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Biomedical subjects

Y Ohashi

Publications and source records attributed to Y Ohashi.

At least 487 records · Page 27Linked to original sources
PubMed1992

Fluorescent-labeled oligonucleotides that exhibit a measurable signal in the presence of complementary DNA.

Oligonucleotide derivatives with a fluorescent dye were designed for exhibiting a measurable signal only when they bind to complementary DNA in aqueous solution. The oligonucleotide with a dansyl group at the specific 2'-sugar residue was synthesized by using the protected 2'-dansylaminouridine phosphorobisamidite. The dansyl-oligonucleotide conjugate binds to its complementary DNA to form duplex with a normal stability and exhibits enhanced fluorescence together with a blue-shift in emission maxima after the hybridization. Another possible candidate involved the use of pyrene-excimer emission upon forming ternary complex between two pyrene-labeled oligonucleotide probes with target DNA. A new and general method for introduction of a pyrene fluorophore into the 3'- or 5'-terminal hydroxyl group of oligonucleotides via different linkers was developed.

DNA↗
PubMed1992

[The expression of IL-2 receptor subunits on various leukemic cells].

Interleukin-2 receptors are composed of at least two polypeptide chains of alpha (55KD) and beta (75KD). The IL-2R beta chain is an essential component of the functional receptor for signal transduction of IL-2. We previously reported the distribution of IL-2R subunits among peripheral blood mononuclear cells. We here present some data regarding the expression of IL-2R subunits on various hemopoietic malignant cells. Fresh leukemic cells obtained from adult T cell leukemia patients expressed both alpha and beta chains, and leukemic cells derived from some patients with T cell leukemia, B cell leukemia or myeloid leukemia expressed the alpha and/or beta chain of IL-2R. The IL-2R beta chain on these leukemic cells were demonstrated to be functional for cell growth signaling. IL-2R alpha and beta chains should be tumor markers.

Biomarkers, Tumor↗
PubMed1992

Effect of rapid glycemic control on progression of diabetic retinopathy.

The effect of the start of glycemic control on the progression of retinopathy was investigated by a case-control study. The changes in glycosylated hemoglobin (HbA1) were compared between a case group, diabetic cases showing progression of retinopathy (Group 1), and a control group, diabetic cases showing no progression of retinopathy (Groups 2-A and 2-B). Group 2-A was matched with Group 1 on the basis of the grade of retinopathy at the first examination and other clinical data. Group 2-B was matched with Group 1 in terms of HbA1 value and methods of control, but had no retinopathy or background retinopathy. The retrospective follow-up period for the three groups was 24 months. On the basis of the respective matching factors, Groups 1 and 2-A were divided into 9 blocks of homogeneous subjects, and Groups 1 and 2-B were similarly divided into 6 blocks. The resulting data was evaluated block by block, using the analysis of variance (ANOVA) and a conditional logistic regression analysis. In Group 1, the HbA1 value decreased rapidly 10-6 months before the progression of retinopathy, but the HbA1 value did not change in Groups 2-A and 2-B during the 24-month follow-up. The difference in the estimated mean HbA1 value between 10-9 months and 1-0 month before the progression of retinopathy was 2.46% greater in Group 1 than in Group 2-A, as determined by ANOVA. The relative risks of a 1, 2 and 3% increase in HbA1 value for 7-6 months were estimated as 1.6, 2.4 and 3.8, respectively, by conditional logistic regression analysis. These findings indicate that the decrease in HbA1 value during any 6-month period should be limited to less than 2% in order to prevent the progression of retinopathy. It is also evident that too rapid a decrease at the initiation of glycemic control could cause severe or transient exacerbation of the progression of retinopathy.

Analysis of Variance↗
PubMed1992

Eosinophil infiltration and enhancement of airway reactivity by leukocyte chemotactic factor, formyl-methionyl-leucyl-phenylalanine (fMLP), in guinea pigs.

