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Biomedical subjects

Y Honda

Publications and source records attributed to Y Honda.

At least 289 records · Page 16Linked to original sources
PubMed1997

Distribution of plasmalemmal Ca(2+)-pump and caveolin in the corneal epithelium during the wound healing process.

PURPOSE: Caveolae are small plasmalemmal invaginations which are assumed to play various physiological functions. In the present study, distribution of two caveolae-specific proteins, the plasmalemmal Ca(2+)-pump and caveolin, was examined in the corneal epithelium in the normal state and after artificial wounding. METHODS: A central epithelial ablation was made in the mouse cornea by a razor blade. After various intervals, the corneas were excised, fixed, and rapidly frozen. The specimens were subjected to immunofluorescence microscopy and immunoelectron microscopy, using antibodies against the plasmalemmal Ca(2+)-pump or caveolin. RESULTS: In the normal corneal epithelium, both plasmalemmal Ca(2+)-pump and caveolin were observed along the cell surface by immunofluorescence microscopy, and were localized to caveolae by immunogold electron microscopy. In the regenerating epithelium, 12-18 h after injury, plasmalemmal Ca(2+)-pump was seen as many dots in the cytoplasm by immunofluorescence microscopy; in contrast, caveolin persisted along the cell surface. Immunoelectron microscopy revealed that the labeling for the plasmalemmal Ca(2+)-pump was located around membranous structures in the cytoplasm and was scarce along the plasma membrane, while caveolin remained in caveolae. The Ca(2+)-pump regained normal distribution when the wound was closed. By quantitation in electron micrographs, the number of caveolae per unit plasma membrane length was found to be decreased in the wounded corneal epithelium. CONCLUSIONS: The present results indicate that caveolae undergo compositional modification during the wound healing process of the corneal epithelium. Considering putative caveolar functions, the phenomenon may be related to possible fluctuations of the intracellular Ca(2+)-concentration in the regenerating epithelium.

Animals↗
PubMed1997

Expression of neurotrophic factors in cultured human retinal pigment epithelial cells.

PURPOSE: To see if cultured human retinal pigment epithelial (RPE) cells have the capacity to synthesize neurotrophins, including nerve growth factor (NGF), brain-derived growth factor (BDNF), and neurotrophin-3 (NT-3). METHODS: Expression of mRNAs for the neurotrophins was studied by the reverse transcription polymerase chain reaction (PCR) method. Quantitative analysis of the gene expression was done by using a semiquantitative PCR method. Secretion of NGF-like immunoreactivity (NGF-LI) into the culture medium was analyzed by enzyme immunoassay (EIA). RESULTS: Cultured human RPE cells were found to express mRNAs for NGF, BDNF and NT-3. In the conditioned culture medium of the human RPE, 9.44 +/- 0.62 pg/ml (mean +/- SEM, n = 6) NGF-LI was found. Pretreatment of human RPE cells with interleukin-l (IL-1) (20 ng/ml), phorbol myristate acetate (PMA) (100 ng/ml) or tumor necrosis factor-alpha (TNF-alpha) (40 ng/ml) was found to increase the mRNA expression of neurotrophins and also to increase secretion of NGF-LI into the culture medium. CONCLUSIONS: Our data demonstrate that cultured human RPE cells have the capacity to synthesize neurotrophins, and that various stimulations can up-regulate gene and protein expression of NGF by these cells.

Brain-Derived Neurotrophic Factor↗
PubMed1997

Influence of the sensory retina on healing of the rabbit retinal pigment epithelium.

PURPOSE: To compare the healing process of the retinal pigment epithelium (RPE) with and without the overlying sensory retina. METHODS: A dome-shaped retinal detachment was created in the pigmented rabbit eye by injecting balanced salt solution into the subretinal space. The detached retina was partially removed with a vitrector; in some eyes, the detached retina was removed completely. RPE about 1.5 mm in diameter was removed from Bruch's membrane and aspirated through the retinal break. All eyes were examined morphologically. RESULTS: Independent of the sensory retina, 4 days postoperatively the RPE wound was covered by immature RPE cells that gradually formed an epithelial-like sheet by 2 weeks postoperatively. In eyes with overlying sensory retina, regenerated RPE cells similar to normal RPE cells formed a monolayer in most areas. The RPE-photoreceptor outer segment interface gradually organized. In eyes with no sensory retina, the regenerated RPE cells were longer, mounded, and their microvilli were shorter and disorganized. The RPE cells were multilayered in some areas and often had a tubuloacinar structure. CONCLUSIONS: The RPE wounds healed rapidly, independent of the presence of the overlying sensory retina, up to 2 weeks after RPE removal. Reconstruction of the RPE monolayer and the apical morphology of regenerated RPE cells were influenced by the sensory retina.

