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Biomedical subjects

Y Jin

Publications and source records attributed to Y Jin.

At least 469 records · Page 26Linked to original sources
PubMed1993

The low carcinogenicity of electron radiation relative to argon ions in rat skin.

The carcinogenicity of electron radiation relative to argon ions in rat skin was examined, specifically investigating whether the linear-quadratic model is useful for predicting cancer yield for one type of radiation based on yields observed for a different type. Three experiments were conducted to obtain information on the relationship between cancer yield and the dose of electron radiation: (1) a conventional dose-response protocol where the number of rats per group was based on the expected tumor yield; (2) a multiple-fraction protocol designed to take advantage of yield additivity as a way to estimate carcinogenicity at lower doses; and (3) a protocol to examine the effect of age at the time of irradiation on the dose-response relationship for cancer induction. Published data on the induction of skin cancer in rats irradiated with electrons were reanalyzed and combined with results of the new experiments. Skin cancer yield versus dose for argon ions was consistent with the linear-quadratic model, but the cancer yield for electrons was considerably lower (by a factor of 6.7 at 10 Gy) than the prediction based on the linear-quadratic model. The cancer yield for electron radiation was better fitted by a dose-cubed power function than a linear-quadratic function. The results indicate a substantially lower carcinogenic effectiveness for electron radiation, especially at lower doses, in comparison to argon ions and suggest that electrons may cause cancer by a three-event pathway instead of the two-event pathway that is consistent with the results for argon ions.

Animals↗
PubMed1992

Pseudodiploid karyotypes in adenosquamous carcinomas of the lung.

Pseudodiploid karyotypes with clonal structural rearrangements were observed in short-term cultures from two adenosquamous carcinomas (ASC) of the lung, a tumor type hitherto virtually uncharacterized cytogenetically. The karyotypes were 46,XX,der(1)t(1;14)(q44;q22),add(9)(q34) in the first tumor and 46,XX,i(17)(q10) in the second tumor. We suggest that ASC of the lung differ from other lung cancers by having pseudodiploid instead of massively aneuploid tumor stemlines.

Aneuploidy↗
PubMed1992

Transcriptional regulation and increased functional expression of the inositol trisphosphate receptor in retinoic acid-treated HL-60 cells.

The inositol trisphosphate (InsP3) receptor is an essential regulator of intracellular calcium in many cells including chemoattractant- and cytokine-stimulated neutrophils and differentiated promyelocytic leukemic (HL-60) cells. We examined the expression and function of the InsP3 receptor and the transcriptional regulation of the InsP3 receptor gene in HL-60 cells and in HL-60 cells treated for 1-5 days with 1 microM retinoic acid. Radioligand binding studies using membranes from control and retinoic acid-treated HL-60 cells showed that the Bmax of InsP3 receptor increased progressively from 0.24 to 0.69 pmol/mg protein during 5 days retinoic acid treatment with no change in KD (19 nM). During this period, maximal InsP3-stimulated Ca2+ mobilization increased 2-3-fold. InsP3 receptor mRNA was present at low levels in HL-60 cells but was increased significantly after treatment with retinoic acid, reaching maximal levels of approximately 4-fold greater than untreated cells after 4 days treatment with retinoic acid. Nuclear run-on assays indicated that the elevated steady state level of InsP3 receptor mRNA in retinoic acid-treated HL-60 cells was primarily the result of enhanced transcription of the InsP3 receptor gene. Furthermore, the transcriptional enhancing effect of retinoic acid was seen in the presence of cycloheximide, suggesting that the InsP3 receptor gene is directly regulated by retinoic acid. The studies also demonstrate that the InsP3 receptor mRNA is rapidly degraded in HL-60 cells by a mechanism that also requires protein synthesis.

Actins↗
PubMed1992

IL-3 and GM-CSF induce the expression of the inositol trisphosphate receptor in K562 myeloblast cells.

When treated with IL-3 plus GM-CSF, K562 myeloblast cells acquired the ability to mobilize nonmitochondrial stores of intracellular Ca2+ in response to added Ins (1, 4, 5) P3. Untreated K562 cells are capable of sequestering intracellular Ca2+ but released none of this Ca2+ in response to Ins (1, 4, 5) P3. Untreated K562 cells were shown to have no detectable specific [3H] Ins (1, 4, 5) P3 binding sites and no InsP3 receptor mRNA as assayed by Northern blot and PCR. However, following IL-3 and GM-CSF treatment, both a single class of low nM KD Ins (1, 4, 5) P3 binding site and a 10 kb InsP3 receptor mRNA were detectable. The results suggest that IL-3 and GM-CSF regulate the expression of the Ins (1, 4, 5) P3 receptor gene.