N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) is a bacterial-derived chemotactic factor for eosinophils and neutrophils. This study is aimed to examine whether or not eosinophil infiltration induced by intra-airway administration of fMLP causes the damage of the bronchial epithelium and results in airway hyperresponsiveness in normal non-sensitized guinea pigs. In normal guinea pigs fMLP administered by aerosol inhalation or intratracheal injection caused significant infiltration of eosinophils in the tracheal mucosa and enhanced bronchial reactivity to inhaled histamine 6 and 24 hours after exposure. Electron microscopic examination showed damage of the alignment of the epithelial cells in the bronchial mucosa in fMLP-treated guinea pigs. PAF antagonists CV3988 and WEB2086 and a 5-lipoxygenase inhibitor (AA-861) did not prevent fMLP induced eosinophil infiltration, which suggests that fMLP caused eosinophil infiltration mainly by its chemotactic activity, not by the release of platelet activating factor (PAF) or leukotrienes in this experimental condition. These results showed that in normal guinea pigs a bacteria-derived chemoattractant of fMLP could reproduce a sequence of eosinophil infiltration and airway hyperresponsiveness, similar to the inflammatory pathophysiology after antigen challenge in sensitized animals. We concluded that eosinophil infiltration induced by either immunological or non-immunological mechanisms can cause airway damage and airway hyperresponsiveness.

Administration, Inhalation↗
PubMed1992

[Flow cytometry cell-cycle analysis for in vivo corneal epithelium].

To investigate the cell-cycle kinetics of in vivo corneal epithelium, S phase cell analysis using either bromodeoxyuridine or 3H-thymidine incorporation and mitotic counts on flat preparations have been used extensively. This type of analysis represents S-phase cells, but not G0, G1, or M-phase cells. In this study, in vivo and in vitro rabbit corneal epithelial cells, in which the nuclei were stained with propidium iodide, were analyzed by flow cytometry to observe the overall distribution of each cell cycle. The method requires single cell suspensions from corneal epithelium. For this, an intact sheet of corneal epithelium obtained using low concentration of neutral protease, dispase II, was treated with trypsin and EDTA. The present results indicated that in in vivo corneal epithelium 97% of total cells were in the G0/G1 phase, 2% in the S phase and 1% in the G2/M phases; while in the in vitro epithelium 71% of cells were in the G0/G1 phase, 14% in the S phase and 15% in the G2/M phase. Although the present method can be applied to observe the cell-cycle in in vivo epithelium if used properly, methodologies to maintain single cell suspensions are required for future studies.

Animals↗
PubMed1992

[Effect of trigeminal denervation on rabbit corneal epithelium].

To investigate the effects of trigeminal denervation on the corneal epithelium, left postganglionic trigeminal neurotomy via intracranial approach was performed in 22 rabbits. Among 16 rabbits survived successfully, 13 denervated eyes (81%) showed corneal epithelial abnormalities that included 4 epithelial defects and 9 epithelial opacities. The remaining 3 eyes were normal. Histological examination showed many atrophic epithelial cells and the thinning of the corneal epithelial layer in the denervated eyes with corneal opacities. There was no abnormality in corneal stroma or endothelium. The ratio of epithelial to total corneal thickness calculated by a computer-assisted image analyzer was 6.5 +/- 2.1 (%) in control eyes and 3.8 +/- 1.9 (%) in the denervated eyes, the two values being significantly statistically different (p less than 0.001).

Animals↗
PubMed1991

Fast-atom-bombardment chemistry of sulfatide (3-sulfogalactosylceramide)

F.a.b.-m.s. of sulfatide (3-sulfogalactosylceramide, 1) in the negative-ion mode reveals the molecular weight and the presence of the sulfate ester without ambiguity. The size of the long-chain base is represented as the (M - H)- ion of the corresponding lyso-form (deacylated molecule) only when the fatty acid is alpha-hydroxylated. The spectrum in the positive-ion mode indicates the molecular weight by a pair of sodium adduct ions separated by 102 a.m.u. However, the desulfated fragment ion is not shown in the B/E-constant linked-scanning mode. If the long-chain base ion [CH2C(NH2) = CHR]+ is present, B/E-constant linked scanning confirms that the double bond is located at C-4. B/E-Constant linked scanning of the (M - H)- ions in the negative-ion mode indicates the location of a double bond in the fatty acid moiety at C-15 for the most abundant molecular species c24:1.

