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Biomedical subjects

H Okamoto

Publications and source records attributed to H Okamoto.

At least 127 records · Page 7Linked to original sources
PubMed2001

A clinical application of autotransplantation using furcation-involved root.

BACKGROUND, AIMS: The present case report describes the clinical application of autotransplantation using furcation involved roots. METHOD: After initial therapy, root resection was performed upon the patient's molar teeth with furcation involvement in the mandible. 2 distal roots of the molar teeth were autotransplanted as abutments to replace missing premolar and molar teeth in the mandible. RESULTS: On re-examination, 1 year after the transplantation, these roots showed no signs of periodontal or technical complications. The results suggest the potential use of autotransplantation techniques using furcation involved roots in reconstructive therapy. This may be a new approach in periodontal therapy.

Bicuspid↗
PubMed2001

Induction of collagenase-2 (matrix metalloproteinase-8) gene expression by interleukin-1beta in human gingival fibroblasts.

Collagenase-2 (matrix metalloproteinase-8 or MMP-8) is synthesized mainly by polymorphonuclear neutrophils and plays a crucial role in inflammatory periodontal tissue destruction. We tested the effect of interleukin(IL)-1beta, a proinflammatory cytokine, on collagenase-2 gene expression in cultured human gingival fibroblasts and also compared this effect with IL-1beta-induced changes in collagenase-1 and -3 gene expression. By a combination of reverse transcription-polymerase chain reaction and Southern analysis, IL-1beta was found to dose-dependently induce gene expression for collagenase-1, -2, and -3 in gingival fibroblasts. Although collagenase-2 mRNA was the least abundant among the three collagenase mRNAs tested in the cultured fibroblast system, addition of 1 ng/ml IL-1beta significantly increased collagenase-2 gene transcription within 6 h, and maximal stimulation was maintained for 12 to 48 h. Significant mRNA induction was observed with as little as 0.1 ng/ml IL-1beta. IL-1beta was also found to increase the stability of collagenase-2 mRNAs after transcription arrest was induced by an RNA polymerase inhibitor. Stimulation of collagenase-2 mRNA expression by IL-1beta was prevented by pretreatment with cycloheximide, an inhibitor of protein synthesis. These results indicate that IL-1beta increased mRNA expression for collagenases including collagenase-2 in gingival fibroblasts. The findings also suggest that enhancement of collagenase-2 mRNA expression by IL-1beta involves both protein synthesis and suppression of mRNA degradation.

Analysis of Variance↗
PubMed2001

Photo-mediated gene activation using caged RNA/DNA in zebrafish embryos.

We report a new and simple technique for photo-mediated temporal and spatial control of gene activation in zebrafish embryos as an alternative to the gene 'knockdown' approach using antisense, morpholino-modified oligonucleotides (morpholinos). The synthetic compound 6-bromo-4-diazomethyl-7-hydroxycoumarin (Bhc-diazo) forms a covalent bond with the phosphate moiety of the sugar-phosphate backbone of RNA, a process known as caging. The 6-bromo-7-hydroxycoumarin-4-ylmethyl (Bhc) group binds to approximately 30 sites on the phosphate moieties per 1 kb of RNA sequence. Bhc-caged mRNA undergoes photolysis (uncaging) when exposed to long-wave ultraviolet light (350 to 365 nm). We show that Bhc-caged green fluorescent protein (Gfp) mRNA has severely reduced translational activity in vitro, whereas illumination of Bhc-caged mRNA with ultraviolet light leads to partial recovery of translational activity. Bhc-caged mRNA is highly stable in zebrafish embryos. In embryos injected with Bhc-caged Gfp mRNA at the one-cell stage, GFP protein expression and fluorescence is specifically induced by ultraviolet light. We also show that, consistent with results obtained using other methods, uncaging eng2a (which encodes the transcription factor Engrailed2a) in the head region during early development causes a severe reduction in the size of the eye and enhanced development of the midbrain and the midbrain-hindbrain boundary at the expense of the forebrain.

Animals↗
PubMed2001

Photobiologic and photoimmunologic characteristics of XPA gene-deficient mice.

