exposure. CONCLUSIONS: These findings suggest that E-cadherin expression on gastric epithelium stabilizes the epithelial barrier against acid, probably through influx of [Ca2+]. This event is thought to be one of the protective mechanisms in gastric mucosa against acid back-diffusion, which is one of the causes of peptic ulcer formation.

Acids↗

PubMed2001

Corneal neovascularization.

Corneal neovascularization (NV) is a sight-threatening condition usually associated with inflammatory or infectious disorders of the ocular surface. It has been shown in the field of cancer angiogenesis research that a balance exists between angiogenic factors (such as fibroblast growth factor and vascular endothelial growth factor) and anti-angiogenic molecules (such as angiostatin, endostatin, or pigment epithelium derived factor) in the cornea. Several inflammatory, infectious, degenerative, and traumatic disorders are associated with corneal NV, in which the balance is tilted towards angiogenesis. The pathogenesis of corneal NV may be influenced by matrix metalloproteinases and other proteolytic enzymes. New medical and surgical treatments, including angiostatic steroids, nonsteroidal inflammatory agents, argon laser photocoagulation, and photodynamic therapy have been effective in animal models to inhibit corneal NV and transiently restore corneal "angiogenic privilege."

Angiostatins↗

PubMed2001

Laser subepithelial keratomileusis: electron microscopy and visual outcomes of flap photorefractive keratectomy.

Laser epithelial keratomileusis (LASEK) is a surgical technique that may be performed in patients with low myopia who are considering conventional photorefractive keratectomy (PRK), in patients with thin corneas, and in patients with professions or lifestyles that predispose them to trauma. Ethanol (18%) is applied for 25 seconds and a hinged epithelial flap is created. After laser ablation, the flap is repositioned over the ablated stroma. Our data showed that epithelial defects occurred in 63% eyes on Day 1. Postoperative pain was absent in 47%. Uncorrected visual acuity of 20/40 or better was achieved in all patients at 1 week. Data from several studies suggest that LASEK may reduce postoperative pain and corneal haze associated with PRK. LASEK offers the potential advantage of avoiding flap-related complications associated with laser in situ keratomileusis and decreasing postoperative pain and corneal scarring associated with PRK. Long-term studies are needed to confirm these potential advantages and to determine the safety, efficacy, and predictability of this surgical technique.

Epithelium, Corneal↗

PubMed2001

Porphyromonas gulae sp. nov., an anaerobic, gram-negative coccobacillus from the gingival sulcus of various animal hosts.

A new species, Porphyromonas gulae sp. nov., is proposed to include strains isolated from the gingival sulcus of various animal hosts which are distinct from related strains of Porphyromonas gingivalis of human origin. This bacterium exhibits the following characteristics: black-pigmented colonies; asaccharolytic, obligate anaerobic growth; and Gram-negative, non-motile and non-spore-forming, rod-shaped cells. Colonies do not fluoresce under UV light. Vitamin K1 and haemin are required for growth. Cells haemagglutinate sheep erythrocytes. Major fatty acid end products are butyric acid, isovaleric acid, succinic acid and phenylacetic acid. Strains are catalase-positive and indole is produced. Alkaline phosphatase, trypsin-like and N-acetyl-beta-glucosaminidase activities are strong. A beta-galactosidase and a glutamylglutamic acid arylamidase are also present. The G+C content of the chromosomal DNA is 51 mol%. DNA-DNA homology data and 16S rRNA gene sequence analysis provide strong evidence that strains from the animal biotype of P. gingivalis represent a Porphyromonas species that is distinct from P. gingivalis. The type strain of P. gulae is Loup 1T (= ATCC 51700T = NCTC 13180T).

Animals↗

PubMed2001

Incidental learning of real-world regularities.

The large literature on incidental learning relies almost exclusively on laboratory experiments. Whenever researchers have attempted to demonstrate incidental learning of real-world regularities, they have typically failed to show learning. For example, it is well established that people do not learn regularities in everyday objects, such as the left-right orientation of faces on coins, despite a very large exposure to them. In this report, we examine this apparent contradiction. We argue that most studies exploring real-life incidental learning use tests that are not as sensitive to low-confidence information as those traditionally used in laboratory tasks. Using more sensitive measures, we show that it is possible to learn regularities from British and Japanese cultural life as a direct result of exposure to these regularities. Further, confidence measures suggest that although the information may be acquired incidentally, it can be expressed with and without concomitant awareness of that knowledge.

Adult↗

PubMed2001

Antitumor activity and pharmacokinetics of TAS-106, 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine.

We examined the effects of dosage schedule on antitumor activity in vitro and in vivo to determine the optimal administration schedule for a new nucleoside antimetabolite 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd, TAS-106). The cytotoxicity of TAS-106 in vitro against human tumors was evaluated at three drug exposure periods. TAS-106 exhibited fairly potent cytotoxicity even with 4 h exposure, and nearly equivalent and sufficiently potent cytotoxicity with 24 and 72 h exposures. These results suggest that long-term exposure to TAS-106 will not be required to achieve maximal cytotoxicity. The antitumor activity of TAS-106 in vivo was compared in nude rat models bearing human tumors on three administration schedules, once weekly, 3 times weekly, and 5 times weekly for 2 or 4 consecutive weeks. TAS-106 showed strong antitumor activity without serious toxicity on all three schedules, but the antitumor activity showed no obvious schedule-dependency in these models. When tumor-bearing nude rats were given a single i.v. dose of [(3)H]TAS-106, tumor tissue radioactivity tended to remain high for longer periods of time as compared to the radioactivity in various normal tissues. Furthermore, when the metabolism of TAS-106 in the tumor was examined, it was found that TAS-106 nucleotides (including the active metabolite, the triphosphate of TAS-106) were retained at high concentrations for prolonged periods. These pharmacodynamic features of TAS-106 may explain the strong antitumor activity without serious toxicity, observed on intermittent administration schedules, in nude rat models with human tumors. We therefore consider TAS-106 to be a promising compound which merits further investigation in patients with solid tumors.

Animals↗

PubMed2001

Recognition of YKL-39, a human cartilage related protein, as a target antigen in patients with rheumatoid arthritis.

OBJECTIVE: To investigate whether autoimmunity to YKL-39, a recently cloned cartilage protein, occurs in patients with rheumatoid arthritis (RA). METHODS: Autoantibody to YKL-39 was assayed by enzyme linked immunosorbent assay (ELISA) and western blotting in serum samples from patients with RA, systemic lupus erythematosus (SLE), and healthy donors, using recombinant YKL-39 protein. This reactivity was compared with that against a YKL-39 homologue, YKL-40 (human cartilage gp-39/chondrex), which has been reported to be an autoantigen in RA. RESULTS: Autoantibody to YKL-39 was detected in seven of 87 patients with RA (8%), but not in serum samples from patients with SLE or healthy donors. YKL-40 reactivity was found in only one of 87 RA serum samples (1%), with no cross reactivity to YKL-39. CONCLUSION: The existence of anti-YKL-39 antibody in a subset of patients with RA is reported here for the first time. Further, it was shown that the immune response to YKL-39 was independent of that to YKL-40. Clarification of the antibody and T cell responses to autoantigens derived from chondrocyte, cartilage, or other joint components may lead to a better understanding of the pathophysiology of joint destruction in patients with RA.

Adipokines↗