Animals↗
PubMed1991

Demonstration of herpes simplex virus DNA in idiopathic corneal endotheliopathy.

A 56-year-old man developed idiopathic corneal endotheliopathy. The lesion consisted of severe stromal edema at the lower half of the cornea along with a number of associated keratic precipitates and steadily progressed to the upper half of the cornea. By polymerase chain reaction, herpes simplex virus DNA was demonstrated in the aqueous humor of this patient. Corneal stromal edema was resolved in response to treatment with topically applied and systemic acyclovir. Herpes simplex virus DNA was repeatedly demonstrated in the aqueous humor when the endothelial lesion recurred later. This evidence strongly indicates that this unique endothelial disorder is of viral origin.

Antibodies, Viral↗
PubMed1991

Longitudinal study on age-related changes of working and reference memory in the rat.

Age-related changes of working memory and reference memory were examined using different age groups of Fischer 344 rats (cross-sectional study) and one group of the same strain which was repeatedly tested at different age points (longitudinal study). Delayed non-matching test in a T-maze revealed 3 points as follows: (1) since motivation by food deprivation in the task performance seemed to decrease with aging, it was needed to adjust the food deprivation level so as to attain a similar degree of motivation in different age groups; (2) scores in reference memory task remained very high in the aged in both cross-sectional and longitudinal studies; and on the other hand (3) performance of working memory task declined with aging to the same degree in both cross-sectional and longitudinal studies, suggesting that working memory progressively deteriorates in advancing age.

Aging↗
PubMed1991

Upstream sequences of rice proliferating cell nuclear antigen (PCNA) gene mediate expression of PCNA-GUS chimeric gene in meristems of transgenic tobacco plants.

The transgenic tobacco plants have been generated that express the E. coli beta-glucuronidase (GUS) gene under control of the promoter from the rice proliferating cell nuclear antigen (PCNA, DNA polymerase auxiliary protein) gene. GUS expression detected in situ by staining with the chromogenic substrate, 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-Gluc), was restricted to meristems in the organs of the transgenic tobacco plants. This expression responded to the phytohormones which promote callus formation. Furthermore, in situ thymidine uptake showed that the GUS expression pattern corresponded well to the active sites of DNA synthesis. Deletion analysis of the 5' upstream sequence confined the GUS expression pattern to a fragment extending 263 bp upstream of the transcription start site of the rice PCNA gene. Thus, we have identified this fragment as a main regulatory element of the rice PCNA gene promoter.

Blotting, Northern↗
PubMed1991

Incidence of prominent corneal nerves in multiple endocrine neoplasia type 2A.

We studied the increased visibility of corneal nerves inside an 8-mm diameter central corneal area in 14 patients with multiple endocrine neoplasia type 2A, one patient with multiple endocrine neoplasia type 2B, five patients with nonhereditary medullary thyroid carcinoma, ten patients with anterior keratoconus, and ten normal subjects. We used a grading system (grade 0 through grade 4) for nerve visibility based on slit-lamp biomicroscopic examination and photographic documentation. All 20 normal eyes showed either grade 0 or grade 1, which indicated no pathologic thickening of corneal nerves. Sixteen of the 28 eyes (57%) with multiple endocrine neoplasia type 2A, however, were evaluated as grade 2 or higher, which indicated thickened corneal nerves. The incidence of high nerve visibility in eyes with multiple endocrine neoplasia type 2A was significantly greater compared to normal eyes (P less than .0001), anterior keratoconus (P less than .0001), and nonhereditary medullary thyroid carcinoma (P = .0012). Furthermore, eight of the 28 eyes (29%) with multiple endocrine neoplasia type 2A showed markedly prominent corneal nerves (grade 3 and 4), a prominence similar to those seen in eyes with multiple endocrine neoplasia type 2B. There was no definite relationship among prominent nerve, age of the patient, and occurrence of pheochromocytoma. These findings suggest that over half of all patients with multiple endocrine neoplasia type 2A show corneal nerves pathologically thickened to different degrees.

