501
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Shin SC, Whang ST, Kim CH, Lee HY. Korean version of the Geriatric Social Readjustment Questionnaire: cross-cultural comparison between Koreans and Americans in the perception of life events. Yonsei Med J 1989; 30:38-44. [PMID: 2741473 DOI: 10.3349/ymj.1989.30.1.38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The purpose of this study was to construct a Korean version of the Geriatric Social Readjustment Questionnaire (K-GSRQ), to investigate its applicability to the elderly and to compare cross-cultural differences in the perception of the life events between Koreans and Americans. The K-GSRQ consists of 33 items. Most of the life events considered as crucial in old age were similar in ranking in comparison between Koreans and Americans. Some differences in ranking can be attributed to the differences in Socio-cultural backgrounds. The K-GSRQ was applied to controls, neurotic cases and cases with physical illnesses. The result suggest that the Korean version of the Geriatric Social Readjustment Questionnaire is applicable for the study of the health status of the elderly in Korea.
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502
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Nakane Y, Ohta Y, Uchino J, Takada K, Yan HQ, Wang XD, Min SK, Lee HY. Comparative study of affective disorders in three Asian countries. I. Differences in diagnostic classification. Acta Psychiatr Scand 1988; 78:698-705. [PMID: 3223328 DOI: 10.1111/j.1600-0447.1988.tb06407.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A study aimed at the standardization of symptom evaluation of patients with depression was carried out as the first step in an extensive collaborative study on affective disorders between centers in Nagasaki, Shanghai and Seoul. This study was initiated in order to clarify the factors affecting the low reported prevalence rates of depressive disorders in Asia. No significant difference in evaluation of psychiatric symptoms was observed between the 3 centers. Nevertheless, the diagnoses given by ICD-9 showed very interesting differences. For any given case, Nagasaki tended to make a diagnosis of an affective psychosis depression, while Shanghai made a diagnosis of neurotic disorder. No significant tendency was observed in the Seoul center. These findings are discussed in terms of their importance for future international collaborative studies.
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503
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Nagele RG, Bush KT, Lee HY. A morphometric study of cytoskeletal reorganization in rat sciatic nerve axons following beta,beta'-iminodipropionitrile (IDPN) treatment. Neurosci Lett 1988; 92:241-6. [PMID: 3200482 DOI: 10.1016/0304-3940(88)90596-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Electron microscopy and morphometry were used to study changes in the organization of cytoskeletal elements (microtubules (MTs) and neurofilaments (NFs] in myelinated rat sciatic nerve axons resulting from exposure to beta,beta'-iminodipropionitrile (IDPN). Adult male rats were injected subepineurially with IDPN and sacrificed at intervals. Electron micrographs of thin sections through injected nerve segments revealed that MTs segregated from NFs in axons and formed prominent clusters. Morphometric measurements of intermicrotubular distances within these clusters showed that adjacent MTs had a fairly uniform spatial separation that appeared to be maintained by granular MT-associated cross-bridges. In addition, MT clusters underwent a progressive, but reversible, compaction during the first 12 h of IDPN treatment.
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504
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Ephros HD, Lee HY. Amylophagia and iron deficiency anemia. ORAL SURGERY, ORAL MEDICINE, AND ORAL PATHOLOGY 1988; 66:448-9. [PMID: 3263607 DOI: 10.1016/0030-4220(88)90265-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Iron deficiency anemia may be associated with dietary practices such as amylophagia, which is seen frequently in women of certain ethnic origins. Starch eating may be a direct or indirect cause or symptom of iron deficiency anemia. Orofacial symptoms of amylophagia and iron deficiency anemia are discussed. A case in which anemia and dietary aberration were incidental to the admitting diagnosis is presented.
