[An agranulocytic case with Aspergillus diffuse external otitis cured by amphotericin B topic administration].
Explore the source record for details and available documents.
Administration, Topical↗
Biomedical subjects
Y W Lin
Publications and source records attributed to Y W Lin.
Prospective study of mutant frequencies at the hprt and T-cell receptor gene loci in pediatric cancer patients during chemotherapy.
Mutant frequencies (MFs) at the hypoxanthine phosphoribosyl transferase gene and the T-cell receptor (TCR) gene loci were evaluated in nine pediatric cancer patients before and during anticancer chemotherapy. The study population consisted of three patients with Hodgkin's disease, four patients with neuroblastoma, and two patients with Wilms' tumor. Except for one patient with neuroblastoma and one patient with Wilms' tumor, MFs at the hypoxanthine phosphoribosyl transferase locus tended to increase during the early cycles of treatment. The elevation was most striking and persistent in patients with Hodgkin's disease. The clonal relationship was determined in mutant cells derived from Hodgkin's disease patients by TCR-gamma gene rearrangement pattern and showed that the elevation of MFs resulted from increased mutational events rather than from clonal expansion of mutants. An increase in TCR MF was also found during chemotherapy in most patients, but the time of TCR MF elevation was variable among patients. Among the chemotherapeutic agents used in this study, cyclophosphamide was considered to be the most mutagenic. Our present study clearly demonstrates that anticancer chemotherapy can induce mutagenesis in vivo in various pediatric cancer patients.
Antineoplastic Combined Chemotherapy Protocols↗
NADH dehydrogenase deficiency in an apoptosis-resistant mutant isolated from a human HL-60 leukemia cell line.
An apoptosis-resistant mutant (VC-33) was selected from HL-60 by alternating exposure to camptothecin and etoposide. VC-33 cells demonstrated resistance to apoptosis as induced not only by camptothecin and etoposide but by a variety of other agents as well, including 1-beta-D-arabinofuranosylcytosine, hydroxyurea, calcium ionophore (A23187), cycloheximide, and UV irradiation. In an effort to identify the mechanism of such apoptosis resistance, a mRNA differential display analysis was used. Among a total of 12 bands with reduced expression in VC-33 cells, 1 cDNA clone was isolated that was hybridized to the wild-type transcript but not to the VC-33 transcript on Northern blotting. Partial sequence of this gene revealed 98% homology to mitochondrial NADH dehydrogenase subunit 5. When cell growth and intracellular ATP levels under glucose starvation were measured, VC-33 cells were found to be more sensitive than wild-type cells. Thus, NADH dehydrogenase deficiency may contribute, at least in part, to the mechanism of resistance to apoptosis in VC-33 cells.
Antineoplastic Agents↗
Apoptosis-resistant phenotype selected by alternating exposure to camptothecin and etoposide.
We selected an apoptosis-resistant subline (VC-33) in a human promyelocytic leukemia cell line, HL-60, by alternating exposure to camptothecin (CPT) and etoposide (VP-16). When wild-type (WT) and VC-33 cells were incubated with various concentrations of either CPT or VP-16 for 4 h, VC-33 showed several-fold resistance to apoptosis induced by these agents in comparison with WT cells. VC-33 cells also exhibited cross-resistance to apoptosis induced by 1-beta-d-arabinofuranosylcytosine, hydroxyurea, a calcium ionophore (A23187), cycloheximide, or UV irradiation. The levels of protein-DNA cross-linking induced by CPT or VP-16, and the amounts of ara-CTP generation, tended to be smaller in VC-33 cells, but the difference was not sufficient to explain the difference in the sensitivity to apoptosis. The initial rise of intracellular calcium ions with A23187 and the expression of P-glycoprotein, Bcl-2, and Bcl-Xl were comparable between WT and VC-33 cells. This mutant may represent a new phenotype of resistance to apoptosis induced by a variety of agents, and may thus be useful in the study of the mechanisms of apoptosis.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Constitutive endonuclease to induce high molecular weight or internucleosomal DNA fragmentation in freshly isolated leukemia cells.
Using an autodigestion method, we investigated endogenous endonuclease(s) in leukemia cells freshly obtained from pediatric patients with various types of leukemia. Endonucleolytic activity was found to cause both high molecular weight and internucleosomal DNA fragmentation at a neutral pH in whole cell lysates of all common acute lymphoblastic leukemia (cALL) blasts, which was Mg2+-dependent and Ca2+-independent. Whole lysates from most acute myeloblastic leukemia (AML) cells possessed similar endonuclease activity, but both Mg2+ and Ca2+ were required for the activity. Our results suggest that leukemia cells of different lineages have distinct constitutive endonucleases, which may play a role in the occurrence of apoptosis in these cells.
