Biomedical subjects

H Nagata

Publications and source records attributed to H Nagata.

At least 91 records · Page 5Linked to original sources

PubMed1999

Mutagenic activation of environmental carcinogens by microsomes of gastric mucosa with intestinal metaplasia.

Coexpression of cytochrome P450 monooxygenases (CYPs) and reductase was found in human gastric mucosa with intestinal metaplasia. Immunohistochemistry showed reactivity to P450 reductase in metaplastic epithelial cells and in pyloric gland cells in glands showing intestinal metaplasia. These cells exhibit NADPH-diaphorase activity. Reverse transcription-PCR analysis and Western blotting showed that CYP1A1 and CYP1A2 were expressed in specimens with intestinal metaplasia. Tissue distribution of CYP1A1 coincided with that of P450 reductase. However, immunoreactivity to CYP1A2 protein was localized only in the pyloric gland cells near the intestinal metaplastic gland. Salmonella typhimurium mutagen assay definitively revealed that microsomes prepared from gastric mucosa with intestinal metaplasia, in particular in the pyloric gland, functionally activated benzo(a)pyrene and 2-amino-3-methylimidazo [4,5-f]quinoline. These results indicate that carcinogen activation by CYP enzymes expressed in the gastric mucosa may contribute to carcinogenesis of the stomach.

Carcinogens, Environmental↗

PubMed1999

Acute exercise causes mitochondrial DNA deletion in rat skeletal muscle.

The present study was conducted to determine the effects of acute overload exercise on mitochondrial DNA and the structure of skeletal muscles. Rats were forced to run for 20 min until reaching complete exhaustion. We detected the large-scale deletion (7052 bp) of mitochondrial DNA by the nested polymerase chain reaction, and also observed mitochondrial ultrastructural changes in the soleus muscle.

Animals↗

PubMed1999

Application of Bead-ELISA method to detect Helicobacter pylori VacA.

Helicobacter pylori is an etiological agent of gastritis, gastric ulcer and gastric cancer. In order to clarify the significance of vacuolating cytotoxin (VacA) for the pathogenesis of Helicobacter pylori infection, we established and applied the sandwich bead enzyme-linked immunosorbent assay (Bead-ELISA) for quantitative determination of VacA in the culture mediums of H. pylori and other species of Helicobacter. The minimum concentration of VacA in culture medium detected by Bead-ELISA was 25 pg VacA/ml and its sensitivity was found to be quite high compared to vacuolation assay and Western blot analysis, e.g. the minimum concentrations of VacA in culture medium required for detection by vacuolation assay and Western blotting were 11 ng/ml and 38 ng/ml, respectively. All the H. pylori strains used were found to produce VacA in the culture medium by Bead ELISA, even though some strains were negative by Western blot and vacuolation assay. The results obtained by Bead-ELISA was consistent with those by PCR amplification of a 785 bp vacA fragments. A toxin immunologically similar to VacA produced by other strains of Helicobacter such as H. muridarum (ATCC49282), H. mustelae (F10) and H. felis (ATCC49179) could not be detected by Bead-ELISA as well as Western Blot.

Animals↗

PubMed1999

Retroperitoneoscopic adrenalectomy by a lumbodorsal approach: clinical experience with solo surgery.

Laparoscopic adrenalectomy by transperitoneal approaches necessitates the retraction of intraperitoneal organs and, hence, the creation of extra ports for retractors and assistants. The feasibility of retroperitoneoscopic adrenalectomy by a lumbodorsal approach was assessed in 26 patients with adrenal tumors. In six patients the procedure was carried out as solo surgery using the ABSOP robot camera holder, and the performance was compared with that reported for the most recent series of six cases operated upon with one human assistant. The procedures were successful in 25 patients. One patient had to be converted due to tension pneumothorax caused by diaphragmatic injury. The mean blood loss was 43.5 +/- 67.5 ml, and the procedure time averaged 144 +/- 33 min. We required an average of only 3.1 trocars to accomplish solo surgery in 5 of 6 patients (83%). The number of lens smearings decreased to one-fourth of that observed by a human assistant.

Adrenal Gland Diseases↗

PubMed1999

Is endoscopic paravascular injection of sclerosing agents reasonable in the control of GI bleeding?