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505
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Lee HY, Kallis JN. Severe notching of inferior border of mandible. ORAL SURGERY, ORAL MEDICINE, AND ORAL PATHOLOGY 1988; 66:268-9. [PMID: 3174062 DOI: 10.1016/0030-4220(88)90105-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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506
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Hershman JM, Lee HY, Sugawara M, Mirell CJ, Pang XP, Yanagisawa M, Pekary AE. Human chorionic gonadotropin stimulates iodide uptake, adenylate cyclase, and deoxyribonucleic acid synthesis in cultured rat thyroid cells. J Clin Endocrinol Metab 1988; 67:74-9. [PMID: 3379138 DOI: 10.1210/jcem-67-1-74] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
hCG stimulates thyroid function, but it has been suggested that it is impurities in commercial hCG preparations or a variant of hCG that are responsible for the thyrotropic activity. In this study, we tested the thyrotropic activity of purified and commercial hCG and compared its action with that of bovine TSH (bTSH) in cultured rat FRTL-5 cells in regard to stimulation of iodide uptake, activation of adenylate cyclase, and synthesis of DNA. Iodide uptake was measured after incubation of the cells for 48-72 h with the test hormones, followed by a 40-min incubation with 0.1 microCi Na125I and 10 mumol/L carrier NaI; the 125I in the washed cells was counted. Adenylate cyclase was measured after incubation of the cells with the test stimulators for 3 h in hypotonic medium by RIA of cAMP in the medium. DNA synthesis was measured after incubation of the cells with the test substances for 24 h, followed by addition of [3H]thymidine for 3 h and then measuring the incorporation of [3H]thymidine into the cells. Both purified and commercial hCG produced a dose-related increase in iodide uptake. The relative potency of commercial hCG was 0.024 microU bTSH/U hCG and that of purified hCG was 0.042 microU bTSH/U hCG; compared with human TSH, the potency of purified hCG was 0.72 microU/U hCG. hCG caused a dose-related increment of adenylate cyclase and [3H]thymidine incorporation. The effect of hCG on iodide uptake and [3H]thymidine incorporation was additive with that of bTSH; hCG was not an antagonist of TSH in these cultured rat thyroid cells. We conclude that hCG has intrinsic thyrotropic activity in FRTL-5 cells in regard to stimulation of iodide uptake, activation of adenylate cyclase, and stimulation of DNA synthesis.
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507
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Igarashi S, Myung SS, Chiba R, Hanaoka K, Miyashita M, Murata H, Yokota H, Bacala A, Imlay R, Kirk P, McNeil RR, Metcalf W, Cheng CP, Mao ZP, Yan Y, Xu YT, Zhou HS, Zhu YC, Abashian A, Gotow K, Kajino F, Naito F, Childers R, Darden C, Edwards J, Lusin S, Rosenfeld C, Wilson S, Johnson D, Frautschi M, Kagan H, Kass R, Trahern CG, Lee HY, Ko W, Lander RL, Maeshima K, Malchow RL, Sparks K, Williams MC, Abe K, Chakrabarti S, Fujii Y, Higashi T, Ishimoto S, Kurihara Y, Maki A, Nozaki T, Omori T, Perez P, Sagawa H, Sakai Y, Sugimoto Y, Takaiwa Y, Terada S, Tsuchiya K, Poling R, Aldritch A, Green J, Park IH, Sakamoto S, Sannes F, Schnetzer S, Stone R. Search for isolated leptons in low-thrust e+e- annihilation events at sqrt s =50 and 52 GeV. PHYSICAL REVIEW LETTERS 1988; 60:2359-2362. [PMID: 10038331 DOI: 10.1103/physrevlett.60.2359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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508
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Aynedjian HS, Nguyen D, Lee HY, Sablay LB, Bank N. Effects of dietary electrolyte supplementation on gentamicin nephrotoxicity. Am J Med Sci 1988; 295:444-52. [PMID: 3376988 DOI: 10.1097/00000441-198805000-00006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effects of electrolyte supplementation via drinking solutions on gentamicin-induced nephrotoxicity were studied in rats. Four groups of animals were injected with gentamicin, 120 mg/kg daily for 5 days and were studied 2-4 days after the last injection. Electrolyte supplements were begun before the gentamicin injections and were continued throughout the study. The drinking solutions were tap water, NaCl, NaCl + KCl, or NaHCO3 + KHCO3 + diamox. At the end of the study, blood urea nitrogen (BUN) and serum creatinine were markedly increased only in the group receiving tap water. Nevertheless, 24 hour creatinine clearance in awake rats and inulin clearance in anesthetized rats were found to be severely reduced in all gentamicin-treated animals. However, the rats receiving NaHCO3 + KHCO3 + diamox had significantly higher creatinine clearance than all other experimental groups. Proximal intratubular free-flow pressure, measured by micropuncture, and internal proximal diameters were significantly increased above normal controls in all groups, but were least abnormal in the rats receiving HCO3- and diamox. Semiquantitative histologic evaluation revealed significantly less tubular necrosis and cast formation in this group than in all the other experimental groups. The observations suggest that dietary sodium, potassium, and chloride supplements, even accompanied by large fluid intake, provide relatively little protection against gentamicin nephrotoxicity. In contrast, HCO3- and diamox supplements resulted in significant, albeit incomplete, protection of GFR and renal histology.