Apoptosis↗
Characterization of protein kinase C beta isoform activation on the gene expression of transforming growth factor-beta, extracellular matrix components, and prostanoids in the glomeruli of diabetic rats.
Induction of protein kinase C (PKC) pathway in the vascular tissues by hyperglycemia has been associated with many of the cellular changes observed in the complications of diabetes. Recently, we have reported that the use of a novel, orally effective specific inhibitor of PKC beta isoform (LY333531) normalized many of the early retinal and renal hemodynamics in rat models of diabetes. In the present study, we have characterized a spectrum of biochemical and molecular abnormalities associated with chronic changes induced by glucose or diabetes in the cultured mesangial cells and renal glomeruli that can be prevented by LY333531. Hyperglycemia increased diacylglycerol (DAG) level in cultured mesangial cells exposed to high concentrations of glucose and activated PKC alpha and beta1 isoforms in the renal glomeruli of diabetic rats. The addition of PKC beta selective inhibitor (LY333531) to cultured mesangial cells inhibited activated PKC activities by high glucose without lowering DAG levels and LY333531 given orally in diabetic rats specifically inhibited the activation of PKC beta1 isoform without decreasing PKC alpha isoform activation. Glucose-induced increases in arachidonic acid release, prostaglandin E2 production, and inhibition of Na+-K+ ATPase activities in the cultured mesangial cells were completely prevented by the addition of LY333531. Oral feeding of LY333531 prevented the increased mRNA expression of TGF-beta1 and extracellular matrix components such as fibronectin and alpha1(IV) collagen in the glomeruli of diabetic rats in parallel with inhibition of glomerular PKC activity. These results suggest that the activation of PKC, predominately the beta isoform by hyperglycemia in the mesangial cells and glomeruli can partly contribute to early renal dysfunctions by alteration of prostaglandin production and Na+-K+ ATPase activity as well as the chronic pathological changes by the overexpression of TGF-beta1 and extracellular matrix components genes.
Administration, Oral↗
Myelodysplastic syndrome presenting as third malignancy after non-Hodgkin's lymphoma and osteosarcoma.
The patient was initially diagnosed as having non-Hodgkin's lymphoma and was cured following treatment with prednisolone, vincristine, daunorubicin, 1-asparaginase, and cyclophosphamide. Seven years and two months later, he developed osteosarcoma in his right femur. He received chemotherapy consisting of methotrexate, carboplatin, etoposide, and ifosfamide and again obtained remission. After 2 years and 7 months, however, he was found to have pancytopenia with morphological abnormalities in the erythroid and myeloid series. Diagnosis of myelodysplastic syndrome (MDS) was made. Cytogenetic analysis of bone marrow cells revealed -5 and -7, which is typical for secondary MDS. This is a rare case of third malignancy presumably caused by alkylating agents.
Adolescent↗
Inhibition of superoxide production and chemotaxis by methotrexate in neutrophils primed by TNF-alpha or LPS.
We have demonstrated recently that methotrexate (MTX) inhibits superoxide generation and chemotaxis induced by N-formylmethionyl-leucyl-phenylalanine (fMLP) in neutrophils primed by granulocyte colony-stimulating factor (G-CSF). To extend these observations, we examined the in vitro effect of MTX on fMLP-stimulated superoxide generation and chemotaxis in neutrophils primed by either tumor necrosis factor alpha (TNF-alpha) or bacterial lipopolysaccharide (LPS). MTX inhibited superoxide generation and chemotaxis more efficiently in TNF-alpha- or LPS-primed neutrophils than in unprimed neutrophils. When either hypoxanthine or guanosine was added to the culture medium, the effects of MTX were partially counteracted. Furthermore, MTX caused a significant inhibition of both superoxide production induced by phorbol 12-myristate-13-acetate and chemotaxis induced by interleukin 8 in G-CSF-primed neutrophils. These results may support the hypothesis that neutrophils primed by different stimuli are more susceptible to the inhibitory effects of MTX on superoxide generation and chemotaxis irrespective of chemoattractants. Such an effect can be partly attributed to the perturbation of purine nucleotide biosynthesis.
Cells, Cultured↗
Molecular characterization of beta-thalassemia in Taiwan and the identification of two new mutations.
