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Biomedical subjects

D H Shin

Publications and source records attributed to D H Shin.

At least 199 records · Page 11Linked to original sources
PubMed1994

Increased thallium-201 uptake in collapsed lung: a pitfall in scintigraphic evaluation of central bronchogenic carcinoma.

UNLABELLED: This study evaluated whether 201Tl scintigraphy can differentiate a central bronchogenic cancer from a distal collapse consolidation. METHODS: Nine patients with squamous carcinoma with collapse confirmed by surgery and pathology were included. All patients underwent SPECT 1 hr after an intravenous injection of 3 mCi of 201Tl. Four-hour delayed SPECT was performed in five of the nine patients. The thallium activity in tumor and collapse was visually assessed on the basis of the pathologic findings. The specimens were prepared to have the same orientation and level with the SPECT image. RESULTS: The tumor activity appeared higher than that of the collapse in four patients, equal in three patients and lower in two patients. Both collapsed lung with and without superimposed inflammation also showed increased thallium activity. Delayed SPECT aided in tumor detection within a collapsed lung in only two of the five patients. CONCLUSION: Our study illustrates the need for caution in the interpretation of thallium scintigraphy in patients with central bronchogenic cancer and distal collapse.

Aged↗
PubMed1993

Trabeculectomy, phacoemulsification, and posterior chamber lens implantation with and without 5-fluorouracil.

Subconjunctival 5-fluorouracil has been an effective adjunct in glaucoma filtering surgery. We investigated the effectiveness of 5-fluorouracil in primary trabeculectomy combined with phacoemulsification and posterior chamber intraocular lens implantation (glaucoma triple procedure). Seventy-four patients were enrolled and randomly assigned into two groups to receive either no 5-fluorouracil (control patients) or low-dose 5-fluorouracil (mean total dose, 24.8 mg; mean number of injections, 5.0 +/- 1.3). The mean preoperative intraocular pressure was 20.1 +/- 5.4 mm Hg for the 5-fluorouracil group and 21.0 +/- 5.2 mm Hg for the control group (P = .48, Student's unpaired t-test). The mean number of medications was 2.2 +/- 1.0 and 2.0 +/- 1.0 (P = .49, Mann Whitney U test), respectively. At all postoperative visits, there were no statistically significant differences in mean intraocular pressures between the two groups. Mean follow-up was 13.2 months for 5-fluorouracil-treated patients and 15.0 months for control patients. At the last postoperative visit, mean intraocular pressures were 15.4 +/- 3.7 mm Hg and 15.0 +/- 5.0 mm Hg, respectively (P = .45, Student's unpaired t-test). Both groups showed comparable visual outcome (20/40 or better in 31 of 38 5-fluorouracil-treated patients [82%] vs 32 of 36 control patients [89%]) and a decrease in number of medications needed, 0.7 +/- 1.0 and 0.7 +/- 0.9, respectively (P = .96, Mann Whitney U test). Thus, 5-fluorouracil administered as in our study did not seem to have any effect in primary trabeculectomy combined with phacoemulsification and posterior chamber intraocular lens implantation.

Aged↗
PubMed1993

Crystallization and preliminary X-ray crystallographic analysis of the protease inhibitor ecotin.

Ecotin, a novel serine protease inhibitor isolated from Escherichia coli, has been crystallized using polyethylene glycol 1500 as the precipitating agent. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit cell parameters of a = 39.22 A, b = 84.86 A, and c = 98.74 A. The asymmetric unit contains one dimeric molecule of ecotin, with a crystal volume per protein mass (Vm) of 2.55 A3/Da and a solvent content of 51.8% by volume. The crystals diffract to at least 2.2 A using a conventional X-ray source, and X-ray data have been collected to 2.7 A Bragg spacing from a native crystal.

Bacterial Proteins↗
PubMed1993

Diffuse malignant mesothelioma of the pleura: a clinicopathological study of six patients with a prolonged symptom-free interval or extended survival after biopsy and a review of the literature of long-term survival.

Diffuse malignant mesothelioma of the pleura generally proceeds rapidly with clinical deterioration soon after the initial histopathological diagnosis of the tumor. We encountered six patients in whom the symptom-free interval after biopsy was surprisingly prolonged. Histopathologically, the tumor in each case was epithelioid with prominent myxoid stroma and formation of tubules and micropapillae. Cytologically, the malignant cells had relatively regular nuclei with bland chromatin. As individual findings, these histological and cytological features are common in diffuse malignant mesothelioma. However, the combination of (1) bland cytology of epithelioid cells, (2) formation of tubular and micropapillary patterns, (3) a myxoid stroma and (4) an absence of sclerosing desmoplasia, as observed in these six cases, might indicate indolent disease at the outset in a few patients. It is possible that these features are related to early stage of disease rather than having discriminatory value in their own right. We do not conclude that initially restrained disease necessarily presages a longer mean survival because the follow-up in these patients has not been long enough. We present these observations because, to date, this malignancy has proven so refractory to clinical management.