BACKGROUND: The pharmacologic response and microvascular effects associated with the endoscopic injection of sclerosing agents around vessels (paravascular injection) to stop bleeding from the digestive tract remain to be clarified. METHODS: Using in vivo microscopy, we directly visualized submucosal microvessels of the rat stomach and intestine. We studied differences among sclerosing agents in thrombus formation and vascular diameter change that occur through a pharmacologic response and/or local compression after topical application or paravascular injection of the agents. RESULTS: Except for absolute ethanol, topical application of the agents did not cause constriction or thrombi in either arterioles or venules. Polidocanol topical application and paravascular injection significantly dilated arterioles. Injecting ethanolamine oleate near venules constricted them the longest and most effectively, but vasoconstriction in arterioles was transient. Injecting absolute ethanol formed long-lasting thrombi and caused vasoconstriction in venules, but arteriole thrombi persisted no more than 3 minutes. The vascular response to thrombin did not significantly differ from that to physiologic saline. CONCLUSION: The paravascular injection of ethanolamine oleate, because of its long-lasting vasoconstriction, or of absolute ethanol, because of its thrombogenic effect, is a valid therapeutic approach to treating venous bleeding. The efficacy of paravascular injection of sclerosing agents for treating acute arterial bleeding, however, is not supported in this experimental model.

Animals↗

PubMed1999

Response to cyclosporin and low-dose methylprednisolone in aggressive systemic mastocytosis.

BACKGROUND: There is no effective treatment for aggressive systemic mastocytosis. OBJECTIVE: The purpose of this study was to investigate the effect of cyclosporin and low-dose methylprednisolone in a 64-year-old man with aggressive systemic mastocytosis. METHODS: Immunohistochemical studies were done on biopsy specimens from the skin and other organs. Mast cells, predominantly containing tryptase, were derived from human umbilical cord blood cells cultured in the presence of stem-cell factor and IL-6. IgE-sensitized cultured human mast cells were activated by anti-IgE, and the effect of cyclosporin on histamine release was investigated. In addition, blood and urine levels of various mediators were measured in the patient before and after therapy. RESULTS: Biopsy specimens of the patient's skin lesions showed an increase of mast cells; cells containing tryptase (but not chymase) comprised 20% to 50% of the skin mast cells. Histamine release from activated cultured mast cells was inhibited by cyclosporin in a concentration-dependent manner. When the patient was treated with cyclosporin and low-dose methylprednisolone, he showed a good response. CONCLUSION: Cyclosporin combined with low-dose methylprednisolone may be a reasonable therapy for aggressive systemic mastocytosis.

Bone Marrow Cells↗

PubMed1999

Nerve growth factor release with mast-cell-derived mediators in a patient with systemic mastocytosis after middle-wave ultraviolet irradiation.

BACKGROUND: The symptoms of a 56-year-old man with systemic mastocytosis became worse with exposure to sunlight. We evaluated mast-cell-derived mediators and cytokines before and after exposure to ultraviolet light in the patient. METHODS: The patient was irradiated with middle-wave ultraviolet light, so-called ultraviolet light B, and the levels of mediators and cytokines were measured serially. The point mutation Asp816Val in c-kit was investigated by analyzing polymerase chain reaction products from the complementary DNA of peripheral blood mononuclear cells. RESULTS: Before irradiation, the levels of mast-cell-derived mediators and metabolites were elevated. Among various cytokines measured, including soluble c-kit and stem cell factor, only the level of nerve growth factor was elevated. After irradiation, the nerve growth factor level was further increased along with the levels of mast-cell-derived mediators and metabolites. The point mutation Asp816Val in c-kit was not detected in peripheral blood mononuclear cells. CONCLUSIONS: Middle-wave ultraviolet light may activate mast cells to release nerve growth factor and mediators in systemic mastocytosis.

Cytokines↗

PubMed1999

Cord blood-derived human cultured mast cells produce transforming growth factor beta1.