Xeroderma pigmentosum group A (XPA) gene-deficient mice cannot repair UV-induced DNA damage and easily develop skin cancers by UV irradiation. Just like human XP patients, homozygous (-/-) mice developed stronger longer-lasting acute inflammation than did wild-type mice after a single irradiation with UVB. Moreover, the model mice showed more severe UV-induced damage of keratinocytes and Langerhans cells than did the control mice. UVB-induced local and systemic immunosuppression was greatly enhanced in the (-/-) mice. Treatment with indomethacin, an inhibitor of prostaglandin (PG) synthesis, inhibited UV-induced inflammation and abrogated immunosuppression. In XPA-deficient mice, the amount of PGE2 and the expression level of COX-2 mRNA greatly increased after UVB irradiation compared with wild-type mice. These results suggest that the excess DNA photoproducts remaining in XPA-deficient cells after UV radiation induce COX-2 expression and subsequently produce a high amount of PGE2, which causes the enhancement of inflammation and immunosuppression. In XPA-deficient mice, the natural killer cell activity significantly decreased after repeated exposures to UVB. Our experimental data indicate that cancer development in XP patients involves not only mutagenesis due to the defect in DNA repair, but also the enhanced UV-immunosuppression and intensified impairment of natural killer function.

Animals↗
PubMed2001

Heightened ability of monocytes from sarcoidosis patients to form multi-nucleated giant cells in vitro by supernatants of concanavalin A-stimulated mononuclear cells.

The main immunocompetent cells in sarcoidal lesions are epithelioid cells and multi-nucleated giant cells (MGC), both of which are derived from monocyte-macrophage lineage cells. To understand further the relevance of monocytes in sarcoidosis, we examined in vitro MGC formation using monocytes from sarcoidosis patients, patients with other granulomatous diseases (OGD) and healthy control subjects. The supernatant of concanavalin A-stimulated peripheral blood mononuclear cells (conditioned medium) generated Langhans type-MGC and foreign body type-MGC from monocytes. Conditioned medium from any three groups had the same ability to form MGC from normal monocytes. On the other hand, MGC were more highly formed using monocytes from sarcoidosis patients than from other groups. When macrophages induced by treatment of monocytes with macrophage colony-stimulating factor (M-CSF) were used, the rate of MGC formation in sarcoidosis patients was about threefold or fourfold as much as that in OGD patients or healthy controls, respectively. Oxidized ATP inhibited MGC formation in all groups. The susceptibility of monocytes cultured in conditioned medium for 24 h to 2'- and 3'-o-(4-benzoyl-benzoyl)ATP-mediated cytolysis was significantly higher in sarcoidosis patients than other groups. These findings suggest that the ability of monocytes to form MGC through P2x7 receptors is enhanced in sarcoidosis patients.

Adenosine Triphosphate↗
PubMed2001

Anti-CD38 autoimmunity in patients with chronic autoimmune thyroiditis or Graves' disease.

Autoantibodies directed against human CD38 (an enzyme catalysing the interconversion of NAD(+) and cyclic ADP-ribose) have been demonstrated recently in patients with type 2 diabetes. We tested 220 consecutive Caucasian patients with autoimmune chronic thyroiditis, 104 patients with Graves' disease, 220 subjects from the general population (control I) and 78 healthy control subjects not affected by thyroid autoimmune disorders (control II) for the presence of anti-CD38 autoimmunity. Using Western blot analysis and optical densitometry, a specific band corresponding to human recombinant CD38 was identified in the serum of several subjects. By defining anti-CD38 positivity as a standardized optical reading > 3 s.d. higher than the mean value of control I, 10.4% of patients with thyroiditis and 7.7% of Graves' patients were anti-CD38 positive (P = 0.0009 versus 1.8% of control I). Similarly, 13.1% of patients with thyroiditis and 10.5% of Graves' patients had a standardized optical reading > 3 s.d. higher than the mean value of the subjects not affected by thyroid autoimmune disorders (P = 0.002 versus 1.2% of control II). Anti-CD38 autoimmunity did not differ between euthyroid, hyperthyroid or hypothyroid patients or between patients with or without thyroid hypoechogenicity. Anti-CD38 autoantibodies were associated with higher levels of circulating antithyroid-peroxidase antibodies (P = 0.03) and they were more frequent in Graves' patients with ophthalmopathy (P < 0.05). Anti-CD38 autoantibodies are a new autoimmune marker in chronic autoimmune thyroiditis and Graves' disease. The specific role of CD38 and its autoantibodies in the modulation of thyroid cell function or growth remains to be investigated.

ADP-ribosyl Cyclase↗
PubMed2001

A deficiency of coproporphyrinogen III oxidase causes lesion formation in Arabidopsis.

