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Biomedical subjects

S Roh

Publications and source records attributed to S Roh.

At least 19 recordsLinked to original sources
PubMed2000

Purification and embryotropic roles of tissue inhibitor of metalloproteinase-1 in development of "HanWoo" (Bos taurus coreanae) oocytes co-cultured with bovine oviduct epithelial cells.

This study was conducted to purify a tissue inhibitor of metalloproteinase (TIMP)-1 in a serum-free medium conditioned with bovine oviduct epithelial cells (BOEC) and to evaluate its effect on development of "HanWoo" (Bos taurus coreanae) embryos to the blastocyst stage. In the first study using SDS-PAGE electrophoresis, the presence of 32 kDa proteins, which contains TIMP-1, was detected in the medium conditioned with BOEC, and TIMP-1 was then purified from the medium by gel filtration and HPLC techniques. When examined TIMP-1 secretion, fluorescent foci indicating the secretion of TIMP-1 were found after stained BOEC with fluorescein isothiocyanate. In the next experiment, two-cell embryos derived from in vitro-fertilization were cultured in a serum-free medium, to which 0, 1.25, 2.5 or 5 microg/ml of purified TIMP-1 was supplemented. More (P<0.05) embryos developed to the morula and blastocyst stages after the addition of 2.5 microg/ml to culture medium than after no addition. In conclusion, our data indicate that BOEC secrete TIMP-1 and this glycoprotein promotes the prehatched development of "HanWoo" embryos derived from in vitro-fertilization.

Animals↗
PubMed1998

Effect of optic nerve head drusen on nerve fiber layer thickness.

OBJECTIVE: The purpose of the study was to evaluate the effect of optic nerve head drusen (ONHD) on nerve fiber layer (NFL) thickness by visual field testing, red-free photography of NFL, and optical coherence tomography (OCT). DESIGN: The study design was a prospective clinical study. PARTICIPANTS: Twenty-three eyes of 15 consecutive patients with ONHD and 27 eyes of 27 age-matched control subjects participated. INTERVENTION: Ophthalmologic examination, color and red-free photography, automated Humphrey visual field testing, and OCT were performed. Each of the drusen study eyes were graded on a scale of 0 to III based on the amount of visible ONHD. Grade 0 represented the absence of clinically visible ONHD, and grade III represented an optic nerve head with abundant drusen. MAIN OUTCOME MEASURES: Findings from clinical evaluation and color optic nerve head photographs and NFL evaluation by red-free photography, visual fields, and OCT were measured. RESULTS: The number of study eyes with visual field defects increased with the higher grade drusen discs, corresponding both with progressively thinner NFL measurements by OCT and NFL loss shown by NFL photography. The NFL evaluation showed NFL thinning by red-free photography in 12 (71%) of 17 eyes with visible drusen (grades I-III discs) and visual field defects in 9 (53%) of 17 eyes in this group. By OCT measurements, the superior and inferior NFLs were significantly thinner in the eyes with visible ONHD compared with those of control eyes in the superior quadrant (P < 0.001) and inferior quadrant (P = 0.004). Compared with grade 0 discs, grades I through III discs showed statistically significant thinning of the NFL superiorly (P < 0.001). No statistical significant thinning of the NFL was seen in grade 0 discs compared with those of control subjects. CONCLUSIONS: Optical coherence tomography is able to detect NFL thinning in eyes with ONHD and appears to be a sensitive and early indicator of NFL thinning. Increased numbers of clinically visible ONHD correlated with NFL thinning shown by OCT measurements and both visual field defects and NFL loss seen by red-free photography.

Female↗
PubMed1998

The in vitro effect of leptin on basal and growth hormone-releasing hormone-stimulated growth hormone secretion from the ovine pituitary gland.

We have studied the direct effect of leptin on the secretion of GH from the anterior pituitary gland of the sheep. Using primary cultures of ovine pituitary cells, leptin (10(-9)-10(-7) M) treatment for 30 min did not affect basal or GHRH (10(-7) M)-stimulated GH secretion. Following treatment for 24 h, a dose of 10(-7) M leptin stimulated basal GH secretion. In contrast, doses of 10(-7) and 10(-8) M leptin inhibited GHRH-stimulated GH secretion after 24 h of treatment. These results suggest that leptin can have long-term effects on the somatotropes, but no acute effect. Furthermore, leptin appears to have opposite effects on basal and GHRH-stimulated GH secretion.

Animals↗
PubMed1997

Juvenile pilocytic astrocytoma masquerading as amblyopia.

PURPOSE: A healthy 13-year-old girl, previously diagnosed with amblyopia in her right eye, was seen in consultation after her vision continued to decrease. METHODS: A complete ophthalmologic examination including visual field testing and optic nerve photography was performed in the neuro-ophthalmologic clinic. Magnetic resonance imaging study was also obtained. RESULTS: Visual sensory deficits and pale optic nerves were noted on clinical examination. Visual field testing showed a chiasmatic junctional defect. Magnetic resonance imaging verified a large chiasmatic mass, histologically proven to be a juvenile pilocytic astrocytoma. CONCLUSION: Early recognition of signs and symptoms of chiasmatic lesions is essential for preventing visual loss.

Adolescent↗
PubMed1997

Evaluation of coexisting optic nerve head drusen and glaucoma with optical coherence tomography.