Animals↗
PubMed1997

Biodegradable polymeric device for sustained intravitreal release of ganciclovir in rabbits.

PURPOSE: A scleral plug made of biodegradable polymer implanted at the pars plana was evaluated to determine its ability to control the intravitreal release of ganciclovir. METHODS: Scleral plugs containing 25% ganciclovir were prepared with poly(lactic-glycolic acid) (molecular weight, 121 kDa). The release of ganciclovir was evaluated in vitro by spectrophotometry. In vivo intravitreal ganciclovir concentrations were measured by high performance liquid chromatography following plug implantation in pigmented rabbits. The biocompatibility of the device was determined by indirect ophthalmoscopy, electroretinography, and light and electron microscopy. RESULTS: The in vitro study showed that the plug released ganciclovir throughout a 10-week period. The in vivo study demonstrated that the plugs maintained the drug concentration in the vitreous in a therapeutic range adequate to treat cytomegalovirus (CMV) retinitis for 12 weeks. No significant retinal toxicity was observed. CONCLUSIONS: This study demonstrated that this drug delivery system can potentially be useful to treat CMV retinitis.

Animals↗
PubMed1997

Biodegradable scleral implant for intravitreal controlled release of fluconazole.

PURPOSE: To evaluate the feasibility of using a biodegradable polymeric scleral implant containing fluconazole (FLCZ), a bis-triazole antifungal agent, as a potential intravitreal-controlled drug delivery system. METHODS: The scleral implants, loaded with 10, 20, 30, and 50% FLCZ, were prepared with biodegradable polymers of poly (DL-lactide-co-glycolide). Those with all loading doses were used for the in vitro release studies; those with 30% FLCZ were used for the intravitreal release studies in pigmented rabbits. The in vitro and in vivo release rates of FLCZ from the implants were measured periodically with spectrophotometry and high performance liquid chromatography, respectively. The effects of the implants on ocular tissues were evaluated ophthalmoscopically, histologically, and electrophysiologically. RESULTS: The scleral implants loaded with 10, 20, and 30% doses gradually released FLCZ over 4 weeks in vitro; those with 50% FLCZ released most of the drug in one week. FLCZ concentration in the rabbit vitreous remained within the 99% inhibitory concentration for Candida albicans for 3 weeks after implantation. The scleral implant gradually biodegraded, and it disappeared by 4 months after implantation. The electrophysiologic and histopathologic findings demonstrated no substantial toxic reactions in the ocular tissues. CONCLUSION: The current study suggests that a biodegradable, polymeric scleral implant containing FLCZ may be a promising intravitreal drug delivery system to treat fungal endophthalmitis.

Animals↗
PubMed1997

Relationship between levels of soluble interleukin-2 receptors and the types and activity of vitiligo.

Levels of serum-soluble interleukin-2 receptors (serum sIL-2R) are thought to indicate the activation of immunocompetent cells, mainly lymphocytes. Elevated levels of serum sIL-2R have been observed in various infectious and autoimmune diseases and also after organ transplantation. It has been hypothesized that autoimmune mechanisms are involved in the pathogenesis of vitiligo. Therefore, we studied serum sIL-2R levels in relation to disease types and activity of vitiligo. We used sera separated from venous blood samples from 12 patients with dermatomally distributed type B vitiligo, 17 patients with non-dermatomally distributed type A vitiligo during the active stage, 9 patients with type A vitiligo during the inactive stage, and 12 normal control subjects. Serum sIL-2R levels were similar in type B vitiligo patients and the controls but were significantly elevated in patients with active type A vitiligo compared with controls and inactive type A vitiligo patients. It is suggested that the immune system is activated in patients with type A vitiligo during the active stage and that autoimmune mechanisms may play a role only in type A vitiligo.

Autoimmunity↗
PubMed1997

Monoclonal antibody #5-2-26 recognizes the phosphatase-sensitive epitope of rabies virus nucleoprotein.