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509
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Sagawa H, Mori T, Abe K, Chakrabarti S, Fujii Y, Higashi Y, Ishimoto S, Kurihara Y, Maki A, Mani P, Nozaki T, Omori T, Perez P, Sakai Y, Sugimoto Y, Takaiwa Y, Terada S, Tsuchiya K, Bacala A, Imlay R, Kirk P, Marterer W, McNeil RR, Metcalf W, Cheng CP, Mao ZP, Yan Y, Xu YT, Zhou HS, Zhu YC, Abashian A, Gotow K, Kajino F, Naito F, Avignone F, Childers R, Darden C, Edwards J, Lusin S, Rosenfeld C, Wilson S, Johnson D, Frautschi M, Kagan H, Kass R, Trahern CG, Lee HY, Ko W, Lander RL, Maeshima K, Malchow RL, Saroff D, Sparks K, Williams MC, Aldritch A, Green J, Park IH, Sakamoto S, Sannes F, Schnetzer S, Stone R, Trentalange S, Zimmerman D, Miyano K. Measurements of R and a search for heavy-quark production in e+e- annihilation at sqrt s =50 and 52 GeV. PHYSICAL REVIEW LETTERS 1988; 60:93-96. [PMID: 10038207 DOI: 10.1103/physrevlett.60.93] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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510
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Lee HY, Choi KH, Bank N. Protective effect of urinary alkalinization on gentamicin nephrotoxicity in rats. Yonsei Med J 1988; 29:225-32. [PMID: 3143188 DOI: 10.3349/ymj.1988.29.3.225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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511
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Lee HY, Kim JQ, Kim SI. Sperm auto-immunity associated with vasectomy, vasovasostomy and epididymovasostomy in Korean males. CLINICAL REPRODUCTION AND FERTILITY 1987; 5:347-57. [PMID: 3505829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The prevalence and pattern of circulating antisperm antibodies were assessed in the serum of Korean males undergoing vasectomy, vasovasostomy, epididymovasostomy and in a control group of men with normal semen by means of the gelatin agglutination test and the tray agglutination test. Sperm-agglutinating antibodies in serum were positive at a titre of 1:32 or greater in 3% of normospermic control males and in 27% of vasectomized men. No significant changes were observed in prevalence of the antibodies over the period following vasectomy. There were no significant differences in prevalence of antibodies in patients with and without postoperative sperm granulomas. Antibodies were positive in 35% of vasectomized men just prior to vasovasostomy and in 29% of patients 12 months after a successful (patent) reversal operation. There was no significant difference in prevalence of antibodies in patients with successful and unsuccessful vasovasostomies. Antibodies were positive in 20% of men who achieved pregnancies and in 43% of those with persisting infertility in the presence of a patent vasovasostomy. Sperm agglutinating antibodies were present in 5% of the patients with pathological epididymal obstruction. They were negative in patients with a patent epididymovasostomy and positive in 17% of those with an unsuccessful epididymovasostomy. The four patients who achieved a pregnancy after epididymovasostomy were antibody-negative. The prevalence of antibodies in the serum of patients with azoospermia due to surgical vasal obstruction was higher than that in patients with azoospermia due to pathological epididymal obstruction. The agglutination patterns produced by sperm antibodies in the total group of positive sera were tail-to-tail in 56%, head-to-head in 30% and mixed in 14%.
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512
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Yuan CY, Juan CC, Lee HY, Huang AH. Intestinal tuberculosis manifesting as multiple fistulas: report of a case. TAIWAN YI XUE HUI ZA ZHI. JOURNAL OF THE FORMOSAN MEDICAL ASSOCIATION 1987; 86:1299-302. [PMID: 3443849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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513
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Nagele RG, Hunter E, Bush K, Lee HY. Studies on the mechanisms of neurulation in the chick: morphometric analysis of force distribution within the neuroepithelium during neural tube formation. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1987; 244:425-36. [PMID: 3443831 DOI: 10.1002/jez.1402440309] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Changes in the shape of neuroepithelial cells, particularly apical constriction, are generally thought to play a major role in generating the driving forces for neural tube formation. Our previous study [Nagele and Lee (1987) J. Exp. Zool., 241:197-205] has shown that, in the developing midbrain region of stage 8+ chick embryos, neuroepithelial cells showing the greatest degree of apical constriction are concentrated at sites of enhanced bending of the neuroepithelium (i.e., the floor and midlateral walls of neural tube), suggesting that driving forces resulting from apical constriction are concentrated at these sites during closure of the neural tube. In the present study, we have used morphometric methods to 1) measure regional variations in the degree of apical constriction and apical surface folding at selected regions along the anteroposterior axis of stage 8+ chick embryos, which closely resemble the various ontogenetic phases of neural tube formation, and 2) investigate how forces resulting from apical constriction are distributed within the neuroepithelium during transformation of the neural plate into a neural tube. Results show that, during neural tube formation, driving forces resulting from apical constriction are not distributed uniformly throughout the neuroepithelium but rather are concentrated sequentially at three distinct locations: 1) the floor (during transformation of the neural plate to a V-shaped neuroepithelium), 2) the midlateral walls (during transformation of the V-shaped neuroepithelium into a C-shaped neuroepithelium), and 3) the upper walls (during the transformation of the C-shaped neuroepithelium into a closed neural tube).