Adult↗
PubMed1991

Long-term results of keratoepithelioplasty in Mooren's ulcer.

A consecutive series of 20 eyes with Mooren's ulcer was treated by a new surgical approach: keratoepithelioplasty alone or in combination with corneoscleral lamellar graft. Eighteen (90%) eyes showed complete remission promptly after surgery; the other two also healed with the administration of additional systemic and topical steroids. During the follow-up periods (mean, 3.1 years), minor recurrence was found in 5 (25%) eyes for the first 6 months, in none (0%) for the second 6 months, in 2 (12%) for the third 6 months, and none thereafter. All seven eyes with recurrence were cured by additional steroid treatment, alone or with conjunctival excision and/or keratoepithelioplasty. In the 18 (90%) eyes, the lenticules, constantly observed, remained silent on the scleras, which were free from conjunctival invasion. These results strongly support the authors' theory that keratoepithelioplasty using donor corneal lenticules can heal Mooren's ulcer via blockage of infiltrated conjunctival invasion.

Adult↗
PubMed1991

Three-dimensional analysis of condylar hyperplasia with computed tomography.

Three-dimensional surface reconstruction imaging from CT scans was used to study the deformity of the mandible in six patients with mandibular asymmetry. High-resolution axial CT scans of the mandible were obtained using Somatom-DR3 (Siemens). COSMOZONE-2SA (Nikon) with PC-9801VX21 (NEC) was used to reconstruct the three-dimensional images. The six patients were divided into two groups. One group was classified as unilateral hybrid forms and the other group was classified hemimandibular elongation on the diagnostic criteria of Obwegeser and Makek (1986). In the three-dimensional surface reconstruction, exact location and the degree of the deformity in the region from the ascending ramus to the condylar head and the lingual aspect from the ascending ramus to the mandibular body were accurately represented. In addition, the three-dimensional images could be easily rotated arbitrarily, precise evaluation could be done at every part of the mandible. On diagnosis, the mandibular morphology classified into the unilateral hybrid forms was presumed to vary from case to case even in the same classification.

Adolescent↗
PubMed1991

Effects of proteolytic enzyme inhibitors on the nasal absorption of vasopressin and an analogue.

Proteolytic enzyme inhibitors were examined as absorption enhancers for the nasal delivery of vasopressin (AVP) and desmopressin (1-d-8-DAVP) in rats. Aprotinin, soybean trypsin inhibitor, and camostat mesilate were used as enzyme inhibitors. The nasal absorption of AVP and 1-d-8-DAVP was evaluated by measuring its antidiuretic effect. Nasal administration of AVP (0.005 IU/kg) or 1-d-8-DAVP alone (2.5 ng/kg) produced a small antidiuretic effect. Coadministration with aprotinin (1000 and 10000 KIU/kg) or soybean trypsin inhibitor (1.25 and 6.25 mM) did not change the antidiuretic effect. However, coadministration with camostat mesilate (1 to 50 mM) significantly increased the antidiuretic effect and, thus, the nasal absorption of AVP and 1-d-8-DAVP. The activities of aminopeptidase, cathepsin-B, and trypsin in the nasal mucosal tissue of rats were 7 nmol/min/mg protein, 0.7 nmol/min/mg protein, and 4.6 pmol/min/mg protein, respectively. Aprotinin and soybean trypsin inhibitor inhibited only the trypsin activity, whereas camostat mesilate inhibited aminopeptidase and trypsin activities. Aprotinin (MW 6500) and soybean trypsin inhibitor (MW 8000), with relatively high molecular weights, may not permeate into the nasal mucosal tissue. In contrast, camostat mesilate is slowly absorbed (8%/hr) and could inhibit the proteolytic activity in the nasal mucosa, resulting in enhanced nasal absorption of AVP and 1-d-8-DAVP.