OBJECTIVE: Optic nerve head drusen often make evaluation of the nerve head difficult to interpret. In addition, visual field defects are known to occur in patients with optic disk drusen, resembling glaucomatous damage. The authors report two cases of coincident optic nerve head drusen and glaucoma, in which the use of optical coherence tomography (OCT) in evaluating the nerve fiber layer was beneficial. PARTICIPANTS: Two patients with both optic nerve head drusen and glaucoma, one with primary open angle glaucoma, the other with pseudoexfoliation glaucoma were evaluated. Both patients had asymmetric optic disk drusen, with clinically visible drusen only in one eye. INTERVENTION: Ophthalmologic examination, color and red-free photography, automated Humphrey visual field testing and OCT were performed. RESULTS: Nerve fiber layer loss as measured by OCT was found to be greater than expected by the appearance of the optic nerve head and red-free photography, with visual fields consistent with findings in case 1. In case 2, visual fields were full, despite nerve fiber layer thinning seen by OCT and red-free photography. CONCLUSIONS: There can be significant nerve fiber layer thinning in patients with both glaucoma and optic disk drusen, despite the appearance of the optic nerve head in these patients. The cup margin may be obscured by the drusen, giving rise to a falsely full-appearing disk. In such cases, OCT may provide a useful means to quantitatively measure the nerve fiber layer thickness and to aid in the management of these patients by detecting nerve fiber layer thinning earlier than would otherwise be possible.

Aged↗
PubMed1996

[Apropos hygiene].

Explore the source record for details and available documents.

Disinfection↗
PubMed1994

Light damage to the eye.

The effects of light on the eye are being increasingly recognized. In addition to visible radiation, we are constantly exposed to infrared and ultraviolet radiation throughout life. Acute light damage such as sunburn of eyelids, photokeratitis and solar retinopathy are well recognized and fairly obvious. The effects of chronic light exposure have been more controversial. Recent epidemiologic studies are showing an association between long-term sunlight exposure and ocular diseases such as cataracts, age-related macular degeneration, pterygium and climatic droplet keratopathy. Furthermore, the role of photosensitizers contributing to light-induced ocular damage needs to be kept in mind. The ocular hazard from photosensitizing drugs and sunlight in general is greatest in aphakic eyes that have lost their natural ultraviolet filter (the ocular lens) and in young children, whose own lenses readily transmit ultraviolet light. At present, there is enough evidence to assume that chronic sunlight exposure contributes to ocular disease and to institute preventive measures.

Eye↗
PubMed1993

Cataract incidence and analysis of lens crystallins in the water-, urea- and SDS-soluble fractions of Emory mice fed a diet restricted by 40% in calories.

Restriction of dietary calorie intake is associated with life extension and with the delay of age-related disorders. Preliminary studies demonstrated that by feeding the Emory mouse a diet restricted by 21% in calories cataract and insolubilization of protein could also be delayed. To observe the effects of calorie restriction over prolonged portions of adulthood, Emory mice were fed the control diet (C) or a diet restricted by 40% in calories (R). Feeding the R diet was associated with delayed formation or progress of cataract over virtually the entire second half of life. At 11 months of age, bilateral grade 5 cataracts were present in 17% and 2% of C and R lenses, respectively. At 22 months of age, bilateral grade 5 cataracts were present in 90% and 18% of C and R lenses, respectively. The distribution of alpha-, beta-, and gamma- crystallins in the water-soluble, urea-soluble, and SDS-soluble fractions indicates more similarities than differences between C and R lenses with a specific grade of cataract or of a given age. However, there were significant and abrupt (after grade 4 cataract) losses of particular gamma-crystallins; gamma-crystallins which were not prominent at earlier stages became the major gamma-crystallin moieties. Losses of alpha-crystallins were also noted upon cataract formation or aging in most of the fractions. Aggregates including gamma- and alpha-crystallins also accumulate faster in the C group.

Aging↗
PubMed1992

Molecular cloning and characterization of catechol 2,3-dioxygenases from biphenyl/polychlorinated biphenyls-degrading bacteria.

Catechol 2,3-dioxygenases were cloned from Alcaligenes sp. KF711, Pseudomonas putida KF715, and Achromobacter xylosoxidans KF701 which are biphenyl/polychlorinated biphenyls-degrading bacteria. All of the cloned enzymes were purified by preparative polyacrylamide gel electrophoresis (PAGE). The purified catechol 2,3-dioxygenases were significantly different from one another in ring-fission activities to catechol and its derivatives. The catechol 2,3-dioxygenase from Alcaligenes sp. KF711 exhibited higher ring-fission activity to 4-chlorocatechol than those from P. putida KF715 and A. xylosoxidans KF701. In electrophoretic mobilities, the three enzymes were different from one another on nondenaturing PAGE but the same on SDS-PAGE.

Alcaligenes↗
PubMed1992

Viral infections of the choroid and retina.

DNA (herpes viruses) and RNA (rubella, rubeola) group viruses are recognized causes of viral retinitis. Severe damage is often the result, not only because the viruses have a cytologic effect but also because the antigens may cause immune complex deposition that results in vasculitis. Most of the viral retinitides are associated with systemic disease; immune-compromised individuals are more susceptible than healthy individuals. A distinct clinical entity, acute retinal necrosis, affects the eye only in healthy individuals and is associated with the herpes family of viruses.

Chorioretinitis↗