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514
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Lee HY, Suhl J, Pekary AE, Hershman JM. Secretion of thyrotropin with reduced concanavalin-A-binding activity in patients with severe nonthyroid illness. J Clin Endocrinol Metab 1987; 65:942-5. [PMID: 3667887 DOI: 10.1210/jcem-65-5-942] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Patients with nonthyroid illness (NTI) often have reduced serum T3, free T3, T4, and free T4 concentrations. Paradoxically, serum TSH is usually in the normal range. The data suggest a diagnosis of hypothalamic hypothyroidism, in which TSH may have reduced biological activity because TRH, which is necessary for key steps in the glycosylation of TSH, is deficient. To study the glycosylation of TSH in patients with NTI, we measured the serum TSH concentration in 36 such patients hospitalized on our intensive care units and compared the results with those from a group of 18 normal subjects. Serum TSH was measured in 2 assays: 1) a sensitive TSH RIA of unextracted serum (TSH-RIA) and 2) a RIA of serum TSH after its extraction with Concanavalin-A (Con-A), a lectin which binds glycoproteins containing mannose residues in their oligosaccharide side-chains (TSH-Con-A). The ratio of TSH-Con-A to TSH-RIA was significantly reduced in the NTI patients [0.61 +/- 0.03 (+/- SE) vs. 0.89 +/- 0.05 in the normal subjects] due to reduced binding of the TSH to the Con-A. This change was not dependent on the extent of the abnormalities of thyroid hormone levels. The data suggest that the TSH secreted in NTI has altered glycosylation which is associated with reduced biological activity. This finding may explain in part the low serum T4 level in NTI patients in the face of an apparently normal immunoreactive TSH level.
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515
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Lee HY, Samit A, Mashberg A. Extensive post-traumatic subcutaneous emphysema and pneumomediastinum following a minor facial injury. J Oral Maxillofac Surg 1987; 45:812-5. [PMID: 3476706 DOI: 10.1016/0278-2391(87)90210-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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516
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Lee HY, Pekary AE, Smith VP, Sladek J, Hershman JM. Immunoenzymatic quantification of low concentrations of thyrotropin. Clin Chem 1987. [DOI: 10.1093/clinchem/33.7.1223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
We evaluated an immunoenzymatic assay (Abbott HTSH EIA) for thyrotropin (TSH) as a tool for detecting hyperthyroidism and for monitoring thyroid hormone suppressive therapy in patients with nodular goiter, thyroid carcinoma, and hypopituitarism. We also tested with thyroliberin (TRH), to determine the correlation between peak and basal TSH in suppressed patients. For comparison, we used a nonequilibrium radioimmunoassay optimized for maximum sensitivity (J Clin Endocrinol Metab 1975;41:676). Hyperthyroid patients with values for either or both triiodothyronine and thyroxin above the normal reference interval had Abbott assay values less than or equal to 0.2 milli-int. unit/L, clearly below the Abbott assay normal range, as determined in 116 euthyroid subjects. We detected one-third of the suppressed patients (greater than or equal to 0.3 milli-int. unit/L) with RIA, 69% with the Abbott assay (TSH greater than or equal to 0.04 milli-int. unit/L). Only 20% of patients with undetectable basal TSH values in the Abbott assay responded to TRH with a detectable peak TSH value; the peak TSH value after TRH was proportional to the basal TSH value. A single basal TSH measurement by the Abbott HTSH EIA should be adequate for monitoring the degree of thyroidal suppression in thyroid-hormone-treated patients.