Administration, Intranasal↗
PubMed1991

Effects of viscous hyaluronate-sodium solutions on the nasal absorption of vasopressin and an analogue.

The effects of viscous solutions of hyaluronate-sodium of various average molecular weights (MW) on the nasal absorption of vasopressin (AVP) and its analogue, 1-deamino-8-D-arginine vasopressin (1-d-8-DAVP), were examined in rats. Solutions of hyaluronate with MW greater than 3 x 10(5) daltons enhanced the nasal absorption of AVP; solutions of MW 5.5 x 10(4) daltons were not effective. The enhancing effects on the nasal absorption of AVP and 1-d-8-DAVP were dependent on the concentration in the range of 0-1.5% (w/v) hyaluronate (MW 1.4 x 10(6) daltons). The nasal absorption of AVP was increased with this solution at lower pH. Bioavailabilities after nasal administration of AVP and 1-d-8-DAVP in hyaluronate solutions (MW 1.4 x 10(6) and 2 x 10(6) daltons) increased more than 2-and 1.6-fold as compared to nasal administration of AVP and 1-d-8-DAVP in buffer solutions (pH 7.0), respectively. Hyaluronate solution (MW 1.4 x 10(6) daltons) did not affect the ciliary beat frequency of rabbit nasal mucosal membranes in vitro. Therefore, hyaluronate solution may be useful as a vehicle for nasal delivery of AVP and 1-d-8-DAVP.

Absorption↗
PubMed1991

Light-Independent Expression of cab and rbcS Genes in Dark-Grown Pine Seedlings.

In angiosperms, light has been shown to induce the expression of cab and rbcS genes, which encode the apoprotein of light-harvesting chlorophyll a/b binding protein (LHCP) and the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), respectively. By contrast, chlorophylls are synthesized in the cotyledons of pine seedlings even if seeds are germinated in the dark. We have examined the expression of cab and rbcS genes in the cotyledons of pine (Pinus thunbergii) seedlings grown in darkness. The proteins of LHCP and the large subunit and the small subunit of Rubisco were detected in the cotyledons of dark-grown seedlings. The transcripts of cab and rbcS genes were present at substantial levels in dark-grown seedlings. However, the transcripts and the translated products of the genes were not found in the embryos of dry seeds. These results indicate that light is not required for the expression of cab and rbcS genes during the course of development of the cotyledons of pine seedlings. The processing of the precursor polypeptides of the mature proteins also appears to take place even in the dark.

Journal Article↗
PubMed1991

Comparison of the effects of intraocular irrigating solutions on the corneal endothelium in intraocular lens implantation.

We conducted a randomised prospective controlled study to determine the effects of a glucose glutathione bicarbonate solution (BSS Plus) and a citrate acetate bicarbonate solution (S-MA2) on the corneal endothelium in patients undergoing extracapsular cataract extraction with posterior chamber lens implantation. One eye of each patient was randomly assigned to receive BSS Plus, and the other eye to receive S-MA2. BSS Plus caused significantly less corneal swelling on the first postoperative day than did S-MA2. There was no difference between the two solutions in their effect on corneal thickness one week and one month postoperatively. Computer assisted morphometric analysis of wide-field specular microscopic photographs demonstrated minimal changes in endothelial morphological characteristics in the eyes irrigated with BSS Plus. By comparison S-MA2, caused a significant loss of endothelial cells and a marked reduction in the figure coefficient. These results indicated that BSS Plus has a clinical advantage over S-MA2 with respect to the corneal endothelium.

Aged↗