We isolated an Arabidopsis lesion initiation 2 (lin2) mutant, which develops lesion formation on leaves and siliques in a developmentally regulated and light-dependent manner. The phenotype of the lin2 plants resulted from a single nuclear recessive mutation, and LIN2 was isolated by a T-DNA tagging approach. LIN2 encodes coproporphyrinogen III oxidase, a key enzyme in the biosynthetic pathway of chlorophyll and heme, a tetrapyrrole pathway, in Arabidopsis. The lin2 plants express cytological and molecular markers associated with the defense responses, usually activated by pathogen infection. These results demonstrate that a porphyrin pathway impairment is responsible for the lesion initiation phenotype, which leads to the activation of defense responses, in Arabidopsis. Lesion formation was not suppressed, and was even enhanced when accumulation of salicylic acid (SA) was prevented in lin2 plants by the expression of an SA-degrading salicylate hydroxylase (nahG) gene. This suggests that the lesion formation triggered in lin2 plants is determined prior to or independently of the accumulation of SA but that the accumulation is required to limit the spread of lesions in lin2 plants.

Amino Acid Sequence↗
PubMed2001

Analysis of haploid development based on expression patterns of developmental genes in the medaka Oryzias latipes.

The abnormalities of haploid medaka embryos were characterized by comparative analysis of histologic sections and expression patterns of some developmental marker genes between haploids and diploids to clarify whether medaka haploids are useful for identifying mutants. During gastrulation, an obvious defect was first observed as a delay of epiboly and involution. This delay was shown to be caused not by the perturbation of mesoderm induction, but by widespread cell death and disorganization of cell arrangement in the blastoderm. This disorganization of cell arrangement was also detected in various organs, such as the brain, somite and notochord, at a late developmental stage. Ten days after fertilization, a small head and a short body axis were formed; these changes were also observed in haploid embryos in other species, but their cause is unknown. Based on the expression patterns of HNF3beta and goosecoid, it was demonstrated that a short and impotent prechordal plate induced near the marginal zone in haploid embryos was responsible for this defect. However, in these experiments it was also demonstrated that many major organs in haploids, such as the somite and notochord, differentiated incompletely but were present. Therefore, it was concluded that haploid screening is suitable for identifying mutations revealed by an obvious phenotype, such as dorsoventral polarity.

Amino Acid Sequence↗
PubMed2001

Fiberoptic colonoscopic polypectomy in childhood: report and review of cases.

BACKGROUND: Fiberoptic colonoscopy has been a routine therapeutic modality for colorectal polyps in pediatric patients. Methods of bowel preparation, anesthesia, area of investigation and treatment depending on histopathology are still controversial. In order to clarify the rationale of pediatric colonoscopy the present study was performed. METHODS AND RESULTS: We analyzed the results of colonoscopic examination in 21 patients with colorectal polyps. Mean patient age was 3.7 years, with a range of 1--7 years. Rectal polyps were seen in 10 cases: seven had a solitary polyp (juvenile in six and adenoma in one) and three had multiple polyps (juvenile, lymphoid and Peutz--Jeghers coexisting with hyperplastic polyps). Sigmoid colon polyps were seen in 10 cases: all were solitary juvenile polyps, but one had adenomatous change. Another had multiple Peutz-- Jeghers polyps located in the entire colon. Flexible colonoscopic polypectomy was performed in 16 patients and transanal polypectomy was performed in four patients. Autoamputation was seen in two cases of juvenile polyp (resection was ultimately performed in a case having repeated autoamputation). After removing the polyps, all patients have had no recurrence for a period ranging from 6 months to 15 years, except for one case with Peutz--Jeghers syndrome. CONCLUSIONS: Most polyps are located in the rectum or the sigmoid colon. Although the majority are solitary or juvenile polyps, because histopathologic variety is seen in pediatric colon polyps, histopathologic examination of each polyp is important to detect any dysplastic or adenomatous element with malignant potential and to make a suitable follow-up schedule. Symptomatic polyps should be removed by fiberoptic colonoscopy or transanal resection with total colon endoscopic examination under general anesthesia. Polypectomy using the electrocautery snare and clip is effective and safe and bowel preparation using polyethylene glycol electrolyte solution is sufficient for the procedure.

Child↗
PubMed2001

Effect of low-dose milrinone on gastric intramucosal pH and systemic inflammation after hypothermic cardiopulmonary bypass.

