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Biomedical subjects

D H Shin

Publications and source records attributed to D H Shin.

At least 253 records · Page 14Linked to original sources
PubMed1989

Human fetal Schwann cells in culture: phenotypic expressions and proliferative capability.

In this report we examined the phenotypic expressions and the proliferative capability of cultured human fetal Schwann cells. Antigens that were expressed included laminin, nerve growth factor receptor, neural cell adhesion molecule, S-100 protein, and that recognized by the monoclonal antibody HNK-1. In addition, HLA-A,B,C and HLA-DR, respectively, class I and class II antigens of the major histocompatibility complex, were demonstrated on Schwann cells. Mitotic capability was high, with an average of 34% of Schwann cells undergoing proliferation over a 2-day period.

Antigens, Surface↗
PubMed1989

Oncogene expressions detected by in situ hybridization of squamous metaplasia, dysplasia and primary lung cancer in human.

In order to elucidate the dynamic changes of oncogene expression in the sequential cascade of squamous metaplasia, dysplasia, and squamous cell carcinoma of the bronchial epithelium, hybridization in situ was employed with a biotinylated oncogene probe. The expression of c-myc was localized exclusively in nuclei. While normal bronchial epithelium revealed no discernible clumps of c-myc grains, except occasional grains less than 3 per cell, squamous metaplasia showed increased number of grains and a few clusters of c-myc grains. In dysplasia, c-myc expression was more intensive than in squamous metaplasia. Approximately, 1/3 to 2/3 of tumor cell populations of squamous cell carcinomas of the lung revealed tremendously increased c-myc expression. In addition clumpy grains of c-myc in squamous cell carcinoma appeared more frequently than in squamous metaplasia or dysplasia. The c-myc expression was found to vary between different samples and within each cancer, and not all cancer cells expressed c-myc. These data indicate that c-myc oncogene plays it's role on reprogramming for growth control of cell populations particularly in multistage carcinogenesis and progression of lung cancer. These dynamic alterations of c-myc expression suggest that neoplastic transformation may occur conceivably at the dysplastic phase eventually resulting in carcinoma in situ. This means, in turn, squamous dysplasia is a putative precancerous lesion of the human lung.

Bronchial Neoplasms↗
PubMed1989

Is it worthwhile to add dipivefrin HCl 0.1% to topical beta 1-, beta 2-blocker therapy?

In a prospective study, the addition of dipivefrin hydrochloride 0.1% twice daily to one eye of 32 patients with early primary open-angle glaucoma or ocular hypertension, maintained on a bilateral beta 1-, beta 2-blocker twice daily, resulted in a significant decrease of mean intraocular pressure (IOP) from 22.7 +/- 3.9 to 20.2 +/- 3.4 mmHg at 1 week (P = 0.0001) and to 21.0 +/- 3.8 mmHg at 12 weeks (P less than 0.02) in the dipivefrin-treated eyes. On the other hand, no significant change was noted in the fellow eyes (from 21.7 +/- 4.1 to 21.6 +/- 4.0 mmHg at 1 week and to 21.3 +/- 4.2 mmHg at 12 weeks). The addition of dipivefrin resulted in an IOP reduction of 2 mmHg or more in 50% and 3 mmHg or more in 19% of the eyes throughout the 12-week therapy. The result of the current study provides a realistic guideline as to what to expect from the common practice of adding dipivefrin hydrochloride to a beta 1-, beta 2-blocker regimen.

Administration, Topical↗
PubMed1989

Effect of varying drop size on the efficacy and safety of a topical beta blocker.

We studied the effects on efficacy and safety of varying the drop size of a topical solution of levobunolol 0.5%. In a double-masked, crossover acute study, we administered a single drop of either 35 microL of vehicle, or 20, 35, or 50 microL of levobunolol one hour before the subjects began a ten-minute treadmill challenge electrocardiogram. After exercise the mean heart rate was 111 beats per minute (bpm) in the vehicle group and 102 to 103 bpm in the three levobunolol groups, which were significantly different from the control group but not from each other. In a randomized double-masked, parallel, chronic study, 117 patients with elevated intraocular pressure (IOP) instilled one of the three drop sizes of levobunolol twice daily for three months. Mean decreases in IOP ranged from 5.1 to 6.0 mmHg in the three groups, not significantly different from each other in mean IOP, heart rate, or blood pressure. We conclude that drop size in the range tested had no clinically significant effect on either efficacy or safety of a beta blocker such as levobunolol.