Polymerase chain reaction-based techniques were used to study the molecular defects of 480 unrelated beta-thalassemia heterozygotes in Taiwan. Analysis of artificially created restriction sites and gap-polymerase chain reaction were performed to detect four common mutations, i.e. IVS-II-654 (C-->T), codons 41/42 (-TCTT), codon 17 (A-->T), -28 (A-->G), and a deletional form of delta beta-thalassemia in the Chinese population. In cases with negative or ambiguous results with the aforementioned methods, direct DNA cycle sequencing using either S35-dATP or a fluorescent dye terminator, was carried out to determine the defects. A total of 14 different mutations have been found in this series. The IVS-II-654 mutation was the most common (39.6%), followed by the codons 41/42 mutation (37.9%). The four common genotypes accounted for 92.3% of defects. Two new mutations were detected: codon 31 (-C) and codons 40/41 (+T). Both defects resulted in a frameshift and a premature terminator, the former at codon 60, the latter at codon 43. Although we have studied our cases extensively, the molecular defects in seven alleles are still unknown.
Adult↗
Biometric study of acute primary angle-closure glaucoma.
We investigated the biometric characteristics of acute primary angle-closure glaucoma (PACG) patients and sought guidelines to predict subjects at high risk of acute attack. We enrolled 80 patients who suffered acute attack of angle-closure glaucoma and 60 nonglaucoma subjects. The biometric data, measured with A scan ultrasonography, and the outcomes after various treatments were analyzed. Six patients were excluded because they were lost to follow-up. In the acute PACG patients, the axial length (mean +/- standard deviation) was 22.25 +/- 0.77 mm, the anterior chamber depth (corneal thickness included) was 2.28 +/- 0.23 mm, and the lens thickness was 4.94 +/- 0.28 mm. In the nonglaucoma subjects, the axial length was 23.26 +/- 0.76 mm, the anterior chamber depth (corneal thickness included) was 3.11 +/- 0.25 mm, and the lens thickness was 4.48 +/- 0.30 mm. An anterior chamber depth of less than 2.70 mm was the most sensitive (94%) and specific (94%) parameter to differentiate acute PACG patients from nonglaucoma subjects. The intraocular pressure was controlled within the satisfactory range in 58 patients by laser iridectomy, with or without antiglaucoma medication. Eight patients needed additional gonioplasty and eight required filtering surgery to control the intraocular pressure. Our findings provide useful information about the biometric data of eyes of patients with acute angle-closure glaucoma and offer a useful guide to predict those patients at high risk of acute attack.
Acute Disease↗
Normal mutation frequencies of somatic cells in patients receiving growth hormone therapy.
The number of reported cases of malignancy developing in growth hormone (GH) users worldwide has increased to more than 40. However, the causal relationship between GH administration and the occurrence of malignancies is still uncertain. We investigated somatic cell mutation frequencies (Mfs) or variant frequency (Vf) at three gene loci in patients with pituitary dwarfism receiving GH therapy to clarify the genetic effect of GH. Eighty-eight patients receiving GH therapy for at least 3 months and 42 age-matched healthy controls were studied. Mfs at hypoxanthineguanine phosphoribosyltransferase (HPRT) and T-cell receptor (TCR) loci in GH users were not significantly higher than in the controls. Although a few patients seemed to have a slightly increased Vf at the glycophorin A (GPA) locus, the difference was not statistically significant. In addition, there was no tendency for the Mfs (Vf) at these loci to increase with the duration of the GH therapy. These data seem to exclude the possibility that GH induces genetic instability in patients with pituitary dwarfism who are receiving GH therapy.
Adolescent↗
Methotrexate inhibits superoxide production and chemotaxis in neutrophils activated by granulocyte colony-stimulating factor.
Treatment of circulating human neutrophils with recombinant human granulocyte colony-stimulating factor (rhG-CSF) for 30 min augmented superoxide generation and chemotaxis induced by N-formylmethionyl-leucyl-phenylalanine (fMLP) in a dose dependent manner. When neutrophils were treated with 1 microM of methotrexate (MTX) for 60 min after incubation with rhG-CSF (10 ng/ml), the effects of rhG-CSF on superoxide generation and chemotaxis were inhibited by approximately 49 and 29%, respectively. Although inhibitory effects of MTX were also seen in neutrophils not pretreated with rhG-CSF, the degree of inhibition was much less. The addition of either hypoxanthine or guanosine at a concentration of 100 microM to the culture medium significantly attenuated the effects of MTX. However, in neutrophils obtained from a patient with Lesch-Nyhan syndrome, which lacked hypoxanthine-guanine phosphoribosyl transferase activity neither hypoxanthine nor guanosine had any rescue effect. These results suggest that MTX inhibits superoxide generation and chemotaxis in rhG-CSF-activated neutrophils, at least in part, by disturbing purine nucleotide biosynthesis.