BACKGROUND: Mast cells frequently accumulate at the site of fibrosis and their contribution has been suspected in the pathogenesis of fibrotic conditions. However, it still remains unknown whether human mast cells synthesize transforming growth factor beta1 (TGF-beta1). OBJECTIVE: We have investigated whether cord blood-derived human cultured mast cells express messenger RNA (mRNA) for TGF-beta and produce bioactive TGF-beta1. METHODS: Mast cells were obtained by culturing mononuclear cells from cord blood in the presence of stem cell factor and interleukin-6. Expression of mRNA for TGF-beta1 was examined by the method of reverse transcriptase-polymerase chain reaction (RT-PCR). Immunocytochemical staining for TGF-beta and growth-inhibitory assay using Mv1Lu cells were also performed. RESULTS: The cultured human mast cells constitutively expressed mRNA for TGF-beta1. With calcium ionophore A23187, the intensity of the PCR-amplified band for TGF-beta1 was not increased. Immunocytochemical staining showed that the cultured mast cells were positive for both latency-associated peptide and activated forms of TGF-beta. Bioassay with Mv1Lu cells and R 4-2 mutant cells showed that mast-cell conditioned medium had a bioactivity of TGF-beta1. CONCLUSION: Cord blood-derived human cultured mast cells constitutively express mRNA for TGF-beta1 and produce functional TGF-beta1. Because TGF-beta1 has been shown to be highly fibrogenic, these results may highlight a novel role for human mast cells in tissue fibrosis.

Animals↗

PubMed1999

The value of gamma-seminoprotein in combination with prostate specific antigen in detecting prostate cancer.

BACKGROUND: The present study was undertaken to investigate the value of gamma-seminoprotein (gamma-Sm) and the gamma-Sm/prostate specific antigen (PSA) ratio in combination with serum PSA in detecting prostate cancer. METHODS: Prostate specific antigen, gamma-Sm and the gamma-Sm/PSA ratio were evaluated in 112 patients with untreated prostate cancer and 90 patients without prostate cancer who had serum PSA and gamma-Sm levels above their respective detection limits. RESULTS: When data for all of the patients were analyzed, serum PSA and gamma-Sm levels were significantly higher and the gamma-Sm/PSA ratio was significantly lower in patients with prostate cancer than patients without prostate cancer. The serum PSA and gamma-Sm levels significantly increased and the gamma-Sm/PSA ratio significantly decreased with advancing clinical stage in patients with prostate cancer. Among the patients with serum PSA levels ranging from 1.8 to 6 ng/mL, the gamma-Sm/PSA ratio was significantly lower (P < 0.05) and gamma-Sm levels were lower (P = 0.054) in the patients with prostate cancer than in those without prostate cancer, but serum PSA levels were not significantly different (P = 0.53). A receiver operating characteristic (ROC) analysis demonstrated that the areas under the ROC curves were 0.54 for PSA, 0.65 for gamma-Sm and 0.69 for the gamma-Sm/PSA ratio for prediction of prostate cancer in the PSA range from 1.8 to 6 ng/mL, although the ROC analysis suggested that the gamma-Sm/PSA ratio does not provide significant advantage over PSA in detecting prostate cancer when all of the patients were analyzed. CONCLUSIONS: These results suggest that the gamma-Sm/PSA ratio and gamma-Sm may facilitate differentiation between patients with and without prostate cancer who have intermediate PSA levels.

Adenocarcinoma↗

PubMed1999

Extensive interstitial collagen deposition on the basement membrane zone in allergic nasal mucosa.

To clarify whether tissue remodelling of the nasal mucosa is caused by allergic inflammation or not, we studied the amount and distribution of collagen in human nasal mucosa of 13 perennial allergic patients and 13 non-allergic subjects. The total amount of collagen and other proteins in nasal mucosa was determined by absorbency at 540 nm and 605 nm of a solution eluted from tissue sections stained with sirius red and fast green. Distribution of collagen type I, III and IV was observed by immunohistochemistry. The thickness of the basement membrane zone underlying epithelia was histologically estimated. Results were as follows: i) There was no significant difference in the total amount of collagen between allergic and non-allergic subjects. ii) Although there was no obvious change in localization of the three types of collagen, extensive immunoreactivity for types I and III collagen was observed at subepithelial basement membrane zone in allergic subjects. iii) The thickness of the basement membrane zone, which corresponds to regions positive for types I and III collagen antibodies, was statistically significantly greater in allergic subjects than in non-allergic ones. We thus concluded that tissue remodelling occurs in the allergic nasal mucosa, and that it is especially obvious in the basement membrane zone.