Administration, Topical↗
PubMed1988

Implantation of posterior chamber lens in the absence of capsular and zonular support.

We have developed surgical techniques for implanting a posterior chamber lens in the absence of capsular and zonular support by securing both haptics of the posterior chamber lens to the sclera at the ciliary sulcus with 10-0 prolene suture. These techniques have been successfully performed and have produced good visual results in six monocularly aphakic patients who had contact lens intolerance and/or contraindications to anterior chamber lens implantations. In consideration of the high incidence and the great variety of complications associated with anterior chamber lenses, these newly developed surgical techniques will be a useful alternative to anterior chamber lenses, even in patients who do not have definite contraindications to anterior chamber lens implantations.

Humans↗
PubMed1988

Comparison of the Tono-Pen to the Goldmann applanation tonometer.

Oculab Tono-Pen tonometry was compared with Goldmann applanation tonometry in 142 eyes of 71 patients without corneal problems. Overall we found 63% of the Tono-Pen readings to be within +/- 2 mm Hg of the Goldmann applanation tonometry readings and 77% to be within +/- 3 mm Hg, while 4% were within at least +/- 7 mm Hg difference. The correlation coefficient between the readings of the two instruments was .84. The mean value of the paired differences was 0.81 +/- 3.09 mm Hg overall, -1.78 +/- 1.86 mm Hg in the 4 to 10 mm Hg interval, 0.07 +/- 2.97 mm Hg in the 11 to 20 mm Hg interval, 1.27 +/- 2.62 mm Hg in the 21 to 30 mm Hg interval, and 4.15 +/- 2.28 mm Hg in the 31 to 45 mm Hg interval. We conclude that the Tono-Pen measures intraocular pressure in a manner that corresponds well to the Goldmann tonometer in the 11 to 20 mm Hg interval, and fairly well in the 4 to 10 mm Hg and 21 to 30 mm Hg intervals. It lacks good correspondence in the 31 to 45 mm Hg interval.

Humans↗
PubMed1988

Growth factors for human glial cells in culture.

Using a new double-labeling immunofluorescence technique, we assessed various growth factors on their ability to promote proliferation of cultured human glial cells. Cells studied were fetal astrocytes, fetal Schwann cells, adult astrocytes, and adult oligodendrocytes. Effective agents for fetal astrocytes were glial growth factor from the bovine pituitary, platelet-derived growth factor, fibroblast growth factor, and 4 beta-phorbol 12,13-dibutyrate. For fetal Schwann cells, mitogens were glial growth factor from the bovine pituitary, platelet-derived growth factor, nerve growth factor, and 4 beta-phorbol 12,13-dibutyrate. Adult astrocytes and oligodendrocytes did not normally divide in culture, and none of the agents tested were effective in inducing their proliferation. The report that interleukin-2 was a mitogen for oligodendrocytes could not be replicated in the present study on any of the glial cell types.

Aged↗
PubMed1988

Long-term culture of human fetal spinal cord neurons: morphological, immunocytochemical and electrophysiological characteristics.