Cells, Cultured↗
Intragenic homozygous deletions of MTS1 gene in gastric cancer in Taiwan.
The multiple tumor suppressor 1 (MTS1) and 2 (MTS2) genes, located on chromosome 9p21, have been reported to be deleted or mutated in many malignant cell lines and in a high percentage of some primary carcinomas. To determine whether these genes are altered, and if so, what is the nature of the alterations, in human gastric adenocarcinoma, we investigated their frequency of mutation by Southern blotting, polymerase chain reaction (PCR) and direct sequencing in 55 patients. Furthermore, loss of heterozygosity (LOH) of chromosome 9p21 at the IFNA locus and D9S171 was assessed. Homozygous deletions of exon 1 of the MTS1 gene were identified in 5 of 55 (9.1%) primary tumors. No deletion of MTS2 gene was noted. LOH was observed in 7 (14.3%) of 49 informative cases (5 cases at IFNA locus, 2 cases at D9S171 and one case with combined LOH at D9S171 and homozygous deletion at exon 1 of MTS1). Direct sequencing of PCR products of the MTS1 and MTS2 gene did not reveal any point mutation in these 55 patients. These data indicate that alterations of the MTS1 and MTS2 genes are infrequently encountered. Additional studies of LOH with more microsatellite markers near 9p21 are mandatory to elucidate whether another tumor suppressor gene exists in the vicinity of MTS1 in primary gastric adenocarcinoma.
Blotting, Southern↗
Endothelin-1 action via endothelin receptors is a primary mechanism modulating retinal circulatory response to hyperoxia.
PURPOSE: To determine the role of endothelin (ET)-ETA receptor mediation and endogenous production of endothelin-1 (ET-1) in the retinal response to hyperoxia. METHODS: Brown-Norway rats (n = 30) were injected intravitreally with an ETA receptor-selective antagonist, BQ-123, and an inhibitor of ET-converting enzyme (ECE), phosphoramidon, and were exposed to a 100% oxygen breathing mixture. Control rats underwent intravitreal injection of vehicle alone (2.5% Emulphor in phosphate-buffered saline). The retinal hemodynamic responses were analyzed using video-based fluorescein angiography (VFA) methodology. Baseline measurements were made with the animals breathing room air, and this was followed by intravitreal injections of the above agents. Subsequent VFA measurements were made after 5, 10, and 15 minutes of breathing 100% oxygen. RESULTS: The 10 rats injected with vehicle alone demonstrated the expected retinal response to hyperoxia, with significant (P < 0.001) vessel constriction (18% +/- 5%), an increase in retinal mean circulation time (0.84 +/- 0.13 seconds in room air and 1.59 +/- 0.27 seconds in 100% oxygen), and a decrease in blood flow (110.7 +/- 19.2 pixel2/second in room air and 41.9 +/- 9.0 pixel2/second in 100% oxygen), compared to values measured during room air breathing. The hyperoxic response in rats (n = 9) injected with 10(-4) M BQ-123 was significantly (P < 0.001) blunted compared to the group injected with vehicle alone. In contrast, intravitreal injection of saralasin, a specific angiotensin II receptor antagonist, had no significant effect on the retinal response to hyperoxia (n = 5). Intravitreal phosphoramidon (10(-3) M, n = 6) injection also resulted in a significantly (P < 0.001) blunted circulatory response to hyperoxia compared to rats injected with vehicle alone. This blunted response after ECE inhibition was comparable to that measured after ETA receptor antagonism with BQ-123 injection. CONCLUSIONS: These results demonstrate that the enhancement of ET-1 action, possibly caused by the activation of ECE, plays a primary role in regulating the retinal hemodynamic response to hyperoxia.
Angiotensin Receptor Antagonists↗
Regulation of retinal hemodynamics in diabetic rats by increased expression and action of endothelin-1.