OBJECTIVE: To investigate the usefulness of low-dose milrinone on gastric intramucosal pH (pHi) and systemic inflammation in patients undergoing hypothermic cardiopulmonary bypass (CPB). DESIGN: Prospective randomized study. SETTING: University hospital. PARTICIPANTS: Twenty patients scheduled for cardiac surgery. INTERVENTIONS: Ten patients were administered a low dose of milrinone, 0.25 microg/kg/min, from the initiation of CPB to 1 hour after admission to the intensive care unit. The other patients were administered saline. Supplemental inotropes and intravenous fluid were given to obtain adequate mean arterial blood pressure and pulmonary artery occlusion pressure. MEASUREMENTS AND RESULTS: Gastric pHi and carbon dioxide pressure (PCO2) were assessed by capnometric air tonometry. The difference between PCO2 and arterial carbon dioxide pressure (PaCO2), PCO2-gap, was also examined. Systemic inflammatory responses were evaluated by serum interleukin-6 and leukocyte counts. Hemodynamics, oxygen delivery index, and oxygen uptake index were monitored with catheters in the radial and pulmonary arteries (thermodilution). The hepatic venous blood flow and left ventricular flow were measured using transesophageal echocardiography. Milrinone prevented gastric intramucosal acidosis, detected as a decrease in pHi or an increase in PCO2-gap, without affecting hepatic venous blood flow. Increases in interleukin-6, leukocyte count, and oxygen uptake index, all of which developed after CPB, were significantly less in the milrinone group than in the control group. CONCLUSION: These results suggest that in patients undergoing hypothermic CPB, supplemental low-dose milrinone prevents gastric intramucosal acidosis and increases in some markers of systemic inflammation.

Body Temperature↗
PubMed2001

Human REG I gene is up-regulated in intrahepatic cholangiocarcinoma and its precursor lesions.

The Reg I gene (regenerating gene) and its product (Reg protein) are a regenerating and/or proliferating factor(s) of pancreatic islet cells. The ectopic expression of REG Ialpha was shown in colorectal carcinomas, suggesting that REG Ialpha is related to their carcinogenesis. In this study, we examined the expression of REG I in intrahepatic cholangiocarcinoma (ICC) and its precursor lesion (biliary dysplasia). By polymerase chain reaction and in situ hybridization (ISH) studies using a total of 16 fresh liver specimens, REG Ialpha mRNA was demonstrated in 6 of 11 (55%) ICC cases, but in 0 of 5 (0%) normal livers. Immunohistochemistry for REG I protein was performed in 100 formalin-fixed, paraffin-embedded sections obtained from the 18 cases of ICC alone, 45 hepatolithiasis with ICC (n = 19) or biliary dysplasia (n = 26), 21 hepatolithiasis alone (all with hyperplasia), and 16 normal livers. In ICC, the expression of REG I protein was significantly dependent on the histologic differentiation; 12 of 13 (92%) cases in papillary and well-differentiated, 6 of 16 (38%) cases in moderately differentiated, and 0 of 8 (0%) cases in poorly differentiated types. Moreover, in the lesions of hyperplasia, low-grade dysplasia, and high-grade dysplasia in hepatolithiasis, REG I protein was expressed in 4 of 21 (19%), 7 of 12 (58%), and 13 of 14 (93%) cases, respectively. In normal liver, intrahepatic bile ducts were constantly negative for REG I protein. These findings suggest that neoexpression of REG I is a good marker for biliary mucosa at risk for development of ICC, and also that REG I plays a role in the early stages of biliary carcinogenesis, probably via a cell-proliferative effect.

Bile Duct Neoplasms↗
PubMed2001

Infection of TT virus in patients with idiopathic pulmonary fibrosis.

The precipitating factors of idiopathic pulmonary fibrosis (IPF) have not been elucidated. Recently, a novel DNA virus named TTvirus (TTV) was discovered in a patient with post-transfusion hepatitis of unknown aetiology TTV is a circular, single-stranded DNA virus of 3.8 kB. To evaluate the relationship between TTV and IPF, the sera of 33 patients with IPF were tested for the presence of TTV DNA by semi-nested polymerase chain reaction. TTV DNA was detected in 12 (36.4%) IPF patients. The serum lactate dehydrogenase (LDH) level was significantly higher in the IPF patients withTTV than in those without TTV (802 +/- 121 vs. 530 +/- 49 IU l(-1), p < 0.05). Six (50%) of 12 patients in theTTV DNA-positive group died during the observation period, while only six (28.6%) of 21 patients in theTTV DNA-negative group died. The 3-year-survival rate was significantly lower in the TTV DNA-positive group than in theTTV DNA-negative group (58-3% vs. 95.2%, P <0-02). Replicative intermediate forms of TTV DNA were detected in the lung specimen from a TTV-infected IPF patient. TTV infection influences the disease activityand prognosis of IPF in some cases. Further studies are required to elucidate the clinical significance of TTV in IPF.