We prepared monoclonal antibodies (MAbs) against the rabies virus N protein, among which one antibody (MAb 5-2-26) was shown to lack reactivity with the phosphatase-treated N protein. The MAb was able to recognize the sodium dodecyl sulfate (SDS)-denatured N protein. The MAb did not recognize the N-protein analogues produced in Escherichia coli (E. coli), indicating that the N-gene products were not normally processed in E. coli after translation. On the other hand, the MAb reacted normally with N-gene products produced in COS-7 cells, but not with those produced in the presence of K-252a (a protein kinase inhibitor of a broad spectrum). The MAb displayed weak cross-reactivity with the Triton-insoluble network structures composed of several components, while another phosphoprotein (M1) of the virus was not recognized at all. These results suggest that MAb 5-2-26 preferentially recognizes a phosphatase-sensitive linear epitope of N protein, which may enable further investigations to be conducted on the mechanism of N-protein phosphorylation and its role(s) in virus replication.

Animals↗
PubMed1997

Triplet repeat polymorphism within the NOTCH4 gene located near the junction of the HLA class II and class III regions in narcolepsy.

A polymorphic (CTG)n microsatellite repeat was found in the signal peptide domain of the NOTCH4 gene located near the junction of the class II and class III regions of the human major histocompatibility complex. This gene belongs to a multigene family of NOTCH originally identified as a differential factor of neuronal cells. To ascertain whether the NOTCH4 gene is involved in the development of neurogenic disease, narcolepsy, which is known to be tightly associated with HLA-DR15, this microsatellite polymorphism of the (CTG)n repeat was analyzed in Japanese patients with narcolepsy One allele, 9 repetitions of CTG (Leu) was significantly increased in the patient group. However, the significant increase of this allele in the patient group could be explained by a strong linkage disequilibrium with the HLA class II alleles, DRB1*1501, DQA1*0102 and DQB1*0602, which were more strongly associated with the disease. These results suggest that the (CTG)n repeat polymorphism in NOTCH4 does not primarily determine the susceptibility to narcolepsy.

Alleles↗
PubMed1997

Alpha-delta sleep in a case with non-24 h sleep-wake syndrome: quantitative electroencephalogram analysis of alpha and delta band waves.

Four all-night polysomnograms of a 39-year-old male patient with non-24 h sleep-wake syndrome were recorded. We analysed electroencephalograms (EEG) with the power spectrum method and the wave pattern recognition analysis of Fujimori. The EEG of the rest waking condition showed normal patterns. High-voltage diffuse alpha band waves were observed in sleep stages 2, 3 and 4. The integrated area of the alpha band waves in the analysis epochs showed a strong positive correlation to the delta band components in the power spectrum of the same epoch during sleep (correlation coefficients r = 0.762-0.815). Alpha band waves during sleep were clearly different from the alpha waves in the rest waking condition, with respect to slower peak frequency and the frontal dominant voltage distribution.

Adult↗
PubMed1997

The whole nucleotide sequence and chromosomal localization of the gene for human metabotropic glutamate receptor subtype 6.

Metabotropic glutamate receptor subtype 6 (mGluR6) is restrictedly expressed in the retinal ON bipolar cells and ablation of mouse mGluR6 by gene targeting results in a loss of ON responses to light stimulus and impairs the detection of visual contrasts. We have isolated genomic clones containing the human mGluR6 gene and determined the whole nucleotide sequence of the mGluR6 gene. The transcription initiation site of the human mGluR6 gene has been identified using primer extension analysis in combination with reverse transcriptase-mediated polymerase chain reaction analysis of human retinal RNA, while the termination of the mGluR6 mRNA has been assigned by the analysis of rapid amplification of 3'-cDNA ends. The human mGluR6 gene consists of 16,742 base pairs with 10 exons separated by nine introns. The human mGluR6 is composed of 877 amino acid residues with a signal peptide of 24 amino acid residues and the mature protein shows a 94.6% homology with the rat counterpart. A CpG-rich island is present at exon 1 and its preceding putative promoter region and this unusual sequence, like several tissue-specific genes, may be important for a specific expression of the mGluR6 gene in the retinal bipolar cells. The human mGluR6 gene has been mapped to chromosome 5q35 by the analyses of blot hybridization of a DNA panel of human/mouse/hamster somatic cell hybrids and fluorescence in situ hybridization of human chromosomes. This study should provide the genetic basis for not only better understanding the molecular mechanism underlying a tissue-specific expression of the mGluR6 gene but also exploring a potential defect in human mGluR6 in a certain inherited eye disease.