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517
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Lee HY, Pekary AE, Smith VP, Sladek J, Hershman JM. Immunoenzymatic quantification of low concentrations of thyrotropin. Clin Chem 1987; 33:1223-6. [PMID: 3109781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We evaluated an immunoenzymatic assay (Abbott HTSH EIA) for thyrotropin (TSH) as a tool for detecting hyperthyroidism and for monitoring thyroid hormone suppressive therapy in patients with nodular goiter, thyroid carcinoma, and hypopituitarism. We also tested with thyroliberin (TRH), to determine the correlation between peak and basal TSH in suppressed patients. For comparison, we used a nonequilibrium radioimmunoassay optimized for maximum sensitivity (J Clin Endocrinol Metab 1975;41:676). Hyperthyroid patients with values for either or both triiodothyronine and thyroxin above the normal reference interval had Abbott assay values less than or equal to 0.2 milli-int. unit/L, clearly below the Abbott assay normal range, as determined in 116 euthyroid subjects. We detected one-third of the suppressed patients (greater than or equal to 0.3 milli-int. unit/L) with RIA, 69% with the Abbott assay (TSH greater than or equal to 0.04 milli-int. unit/L). Only 20% of patients with undetectable basal TSH values in the Abbott assay responded to TRH with a detectable peak TSH value; the peak TSH value after TRH was proportional to the basal TSH value. A single basal TSH measurement by the Abbott HTSH EIA should be adequate for monitoring the degree of thyroidal suppression in thyroid-hormone-treated patients.
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518
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Wimalaratna HS, Capildeo R, Lee HY. Herpes zoster of second and third segments causing ipsilateral Horner's syndrome. BMJ : BRITISH MEDICAL JOURNAL 1987; 294:1463. [PMID: 3111588 PMCID: PMC1246615 DOI: 10.1136/bmj.294.6585.1463] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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519
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Abstract
A total of 255 patients of 281 patients with side-to-side epididymovasostomy for postpathologic epididymal obstruction were followed from 1964 to 1983. The success rates were higher in patients with nontuberculous epididymitis than in those with tuberculous epididymitis. There were no significant differences among anastomotic levels of the epididymal incision. The success rates were 31% for patency and 12% for pregnancy in the 97 patients with macrosurgery and 37% for patency and 20% for pregnancy in the 158 with microsurgery. The causes of anatomic failure were scar formation at the anastomotic site and blockage of opening of the original epididymal tubule. The cause of functional failure was poor semen quality after epididymovasostomy.
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520
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Han DH, Lee HY. [Photoelastic stress patterns produced by abutment retainer designs for tooth-supported dentures]. TAEHAN CH'IKKWA UISA HYOPHOE CHI 1987; 25:155-70. [PMID: 3298500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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521
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Nagele RG, Lee HY. Studies on the mechanisms of neurulation in the chick: morphometric analysis of the relationship between regional variations in cell shape and sites of motive force generation. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1987; 241:197-205. [PMID: 3559504 DOI: 10.1002/jez.1402410206] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Microfilaments, which are organized into bundles in the apical ends of neuroepithelial cells, are generally thought to play a major role in generating the driving forces for neural tube closure. Because of their proximity to the luminal surface, the contractile activity of these microfilament bundles results in conspicuous changes in the overall shape of neuroepithelial cells, most notably apical constriction and apical surface folding. In the present study, we have used morphometric methods and computer-assisted image analysis to reveal the distribution of microfilament-mediated forces in the developing midbrain during initial contact of apposing neural folds in chick embryos at Hamburger and Hamilton stage 8+ of development (Hamburger and Hamilton (1951) J. Morphol., 88:49-92). The degree of apical constriction, apical surface folding, and bending of the neuroepithelium was used as a barometer of local microfilament activity. Results indicate that cells forming the floor and midlateral walls of the developing midbrain consistently show a higher degree of apical constriction and surface folding than those at other locations. These same regions of the neuroepithelium also exhibit the greatest degree of bending. We conclude that the principal driving forces for closure of the neural tube, at the level of the midbrain, are concentrated in certain regions of the neuroepithelium (i.e., the floor and midlateral walls of the forming neural tube) rather than uniformly distributed.
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522
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523
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Lee HY, Rajulton F, Wijewickrema S, Lesthaeghe R. [Family formation in Flanders: new patterns, different timing]. TIJDSCHRIFT VOOR SOCIOLOGIE 1987; 8:35-68, 279. [PMID: 12280765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
"The article presents a statistical study of the starting age and the speed of transitions in the process of family formation in Flanders. It contrasts two sets of generations, three groups according to educational achievement and three groups with differing religious practice. The methodology of shifted proportional hazard models is used and transition probabilities are fed into a semi-Markovian chain. Higher educational achievement results in later starting points, but not in a differing pace once started. By contrast, lower religious involvement speeds up the transitions to first sexual contact and premarital cohabitation, while it considerably retards the transition to parenthood among the generations born after 1950." (SUMMARY IN ENG AND FRE)
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524
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Jeon YS, Lee HY. [An experimental study on retentive capacities of clasps affected by vertical distance in an undercut]. TAEHAN CH'IKKWA UISA HYOPHOE CHI 1986; 24:1061-8. [PMID: 3298498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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525
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