PURPOSE: To investigate the role of endogenous endothelin-1 (ET-1) expression and its interaction with the ETA receptor in the physiologic regulation of vascular tone as well as in the development of abnormal retinal hemodynamics in diabetes. METHODS: Retinal blood flow, using digitized video fluorescein angiography recordings, was quantitated after intravitreous injections of ET-1; BQ-123, an ETA receptor antagonist; and phosporamindon, an endothelin converting enzyme inhibitor in the eyes of diabetic and nondiabetic rats. A total of 154 rats were used for these experiments. Message levels of preproendothelin-1 (preproET-1) were measured from the retina of diabetic and nondiabetic rats using competitive polymerase chain reaction (PCR) techniques. RESULTS: Retinal blood flow was reduced (33%, P < 0.001) in diabetic rats compared to nondiabetic rats. BQ-123, an ETA receptor antagonist, but not saralasin, an angiotensin receptor antagonist, increased retinal blood flow in a dose-dependent manner in diabetic (EC50 of 8 x 10(-7) M) and in nondiabetic rats (EC50 of 8 x 10(-8) M). Besides being resistant to BQ-123, the maximal response in diabetic animals occurred 20 minutes later than in nondiabetic animals. Decreasing ET-1 levels by inhibiting endothelin-converting enzyme with phosphoramidon normalized retinal blood flow in diabetic rats. In nondiabetic rats, the intravitreous injection of exogenous ET-1 (10(-8) M) resulted in retinal blood flow decreases comparable to those measured in diabetic animals, and the subsequent injection of 10(-4) M BQ-123 produced retinal blood flow changes comparable to those measured in BQ-123 injected diabetic rats. Comparison of preproET-1 messenger RNA expression in the retina, brain and lung of control and diabetic rats using quantitative PCR and Northern blot analysis showed 2.0- and 1.7-fold increases in the retina and the brain, respectively, without changes in the lung. CONCLUSIONS: These data suggest that ET-1 is involved in the regulation of retinal blood flow in normal physiologic outcome, and an increase in the endogenous expression of ET-1 contributes to the reduction of retinal blood flow reported in the early stages of diabetes mellitus.
Animals↗
Increased invasive activity of human hepatocellular carcinoma cells is associated with an overexpression of thyroid hormone beta 1 nuclear receptor and low expression of the anti-metastatic nm23 gene.
To understand the role of thyroid hormone in metastasis, we studied the expression of the anti-metastatic nm23 gene in eight human hepatocellular carcinoma (HCC) cell lines. These cells differentially expressed the anti-metastatic nm23 gene. A low level of nm23 proteins was found to have a high in vitro invasive activity which correlated closely with an overexpression of the thyroid hormone beta 1 nuclear receptor (h-TR beta 1). Concurrent with the down-regulation of h-TR beta 1, the invasive activity of HCC cells was suppressed by the thyroid hormone, 3,3',5-triiodo-L-thyronine (T3). These results indicate that the invasive activity of HCC cells was regulated by T3, suggesting that T3 could be involved in modulating the functions of nm23.
Carcinoma, Hepatocellular↗
Selection and partial characterization of calcium ionophore (A23187) resistant cells.
We have selected calcium ionophore (A23187)-resistant cells (AR-7) in a human promyelocytic leukemia cell line, HL-60. AR-7 showed approximately 8.5-fold resistance to A23187 compared with the wild type cells after continuous exposure for 3 days. AR-7 had cross resistance to ionomycin (4.6-fold) and thapsigargin (340-fold) which can also increase intracellular Ca++. Similar magnitude of resistance to apoptosis, as defined by characteristic morphology and internucleosomal DNA fragmentation, induced by these agents was observed after 4 hr of incubation. However, both the elevation of intracellular Ca++ following stimulation with various concentrations of A23187 and the sensitivity to anti-cancer agents including etoposide, 1-beta-D arabinofuranosylcytosine, and hydroxyurea were comparable between the two cell types. This cell line is considered to be useful for exploring the mechanism(s) of cell death, especially apoptosis, induced by calcium ionophore.
Antineoplastic Agents↗
Association of high molecular weight DNA fragmentation with apoptotic or non-apoptotic cell death induced by calcium ionophore.
Calcium ionophore (A23187)-induced high molecular weight (HMW) and internucleosomal DNA fragmentation were investigated in human leukemia cell lines. An apoptosis-sensitive cell line, HL-60, showed HMW, internucleosomal DNA fragmentation and morphological changes of apoptosis by A23187. MOLT-4, which is resistant to apoptosis, exhibited only HMW DNA fragmentation and died of necrosis under the same conditions. Autodigestion experiments suggested the endonucleolytic activity to cause HMW fragmentation in the cytoplasm of both cell lines. The activity was more dependent on Mg2+ than Ca2+ in HL-60, whereas it was Ca(2+)-dependent in MOLT-4. These results suggest that HMW DNA fragmentation is not specific to apoptosis.
Apoptosis↗