Acute Disease↗
PubMed2001

Naproxen particle design using porous starch.

Naproxen (Nap) was embedded in porous starch by preferential grinding, and we examined the physicochemical properties of these particles, including pore diameter, pore volume, and dissolution of naproxen. Porous starch (PS) particles made by preferential grinding with a Mechanofusion system had a higher content of naproxen than those made using the Mechanomill as determined using a mercury porosimeter. Neither sample showed any significant changes in crystallization state of naproxen in particles as determined by powder X-ray diffraction and differential scanning calorimetry (DSC). No interactions occurred between naproxen and porous starch due to preferential grinding as determined by powder X-ray diffraction and DSC. The dissolution rate of drug from particles prepared by preferential grinding was faster than that from physical mixtures.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

A novel germline mutation of the MEN1 gene, L259del, in a patient with sporadic multiple endocrine neoplasia type 1 (MEN1).

A Japanese woman was treated for insulinoma when she was 29 years old. Ten years later, heperparathyroidism and non-functioning adrenal tumor were found and she was diagnosed as having multiple endocrine neoplasia type 1 (MEN1). No other family members have developed MEN-related lesion(s). Genomic DNA of the patient was analyzed by sequencing for the MEN1 gene and a novel, three-base in-frame deletion resulting in deletion of an amino acid Leu259 was identified. Her two children showed a wild-type sequence at this codon.

Adult↗
PubMed2001

Overexpression of the heterotrimeric G-protein alpha-subunit enhances phytochrome-mediated inhibition of hypocotyl elongation in Arabidopsis.

Plant heterotrimeric G-proteins have been implicated in a number of signaling processes. However, most of these studies are based on biochemical or pharmacological approaches. To examine the role of heterotrimeric G-proteins in plant development, we generated transgenic Arabidopsis expressing the Galpha subunit of the heterotrimeric G-protein under the control of a glucocorticoid-inducible promoter. With the conditional overexpression of either the wild type or a constitutively active version of Arabidopsis Galpha, transgenic seedlings exhibited a hypersensitive response to light. This enhanced light sensitivity was more exaggerated in a relatively lower intensity of light and was observed in white light as well as far-red, red, and blue light conditions. The enhanced responses in far-red and red light required functional phytochrome A and phytochrome B, respectively. Furthermore, the response to far-red light depended on functional FHY1 but not on FIN219 and FHY3. This dependence on FHY1 indicates that the Arabidopsis Galpha protein may act only on a discrete branch of the phytochrome A signaling pathway. Thus, our results support the involvement of a heterotrimeric G-protein in the light regulation of Arabidopsis seedling development.

Arabidopsis↗
PubMed2001

Comprehensive analysis of 28 patients with latex allergy and prevalence of latex sensitization among hospital personnel.

Recently anaphylactic shock caused by latex gloves and medical instruments has been discussed as an important problem in surgical operations. Patients with contact urticaria or anaphylaxis due to natural rubber latex were first reported in Japan in 1993, and the number of cases is gradually increasing. In the present study, we analyzed 28 patients examined in our clinic from 1993 to 1998. The diagnosis of latex allergy was made on the basis of clinical history, latex specific IgE antibody, skin test, and use test. The 3 male and 25 female patients included 20 nurses, 4 doctors, 2 housewives, one animal hospital employee, and one worker in a senile rehabilitation center. The majority were health care workers. Contact urticaria from rubber gloves was the most common clinical symptom. Some of the patients developed severe attacks of anaphylaxis. During the period from 1995 to 1997, we also performed a questionnaire study and a serum examination of latex specific IgE antibody among the personnel of our university hospital. The screening test for the antibody was more reliable than our questionnaire study in detecting latex-sensitive persons. The prevalence of latex allergy was found to be 4.6%. This indicates that not only dermatologists but also all hospital workers should be aware of this type of allergy.

Adult↗