4101
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Liu L, Yang SZ, Zhao XW, Wang JH, Li GR, Tang XJ, Xiao BL, Li QY. [Preliminary study of the effects of diagnostic ultrasound in early pregnant women on the chorionic villi]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1987; 18:71-4. [PMID: 3305303] [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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4102
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Liu L, Song QB. [PNA-glycoprotein patterns of the chick retina during embryo development]. SHI YAN SHENG WU XUE BAO 1987; 20:61-9. [PMID: 3630517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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4103
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Liu P, Xu H, Lin YT, Xiao ZM, Liu L, Jiang K. Liquid and solid two-phase radioimmunoassay--simultaneous measurement of levels of triiodothyronine and thyroxine of human serum in a single specimen. SCIENTIA SINICA. SERIES B, CHEMICAL, BIOLOGICAL, AGRICULTURAL, MEDICAL & EARTH SCIENCES 1987; 30:169-75. [PMID: 3616602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The principle of the liquid and solid two-phase radioimmunoassay and its application to measuring the concentrations of triiodothyronine and thyroxine of human serum in a single sample at the same time are described in this paper. Rabbit anti-triiodothyronine antiserum was immobilized on the inner surface of a plastic tube as solid-phase radioimmunoassay system of testing triiodothyronine and donkey anti-rabbit gamma globulin antiserum was used to separate immunocomplex in liquid-phase radioimmunoassay system of thyroxine reaction. In both systems, radioiodine-125-labelled antigens were used as tracer. Through simple calculation, we can get the results of serum concentrations of triiodothyronine and thyroxine in a single sample. Compared with classical single-component radioimmunoassay of triiodothyronine and thyroxine and by methodological appraisal of two-phase radioimmunoassay itself, this method has the advantages of very high efficiency, reliability and also has the same specificity and precision.
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4104
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Liu L, Russell SM, Nicoll CS. Growth and differentiation of transplanted rat embryos in intact, diabetic and hypophysectomized hosts: comparison with their growth in situ. BIOLOGY OF THE NEONATE 1987; 52:307-16. [PMID: 3435734 DOI: 10.1159/000242726] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The objectives of this investigation were to evaluate the suitability of a transplant system for studying the endocrine control of growth and differentiation in rat embryonic/fetal tissues, and to gain information on the development of their hormone dependence. Whole 10-day-old rat embryos were transplanted under the kidney capsule of intact, hypophysectomized (Hx) or diabetic (Db) juvenile syngeneic female hosts, and grown there for 3, 6, 9 or 12 days. The wet weight, DNA and protein content of the transplants and of age-matched in situ embryos/fetuses were measured to assess their growth. The transplants in intact hosts increased more than 300-fold in all parameters during 12 days of incubation. However, this increase was only about 4% of the in situ growth. The severe impairment in growth occurred mainly during the first 3-day period when the transplants grew only 5% as much as the in situ embryos. Between days 13 and 22 of gestational age, the increment in transplant growth was 70% of that occurring in situ. Tissue differentiation of the transplants in intact hosts was essentially normal, although they grew as teratomas. Growth and differentiation of transplants in Db and Hx hosts were delayed or inhibited. This inhibition occurred as early as day 3 after transplantation and was corrected by appropriate hormone replacement therapy of the hosts. We conclude that rat embryos/fetuses develop a dependence on a growth hormone-dependent factor (possibly somatomedin) and/or insulin for growth before day 13 of development. This transplant system will be useful for studying other aspects of the control of growth and differentiation of rat embryos/fetuses between days 10 and 22 of gestation.
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4105
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Payne NI, Cosgrove RF, Green AP, Liu L. In-vivo studies of amphotericin B liposomes derived from proliposomes: effect of formulation on toxicity and tissue disposition of the drug in mice. J Pharm Pharmacol 1987; 39:24-8. [PMID: 2880979 DOI: 10.1111/j.2042-7158.1987.tb07156.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The repeat dose toxicity of various liposomal formulations containing amphotericin B has been determined in mice. In general, small liposomes (e.g. 100-150 nm) were found to be more toxic than their large counterparts (e.g. about 2000 nm). However, the repeat dose toxicity of small liposomes could be diminished substantially by the inclusion of sterol (i.e. ergosterol) into the liposomal membranes. Tissue accumulation studies of amphotericin B after repeat dosing may be a useful adjunct to formulation development.