Cultures were prepared from ventral spinal cord tissue from 8-11-week gestational human fetuses and grown for a period of up to 6 months. These cultures were studied by morphological, immunocytochemical and intracellular electrophysiological techniques. From 2 weeks in vitro and onward, small bipolar cells were found in outgrowths of spinal cord explants and were identified as neurons by positive immunoreactions with an antibody specific for neurofilament protein. In addition, a large population of glial fibrillary acidic protein-positive astrocytes and a smaller number of galactocerebroside-positive oligodendrocytes were recognized in these cultures. The development of synaptic terminals was also studied by electron microscopy. The first appearance of synaptic terminal was found in a 3-week culture and was an axo-dendritic synapse. During the next 2 months, there was a steady increase in number and structural maturation of synaptic profiles. In addition to axo-dendritic synapses, which were most common, axo-somatic and axo-axonic synapses were demonstrated. After 3 months in culture, the occurrence of large neurons possessing the characteristic features of mature neurons was also noted. Although the occurrence of oligodendrocytes in these cultures was confirmed, no myelination of axons was demonstrated by electron microscopy. Intracellular recordings were obtained from the cultured spinal cord cells, and these cells were identified clearly as neurons by their action potential responses to depolarizing current pulses. The average input resistance of these neurons was 31 M omega with resting membrane potential of -52 +/- 2.3 mV.

Culture Techniques↗
PubMed1988

Hormonal secretion by adult pituitary cells in culture.

Cells isolated from 24 autopsied adult human pituitary glands by enzymatic dissociation and Percoll density gradient methods were maintained in culture for up to 10 months. Using rabbit antisera specific for individual pituitary hormones and immunoperoxidase staining, we found a large number of cultured pituitary cells to react positively to growth hormone, prolactin, adrenocorticotropin, follicle-stimulating hormone, luteinizing hormone, and thyrotropin immunoreactions. Electron microscopic examination of cultured pituitary cells demonstrated the occurrence of secretory granules in cytoplasm characteristic of in vivo human pituitary cells. The hormone secretion in culture by these pituitary cells was confirmed by the detection of prolactin, thyrotropin, and follicle-stimulating hormone in the culture medium by radioimmunoassay.

Adolescent↗
PubMed1987

Bilateral effects of long-term monocular timolol therapy.

We studied the bilateral intraocular pressure lowering effect of long-term unilateral timolol maleate 0.5% in 30 patients in whom early primary open-angle glaucoma had recently been diagnosed. A significant intraocular pressure reduction was found in the untreated fellow eyes (21.9 mm Hg from 26.4 mm Hg at baseline) (P less than .001), as well as in the treated eyes (21.0 mm Hg from 28.5 mm Hg at baseline) (P less than .001). Fourteen patients (47%) showed a significant bilateral intraocular pressure reduction (P less than .001), with little difference between the treated (8.2 mm Hg) and the untreated eyes (7.7 mm Hg) (P greater than .8).

Adult↗
PubMed1987

Transplantation of cultured human adrenal chromaffin cells into 6-hydroxydopamine-lesioned rat brain.

Adult young rats were subjected to a unilateral 6-hydroxydopamine lesion of the nigrostriatal dopamine pathway and then given intrastriatal grafts of human fetal adrenal chromaffin cell cultures. Amphetamine-induced ipsiversive turning behavior in the lesioned rats was largely reversed in four of eight rats given such transplants when tested at 1.5 and 4.5 months post-transplantation. Two rats showed a transient recovery at 1.5 months followed by deterioration at 4.5 months, while two other rats showed continuous deterioration. Six rats given sciatic nerve grafts as controls all showed deterioration from the pretransplantation levels. Catecholamine fluorescent and immunohistochemical examination of chromaffin-cell-transplanted brains demonstrated neurons and neuronal processes positive for catecholamines or tyrosine hydroxylase in the transplanted area. This transplantation of cultured human fetal cells to an animal model may provide the necessary basic experimental system for assessing the possible utility of human neuronal transplants.

Adrenal Medulla↗
PubMed1987

Removable-suture closure of the lamellar scleral flap in trabeculectomy.

Removable-suture closure of the lamellar scleral flap was attempted in trabeculectomy, with the goal of increasing the degree of filtration during the immediate postoperative period by removing the suture so as to undo the closure whenever the need arose. The incorporation of the removable-suture closure of the lamellar scleral flap resulted in an additional mechanism of control over the degree of filtration after trabeculectomy. Furthermore, the availability of such a mechanism allowed the surgeon to close the lamellar scleral flap relatively tightly; this resulted in a decreased incidence of postoperative complications.

Adult↗