Adolescent↗

PubMed1999

Left atrial tachycardia after right atrial separation for chronic atrial fibrillation with atrial septal defects.

A right atrial separation procedure was performed for the ablation of chronic atrial fibrillation in four cases, concomitant with the repair of the atrial septal defect. After the operation, chronic atrial fibrillation disappeared in three of them and left atrial tachycardia occurred in the other one. Left atrial tachycardia is an arrhythmia encountered after a right atrial separation procedure.

Aged↗

PubMed1999

Surgical orthodontic treatment of skeletal Class III malocclusion with anterior disc displacement without reduction (ADNR): a case report.

A female patient with skeletal problems and left temporomandibular joint (TMJ) derangement was treated with an occlusal splint, arthroscopic irrigation, and orthodontic surgery. The left side disc was displaced anteriorly without reduction; and mobility of the left condylar head was restricted. With arthroscopic irrigation, the jaw functions were recovered, but the disc position remained the same. After TMJ therapy, orthodontic and orthognatic surgery treatments were performed to correct the dentofacial deformity. Stable facial esthetics and occlusion devoid of temporomandibular joint disorder (TMD) symptoms were obtained and the patient's progress was monitored over a 5-year period.

Adolescent↗

PubMed1999

Secretion of functional salivary peptide by Streptococcus gordonii which inhibits fimbria-mediated adhesion of Porphyromonas gingivalis.

Porphyromonas gingivalis, a putative periodontopathogen, can bind to human salivary components with its fimbriae. We have previously shown that fimbriae specifically bind to a peptide domain shared by a major salivary component, i.e., proline-rich (glyco)proteins (PRPs). The synthetic domain peptide PRP-C (pPRP-C) significantly inhibits the fimbrial binding to PRPs. In this study, a recombinant strain of Streptococcus gordonii secreting pPRP-C was generated as a model of a possible approach to prevent the oral colonization by the pathogen. A duplicate DNA fragment (prpC) encoding pPRP-C was obtained by self-complementary annealing of synthetic oligonucleotides. prpC was connected downstream to a promoter and a gene encoding a signal peptide of Streptococcus downei glucosyltransferase I in frame. The linked fragments were inserted into the plasmid pMNK-4 derived from pVA838. The constructed plasmid was inserted to produce the transformant S. gordonii G9B, which then successfully secreted recombinant pPRP-C (r-pPRP-C) of the expected size. The concentrated bacterial culture supernatant containing r-pPRP-C inhibited the binding of P. gingivalis cells and fimbriae to PRP1 in a dose-dependent manner up to 72 and 77%, respectively. The r-pPRP-C concentrate also inhibited the coaggregation of P. gingivalis with various streptococcal strains as effectively as synthetic pPRP-C in a dose-dependent manner. Collectively, pPRP-C was found to be able to prevent P. gingivalis adherence to salivary receptor protein and plaque-forming bacteria. These results suggest that this recombination approach with a nonperiodontopathic bacterium may be suitable for the therapeutic prevention of P. gingivalis adherence to the oral cavity.

Bacterial Adhesion↗

PubMed1999

Pathophysiological features of the nasal mucosa in patients with idiopathic rhinitis compared to allergic rhinitis.

BACKGROUND: The literature on abnormality of vasomotor responses of the nasal mucosa to cold stimulation of the skin in idiopathic rhinitis is conflicting. The objective of this study was to elucidate pathophysiological features of the nasal mucosa in idiopathic rhinitis compared to allergic rhinitis. METHODS: The following were studied in patients with idiopathic rhinitis and allergic rhinitis and in normal controls: (1) threshold of the nasal reaction to histamine; (2) inflammatory cells in nasal lavage and scraped nasal mucosal epithelium, and (3) nasal vasomotor response to cold stimulation of the feet evaluated by acoustic rhinometry. RESULTS: Inflammatory cells were not found to be involved in idiopathic rhinitis. Nasal reactivity to histamine was significantly enhanced in patients with idiopathic rhinitis compared to normal controls, but was significantly lower compared to those with allergic rhinitis. The most prominent finding in idiopathic rhinitis was nasal mucosal swelling induced by cold stimulation of the feet. While in normal controls, cold stimulation of the feet caused mucosal contraction due to sympathetic excitation, sympathetic nasal vasomotor response in idiopathic rhinitis patients was significantly inhibited and caused mucosal swelling and enhanced nasal secretion. Mucosal reactions observed in allergic rhinitis were between those observed in idiopathic rhinitis and in normal controls. Cold stimulation of the feet increased systolic blood pressure by 5-15 mm Hg, but the degree of increase observed in the 3 groups was almost equal. CONCLUSIONS: The above findings indicate that patients with idiopathic rhinitis have abnormalities that inhibit sympathetic reactions and enhance parasympathetic vasomotor response at peripheral levels, possibly in the nasal mucosa.