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4106
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Zhou XZ, Liu L, Zhen DK. [Studies on the method of nucleic acid precipitation with metallic ions]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1986; 8:490-3. [PMID: 2439219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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4107
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Abstract
Three myogenic clonal cell lines were isolated from C3H 10T1/2 C18 cells (10T1/2) treated with 5-azacytidine (5-aza-CR). These lines reproducibly underwent fusion at confluence into functional myotubes capable of contracting in response to acetylcholine. The degree of fusion could be increased two- to threefold if the cells were grown on gelatin-coated dishes. All of the cell lines lost some of their myogenic potential after repeated passaging and the percentage of colonies capable of forming muscle was not increased by permissive media containing 2% horse serum. The 10T1/2 cells expressed only the BB form of creatine phosphokinase but all of the myogenic clones expressed additionally the MM and MB forms of the isozyme after fusion. The overall genomic level of 5-methylcytosine was decreased in some but not all of the cell clones tested. Comparisons between the 10T1/2 cells which never form muscle without 5-aza-CR treatment and clonal derivatives of committed cell types might be of value in understanding the molecular basis of the commitment process.
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4108
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Liu L, Cui YE, Wang LY. [Ultrastructural study of bone marrow red cell series of patients with iron-deficiency anemia]. ZHONGHUA NEI KE ZA ZHI 1986; 25:611-2, 638. [PMID: 3568845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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4109
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Liu L, Halfter W, Layer PG. Inhibition of cell proliferation by cytosine-arabinoside and its interference with spatial and temporal differentiation patterns in the chick retina. Cell Tissue Res 1986; 244:501-13. [PMID: 3719673 DOI: 10.1007/bf00212527] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Incubation of chick embryos with 200 nmoles/egg of cytosine arabinoside (AraC) completely inhibits cell proliferation in the embryo. At an age older than embryonic day 4 (E4) more than 90% of the embryos survive this treatment. The drug induces various malformations; in particular the retina is heavily affected. This simple method offers the possibility to study the effect of a more or less decreased cell production on processes of further differentiation and histogenesis of retinal tissue. The following results are obtained: In spite of the inhibition of cell proliferation in the retina by AraC an abnormally thick basal lamina is found and the expansion of the eye still proceeds, indicating that eye growth is not only dependent on retinal cell numbers. Stereotyped malformations of retinal histogenesis are induced and categorized into three groups: in addition to areas of normal structure cells are found arranged in rosettes and in half-rosettes sometimes linked by areas of undefined transient cell arrangements. The results point to a strong tendency of a severely diminished cell population to form regularly laminated retinal-like structures as long as a minimal ratio of cell types is given. The spatio-temporal appearance of the type of retinal malformation in a given retinal area is dependent on the time of AraC exposure and thus on the degree of differentiation reached at a "spatio-temporal spot": Full rosettes develop at earlier, and half-rosettes at later stages of AraC interference. Furthermore, deformities first appear on temporal and ventral sides. Thus, the establishment of these malformations follows and reflects the normal sequence of differentiation within the retina. Cells within rosettes organize in specific layers and start to differentiate normally. This shows that earlier formed cells are not dependent on the influence of factors derived from cells that are formed later for their proper differentiation.
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4110
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Nyce J, Liu L, Jones PA. Variable effects of DNA-synthesis inhibitors upon DNA methylation in mammalian cells. Nucleic Acids Res 1986; 14:4353-67. [PMID: 3086840 PMCID: PMC339866 DOI: 10.1093/nar/14.10.4353] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Post-synthetic enzymatic hypermethylation of DNA was induced in hamster fibrosarcoma cells by the DNA synthesis inhibitors cytosine arabinoside, hydroxyurea and aphidicolin. This effect required direct inhibition of DNA polymerase alpha or reduction in deoxynucleotide pools and was not specific to a single cell type. At equivalently reduced levels of DNA synthesis, neither cycloheximide, actinomycin D nor serum deprivation affected DNA methylation in this way. The topoisomerase inhibitors nalidixic acid and novobiocin caused significant hypomethylation indicating that increased 5-mCyt content was not a necessary consequence of DNA synthesis inhibition. The induced hypermethylation occurred predominantly in that fraction of the DNA synthesized in the presence of inhibitor; was stable in the absence of drug; was most prominent in low molecular weight DNA representing sites of initiated but incomplete DNA synthesis; and occurred primarily within CpG dinucleotides, although other dinucleotides were overmethylated as well. Drug-induced CpG hypermethylation may be capable of silencing genes, an effect which may be relevant to the aberrantly expressed genes characteristic of neoplastic cells.
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4111
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Whitaker Dowling P, Dowling JN, Liu L, Youngner JS. Interferon inhibits the growth of Legionella micdadei in mouse L cells. JOURNAL OF INTERFERON RESEARCH 1986; 6:107-14. [PMID: 2425011 DOI: 10.1089/jir.1986.6.107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The intracellular growth of Legionella micdadei was inhibited in mouse L cells treated with interferon (IFN). This IFN-mediated restriction was dose-dependent and required preincubation of the L cells with high doses of IFN (1,000 U/ml) for maximal inhibition. Incubation of L. micdadei with IFN alone had no detectable effect on growth of the bacteria. The IFN-mediated growth restriction was not dependent upon tryptophan concentration in the culture medium.