Adult↗
PubMed1993

A paradoxical stimulatory effect of berberine on guinea-pig ileum contractility: possible involvement of acetylcholine release from the postganglionic parasympathetic nerve and cholinesterase inhibition.

The effects of berberine on guinea-pig ileum contractility were studied in both transmurally-stimulated and unstimulated preparations. Transmural stimulation (80 V, 0.5 ms, 0.05 Hz) of the guinea-pig ileal segments produced a twitch response. Berberine (10(-8)-10(-5) M) enhanced this response dose-dependently. Atropine (10(-7) M), but not mecamylamine (10(-5) M), abolished this response. Acetylcholine (3 x 10(-9) and 10(-8) M) also enhanced the response to transmural stimulation. Pretreatment with hemicholinium (3 x 10(-5) M) antagonized the effect of berberine but failed to change that of acetylcholine. Berberine (10(-5) M) also antagonized the alpha 2-adrenoceptor agonist xylazine (10(-8) and 10(-7) M)-induced inhibition of the twitch response to transmural stimulation. In unstimulated ileal preparations, berberine (10(-5) M) produced contractile responses. In these preparations, atropine (10(-6) M), but not mecamylamine (10(-4) M), abolished the response to berberine. Furthermore, berberine (10(-6)-10(-4) M) inhibited dose-dependently the cholinesterase activity of the guinea-pig blood. The results suggest that berberine increases ileal contractility by: 1) increasing acetylcholine release from the postganglionic parasympathetic nerve terminal, 2) increasing acetylcholine retention through an inhibition of cholinesterase activity, and 3) blocking alpha 2-adrenoceptors, possibly in the postganglionic parasympathetic nerve.

Acetylcholine↗
PubMed1993

Pathologic staging of papillary carcinoma of the thyroid with airway invasion based on the anatomic manner of extension to the trachea: a clinicopathologic study based on 22 patients who underwent thyroidectomy and airway resection.

We received the clinical and pathologic features of 22 cases of papillary carcinoma of the thyroid that invaded the trachea and were treated by thyroidectomy and airway resection with or without reconstructive surgery over an interval of 16 years. We studied the fine relationships between lamina propria and lymphatics in the region between the isthmus of the thyroid and the trachea. The manner of invasion of papillary carcinoma of the thyroid was by blunt dissection along blood vessels and collagen fibers oriented perpendicularly to the tracheal lumen between cartilaginous rings. Although lymph node metastases were found in 14 patients (64%), we observed lymphangitic tumor in the tracheal mucosa in only three patients (14%). We devised a staging system for papillary carcinoma of the thyroid based on the extent of invasion of the trachea. Of the 11 patients with stage I, II, or III disease, none of six (0%) followed for 5 years died of thyroid cancer in the 5-year observation period; one patient in this group died later of thyroid cancer. Of the 11 patients with stage IV disease, five of seven (71%) followed for 5 years died of thyroid cancer in the 5-year observation period; one additional patient in this group died later of thyroid cancer.

Carcinoma, Papillary↗
PubMed1993

Corneal endothelial cell counts after Molteno implantation.

Implantation of a Molteno drainage shunt has been shown to be effective in advanced glaucoma. Foreign substances within the anterior chamber have been known to cause progressive endothelial cell loss. We undertook a study to evaluate the endothelial effects of an indwelling Molteno drainage shunt. Nineteen patients who underwent uneventful implantation of a Molteno drainage shunt for advanced aphakic or pseudophakic glaucoma were followed up. Serial endothelial cell counts were obtained in a masked fashion. During follow-up periods ranging from 5.4 to 25.7 months, endothelial cell loss averaged two cells per square millimeter per postoperative month with a 95% confidence interval of positive seven cells to negative ten cells per square millimeter per postoperative month. No clinically significant progressive trend in endothelial cell loss was seen in patients undergoing uncomplicated Molteno drainage procedures. Larger sample sizes with longer follow-up will be necessary to establish whether a Molteno drainage shunt causes clinically remarkable endothelial cell loss.

Cell Count↗
PubMed1993

Flow cytometric analysis of DNA ploidy in primary non-small cell carcinoma of the lung in Korea.

Flow cytometrically determined nuclear DNA content has been measured on 74 formalin-fixed, paraffin embedded specimens of non-small cell carcinoma of the lung. Of the 60 tumors that were successfully analyzed, 32 (53%) were diploid and 28 (47%) were aneuploid. The mean DNA index of aneuploid tumor was 1.5 +/- 0.25, ranging from 1.1 to 2.0. There was no significant correlation between DNA ploidy and the patient's clinical characteristics, histology of tumor, nodal status or tumor stage. Tumor ploidy was not found as a prognostic determinant in non-small cell carcinoma of the lung in this study.