Blotting, Northern↗
PubMed1992

Clonal structural chromosome aberrations in nonneoplastic cells of the skin and upper aerodigestive tract.

Cytogenetic analyses of tumors of the skin and upper aerodigestive tract have repeatedly revealed small, pseudodiploid clones characterized by balanced structural rearrangements and a high frequency of cells with nonclonal structural aberrations. However, the lack of common cytogenetic denominators within the different histologic subtypes, the discrepancy between cytogenetic findings and data obtained from flow cytometric DNA content studies, and the occasional identification of tumors with massively rearranged karyotypes indicate that the chromosome rearrangements present in pseudodiploid cells have little to do with the tumorigenesis or progression. Further support for this conclusion, and indirect evidence that the pseudolipid clones probably do not represent the tumor cell populations, derives from the present study in which clonal and nonclonal structural rearrangements were also found in short-term cultures from nonneoplastic skin and pharyngeal mucosa. It is possible that the aberrations are present in subepithelial fibroblast that have accumulated DNA damage due to extensive exposure to potentially carcinogenic agents.

Adult↗
PubMed1992

Effects of lofexidine, an alpha 2-adrenoreceptor agonist, on ocular blood flow and ion transport of rabbit iris-ciliary body.

The effect of topical unilateral application of lofexidine, an alpha 2-agonist, on ocular regional blood flow was tested in anesthetized rabbits using radiolabeled microspheres. A significant reduction in blood flow was found only in the ciliary body of the treated eye at 1 hr after lofexidine treatment. However, the IOP of both eyes was decreased significantly at 30 and 60 min post lofexidine treatment. Yohimbine (i.v.) blocked this IOP lowering effect, but only partially prevented the blood flow response. In addition, no significant difference was found in either basal or amphotericin-B stimulated short-circuit current or potential difference of the isolated rabbit iris-ciliary body after 30 minutes of lofexidine treatment. These observations suggest that the IOP lowering effect of lofexidine appears to be mediated by alpha 2-receptors but unrelated to the reduction in the ocular blood flow and net electrogenic ion transport.

Adrenergic alpha-Agonists↗
PubMed1992

Partitioning of pulmonary responses to inhaled methacholine in subjects with asymptomatic asthma.

To partition the central and peripheral airway resistance, a catheter-tip micromanometer sensing lateral pressure of the airway was wedged into the right lower lobe of a bronchus with a 3 mm inner diameter in 10 patients with asymptomatic asthma. We simultaneously measured mouth flow, transpulmonary pressure (PL) and intra-airway lateral pressure during tidal breathing. Total pulmonary resistance (RL) was calculated from PL and mouth flow, and central airway resistance (RC) was calculated from intra-airway lateral pressure and mouth flow. Peripheral airway resistance (Rp) was obtained by subtraction of RC from RL. Therefore, our measurement of Rp included lung tissue resistance. The technique permitted identification of the site of changes in airway resistance. The baseline values of resistances were 2.3 +/- 0.2 cm H2O/L/s in RL, 1.5 +/- 0.1 cm H2O/L/s in RC, and 0.8 +/- 0.1 cm H2O/L/s in Rp, respectively. To determine the site of airway hyperresponsiveness, dose-response curves of central, peripheral, and total airways to inhaled methacholine were separately constructed. Bronchial responsiveness was evaluated by a log methacholine unit requiring a 35% decrease (PC35) and a 50% decrease (PC50) in pulmonary conductance (a reciprocal of RL). We calculated the increase of resistances in total (delta RL), central (delta RC), and peripheral (delta Rp) airways from the baseline values at either PC35 or PC50.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Activation of the easter zymogen is regulated by five other genes to define dorsal-ventral polarity in the Drosophila embryo.

The product of the Drosophila easter gene, a member of the trypsin family of serine proteases, must be more active ventrally than dorsally to promote normal embryonic polarity. The majority of the easter protein in the embryo is present in the unprocessed zymogen form and appears to be evenly distributed in the extracellular space, indicating that the asymmetric activity of wild-type easter must arise post-translationally. A dominant mutant form of easter that does not require cleavage of the zymogen for activity (ea delta N) is active both dorsally and ventrally. The ea delta N mutant bypasses the requirement for five other maternal effect genes, indicating that these five genes exert their effects on dorsal-ventral patterning solely by controlling the activation of the easter zymogen. We propose that dorsal-ventral asymmetry is initiated by a ventrally-localized molecule in the vitelline membrane that nucleates an easter zymogen activation complex, leading to the production of ventrally active easter enzyme.