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4112
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Nagelberg SB, Laue L, Loriaux DL, Liu L, Sherins RJ. Cerebrovascular accident associated with testosterone therapy in a 21-year-old hypogonadal man. N Engl J Med 1986; 314:649-50. [PMID: 3945252 DOI: 10.1056/nejm198603063141017] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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4113
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Liu L, Liu JT. Theory of the bound magnetic polaron in antiferromagnetic semiconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1986; 33:1797-1803. [PMID: 9938487 DOI: 10.1103/physrevb.33.1797] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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4114
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Gao XS, Liu L, Yuan XB. [Median-knee saphenous neurovascular flap for ipsilateral or cross-leg transfer]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1986; 24:36-7, 63. [PMID: 3720447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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4115
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Liu L, Zhang M, Gao JX, Cao L. [Respiratory related neurons in the septum of the limbic system of the rabbit]. SHENG LI XUE BAO : [ACTA PHYSIOLOGICA SINICA] 1985; 37:290-4. [PMID: 3834604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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4116
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Liu L, Zhang M, Gao JX. [Respiratory related neurons in the dorsal hippocampus of the limbic system of the rabbit]. SHENG LI XUE BAO : [ACTA PHYSIOLOGICA SINICA] 1985; 37:295-8. [PMID: 3834605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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4117
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Liu L, Booth J, Merriam GR, Barnes KM, Sherins RJ, Loriaux DL, Cutler GB. Evidence that synthetic 31-amino acid inhibin-like peptide lacks inhibin activity. Endocr Res 1985; 11:191-7. [PMID: 3938735 DOI: 10.1080/07435808509032977] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We studied the biological activity of a recently characterized 31-amino acid inhibin-like peptide (ILP) using a synthetic preparation. While the material yielded a single component on chromatography, amino acid sequence analysis suggested that only 30% of the molecules possess the complete structure. Bioactivity was tested in vitro using whole pituitaries from 25 day-old male Sprague-Dawley rats. Pituitaries were incubated with 500 ng/ml of the ILP preparation or vehicle alone for 60 min, followed by a 3 h exposure to 2 ng/ml of luteinizing hormone releasing hormone (LHRH) or its diluent. In the ILP-incubated pituitary media, no significant suppression of basal FSH and LH release or stimulated FSH release was observed, while a significant increase in stimulated LH release was seen (p less than 0.05). An in vivo bioassay study was performed on 38 day-old male Sprague-Dawley rats. Test animals were injected with 0.1, 1, 10 or 20 mcg of ILP immediately after castration, and 10 and 24 h later. Control animals received bovine serum albumin or vehicle alone. There were no statistically significant differences in serum LH or FSH concentrations taken at 30 h after castration between the ILP-treated rats and controls. Possible reasons for our inability to demonstrate inhibin bioactivity (selective FSH suppression) with this ILP preparation include: Only about 30% of the peptides had the complete amino acid sequence. Other peptides with deletions might have acted as antagonists, thus obscuring the inhibin bioactivity. The 31-amino acid ILP may not be the authentic inhibin molecule. We suggest that further studies are needed to determine the true identity of inhibin.
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4118
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Ross W, Rowe T, Glisson B, Yalowich J, Liu L. Role of topoisomerase II in mediating epipodophyllotoxin-induced DNA cleavage. Cancer Res 1984; 44:5857-60. [PMID: 6094001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Epipodophyllotoxins are an important new class of anticancer agents which include the compounds VM-26 (teniposide) and VP-16 (etoposide). The mechanism of action of these drugs appears to involve production of DNA single- and double-strand breaks by virtue of a temperature-sensitive interaction between drug and a heat-labile intranuclear component. We now report evidence indicating that type II topoisomerase is the likely intracellular target for the DNA strand-breaking effects of the epipodophyllotoxins. Both VM-26 and VP-16 stimulate site-specific DNA cleavage by a highly purified calf thymus type II topoisomerase. VM-26 is 5- to 10-fold more potent than VP-16 in this assay, a difference that is also seen when DNA strand breaks are assayed in isolated nuclei of mouse leukemia cells following drug exposure. Furthermore, a similar potency difference exists with respect to cytotoxicity. Equilibrium dialysis experiments using [3H]VP-16 indicate that the drug does not bind to DNA. Thus, we suggest that the epipodophyllotoxins exert their anti-cancer effects by "poisoning" type II topoisomerase without binding to DNA. In this regard, their actions may be analogous to those of nalidixic acid in bacteria.