Amino Acid Sequence↗
PubMed1997

Angle closure caused by multiple, bilateral iridociliary cysts.

A case of high, broad, peripheral anterior synechiae caused by multiple, bilateral iridociliary cysts is reported. The peripheral anterior synechia in our case extended to the corneal endothelium beyond Schwalbe's line, and iris atrophy in the region of the cysts was found. Ultrasound biomicroscopic imaging showed that multiple, bilateral iridociliary cysts causes elevation of the iris structure.

Adult↗
PubMed1997

Morphologic and histochemical evaluation of muscle in patients with chronic pulmonary emphysema manifesting generalized emaciation.

Twelve severely emaciated patients with emphysema and 4 control patients with mild emaciation were studied. Arterial blood gas analysis, pulmonary function tests, and muscle biopsy were performed. According to the percentage of ideal body weight (%IBW), patients were divided into two groups of 6 patients each; one with %IBW values greater than 70.0 (group 1) and the other with %IBW values less than 70.0 (group 2), and 4 control patients with emphysema whose %IBW values were greater than 85.5. %FEV1.0, PaO2 and Hugh-Jones scores in group 2 patients were consistent with significantly greater deterioration as compared with those in group 1 patients and controls. In the muscle fibers of 11 patients and 4 controls, nicotinamide and adenosine dinucleotide tetrazolium reductase activity was studded with spots. Nemalin rods were detected in 3 specimens in group 2 and in 1 specimen each in both group 1 and controls. These changes probably result from chronic hypoxemia. Fiber type grouping accompanied by type II dominant fiber atrophy was demonstrated in 5 patients of group 2, whereas type II fiber atrophy was shown in 2 specimens from patients of group 1. Diameters of both types I and II fibers in group 2 were smaller than those in group 1 and controls. Significant correlations were observed between fiber diameters and %IBW, %FEV1.0 and %IBW, and PaO2 and %IBW. Neurogenic and disuse muscular atrophy due to both hypoxic axonal disorder and disuse is likely to be the cause of the emaciation, and a 'vicious circle' between muscular atrophy, respiratory function and hypoxemia probably exists in group 2. Since mild or moderate emaciation was observed in controls and group 1 in spite of the lack of fiber atrophy, involvement of fat and connective tissue should also be taken into consideration to determine the cause of emaciation.

Aged↗
PubMed1997

Hypovitaminosis D and decreased bone mineral density in amyotrophic lateral sclerosis.

To assess the bone health of patients with amyotrophic lateral sclerosis (ALS), we evaluated the bone density and serum biochemical indices of bone metabolism in 11 ALS patients. The serum concentration of 25-hydroxyvitamin D (25-OHD) was significantly lower in patients (14.0 +/- 3.7 ng/ml) than in controls (25.2 +/- 4.0 ng/ml), at deficient levels (< 10 ng/ml) in 2, and at insufficient levels (10-20 ng/ml) in 9 patients. Serum levels of parathyroid hormone (PTH) and ionized calcium were elevated in 8 and 6 patients, respectively. Dietary intake of vitamin D was below the recommended level (100 IU) in 10 patients, and 10 patients were in a sunlight-deprived state. The metacarpal bone density (MBD) and the metacarpal index (MCI) of the second metacarpal bone were measured by computed X-ray densitometry. Z scores of the MBD and the MCI were negative in 7 and 6 patients, respectively. The serum concentration of 25-OHD was positively correlated with the Z score of the MBD (p < 0.05, r = 0.727) and negatively with the PTH level (p < 0.05, r = -0.410). The degree of dysfunction of hand grip also correlated with the Z score of the MBD (p < 0.05, r = 0.749). These data underscore the importance of hypovitaminosis D and compensatory hyperparathyroidism in the development of osteopenia in patients with ALS.

Absorptiometry, Photon↗
PubMed1997

Long-term oral anticoagulation reduces bone mass in patients with previous hemispheric infarction and nonrheumatic atrial fibrillation.