Animals↗
PubMed1992

[Effects of fertilization on yield of Asparagus cochinchinensis (Lour.) Merr].

The experiment revealed that the use of various kinds of fertilizers has apparent effect on the yield of Asparagus cochinchinensis during its growth period. Nitrogen fertilizer and compound fertilizer are suitable for the seeding period, while compound fertilizer, phosphorus and potassium fertilizers are suitable for the period of root forming. The quantity of fertilizer to be used depends on the growing and soil conditions.

Fertilizers↗
PubMed1992

[Hygienic epidemiological assessment of electrodialysis drinking water].

It is first reported the hygienic epidemiological assessment of electrodialysis drinking water with multidiscipline methods including environmental epidemiology, toxicology, chemistry and clinical medicine. The results showed that the occurrence of malignant tumours in residents drinking electrodialysis water did not directly associate with their drinking water, we also did not find that there was any influence of electrodialysis water on residents' liver and gastrointestinal function, and the rate of thyroid enlargement, prevalence rates of dental fluorosis and dental caries as well as the level of saliva lysozyme in children. However, the morbidity rate of hypertension in the residents drinking electrodialysis water was higher than that in those drinking non-electrodialysis water.

China↗
PubMed1992

Oncogene amplification detected by in situ hybridization in radiation-induced skin cancers in rats.

Amplification of the c-myc oncogene has been detected by Southern blotting in the DNA of radiation-induced skin cancers in the rat. In the current work the localization of oncogene amplification within specific cells in the different cancers and in multiple biopsies of the same cancer was studied by in situ hybridization. The amount of amplification was measured by counting grains on tissue sections hybridized in situ to biotin-labeled human c-myc third exon, rat v-H-ras, and rat v-Ki-ras probes. The in situ estimates of c-myc amplification were generally correlated with previous findings using the Southern blot method, but within each cancer only a fraction of cells exhibited amplification. Multiple biopsies of a squamous carcinoma showed amplification of v-H-ras and c-myc but not v-Ki-ras during tumor growth, but none of these oncogenes were amplified during tumor regression. The c-myc-positive cells were distributed uniformly within the cancers and exhibited a more uniform nuclear structure in comparison to the more vacuolated c-myc-negative cells. A high [3H]thymidine labeling index was found in irradiated epidermal cells on Day 7 after exposure, and yet no evidence of c-myc oncogene amplification was found in situ. No c-myc amplification was found in unirradiated normal epidermis or in irradiated epidermal cells in the vicinity of radiation-induced cancers. The data indicate that c-myc amplification is cell-specific within radiation-induced carcinomas and does not occur in epidermal cells proliferating in response to radiation exposure.

Animals↗
PubMed1992

[Primary epidermoid carcinoma of the breast. Clinical, histopathologic and prognostic study of 14 patients].

We reviewed the charts of 14 patients with epidermoid breast carcinoma, whether pure or associated with a minor glandular component. These patients were treated between 1970 and 1989 at the Institut Curie and represented 0.06% of all breast cancer patients treated during the same period. No clinical or radiological criteria could help to discriminate these forms from other types of breast cancer. Four out of 13 patients with initial axillary node dissection had nodal involvement. Various combinations of surgery and radiotherapy were used to treat these patients. One out of 14 hormone receptor levels was positive. Median survival was 54 months (9 months-144 months). Two patients had a local recurrence and 7 had metastasis. No event occurred beyond 5 years of follow-up. This suggest that the outcome of epidermoid breast tumors is closer to that of other epidermoid tumors, rather than to other types of breast cancer.

Adult↗
PubMed1992

Western blotting of transforming growth factor beta 2. Optimization of the electrophoretic transfer.

The highest reported detection sensitivity of reduced monomeric transforming growth factor (TGF) beta 2 by Western blotting is 50 ng. The biologically active TGF-beta 2, which is the non-reduced dimeric protein, is even more difficult to detect by this technique. The low sensitivity is due to the poor electrophoretic transfer of the protein from the polyacrylamide gel to the blotting matrices under standard transfer conditions. By studying the effects of different blotting matrices, transfer cells, blotting buffers and their methanol content, current settings and the electrotransfer time, we have established optimal conditions for the blotting of this protein. The pH of the buffer and the blotting time are the most important factors which influence the electrotransfer yield. Optimal transfer of the TGF-beta 2 protein was achieved on PVDF membrane with semi-dry transfer for 4 h at 9 V, using 10 mM CAPS, pH 11.0, containing 5% methanol as transfer buffer. Combined with the use of a commercial antibody and an immunoblot assay kit, our optimised blotting method can detect 2 ng of the dimeric TGF-beta 2.

Blotting, Western↗