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4119
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Murre C, Choi E, Weis J, Seidman JG, Ozato K, Liu L, Burakoff SJ, Reiss CS. Dissection of serological and cytolytic T lymphocyte epitopes on murine major histocompatibility antigens by a recombinant H-2 gene separating the first two external domains. J Exp Med 1984; 160:167-78. [PMID: 6203998 PMCID: PMC2187433 DOI: 10.1084/jem.160.1.167] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
A novel H-2 gene in which the first external (N) domain of the H-2Ld antigen was replaced with that of the H-2Dd antigen was constructed and introduced into L cells. A transformant expressing the products of the hybrid gene was studied for binding to monoclonal antibodies specific for H-2Ld and H-2Dd antigens. It was found that serological determinants are distributed both in the N (Dd) and Cl (Ld) domains. Determinants recognized by allospecific cytotoxic T lymphocytes (CTLs) and virus-specific CTLs also mapped to the N and Cl domains. Determinants recognized by vesicular stomatitis virus (VSV)-specific effect cells, however, were not present on the recombinant molecule. These results show that a recombinant gene of two H-2 antigens in which the first external domain has been reshuffled can express a functional H-2 antigen that can then be used to map serological and CTL determinants to specific domains.
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4120
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Liu L. Social security problems in western European countries. SOCIAL SECURITY BULLETIN 1984; 47:17-22. [PMID: 6701727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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4121
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Liu L, Layer PG. Spatio-temporal patterns of differentiation of whole heads of the embryonic chick as revealed by binding of a FITC-coupled peanut-agglutinin (FITC-PNA). Brain Res 1984; 314:173-82. [PMID: 6423214 DOI: 10.1016/0165-3806(84)90040-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The spatio-temporal expression of specific binding sites for FITC-labeled peanut agglutinin (Arachis hypogaea) in frozen sections of whole embryonic heads of the chick between embryonic day 2 (E2) and embryonic day 8 (E8) is described. PNA-binding sites are present already at E2 on the external limiting membrane and the ventricular boundary of the neural wall. With progressing differentiation fluorescent bands are formed from the outside of the neural wall radiating inside, forming second layers inside the CNS at later stages. The visual system (retina and tectum) shows remarkably little PNA-binding activity until about E7/8, a time when binding sites in the other brain areas are already most abundant. In the telencephalon a fuzzy distribution of fluorescence is found. A possible significance of this finding for fiber guidance from the retina to the tectum is briefly discussed. Local high activities can be observed in different parts of the brain. Intense bands of PNA-fluorescence on parts of the epidermis, along the eye cups, around the fore- and hindbrain and in the medial part of the mesenchyme delineate early biochemical compartments foreshadowing the succeeding ossification.
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4122
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Abstract
The first clinically and biochemically documented case of recurrent thyrotoxicosis after I-131 induced hypothyroidism in a patient with Graves' disease is reported. Two months after the administration of 9.2 mCi of I-131, the subject developed hypothyroidism. One month later, the patient became euthyroid. Then, nine months following ablation, the patient again developed thyrotoxicosis. A second dose of I-131 of 12.5 mCi was required to finally produce permanent hypothyroidism. This case illustrates the recurrence of hypothyroidism after what had seemed to have been adequate I-131 radiation.
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4123
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Liu L. Optical-correlation quasi-interferometry: a new viewpoint on spatial frequency filtering. APPLIED OPTICS 1983; 22:3024. [PMID: 18200148 DOI: 10.1364/ao.22.003024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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4124
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Liu L. Color coding in quasi-interferometry. APPLIED OPTICS 1983; 22:3016. [PMID: 18200147 DOI: 10.1364/ao.22.003016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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4125
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Liu L, Layer PG, Gierer A. Binding of FITC-coupled peanut-agglutinin (FITC-PNA) to embryonic chicken retinas reveals developmental spatio-temporal patterns. Brain Res 1983; 284:223-9. [PMID: 6871724 DOI: 10.1016/0165-3806(83)90007-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
FITC-labeled peanut agglutinin (PNA), a lectin from peanut (Arachis hypogaea) which binds specifically to D-galactose, was used as a probe to trace the distribution of PNA-lectin receptors during early development of chick retina. We found that specific fluorescence within the inner plexiform layer (IPL) and the outer plexiform layer (OPL) appears at different developmental stages. The specific fluorescence of the IPL first appears near the central area of the ventro-posterior quadrant of the 7-day retina, then extends progressively towards the periphery, reaching the ora serrata earlier on the posterior than on the anterior side. The development of the specific fluorescence of the OPL follows the same scheme, but it appears later (starting at day 9) than that of the IPL and it is less pronounced. The spatio-temporal patterns of the expression of the lectin receptors show relationships to those of withdrawal of proliferating cells from mitosis, and of other events related to differentiation.
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