BACKGROUND AND PURPOSE: Vitamin K is an essential factor for synthesis of plasma clotting proteins and for site-specific carboxylation of bone Gla protein and other bone matrix proteins. Low vitamin K has been associated with reduced bone mineral density. Warfarin therapy, which inhibits vitamin K-dependent blood-clotting, has been demonstrated to reduce the risk of stroke in nonrheumatic atrial fibrillation. We evaluated vitamin K and bone mineral density in nonrheumatic atrial fibrillation patients who had long-term warfarin therapy after an ischemic stroke. METHODS: Sera were collected from 64 patients with non-rheumatic atrial fibrillation and ischemic stroke who had been treated with warfarin, 63 stroke patients without warfarin, and 39 control subjects. All stroke patients in both groups had hemiplegia. Sera were assayed for vitamins K1 and K2, bone Gla protein, and 25-hydroxyvitamin D. Bone mineral density was determined in both second metacarpals. RESULTS: Serum vitamin K1 concentrations (ng/mL) were lower in treated patients (.234 +/- .177 ng/mL) than in untreated patients (.329 +/- .284) or controls (.553 +/- .164). Bone Gla protein was lower in treated patients' sera (1.241 +/- .799 ng/mL) than in untreated patients (4.476 +/- 3.226). Concentrations of 25-hydroxyvitamin D were lower in both patient groups. Bone mineral density was lower on both sides in treated patients than in untreated patients (P < .0001). Vitamin K1 and bone Gla protein were significantly related to bone mineral density bilaterally in treated but not in untreated patients. CONCLUSIONS: Bone mineral density was significantly lower in stroke patients with long-term warfarin treatment than in untreated patients. Both warfarin-induced reduction in vitamin K function and lowered vitamin K1 concentrations are probable causes of this osteopenia.

Administration, Oral↗
PubMed1997

Mycobacterium tuberculosis enhances human immunodeficiency virus-1 replication in the lung.

We investigated the in vivo effect of coinfection of Mycobacterium tuberculosis on human immunodeficiency virus type 1 (HIV-1) replication using bronchoalveolar lavage (BAL) of 11 HIV-1-infected patients with pulmonary tuberculosis and 10 patients with no lung disease. Lung segments involved with pulmonary tuberculosis had significantly elevated HIV-1 branched DNA (bDNA) levels and p24 in BAL compared with lung segments uninvolved with tuberculosis or with BAL from patients with no lung disease. The BAL viral burden was higher than plasma HIV-1 in tuberculosis patients, indicating local production of virus. BAL HIV-1 bDNA declined over the course of treatment for tuberculosis in three patients who underwent serial bronchoscopies. Tumor necrosis factor-alpha (TNF-alpha) and HIV-1 bDNA particles were strongly correlated (r2 = 0.9, p < 0.01) in lung segments involved with tuberculosis. The deduced amino acid sequence of HIV-1 gp120 V3 region from involved segments of three patients with pulmonary tuberculosis showed basic substitutions associated with altered viral phenotype. Phylogenetic analysis of V3 sequences demonstrated that BAL HIV-1 RNA had diverged from plasma. These data support the conclusion that pulmonary tuberculosis enhances local HIV-1 replication in vivo.

Adult↗
PubMed1997

Analysis of localization of adult T-cell leukemia-derived factor in the transient ischemic rat retina after treatment with OP-1206 alpha-CD, a prostaglandin E1 analogue.

Prostaglandin E1 (PGE1) is commonly used in therapy for obstructive diseases, including ischemic retinopathy, in which pathogenetic reactive oxygen intermediates are responsible. However, the mechanism(s) of PGE1 in reducing tissue damage is still unclear. Adult T-cell leukemia-derived factor/human thioredoxin (ADF) is induced by oxidative stresses and has protective activity against oxidative cellular injury. To evaluate the possible involvement of ADF in the tissue-protective effect of PGE1, we analyzed ADF expression immunohistochemically using a rat transient retinal ischemia model. Rats were treated orally with 300 micrograms/kg/day OP-1206 alpha-cyclodextrin clathrate (OP-1206), a stable PGE1 analogue, for 14 days after photodynamic retinal vascular thrombosis by rose Bengal. Rats without any OP-1206 treatment were used as controls. In the OP-1206-treated rats, minimal retinal atrophy due to ischemia/reperfusion was observed histologically up to 14 days, whereas in the non-treated rats the inner layer of the retina became markedly atrophic. In parallel with the histological change, after 14 days following thrombosis ADF immunoreactivity was preserved on retinal pigment epithelial cells in the OP-1206-treated rats, whereas it was diminished in the non-treated rats. These findings suggest an important role for ADF in the OP-1206-dependent suppression of retinal tissue damage caused by oxidative insult.

Alprostadil↗