Adolescent↗

PubMed1999

Optic nerve blindness due to paranasal sinus disease.

Patients with total blindness caused by paranasal sinus disease have rarely been reported. We retrospectively studied the prognosis of patients who had optic nerve blindness due to paranasal sinus disease. During the past 10 years, we identified 17 patients with optic nerve disease and posterior paranasal sinus disease. Seven of the 17 patients with optic nerve disease and paranasal sinus disease had no light perception. Five of these 7 patients with paranasal sinus disease had a final visual acuity of 20/200 or better. Two patients showed dramatic visual improvement after endonasal surgery. Because immediate surgery to correct paranasal sinus disease is required in affected patients, computed tomography should be done at the patient's first visit.

Adult↗

PubMed1999

Comparative role of peptide leukotrienes and histamine in the development of nasal mucosal swelling in nasal allergy.

To evaluate the importance of histamine and peptide leukotrienes (LTs) in the development of nasal mucosal swelling in nasal allergy, H1 receptor antagonist (mequitazine, 6 mg, in 2 divided doses, Rhône-Poulenc Rorer, France) and LT receptor antagonist (ONO-1078, pranlukast, 450 mg, in 2 divided doses, Ono Pharmaceutical Co, Ltd, Osaka) were administered orally for 7 days to 16 subjects with perennial nasal allergy to house dust mites, and the effects of receptor blockers of these chemical mediators on the effective cross-sectional area of the nasal cavity (ECA) at rest, at exercise load, at antigen challenge, and at exercise load following antigen challenge were studied. After the administration of H1 receptor antagonist, ECAs at all measurement points slightly increased, but no statistical significance was observed. On the other hand, LT receptor antagonist inhibited ECAs 10 minutes after exercise load, just after the end of antigen challenge, 10 minutes later, and at exercise load following antigen challenge with statistical significance. These results suggest that LTs are involved markedly, and histamine slightly, in the development of nasal mucosal swelling in nasal allergy.

Adolescent↗

PubMed1999

The basic diagnostic approaches used in robotic still-image telepathology.

We investigated the basic diagnostic processes used in telepathology with our robotic still-image system, OLMICOS, by analysing the steps and patterns used in 20 consecutive tissue section diagnoses. Three basic approaches were recognized. One was magnifying a suspect finding in a low-powered microscopic image. This approach was used mostly for confirming or characterizing a tumour. The second approach was scanning over a low-powered image by magnifying square images to form a mesh. This was found to be useful to confirm the presence or absence of signs and was mostly used as the initial step in judging the surgical margin of malignant cases or diagnosing lesions. The third approach was a combination of these two and was used for delineating the surgical margin, confirming the absence of metastases or diagnosing difficult lesions. Recognition of these three basic diagnostic approaches is important in making a rapid and correct remote diagnosis.

Humans↗

PubMed1999

The suture applicator for replacing a bone flap--technical note.

A new instrument was developed for passing and holding sutures during the replacement of a bone flap. The new device is a simple straight aluminum shaft, 6 cm in length and 0.7 mm in diameter with a groove on both ends for holding the suture. The shaft can be easily bent with the fingers to attain the desired curve and more suitable manipulation. Passing the shaft through the straight hole in the cranium or the cranial flap was very easy and convenient. No dural damage occurred during 80 procedures using this shaft. No needle holder or forceps for temporary clipping sutures were necessary, which reduced the operative time and mental and physical burden on the operator and the nurses. The mean time per hole with our instrument (45.8 +/- 9.2 sec) was significantly shorter compared to conventional methods with a circular needle, needle holder, and many forceps for temporary clamping of sutures (65.6 +/- 13.2 sec).

Bone Transplantation↗