Adult↗
PubMed1993

Needling revision of failed filtering blebs with adjunctive 5-fluorouracil.

We investigated the outcome of needling revision with adjunctive subconjunctival 5-fluorouracil (5-FU) performed on 30 eyes of 30 consecutive glaucoma patients with failed filtering blebs 49.0 +/- 65.4 weeks after trabeculectomy. Follow up was 67.3 +/- 22.8 weeks from the time of the first needling revision and 49.9 +/- 26.2 weeks from the last needling procedure. Twenty-four (80%) of the eyes were treatment successes after 2.6 +/- 1.9 needling revisions, with a mean intraocular pressure (IOP) of 13.9 +/- 3.7 mm Hg on 1.5 +/- 1.1 medications, a significantly lower mean IOP and number of medications than before the procedure (32.5 +/- 7.8 mm Hg on 1.7 +/- 1.5 medications [P < .001, paired t-test]). Needling revision with adjunctive 5-FU appears to be a safe and effective means of reestablishing filtration.

Adult↗
PubMed1993

A closed chamber technique for repair of iridodialysis.

We have developed a surgical technique for repair of traumatic iridodialysis, in which a 25-gauge hypodermic needle is used to place a 10-0 polypropylene suture in sewing-machine fashion through a closed anterior chamber. The technique also can be modified to secure a posterior capsule with a partial zonular dialysis, such as may occur during phacoemulsification or cortical clean-up.

Aged↗
PubMed1993

Measured and predicted anterior chamber depth for transscleral suture-fixated posterior chamber intraocular lenses.

Variables in intraocular lens (IOL) power calculations include axial length, average dioptric power of the cornea, and an assumed pseudophakic anterior chamber depth (ACD). In the case of transscleral suture-fixated posterior chamber (PC) IOLs, ACD depends on the placement of the suture and thus might be expected to vary more than it does in eyes with capsular-fixated IOLs. To assess the degree of this variation, we determined the postoperative pseudophakic ACD using A-scan ultrasonography in 15 patients with transscleral suture-fixated PC-IOLs. The mean pseudophakic ACD (posterior corneal vertex to anterior pseudophakos) was 3.47 +/- 0.69 mm. The mean absolute discrepancies in ACD between these measured values and those predicted by the original Binkhorst and the most recent Holladay formulas were 0.579 +/- 0.513 mm and 0.639 +/- 0.519 mm, respectively. In 11 of 15 eyes, the measured ACD was within 1 mm of that predicted by either the Binkhorst or Holladay formula, suggesting that either will provide reasonable estimates of ACD for IOL power calculations for suture-fixated PC-IOLs.

Anterior Chamber↗
PubMed1993

Whatever happened to abstracts from different sections of the association for research in vision and ophthalmology?

PURPOSE: The authors investigated the fate of abstracts from each ARVO section (May 1985 meeting), the overall publication percentage, and the journals in which the abstract-derived articles were published. METHODS: They performed a MEDLINE search by first author for 25 or 26 randomly selected abstracts from each section to identify those that led to full-length articles in peer-reviewed journals. RESULTS: Overall, 63% of abstracts led to full-length articles in peer-reviewed journals within our search period of 87 months. The publication rate of oral presentation abstracts (68%) was significantly higher than that of poster presentation abstracts (56%). A greater proportion of basic science-oriented abstracts (67%) led to publication than the clinically oriented abstracts (56%). The rate of publication was lowest for the Cornea section (40%) and highest for Physiology and Pharmacology (80%) and Biochemistry (76%). The abstract-derived articles were published in 67 different peer-reviewed journals, with 43% of the articles appearing in only five journals. CONCLUSIONS: The fact that the majority of abstracts led to full-length articles supports ARVO's goal of a large interdisciplinary appeal with the exchange of ideas among different investigators.

Congresses as Topic↗
PubMed1992

Visual field defects in patients with normal-tension glaucoma and patients with high-tension glaucoma.

We compared the automated visual field test results of 24 patients with normal-tension glaucoma and 24 patients with high-tension glaucoma who were closely matched for the amount of visual field loss to determine any differences in the characteristics of visual field defects between the two groups. Patients were matched with a maximum allowable difference in mean deviation of 0.3 dB. Although the normal-tension group had a greater amount of focal visual field loss (pattern standard deviation), the difference was not statistically significant (P = .628). Additionally, there was no statistically significant difference in the amount of diffuse or focal visual field damage in the superior hemifields between the two groups; however, the patients with normal-tension glaucoma had a significantly greater amount of localized visual field loss in the inferior hemifield than the patients with high-tension glaucoma (P = .015). Our data support the hypothesis that a vascular mechanism may have a greater role in the pathogenesis of optic nerve damage and visual field loss in patients with normal-tension glaucoma than in patients with high-tension glaucoma.

Aged↗